From c969bb8dbaf2f3628927eae73e7c579a74cf1b6e Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Tue, 20 Sep 2022 19:12:52 +0200 Subject: selinux: use "grep -E" instead of "egrep" The latest version of grep claims that egrep is now obsolete so the build now contains warnings that look like: egrep: warning: egrep is obsolescent; using grep -E fix this by using "grep -E" instead. Cc: Paul Moore Cc: Stephen Smalley Cc: Eric Paris Cc: selinux@vger.kernel.org Signed-off-by: Greg Kroah-Hartman [PM: tweak to remove vdso reference, cleanup subj line] Signed-off-by: Paul Moore --- scripts/selinux/install_policy.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/selinux/install_policy.sh b/scripts/selinux/install_policy.sh index 2dccf141241d..20af56ce245c 100755 --- a/scripts/selinux/install_policy.sh +++ b/scripts/selinux/install_policy.sh @@ -78,7 +78,7 @@ cd /etc/selinux/dummy/contexts/files $SF -F file_contexts / mounts=`cat /proc/$$/mounts | \ - egrep "ext[234]|jfs|xfs|reiserfs|jffs2|gfs2|btrfs|f2fs|ocfs2" | \ + grep -E "ext[234]|jfs|xfs|reiserfs|jffs2|gfs2|btrfs|f2fs|ocfs2" | \ awk '{ print $2 '}` $SF -F file_contexts $mounts -- cgit v1.2.3 From 2fe2fb4ce60be9005d7bfdd5665be03b8efb5b13 Mon Sep 17 00:00:00 2001 From: Paul Moore Date: Tue, 20 Sep 2022 14:11:11 -0400 Subject: selinux: remove runtime disable message in the install_policy.sh script We are in the process of deprecating the runtime disable mechanism, let's not reference it in the scripts. Signed-off-by: Paul Moore --- scripts/selinux/install_policy.sh | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/selinux/install_policy.sh b/scripts/selinux/install_policy.sh index 20af56ce245c..24086793b0d8 100755 --- a/scripts/selinux/install_policy.sh +++ b/scripts/selinux/install_policy.sh @@ -31,8 +31,7 @@ fi if selinuxenabled; then echo "SELinux is already enabled" echo "This prevents safely relabeling all files." - echo "Boot with selinux=0 on the kernel command-line or" - echo "SELINUX=disabled in /etc/selinux/config." + echo "Boot with selinux=0 on the kernel command-line." exit 1 fi -- cgit v1.2.3 From d0f9562ee43a135b941715d9e5e607de88898aca Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Thu, 8 Sep 2022 14:54:44 -0700 Subject: scripts/kallsyms: Ignore __kcfi_typeid_ The compiler generates __kcfi_typeid_ symbols for annotating assembly functions with type information. These are constants that can be referenced in assembly code and are resolved by the linker. Ignore them in kallsyms. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Tested-by: Kees Cook Tested-by: Nathan Chancellor Acked-by: Peter Zijlstra (Intel) Tested-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220908215504.3686827-3-samitolvanen@google.com --- scripts/kallsyms.c | 1 + 1 file changed, 1 insertion(+) (limited to 'scripts') diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index f18e6dfc68c5..ccdf0c897f31 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -119,6 +119,7 @@ static bool is_ignored_symbol(const char *name, char type) "__ThumbV7PILongThunk_", "__LA25Thunk_", /* mips lld */ "__microLA25Thunk_", + "__kcfi_typeid_", /* CFI type identifiers */ NULL }; -- cgit v1.2.3 From 89245600941e4e0f87d77f60ee269b5e61ef4e49 Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Thu, 8 Sep 2022 14:54:47 -0700 Subject: cfi: Switch to -fsanitize=kcfi Switch from Clang's original forward-edge control-flow integrity implementation to -fsanitize=kcfi, which is better suited for the kernel, as it doesn't require LTO, doesn't use a jump table that requires altering function references, and won't break cross-module function address equality. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Tested-by: Kees Cook Tested-by: Nathan Chancellor Acked-by: Peter Zijlstra (Intel) Tested-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220908215504.3686827-6-samitolvanen@google.com --- Makefile | 13 +--- arch/Kconfig | 8 ++- include/asm-generic/vmlinux.lds.h | 37 +++++----- include/linux/cfi.h | 29 ++++++-- include/linux/compiler-clang.h | 14 +--- include/linux/module.h | 6 +- kernel/cfi.c | 144 ++++++++++++++++++-------------------- kernel/module/main.c | 35 +-------- scripts/module.lds.S | 23 ++---- 9 files changed, 133 insertions(+), 176 deletions(-) (limited to 'scripts') diff --git a/Makefile b/Makefile index a4f71076cacb..43e08c9f95e9 100644 --- a/Makefile +++ b/Makefile @@ -921,18 +921,7 @@ export CC_FLAGS_LTO endif ifdef CONFIG_CFI_CLANG -CC_FLAGS_CFI := -fsanitize=cfi \ - -fsanitize-cfi-cross-dso \ - -fno-sanitize-cfi-canonical-jump-tables \ - -fno-sanitize-trap=cfi \ - -fno-sanitize-blacklist - -ifdef CONFIG_CFI_PERMISSIVE -CC_FLAGS_CFI += -fsanitize-recover=cfi -endif - -# If LTO flags are filtered out, we must also filter out CFI. -CC_FLAGS_LTO += $(CC_FLAGS_CFI) +CC_FLAGS_CFI := -fsanitize=kcfi KBUILD_CFLAGS += $(CC_FLAGS_CFI) export CC_FLAGS_CFI endif diff --git a/arch/Kconfig b/arch/Kconfig index 5fd875e18c99..1c1eca0c0019 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -738,11 +738,13 @@ config ARCH_SUPPORTS_CFI_CLANG An architecture should select this option if it can support Clang's Control-Flow Integrity (CFI) checking. +config ARCH_USES_CFI_TRAPS + bool + config CFI_CLANG bool "Use Clang's Control Flow Integrity (CFI)" - depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG - depends on CLANG_VERSION >= 140000 - select KALLSYMS + depends on ARCH_SUPPORTS_CFI_CLANG + depends on $(cc-option,-fsanitize=kcfi) help This option enables Clang’s forward-edge Control Flow Integrity (CFI) checking, where the compiler injects a runtime check to each diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 7515a465ec03..7501edfce11e 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -421,6 +421,22 @@ __end_ro_after_init = .; #endif +/* + * .kcfi_traps contains a list KCFI trap locations. + */ +#ifndef KCFI_TRAPS +#ifdef CONFIG_ARCH_USES_CFI_TRAPS +#define KCFI_TRAPS \ + __kcfi_traps : AT(ADDR(__kcfi_traps) - LOAD_OFFSET) { \ + __start___kcfi_traps = .; \ + KEEP(*(.kcfi_traps)) \ + __stop___kcfi_traps = .; \ + } +#else +#define KCFI_TRAPS +#endif +#endif + /* * Read only Data */ @@ -529,6 +545,8 @@ __stop___modver = .; \ } \ \ + KCFI_TRAPS \ + \ RO_EXCEPTION_TABLE \ NOTES \ BTF \ @@ -537,21 +555,6 @@ __end_rodata = .; -/* - * .text..L.cfi.jumptable.* contain Control-Flow Integrity (CFI) - * jump table entries. - */ -#ifdef CONFIG_CFI_CLANG -#define TEXT_CFI_JT \ - . = ALIGN(PMD_SIZE); \ - __cfi_jt_start = .; \ - *(.text..L.cfi.jumptable .text..L.cfi.jumptable.*) \ - . = ALIGN(PMD_SIZE); \ - __cfi_jt_end = .; -#else -#define TEXT_CFI_JT -#endif - /* * Non-instrumentable text section */ @@ -579,7 +582,6 @@ *(.text..refcount) \ *(.ref.text) \ *(.text.asan.* .text.tsan.*) \ - TEXT_CFI_JT \ MEM_KEEP(init.text*) \ MEM_KEEP(exit.text*) \ @@ -1008,8 +1010,7 @@ * keep any .init_array.* sections. * https://bugs.llvm.org/show_bug.cgi?id=46478 */ -#if defined(CONFIG_GCOV_KERNEL) || defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KCSAN) || \ - defined(CONFIG_CFI_CLANG) +#if defined(CONFIG_GCOV_KERNEL) || defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KCSAN) # ifdef CONFIG_CONSTRUCTORS # define SANITIZER_DISCARDS \ *(.eh_frame) diff --git a/include/linux/cfi.h b/include/linux/cfi.h index 2cdbc0fbd0ab..5e134f4ce8b7 100644 --- a/include/linux/cfi.h +++ b/include/linux/cfi.h @@ -2,17 +2,38 @@ /* * Clang Control Flow Integrity (CFI) support. * - * Copyright (C) 2021 Google LLC + * Copyright (C) 2022 Google LLC */ #ifndef _LINUX_CFI_H #define _LINUX_CFI_H +#include +#include + #ifdef CONFIG_CFI_CLANG -typedef void (*cfi_check_fn)(uint64_t id, void *ptr, void *diag); +enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr, + unsigned long *target, u32 type); -/* Compiler-generated function in each module, and the kernel */ -extern void __cfi_check(uint64_t id, void *ptr, void *diag); +static inline enum bug_trap_type report_cfi_failure_noaddr(struct pt_regs *regs, + unsigned long addr) +{ + return report_cfi_failure(regs, addr, NULL, 0); +} +#ifdef CONFIG_ARCH_USES_CFI_TRAPS +bool is_cfi_trap(unsigned long addr); +#endif #endif /* CONFIG_CFI_CLANG */ +#ifdef CONFIG_MODULES +#ifdef CONFIG_ARCH_USES_CFI_TRAPS +void module_cfi_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, + struct module *mod); +#else +static inline void module_cfi_finalize(const Elf_Ehdr *hdr, + const Elf_Shdr *sechdrs, + struct module *mod) {} +#endif /* CONFIG_ARCH_USES_CFI_TRAPS */ +#endif /* CONFIG_MODULES */ + #endif /* _LINUX_CFI_H */ diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index c84fec767445..42e55579d649 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -66,17 +66,9 @@ # define __noscs __attribute__((__no_sanitize__("shadow-call-stack"))) #endif -#define __nocfi __attribute__((__no_sanitize__("cfi"))) -#define __cficanonical __attribute__((__cfi_canonical_jump_table__)) - -#if defined(CONFIG_CFI_CLANG) -/* - * With CONFIG_CFI_CLANG, the compiler replaces function address - * references with the address of the function's CFI jump table - * entry. The function_nocfi macro always returns the address of the - * actual function instead. - */ -#define function_nocfi(x) __builtin_function_start(x) +#if __has_feature(kcfi) +/* Disable CFI checking inside a function. */ +#define __nocfi __attribute__((__no_sanitize__("kcfi"))) #endif /* diff --git a/include/linux/module.h b/include/linux/module.h index 8937b020ec04..ec61fb53979a 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -27,7 +27,6 @@ #include #include #include -#include #include #include @@ -387,8 +386,9 @@ struct module { const s32 *crcs; unsigned int num_syms; -#ifdef CONFIG_CFI_CLANG - cfi_check_fn cfi_check; +#ifdef CONFIG_ARCH_USES_CFI_TRAPS + s32 *kcfi_traps; + s32 *kcfi_traps_end; #endif /* Kernel parameters. */ diff --git a/kernel/cfi.c b/kernel/cfi.c index e8bc1b370edc..08caad776717 100644 --- a/kernel/cfi.c +++ b/kernel/cfi.c @@ -1,105 +1,101 @@ // SPDX-License-Identifier: GPL-2.0 /* - * Clang Control Flow Integrity (CFI) error and slowpath handling. + * Clang Control Flow Integrity (CFI) error handling. * - * Copyright (C) 2021 Google LLC + * Copyright (C) 2022 Google LLC */ -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -/* Compiler-defined handler names */ -#ifdef CONFIG_CFI_PERMISSIVE -#define cfi_failure_handler __ubsan_handle_cfi_check_fail -#else -#define cfi_failure_handler __ubsan_handle_cfi_check_fail_abort -#endif - -static inline void handle_cfi_failure(void *ptr) +#include + +enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr, + unsigned long *target, u32 type) { - if (IS_ENABLED(CONFIG_CFI_PERMISSIVE)) - WARN_RATELIMIT(1, "CFI failure (target: %pS):\n", ptr); + if (target) + pr_err("CFI failure at %pS (target: %pS; expected type: 0x%08x)\n", + (void *)addr, (void *)*target, type); else - panic("CFI failure (target: %pS)\n", ptr); + pr_err("CFI failure at %pS (no target information)\n", + (void *)addr); + + if (IS_ENABLED(CONFIG_CFI_PERMISSIVE)) { + __warn(NULL, 0, (void *)addr, 0, regs, NULL); + return BUG_TRAP_TYPE_WARN; + } + + return BUG_TRAP_TYPE_BUG; } -#ifdef CONFIG_MODULES +#ifdef CONFIG_ARCH_USES_CFI_TRAPS +static inline unsigned long trap_address(s32 *p) +{ + return (unsigned long)((long)p + (long)*p); +} -static inline cfi_check_fn find_module_check_fn(unsigned long ptr) +static bool is_trap(unsigned long addr, s32 *start, s32 *end) { - cfi_check_fn fn = NULL; - struct module *mod; + s32 *p; - rcu_read_lock_sched_notrace(); - mod = __module_address(ptr); - if (mod) - fn = mod->cfi_check; - rcu_read_unlock_sched_notrace(); + for (p = start; p < end; ++p) { + if (trap_address(p) == addr) + return true; + } - return fn; + return false; } -static inline cfi_check_fn find_check_fn(unsigned long ptr) +#ifdef CONFIG_MODULES +/* Populates `kcfi_trap(_end)?` fields in `struct module`. */ +void module_cfi_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, + struct module *mod) { - cfi_check_fn fn = NULL; - unsigned long flags; - bool rcu_idle; - - if (is_kernel_text(ptr)) - return __cfi_check; - - /* - * Indirect call checks can happen when RCU is not watching. Both - * the shadow and __module_address use RCU, so we need to wake it - * up if necessary. - */ - rcu_idle = !rcu_is_watching(); - if (rcu_idle) { - local_irq_save(flags); - ct_irq_enter(); - } + char *secstrings; + unsigned int i; - fn = find_module_check_fn(ptr); + mod->kcfi_traps = NULL; + mod->kcfi_traps_end = NULL; - if (rcu_idle) { - ct_irq_exit(); - local_irq_restore(flags); - } + secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; + + for (i = 1; i < hdr->e_shnum; i++) { + if (strcmp(secstrings + sechdrs[i].sh_name, "__kcfi_traps")) + continue; - return fn; + mod->kcfi_traps = (s32 *)sechdrs[i].sh_addr; + mod->kcfi_traps_end = (s32 *)(sechdrs[i].sh_addr + sechdrs[i].sh_size); + break; + } } -void __cfi_slowpath_diag(uint64_t id, void *ptr, void *diag) +static bool is_module_cfi_trap(unsigned long addr) { - cfi_check_fn fn = find_check_fn((unsigned long)ptr); + struct module *mod; + bool found = false; - if (likely(fn)) - fn(id, ptr, diag); - else /* Don't allow unchecked modules */ - handle_cfi_failure(ptr); -} -EXPORT_SYMBOL(__cfi_slowpath_diag); + rcu_read_lock_sched_notrace(); -#else /* !CONFIG_MODULES */ + mod = __module_address(addr); + if (mod) + found = is_trap(addr, mod->kcfi_traps, mod->kcfi_traps_end); -void __cfi_slowpath_diag(uint64_t id, void *ptr, void *diag) + rcu_read_unlock_sched_notrace(); + + return found; +} +#else /* CONFIG_MODULES */ +static inline bool is_module_cfi_trap(unsigned long addr) { - handle_cfi_failure(ptr); /* No modules */ + return false; } -EXPORT_SYMBOL(__cfi_slowpath_diag); - #endif /* CONFIG_MODULES */ -void cfi_failure_handler(void *data, void *ptr, void *vtable) +extern s32 __start___kcfi_traps[]; +extern s32 __stop___kcfi_traps[]; + +bool is_cfi_trap(unsigned long addr) { - handle_cfi_failure(ptr); + if (is_trap(addr, __start___kcfi_traps, __stop___kcfi_traps)) + return true; + + return is_module_cfi_trap(addr); } -EXPORT_SYMBOL(cfi_failure_handler); +#endif /* CONFIG_ARCH_USES_CFI_TRAPS */ diff --git a/kernel/module/main.c b/kernel/module/main.c index 0228f44b58e5..70c0b2c6fef8 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -53,6 +53,7 @@ #include #include #include +#include #include #include "internal.h" @@ -2597,8 +2598,9 @@ static int complete_formation(struct module *mod, struct load_info *info) if (err < 0) goto out; - /* This relies on module_mutex for list integrity. */ + /* These rely on module_mutex for list integrity. */ module_bug_finalize(info->hdr, info->sechdrs, mod); + module_cfi_finalize(info->hdr, info->sechdrs, mod); if (module_check_misalignment(mod)) goto out_misaligned; @@ -2660,8 +2662,6 @@ static int unknown_module_param_cb(char *param, char *val, const char *modname, return 0; } -static void cfi_init(struct module *mod); - /* * Allocate and load the module: note that size of section 0 is always * zero, and we rely on this for optional sections. @@ -2791,9 +2791,6 @@ static int load_module(struct load_info *info, const char __user *uargs, flush_module_icache(mod); - /* Setup CFI for the module. */ - cfi_init(mod); - /* Now copy in args */ mod->args = strndup_user(uargs, ~0UL >> 1); if (IS_ERR(mod->args)) { @@ -2955,32 +2952,6 @@ static inline int within(unsigned long addr, void *start, unsigned long size) return ((void *)addr >= start && (void *)addr < start + size); } -static void cfi_init(struct module *mod) -{ -#ifdef CONFIG_CFI_CLANG - initcall_t *init; -#ifdef CONFIG_MODULE_UNLOAD - exitcall_t *exit; -#endif - - rcu_read_lock_sched(); - mod->cfi_check = (cfi_check_fn) - find_kallsyms_symbol_value(mod, "__cfi_check"); - init = (initcall_t *) - find_kallsyms_symbol_value(mod, "__cfi_jt_init_module"); - /* Fix init/exit functions to point to the CFI jump table */ - if (init) - mod->init = *init; -#ifdef CONFIG_MODULE_UNLOAD - exit = (exitcall_t *) - find_kallsyms_symbol_value(mod, "__cfi_jt_cleanup_module"); - if (exit) - mod->exit = *exit; -#endif - rcu_read_unlock_sched(); -#endif -} - /* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */ char *module_flags(struct module *mod, char *buf, bool show_state) { diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 3a3aa2354ed8..da4bddd26171 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -3,20 +3,10 @@ * Archs are free to supply their own linker scripts. ld will * combine them automatically. */ -#ifdef CONFIG_CFI_CLANG -# include -# define ALIGN_CFI ALIGN(PAGE_SIZE) -# define SANITIZER_DISCARDS *(.eh_frame) -#else -# define ALIGN_CFI -# define SANITIZER_DISCARDS -#endif - SECTIONS { /DISCARD/ : { *(.discard) *(.discard.*) - SANITIZER_DISCARDS } __ksymtab 0 : { *(SORT(___ksymtab+*)) } @@ -33,6 +23,10 @@ SECTIONS { __patchable_function_entries : { *(__patchable_function_entries) } +#ifdef CONFIG_ARCH_USES_CFI_TRAPS + __kcfi_traps : { KEEP(*(.kcfi_traps)) } +#endif + #ifdef CONFIG_LTO_CLANG /* * With CONFIG_LTO_CLANG, LLD always enables -fdata-sections and @@ -53,15 +47,6 @@ SECTIONS { *(.rodata .rodata.[0-9a-zA-Z_]*) *(.rodata..L*) } - - /* - * With CONFIG_CFI_CLANG, we assume __cfi_check is at the beginning - * of the .text section, and is aligned to PAGE_SIZE. - */ - .text : ALIGN_CFI { - *(.text.__cfi_check) - *(.text .text.[0-9a-zA-Z_]* .text..L.cfi*) - } #endif } -- cgit v1.2.3 From b66c874fdb6653aefb3019aeaa9b9f8c1aadd6a0 Mon Sep 17 00:00:00 2001 From: Boqun Feng Date: Wed, 27 Jul 2022 17:58:20 +0200 Subject: kallsyms: use `ARRAY_SIZE` instead of hardcoded size This removes one place where the `500` constant is hardcoded. Reviewed-by: Kees Cook Reviewed-by: Geert Stappers Reviewed-by: Greg Kroah-Hartman Signed-off-by: Boqun Feng Co-developed-by: Miguel Ojeda Signed-off-by: Miguel Ojeda --- scripts/kallsyms.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index f18e6dfc68c5..8551513f9311 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -206,7 +206,7 @@ static struct sym_entry *read_symbol(FILE *in) rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name); if (rc != 3) { - if (rc != EOF && fgets(name, 500, in) == NULL) + if (rc != EOF && fgets(name, ARRAY_SIZE(name), in) == NULL) fprintf(stderr, "Read error or end of file.\n"); return NULL; } -- cgit v1.2.3 From b471927ebf9bb54ba6e99f20848d70193e645eed Mon Sep 17 00:00:00 2001 From: Boqun Feng Date: Wed, 27 Jul 2022 20:54:19 +0200 Subject: kallsyms: avoid hardcoding buffer size This introduces `KSYM_NAME_LEN_BUFFER` in place of the previously hardcoded size of the input buffer. It will also make it easier to update the size in a single place in a later patch. Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Signed-off-by: Boqun Feng Co-developed-by: Miguel Ojeda Signed-off-by: Miguel Ojeda --- scripts/kallsyms.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 8551513f9311..25e2fe5fbcd4 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -27,8 +27,14 @@ #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0])) +#define _stringify_1(x) #x +#define _stringify(x) _stringify_1(x) + #define KSYM_NAME_LEN 128 +/* A substantially bigger size than the current maximum. */ +#define KSYM_NAME_LEN_BUFFER 499 + struct sym_entry { unsigned long long addr; unsigned int len; @@ -198,13 +204,13 @@ static void check_symbol_range(const char *sym, unsigned long long addr, static struct sym_entry *read_symbol(FILE *in) { - char name[500], type; + char name[KSYM_NAME_LEN_BUFFER+1], type; unsigned long long addr; unsigned int len; struct sym_entry *sym; int rc; - rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name); + rc = fscanf(in, "%llx %c %" _stringify(KSYM_NAME_LEN_BUFFER) "s\n", &addr, &type, name); if (rc != 3) { if (rc != EOF && fgets(name, ARRAY_SIZE(name), in) == NULL) fprintf(stderr, "Read error or end of file.\n"); -- cgit v1.2.3 From 6e8c5bbd5e83e649251c198e743c8b9e7c48372b Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Wed, 27 Jul 2022 21:41:56 +0200 Subject: kallsyms: add static relationship between `KSYM_NAME_LEN{,_BUFFER}` This adds a static assert to ensure `KSYM_NAME_LEN_BUFFER` gets updated when `KSYM_NAME_LEN` changes. The relationship used is one that keeps the new size (512+1) close to the original buffer size (500). Reviewed-by: Greg Kroah-Hartman Co-developed-by: Boqun Feng Signed-off-by: Boqun Feng Signed-off-by: Miguel Ojeda --- scripts/kallsyms.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 25e2fe5fbcd4..411ff5058b51 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -32,8 +32,18 @@ #define KSYM_NAME_LEN 128 -/* A substantially bigger size than the current maximum. */ -#define KSYM_NAME_LEN_BUFFER 499 +/* + * A substantially bigger size than the current maximum. + * + * It cannot be defined as an expression because it gets stringified + * for the fscanf() format string. Therefore, a _Static_assert() is + * used instead to maintain the relationship with KSYM_NAME_LEN. + */ +#define KSYM_NAME_LEN_BUFFER 512 +_Static_assert( + KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4, + "Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN" +); struct sym_entry { unsigned long long addr; -- cgit v1.2.3 From 73bbb94466fd3f8b313eeb0b0467314a262dddb3 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Mon, 5 Apr 2021 04:58:39 +0200 Subject: kallsyms: support "big" kernel symbols Rust symbols can become quite long due to namespacing introduced by modules, types, traits, generics, etc. Increasing to 255 is not enough in some cases, therefore introduce longer lengths to the symbol table. In order to avoid increasing all lengths to 2 bytes (since most of them are small, including many Rust ones), use ULEB128 to keep smaller symbols in 1 byte, with the rest in 2 bytes. Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Gary Guo Signed-off-by: Gary Guo Co-developed-by: Boqun Feng Signed-off-by: Boqun Feng Co-developed-by: Matthew Wilcox Signed-off-by: Matthew Wilcox Signed-off-by: Miguel Ojeda --- kernel/kallsyms.c | 26 ++++++++++++++++++++++---- scripts/kallsyms.c | 29 ++++++++++++++++++++++++++--- 2 files changed, 48 insertions(+), 7 deletions(-) (limited to 'scripts') diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 3e7e2c2ad2f7..fc5e26348d25 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -50,12 +50,20 @@ static unsigned int kallsyms_expand_symbol(unsigned int off, data = &kallsyms_names[off]; len = *data; data++; + off++; + + /* If MSB is 1, it is a "big" symbol, so needs an additional byte. */ + if ((len & 0x80) != 0) { + len = (len & 0x7F) | (*data << 7); + data++; + off++; + } /* * Update the offset to return the offset for the next symbol on * the compressed stream. */ - off += len + 1; + off += len; /* * For every byte on the compressed symbol data, copy the table @@ -108,7 +116,7 @@ static char kallsyms_get_symbol_type(unsigned int off) static unsigned int get_symbol_offset(unsigned long pos) { const u8 *name; - int i; + int i, len; /* * Use the closest marker we have. We have markers every 256 positions, @@ -122,8 +130,18 @@ static unsigned int get_symbol_offset(unsigned long pos) * so we just need to add the len to the current pointer for every * symbol we wish to skip. */ - for (i = 0; i < (pos & 0xFF); i++) - name = name + (*name) + 1; + for (i = 0; i < (pos & 0xFF); i++) { + len = *name; + + /* + * If MSB is 1, it is a "big" symbol, so we need to look into + * the next byte (and skip it, too). + */ + if ((len & 0x80) != 0) + len = ((len & 0x7F) | (name[1] << 7)) + 1; + + name = name + len + 1; + } return name - kallsyms_names; } diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 411ff5058b51..6502c4001f01 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -487,12 +487,35 @@ static void write_src(void) if ((i & 0xFF) == 0) markers[i >> 8] = off; - printf("\t.byte 0x%02x", table[i]->len); + /* There cannot be any symbol of length zero. */ + if (table[i]->len == 0) { + fprintf(stderr, "kallsyms failure: " + "unexpected zero symbol length\n"); + exit(EXIT_FAILURE); + } + + /* Only lengths that fit in up-to-two-byte ULEB128 are supported. */ + if (table[i]->len > 0x3FFF) { + fprintf(stderr, "kallsyms failure: " + "unexpected huge symbol length\n"); + exit(EXIT_FAILURE); + } + + /* Encode length with ULEB128. */ + if (table[i]->len <= 0x7F) { + /* Most symbols use a single byte for the length. */ + printf("\t.byte 0x%02x", table[i]->len); + off += table[i]->len + 1; + } else { + /* "Big" symbols use two bytes. */ + printf("\t.byte 0x%02x, 0x%02x", + (table[i]->len & 0x7F) | 0x80, + (table[i]->len >> 7) & 0x7F); + off += table[i]->len + 2; + } for (k = 0; k < table[i]->len; k++) printf(", 0x%02x", table[i]->sym[k]); printf("\n"); - - off += table[i]->len + 1; } printf("\n"); -- cgit v1.2.3 From b8a94bfb33952bb17fbc65f8903d242a721c533d Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Mon, 5 Apr 2021 05:03:50 +0200 Subject: kallsyms: increase maximum kernel symbol length to 512 Rust symbols can become quite long due to namespacing introduced by modules, types, traits, generics, etc. For instance, the following code: pub mod my_module { pub struct MyType; pub struct MyGenericType(T); pub trait MyTrait { fn my_method() -> u32; } impl MyTrait for MyGenericType { fn my_method() -> u32 { 42 } } } generates a symbol of length 96 when using the upcoming v0 mangling scheme: _RNvXNtCshGpAVYOtgW1_7example9my_moduleINtB2_13MyGenericTypeNtB2_6MyTypeENtB2_7MyTrait9my_method At the moment, Rust symbols may reach up to 300 in length. Setting 512 as the maximum seems like a reasonable choice to keep some headroom. Reviewed-by: Kees Cook Reviewed-by: Petr Mladek Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Gary Guo Signed-off-by: Gary Guo Co-developed-by: Boqun Feng Signed-off-by: Boqun Feng Signed-off-by: Miguel Ojeda --- include/linux/kallsyms.h | 2 +- kernel/livepatch/core.c | 4 ++-- scripts/kallsyms.c | 4 ++-- tools/include/linux/kallsyms.h | 2 +- tools/lib/perf/include/perf/event.h | 2 +- tools/lib/symbol/kallsyms.h | 2 +- 6 files changed, 8 insertions(+), 8 deletions(-) (limited to 'scripts') diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h index ad39636e0c3f..649faac31ddb 100644 --- a/include/linux/kallsyms.h +++ b/include/linux/kallsyms.h @@ -15,7 +15,7 @@ #include -#define KSYM_NAME_LEN 128 +#define KSYM_NAME_LEN 512 #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s %s]") + \ (KSYM_NAME_LEN - 1) + \ 2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + \ diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index bc475e62279d..ec06ce59d728 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -213,7 +213,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab, * we use the smallest/strictest upper bound possible (56, based on * the current definition of MODULE_NAME_LEN) to prevent overflows. */ - BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128); + BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 512); relas = (Elf_Rela *) relasec->sh_addr; /* For each rela in this klp relocation section */ @@ -227,7 +227,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab, /* Format: .klp.sym.sym_objname.sym_name,sympos */ cnt = sscanf(strtab + sym->st_name, - ".klp.sym.%55[^.].%127[^,],%lu", + ".klp.sym.%55[^.].%511[^,],%lu", sym_objname, sym_name, &sympos); if (cnt != 3) { pr_err("symbol %s has an incorrectly formatted name\n", diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 6502c4001f01..c4793301a27e 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -30,7 +30,7 @@ #define _stringify_1(x) #x #define _stringify(x) _stringify_1(x) -#define KSYM_NAME_LEN 128 +#define KSYM_NAME_LEN 512 /* * A substantially bigger size than the current maximum. @@ -39,7 +39,7 @@ * for the fscanf() format string. Therefore, a _Static_assert() is * used instead to maintain the relationship with KSYM_NAME_LEN. */ -#define KSYM_NAME_LEN_BUFFER 512 +#define KSYM_NAME_LEN_BUFFER 2048 _Static_assert( KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4, "Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN" diff --git a/tools/include/linux/kallsyms.h b/tools/include/linux/kallsyms.h index efb6c3f5f2a9..5a37ccbec54f 100644 --- a/tools/include/linux/kallsyms.h +++ b/tools/include/linux/kallsyms.h @@ -6,7 +6,7 @@ #include #include -#define KSYM_NAME_LEN 128 +#define KSYM_NAME_LEN 512 struct module; diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h index 93bf93a59c99..d8ae4e944467 100644 --- a/tools/lib/perf/include/perf/event.h +++ b/tools/lib/perf/include/perf/event.h @@ -97,7 +97,7 @@ struct perf_record_throttle { }; #ifndef KSYM_NAME_LEN -#define KSYM_NAME_LEN 256 +#define KSYM_NAME_LEN 512 #endif struct perf_record_ksymbol { diff --git a/tools/lib/symbol/kallsyms.h b/tools/lib/symbol/kallsyms.h index 72ab9870454b..542f9b059c3b 100644 --- a/tools/lib/symbol/kallsyms.h +++ b/tools/lib/symbol/kallsyms.h @@ -7,7 +7,7 @@ #include #ifndef KSYM_NAME_LEN -#define KSYM_NAME_LEN 256 +#define KSYM_NAME_LEN 512 #endif static inline u8 kallsyms2elf_binding(char type) -- cgit v1.2.3 From de48fa1a01e7752135c960a20d6c3b26544a8120 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 22 May 2022 03:11:08 +0200 Subject: scripts: checkpatch: diagnose uses of `%pA` in the C side as errors The `%pA` format specifier is only intended to be used from Rust. `checkpatch.pl` already gives a warning for invalid specificers: WARNING: Invalid vsprintf pointer extension '%pA' This makes it an error and introduces an explanatory message: ERROR: Invalid vsprintf pointer extension '%pA' - '%pA' is only intended to be used from Rust code Suggested-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Joe Perches Signed-off-by: Joe Perches Signed-off-by: Miguel Ojeda --- scripts/checkpatch.pl | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 79e759aac543..74a769310adf 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -6783,15 +6783,19 @@ sub process { } if ($bad_specifier ne "") { my $stat_real = get_stat_real($linenr, $lc); + my $msg_level = \&WARN; my $ext_type = "Invalid"; my $use = ""; if ($bad_specifier =~ /p[Ff]/) { $use = " - use %pS instead"; $use =~ s/pS/ps/ if ($bad_specifier =~ /pf/); + } elsif ($bad_specifier =~ /pA/) { + $use = " - '%pA' is only intended to be used from Rust code"; + $msg_level = \&ERROR; } - WARN("VSPRINTF_POINTER_EXTENSION", - "$ext_type vsprintf pointer extension '$bad_specifier'$use\n" . "$here\n$stat_real\n"); + &{$msg_level}("VSPRINTF_POINTER_EXTENSION", + "$ext_type vsprintf pointer extension '$bad_specifier'$use\n" . "$here\n$stat_real\n"); } } } -- cgit v1.2.3 From d1d84b5f73888ccb9fc148dfc3cb3e15d3604d65 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 22 May 2022 17:22:58 +0200 Subject: scripts: checkpatch: enable language-independent checks for Rust Include Rust in the "source code files" category, so that the language-independent tests are checked for Rust too, and teach `checkpatch` about the comment style for Rust files. This enables the malformed SPDX check, the misplaced SPDX license tag check, the long line checks, the lines without a newline check and the embedded filename check. Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Signed-off-by: Miguel Ojeda --- scripts/checkpatch.pl | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 74a769310adf..b5ed31d631fa 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -3616,7 +3616,7 @@ sub process { my $comment = ""; if ($realfile =~ /\.(h|s|S)$/) { $comment = '/*'; - } elsif ($realfile =~ /\.(c|dts|dtsi)$/) { + } elsif ($realfile =~ /\.(c|rs|dts|dtsi)$/) { $comment = '//'; } elsif (($checklicenseline == 2) || $realfile =~ /\.(sh|pl|py|awk|tc|yaml)$/) { $comment = '#'; @@ -3664,7 +3664,7 @@ sub process { } # check we are in a valid source file if not then ignore this hunk - next if ($realfile !~ /\.(h|c|s|S|sh|dtsi|dts)$/); + next if ($realfile !~ /\.(h|c|rs|s|S|sh|dtsi|dts)$/); # check for using SPDX-License-Identifier on the wrong line number if ($realline != $checklicenseline && -- cgit v1.2.3 From 99115db4ecc87af73415939439ec604ea0531e6f Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 5 Dec 2021 19:00:43 +0100 Subject: scripts: decode_stacktrace: demangle Rust symbols Recent versions of both Binutils (`c++filt`) and LLVM (`llvm-cxxfilt`) provide Rust v0 mangling support. Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Signed-off-by: Miguel Ojeda --- scripts/decode_stacktrace.sh | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'scripts') diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh index 7075e26ab2c4..564c5632e1a2 100755 --- a/scripts/decode_stacktrace.sh +++ b/scripts/decode_stacktrace.sh @@ -8,6 +8,14 @@ usage() { echo " $0 -r | [|auto] []" } +# Try to find a Rust demangler +if type llvm-cxxfilt >/dev/null 2>&1 ; then + cppfilt=llvm-cxxfilt +elif type c++filt >/dev/null 2>&1 ; then + cppfilt=c++filt + cppfilt_opts=-i +fi + if [[ $1 == "-r" ]] ; then vmlinux="" basepath="auto" @@ -180,6 +188,12 @@ parse_symbol() { # In the case of inlines, move everything to same line code=${code//$'\n'/' '} + # Demangle if the name looks like a Rust symbol and if + # we got a Rust demangler + if [[ $name =~ ^_R && $cppfilt != "" ]] ; then + name=$("$cppfilt" "$cppfilt_opts" "$name") + fi + # Replace old address with pretty line numbers symbol="$segment$name ($code)" } -- cgit v1.2.3 From 8c4555ccc55cf90e1e3eb2507be3c354f3d15839 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sat, 3 Jul 2021 17:26:15 +0200 Subject: scripts: add `generate_rust_analyzer.py` MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The `generate_rust_analyzer.py` script generates the configuration file (`rust-project.json`) for rust-analyzer. rust-analyzer is a modular compiler frontend for the Rust language. It provides an LSP server which can be used in editors such as VS Code, Emacs or Vim. Reviewed-by: Kees Cook Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Finn Behrens Signed-off-by: Finn Behrens Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Gary Guo Signed-off-by: Gary Guo Co-developed-by: Boris-Chengbiao Zhou Signed-off-by: Boris-Chengbiao Zhou Co-developed-by: Björn Roy Baron Signed-off-by: Björn Roy Baron Signed-off-by: Miguel Ojeda --- .gitignore | 3 + scripts/generate_rust_analyzer.py | 135 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 138 insertions(+) create mode 100755 scripts/generate_rust_analyzer.py (limited to 'scripts') diff --git a/.gitignore b/.gitignore index 265959544978..80989914c97d 100644 --- a/.gitignore +++ b/.gitignore @@ -162,3 +162,6 @@ x509.genkey # Documentation toolchain sphinx_*/ + +# Rust analyzer configuration +/rust-project.json diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py new file mode 100755 index 000000000000..75bb611bd751 --- /dev/null +++ b/scripts/generate_rust_analyzer.py @@ -0,0 +1,135 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0 +"""generate_rust_analyzer - Generates the `rust-project.json` file for `rust-analyzer`. +""" + +import argparse +import json +import logging +import pathlib +import sys + +def generate_crates(srctree, objtree, sysroot_src): + # Generate the configuration list. + cfg = [] + with open(objtree / "include" / "generated" / "rustc_cfg") as fd: + for line in fd: + line = line.replace("--cfg=", "") + line = line.replace("\n", "") + cfg.append(line) + + # Now fill the crates list -- dependencies need to come first. + # + # Avoid O(n^2) iterations by keeping a map of indexes. + crates = [] + crates_indexes = {} + + def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False): + crates_indexes[display_name] = len(crates) + crates.append({ + "display_name": display_name, + "root_module": str(root_module), + "is_workspace_member": is_workspace_member, + "is_proc_macro": is_proc_macro, + "deps": [{"crate": crates_indexes[dep], "name": dep} for dep in deps], + "cfg": cfg, + "edition": "2021", + "env": { + "RUST_MODFILE": "This is only for rust-analyzer" + } + }) + + # First, the ones in `rust/` since they are a bit special. + append_crate( + "core", + sysroot_src / "core" / "src" / "lib.rs", + [], + is_workspace_member=False, + ) + + append_crate( + "compiler_builtins", + srctree / "rust" / "compiler_builtins.rs", + [], + ) + + append_crate( + "alloc", + srctree / "rust" / "alloc" / "lib.rs", + ["core", "compiler_builtins"], + ) + + append_crate( + "macros", + srctree / "rust" / "macros" / "lib.rs", + [], + is_proc_macro=True, + ) + crates[-1]["proc_macro_dylib_path"] = "rust/libmacros.so" + + append_crate( + "bindings", + srctree / "rust"/ "bindings" / "lib.rs", + ["core"], + cfg=cfg, + ) + crates[-1]["env"]["OBJTREE"] = str(objtree.resolve(True)) + + append_crate( + "kernel", + srctree / "rust" / "kernel" / "lib.rs", + ["core", "alloc", "macros", "bindings"], + cfg=cfg, + ) + crates[-1]["source"] = { + "include_dirs": [ + str(srctree / "rust" / "kernel"), + str(objtree / "rust") + ], + "exclude_dirs": [], + } + + # Then, the rest outside of `rust/`. + # + # We explicitly mention the top-level folders we want to cover. + for folder in ("samples", "drivers"): + for path in (srctree / folder).rglob("*.rs"): + logging.info("Checking %s", path) + name = path.name.replace(".rs", "") + + # Skip those that are not crate roots. + if f"{name}.o" not in open(path.parent / "Makefile").read(): + continue + + logging.info("Adding %s", name) + append_crate( + name, + path, + ["core", "alloc", "kernel"], + cfg=cfg, + ) + + return crates + +def main(): + parser = argparse.ArgumentParser() + parser.add_argument('--verbose', '-v', action='store_true') + parser.add_argument("srctree", type=pathlib.Path) + parser.add_argument("objtree", type=pathlib.Path) + parser.add_argument("sysroot_src", type=pathlib.Path) + args = parser.parse_args() + + logging.basicConfig( + format="[%(asctime)s] [%(levelname)s] %(message)s", + level=logging.INFO if args.verbose else logging.WARNING + ) + + rust_project = { + "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src), + "sysroot_src": str(args.sysroot_src), + } + + json.dump(rust_project, sys.stdout, sort_keys=True, indent=4) + +if __name__ == "__main__": + main() -- cgit v1.2.3 From 9a8ff24ce584ad9895f9416fe8fad6f8842f758d Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Thu, 4 Aug 2022 12:20:37 +0200 Subject: scripts: add `generate_rust_target.rs` This script takes care of generating the custom target specification file for `rustc`, based on the kernel configuration. It also serves as an example of a Rust host program. A dummy architecture is kept in this patch so that a later patch adds x86 support on top with as few changes as possible. Reviewed-by: Kees Cook Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: David Gow Signed-off-by: David Gow Signed-off-by: Miguel Ojeda --- scripts/.gitignore | 1 + scripts/generate_rust_target.rs | 171 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 172 insertions(+) create mode 100644 scripts/generate_rust_target.rs (limited to 'scripts') diff --git a/scripts/.gitignore b/scripts/.gitignore index eed308bef604..b7aec8eb1bd4 100644 --- a/scripts/.gitignore +++ b/scripts/.gitignore @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0-only /asn1_compiler /bin2c +/generate_rust_target /insert-sys-cert /kallsyms /module.lds diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs new file mode 100644 index 000000000000..7256c9606cf0 --- /dev/null +++ b/scripts/generate_rust_target.rs @@ -0,0 +1,171 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! The custom target specification file generator for `rustc`. +//! +//! To configure a target from scratch, a JSON-encoded file has to be passed +//! to `rustc` (introduced in [RFC 131]). These options and the file itself are +//! unstable. Eventually, `rustc` should provide a way to do this in a stable +//! manner. For instance, via command-line arguments. Therefore, this file +//! should avoid using keys which can be set via `-C` or `-Z` options. +//! +//! [RFC 131]: https://rust-lang.github.io/rfcs/0131-target-specification.html + +use std::{ + collections::HashMap, + fmt::{Display, Formatter, Result}, + io::BufRead, +}; + +enum Value { + Boolean(bool), + Number(i32), + String(String), + Object(Object), +} + +type Object = Vec<(String, Value)>; + +/// Minimal "almost JSON" generator (e.g. no `null`s, no arrays, no escaping), +/// enough for this purpose. +impl Display for Value { + fn fmt(&self, formatter: &mut Formatter<'_>) -> Result { + match self { + Value::Boolean(boolean) => write!(formatter, "{}", boolean), + Value::Number(number) => write!(formatter, "{}", number), + Value::String(string) => write!(formatter, "\"{}\"", string), + Value::Object(object) => { + formatter.write_str("{")?; + if let [ref rest @ .., ref last] = object[..] { + for (key, value) in rest { + write!(formatter, "\"{}\": {},", key, value)?; + } + write!(formatter, "\"{}\": {}", last.0, last.1)?; + } + formatter.write_str("}") + } + } + } +} + +struct TargetSpec(Object); + +impl TargetSpec { + fn new() -> TargetSpec { + TargetSpec(Vec::new()) + } +} + +trait Push { + fn push(&mut self, key: &str, value: T); +} + +impl Push for TargetSpec { + fn push(&mut self, key: &str, value: bool) { + self.0.push((key.to_string(), Value::Boolean(value))); + } +} + +impl Push for TargetSpec { + fn push(&mut self, key: &str, value: i32) { + self.0.push((key.to_string(), Value::Number(value))); + } +} + +impl Push for TargetSpec { + fn push(&mut self, key: &str, value: String) { + self.0.push((key.to_string(), Value::String(value))); + } +} + +impl Push<&str> for TargetSpec { + fn push(&mut self, key: &str, value: &str) { + self.push(key, value.to_string()); + } +} + +impl Push for TargetSpec { + fn push(&mut self, key: &str, value: Object) { + self.0.push((key.to_string(), Value::Object(value))); + } +} + +impl Display for TargetSpec { + fn fmt(&self, formatter: &mut Formatter<'_>) -> Result { + // We add some newlines for clarity. + formatter.write_str("{\n")?; + if let [ref rest @ .., ref last] = self.0[..] { + for (key, value) in rest { + write!(formatter, " \"{}\": {},\n", key, value)?; + } + write!(formatter, " \"{}\": {}\n", last.0, last.1)?; + } + formatter.write_str("}") + } +} + +struct KernelConfig(HashMap); + +impl KernelConfig { + /// Parses `include/config/auto.conf` from `stdin`. + fn from_stdin() -> KernelConfig { + let mut result = HashMap::new(); + + let stdin = std::io::stdin(); + let mut handle = stdin.lock(); + let mut line = String::new(); + + loop { + line.clear(); + + if handle.read_line(&mut line).unwrap() == 0 { + break; + } + + if line.starts_with('#') { + continue; + } + + let (key, value) = line.split_once('=').expect("Missing `=` in line."); + result.insert(key.to_string(), value.trim_end_matches('\n').to_string()); + } + + KernelConfig(result) + } + + /// Does the option exist in the configuration (any value)? + /// + /// The argument must be passed without the `CONFIG_` prefix. + /// This avoids repetition and it also avoids `fixdep` making us + /// depend on it. + fn has(&self, option: &str) -> bool { + let option = "CONFIG_".to_owned() + option; + self.0.contains_key(&option) + } +} + +fn main() { + let cfg = KernelConfig::from_stdin(); + let mut ts = TargetSpec::new(); + + // `llvm-target`s are taken from `scripts/Makefile.clang`. + if cfg.has("DUMMY_ARCH") { + ts.push("arch", "dummy_arch"); + } else { + panic!("Unsupported architecture"); + } + + ts.push("emit-debug-gdb-scripts", false); + ts.push("frame-pointer", "may-omit"); + ts.push( + "stack-probes", + vec![("kind".to_string(), Value::String("none".to_string()))], + ); + + // Everything else is LE, whether `CPU_LITTLE_ENDIAN` is declared or not + // (e.g. x86). It is also `rustc`'s default. + if cfg.has("CPU_BIG_ENDIAN") { + ts.push("target-endian", "big"); + } + + println!("{}", ts); +} -- cgit v1.2.3 From 78521f3399abce9bb9db16d848044be873e117ac Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Thu, 4 Aug 2022 12:25:53 +0200 Subject: scripts: add `rust_is_available.sh` This script tests whether the Rust toolchain requirements are in place to enable Rust support. It uses `min-tool-version.sh` to fetch the version numbers. The build system will call it to set `CONFIG_RUST_IS_AVAILABLE` in a later patch. It also has an option (`-v`) to explain what is missing, which is useful to set up the development environment. This is used via the `make rustavailable` target added in a later patch. Reviewed-by: Kees Cook Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Finn Behrens Signed-off-by: Finn Behrens Co-developed-by: Miguel Cano Signed-off-by: Miguel Cano Co-developed-by: Tiago Lam Signed-off-by: Tiago Lam Signed-off-by: Miguel Ojeda --- scripts/min-tool-version.sh | 6 + scripts/rust_is_available.sh | 160 +++++++++++++++++++++++++++ scripts/rust_is_available_bindgen_libclang.h | 2 + 3 files changed, 168 insertions(+) create mode 100755 scripts/rust_is_available.sh create mode 100644 scripts/rust_is_available_bindgen_libclang.h (limited to 'scripts') diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh index 250925aab101..b6593eac5003 100755 --- a/scripts/min-tool-version.sh +++ b/scripts/min-tool-version.sh @@ -30,6 +30,12 @@ llvm) echo 11.0.0 fi ;; +rustc) + echo 1.62.0 + ;; +bindgen) + echo 0.56.0 + ;; *) echo "$1: unknown tool" >&2 exit 1 diff --git a/scripts/rust_is_available.sh b/scripts/rust_is_available.sh new file mode 100755 index 000000000000..aebbf1913970 --- /dev/null +++ b/scripts/rust_is_available.sh @@ -0,0 +1,160 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# +# Tests whether a suitable Rust toolchain is available. +# +# Pass `-v` for human output and more checks (as warnings). + +set -e + +min_tool_version=$(dirname $0)/min-tool-version.sh + +# Convert the version string x.y.z to a canonical up-to-7-digits form. +# +# Note that this function uses one more digit (compared to other +# instances in other version scripts) to give a bit more space to +# `rustc` since it will reach 1.100.0 in late 2026. +get_canonical_version() +{ + IFS=. + set -- $1 + echo $((100000 * $1 + 100 * $2 + $3)) +} + +# Check that the Rust compiler exists. +if ! command -v "$RUSTC" >/dev/null; then + if [ "$1" = -v ]; then + echo >&2 "***" + echo >&2 "*** Rust compiler '$RUSTC' could not be found." + echo >&2 "***" + fi + exit 1 +fi + +# Check that the Rust bindings generator exists. +if ! command -v "$BINDGEN" >/dev/null; then + if [ "$1" = -v ]; then + echo >&2 "***" + echo >&2 "*** Rust bindings generator '$BINDGEN' could not be found." + echo >&2 "***" + fi + exit 1 +fi + +# Check that the Rust compiler version is suitable. +# +# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`. +rust_compiler_version=$( \ + LC_ALL=C "$RUSTC" --version 2>/dev/null \ + | head -n 1 \ + | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \ +) +rust_compiler_min_version=$($min_tool_version rustc) +rust_compiler_cversion=$(get_canonical_version $rust_compiler_version) +rust_compiler_min_cversion=$(get_canonical_version $rust_compiler_min_version) +if [ "$rust_compiler_cversion" -lt "$rust_compiler_min_cversion" ]; then + if [ "$1" = -v ]; then + echo >&2 "***" + echo >&2 "*** Rust compiler '$RUSTC' is too old." + echo >&2 "*** Your version: $rust_compiler_version" + echo >&2 "*** Minimum version: $rust_compiler_min_version" + echo >&2 "***" + fi + exit 1 +fi +if [ "$1" = -v ] && [ "$rust_compiler_cversion" -gt "$rust_compiler_min_cversion" ]; then + echo >&2 "***" + echo >&2 "*** Rust compiler '$RUSTC' is too new. This may or may not work." + echo >&2 "*** Your version: $rust_compiler_version" + echo >&2 "*** Expected version: $rust_compiler_min_version" + echo >&2 "***" +fi + +# Check that the Rust bindings generator is suitable. +# +# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`. +rust_bindings_generator_version=$( \ + LC_ALL=C "$BINDGEN" --version 2>/dev/null \ + | head -n 1 \ + | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \ +) +rust_bindings_generator_min_version=$($min_tool_version bindgen) +rust_bindings_generator_cversion=$(get_canonical_version $rust_bindings_generator_version) +rust_bindings_generator_min_cversion=$(get_canonical_version $rust_bindings_generator_min_version) +if [ "$rust_bindings_generator_cversion" -lt "$rust_bindings_generator_min_cversion" ]; then + if [ "$1" = -v ]; then + echo >&2 "***" + echo >&2 "*** Rust bindings generator '$BINDGEN' is too old." + echo >&2 "*** Your version: $rust_bindings_generator_version" + echo >&2 "*** Minimum version: $rust_bindings_generator_min_version" + echo >&2 "***" + fi + exit 1 +fi +if [ "$1" = -v ] && [ "$rust_bindings_generator_cversion" -gt "$rust_bindings_generator_min_cversion" ]; then + echo >&2 "***" + echo >&2 "*** Rust bindings generator '$BINDGEN' is too new. This may or may not work." + echo >&2 "*** Your version: $rust_bindings_generator_version" + echo >&2 "*** Expected version: $rust_bindings_generator_min_version" + echo >&2 "***" +fi + +# Check that the `libclang` used by the Rust bindings generator is suitable. +bindgen_libclang_version=$( \ + LC_ALL=C "$BINDGEN" $(dirname $0)/rust_is_available_bindgen_libclang.h 2>&1 >/dev/null \ + | grep -F 'clang version ' \ + | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \ + | head -n 1 \ +) +bindgen_libclang_min_version=$($min_tool_version llvm) +bindgen_libclang_cversion=$(get_canonical_version $bindgen_libclang_version) +bindgen_libclang_min_cversion=$(get_canonical_version $bindgen_libclang_min_version) +if [ "$bindgen_libclang_cversion" -lt "$bindgen_libclang_min_cversion" ]; then + if [ "$1" = -v ]; then + echo >&2 "***" + echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN') is too old." + echo >&2 "*** Your version: $bindgen_libclang_version" + echo >&2 "*** Minimum version: $bindgen_libclang_min_version" + echo >&2 "***" + fi + exit 1 +fi + +# If the C compiler is Clang, then we can also check whether its version +# matches the `libclang` version used by the Rust bindings generator. +# +# In the future, we might be able to perform a full version check, see +# https://github.com/rust-lang/rust-bindgen/issues/2138. +if [ "$1" = -v ]; then + cc_name=$($(dirname $0)/cc-version.sh "$CC" | cut -f1 -d' ') + if [ "$cc_name" = Clang ]; then + clang_version=$( \ + LC_ALL=C "$CC" --version 2>/dev/null \ + | sed -nE '1s:.*version ([0-9]+\.[0-9]+\.[0-9]+).*:\1:p' + ) + if [ "$clang_version" != "$bindgen_libclang_version" ]; then + echo >&2 "***" + echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN')" + echo >&2 "*** version does not match Clang's. This may be a problem." + echo >&2 "*** libclang version: $bindgen_libclang_version" + echo >&2 "*** Clang version: $clang_version" + echo >&2 "***" + fi + fi +fi + +# Check that the source code for the `core` standard library exists. +# +# `$KRUSTFLAGS` is passed in case the user added `--sysroot`. +rustc_sysroot=$("$RUSTC" $KRUSTFLAGS --print sysroot) +rustc_src=${RUST_LIB_SRC:-"$rustc_sysroot/lib/rustlib/src/rust/library"} +rustc_src_core="$rustc_src/core/src/lib.rs" +if [ ! -e "$rustc_src_core" ]; then + if [ "$1" = -v ]; then + echo >&2 "***" + echo >&2 "*** Source code for the 'core' standard library could not be found" + echo >&2 "*** at '$rustc_src_core'." + echo >&2 "***" + fi + exit 1 +fi diff --git a/scripts/rust_is_available_bindgen_libclang.h b/scripts/rust_is_available_bindgen_libclang.h new file mode 100644 index 000000000000..0ef6db10d674 --- /dev/null +++ b/scripts/rust_is_available_bindgen_libclang.h @@ -0,0 +1,2 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#pragma message("clang version " __clang_version__) -- cgit v1.2.3 From e4b69cb9a99a567d1611f9cced92f475ae224cdb Mon Sep 17 00:00:00 2001 From: Daniel Xu Date: Thu, 4 Aug 2022 12:55:07 +0200 Subject: scripts: add `is_rust_module.sh` This script is used to detect whether a kernel module is written in Rust. It will later be used to disable BTF generation on Rust modules as BTF does not yet support Rust. Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Signed-off-by: Daniel Xu Co-developed-by: Miguel Ojeda Signed-off-by: Miguel Ojeda --- scripts/is_rust_module.sh | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) create mode 100755 scripts/is_rust_module.sh (limited to 'scripts') diff --git a/scripts/is_rust_module.sh b/scripts/is_rust_module.sh new file mode 100755 index 000000000000..28b3831a7593 --- /dev/null +++ b/scripts/is_rust_module.sh @@ -0,0 +1,16 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# +# is_rust_module.sh module.ko +# +# Returns `0` if `module.ko` is a Rust module, `1` otherwise. + +set -e + +# Using the `16_` prefix ensures other symbols with the same substring +# are not picked up (even if it would be unlikely). The last part is +# used just in case LLVM decides to use the `.` suffix. +# +# In the future, checking for the `.comment` section may be another +# option, see https://github.com/rust-lang/rust/pull/97550. +${NM} "$*" | grep -qE '^[0-9a-fA-F]+ r _R[^[:space:]]+16___IS_RUST_MODULE[^[:space:]]*$' -- cgit v1.2.3 From 2f7ab1267dc9b2d1f29695aff3211c87483480f3 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sat, 3 Jul 2021 16:42:57 +0200 Subject: Kbuild: add Rust support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Finn Behrens Signed-off-by: Finn Behrens Co-developed-by: Adam Bratschi-Kaye Signed-off-by: Adam Bratschi-Kaye Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Michael Ellerman Signed-off-by: Michael Ellerman Co-developed-by: Sven Van Asbroeck Signed-off-by: Sven Van Asbroeck Co-developed-by: Gary Guo Signed-off-by: Gary Guo Co-developed-by: Boris-Chengbiao Zhou Signed-off-by: Boris-Chengbiao Zhou Co-developed-by: Boqun Feng Signed-off-by: Boqun Feng Co-developed-by: Douglas Su Signed-off-by: Douglas Su Co-developed-by: Dariusz Sosnowski Signed-off-by: Dariusz Sosnowski Co-developed-by: Antonio Terceiro Signed-off-by: Antonio Terceiro Co-developed-by: Daniel Xu Signed-off-by: Daniel Xu Co-developed-by: Björn Roy Baron Signed-off-by: Björn Roy Baron Co-developed-by: Martin Rodriguez Reboredo Signed-off-by: Martin Rodriguez Reboredo Signed-off-by: Miguel Ojeda --- .gitignore | 2 + Makefile | 172 ++++++++++++++++++- arch/Kconfig | 6 + include/linux/compiler_types.h | 6 +- init/Kconfig | 46 ++++- kernel/configs/rust.config | 1 + lib/Kconfig.debug | 34 ++++ rust/.gitignore | 8 + rust/Makefile | 381 +++++++++++++++++++++++++++++++++++++++++ rust/bindgen_parameters | 21 +++ scripts/Kconfig.include | 6 +- scripts/Makefile | 3 + scripts/Makefile.build | 60 +++++++ scripts/Makefile.debug | 8 + scripts/Makefile.host | 34 +++- scripts/Makefile.lib | 12 ++ scripts/Makefile.modfinal | 8 +- scripts/cc-version.sh | 12 +- scripts/kconfig/confdata.c | 75 ++++++++ 19 files changed, 869 insertions(+), 26 deletions(-) create mode 100644 kernel/configs/rust.config create mode 100644 rust/.gitignore create mode 100644 rust/Makefile create mode 100644 rust/bindgen_parameters (limited to 'scripts') diff --git a/.gitignore b/.gitignore index 97e085d613a2..5da004814678 100644 --- a/.gitignore +++ b/.gitignore @@ -37,6 +37,8 @@ *.o *.o.* *.patch +*.rmeta +*.rsi *.s *.so *.so.dbg diff --git a/Makefile b/Makefile index 647a42a1f800..c759ee315254 100644 --- a/Makefile +++ b/Makefile @@ -120,6 +120,15 @@ endif export KBUILD_CHECKSRC +# Enable "clippy" (a linter) as part of the Rust compilation. +# +# Use 'make CLIPPY=1' to enable it. +ifeq ("$(origin CLIPPY)", "command line") + KBUILD_CLIPPY := $(CLIPPY) +endif + +export KBUILD_CLIPPY + # Use make M=dir or set the environment variable KBUILD_EXTMOD to specify the # directory of external module to build. Setting M= takes precedence. ifeq ("$(origin M)", "command line") @@ -270,14 +279,14 @@ no-dot-config-targets := $(clean-targets) \ cscope gtags TAGS tags help% %docs check% coccicheck \ $(version_h) headers headers_% archheaders archscripts \ %asm-generic kernelversion %src-pkg dt_binding_check \ - outputmakefile + outputmakefile rustavailable rustfmt rustfmtcheck # Installation targets should not require compiler. Unfortunately, vdso_install # is an exception where build artifacts may be updated. This must be fixed. no-compiler-targets := $(no-dot-config-targets) install dtbs_install \ headers_install modules_install kernelrelease image_name no-sync-config-targets := $(no-dot-config-targets) %install kernelrelease \ image_name -single-targets := %.a %.i %.ko %.lds %.ll %.lst %.mod %.o %.s %.symtypes %/ +single-targets := %.a %.i %.rsi %.ko %.lds %.ll %.lst %.mod %.o %.s %.symtypes %/ config-build := mixed-build := @@ -439,6 +448,7 @@ else HOSTCC = gcc HOSTCXX = g++ endif +HOSTRUSTC = rustc HOSTPKG_CONFIG = pkg-config KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \ @@ -447,8 +457,26 @@ KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \ KBUILD_USERCFLAGS := $(KBUILD_USERHOSTCFLAGS) $(USERCFLAGS) KBUILD_USERLDFLAGS := $(USERLDFLAGS) +# These flags apply to all Rust code in the tree, including the kernel and +# host programs. +export rust_common_flags := --edition=2021 \ + -Zbinary_dep_depinfo=y \ + -Dunsafe_op_in_unsafe_fn -Drust_2018_idioms \ + -Dunreachable_pub -Dnon_ascii_idents \ + -Wmissing_docs \ + -Drustdoc::missing_crate_level_docs \ + -Dclippy::correctness -Dclippy::style \ + -Dclippy::suspicious -Dclippy::complexity \ + -Dclippy::perf \ + -Dclippy::let_unit_value -Dclippy::mut_mut \ + -Dclippy::needless_bitwise_bool \ + -Dclippy::needless_continue \ + -Wclippy::dbg_macro + KBUILD_HOSTCFLAGS := $(KBUILD_USERHOSTCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS) KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS) +KBUILD_HOSTRUSTFLAGS := $(rust_common_flags) -O -Cstrip=debuginfo \ + -Zallow-features= $(HOSTRUSTFLAGS) KBUILD_HOSTLDFLAGS := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS) KBUILD_HOSTLDLIBS := $(HOST_LFS_LIBS) $(HOSTLDLIBS) @@ -473,6 +501,12 @@ OBJDUMP = $(CROSS_COMPILE)objdump READELF = $(CROSS_COMPILE)readelf STRIP = $(CROSS_COMPILE)strip endif +RUSTC = rustc +RUSTDOC = rustdoc +RUSTFMT = rustfmt +CLIPPY_DRIVER = clippy-driver +BINDGEN = bindgen +CARGO = cargo PAHOLE = pahole RESOLVE_BTFIDS = $(objtree)/tools/bpf/resolve_btfids/resolve_btfids LEX = flex @@ -498,9 +532,11 @@ CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \ -Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF) NOSTDINC_FLAGS := CFLAGS_MODULE = +RUSTFLAGS_MODULE = AFLAGS_MODULE = LDFLAGS_MODULE = CFLAGS_KERNEL = +RUSTFLAGS_KERNEL = AFLAGS_KERNEL = LDFLAGS_vmlinux = @@ -529,15 +565,43 @@ KBUILD_CFLAGS := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \ -Werror=return-type -Wno-format-security \ -std=gnu11 KBUILD_CPPFLAGS := -D__KERNEL__ +KBUILD_RUSTFLAGS := $(rust_common_flags) \ + --target=$(objtree)/rust/target.json \ + -Cpanic=abort -Cembed-bitcode=n -Clto=n \ + -Cforce-unwind-tables=n -Ccodegen-units=1 \ + -Csymbol-mangling-version=v0 \ + -Crelocation-model=static \ + -Zfunction-sections=n \ + -Dclippy::float_arithmetic + KBUILD_AFLAGS_KERNEL := KBUILD_CFLAGS_KERNEL := +KBUILD_RUSTFLAGS_KERNEL := KBUILD_AFLAGS_MODULE := -DMODULE KBUILD_CFLAGS_MODULE := -DMODULE +KBUILD_RUSTFLAGS_MODULE := --cfg MODULE KBUILD_LDFLAGS_MODULE := KBUILD_LDFLAGS := CLANG_FLAGS := +ifeq ($(KBUILD_CLIPPY),1) + RUSTC_OR_CLIPPY_QUIET := CLIPPY + RUSTC_OR_CLIPPY = $(CLIPPY_DRIVER) +else + RUSTC_OR_CLIPPY_QUIET := RUSTC + RUSTC_OR_CLIPPY = $(RUSTC) +endif + +ifdef RUST_LIB_SRC + export RUST_LIB_SRC +endif + +# Allows the usage of unstable features in stable compilers. +export RUSTC_BOOTSTRAP := 1 + export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC HOSTPKG_CONFIG +export RUSTC RUSTDOC RUSTFMT RUSTC_OR_CLIPPY_QUIET RUSTC_OR_CLIPPY BINDGEN CARGO +export HOSTRUSTC KBUILD_HOSTRUSTFLAGS export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD @@ -546,9 +610,10 @@ export KBUILD_USERCFLAGS KBUILD_USERLDFLAGS export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE +export KBUILD_RUSTFLAGS RUSTFLAGS_KERNEL RUSTFLAGS_MODULE export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE -export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE -export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL +export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_RUSTFLAGS_MODULE KBUILD_LDFLAGS_MODULE +export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL KBUILD_RUSTFLAGS_KERNEL export PAHOLE_FLAGS # Files to ignore in find ... statements @@ -729,7 +794,7 @@ $(KCONFIG_CONFIG): # # Do not use $(call cmd,...) here. That would suppress prompts from syncconfig, # so you cannot notice that Kconfig is waiting for the user input. -%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h: $(KCONFIG_CONFIG) +%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h %/generated/rustc_cfg: $(KCONFIG_CONFIG) $(Q)$(kecho) " SYNC $@" $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig else # !may-sync-config @@ -758,10 +823,17 @@ KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE KBUILD_CFLAGS += -O2 +KBUILD_RUSTFLAGS += -Copt-level=2 else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE KBUILD_CFLAGS += -Os +KBUILD_RUSTFLAGS += -Copt-level=s endif +# Always set `debug-assertions` and `overflow-checks` because their default +# depends on `opt-level` and `debug-assertions`, respectively. +KBUILD_RUSTFLAGS += -Cdebug-assertions=$(if $(CONFIG_RUST_DEBUG_ASSERTIONS),y,n) +KBUILD_RUSTFLAGS += -Coverflow-checks=$(if $(CONFIG_RUST_OVERFLOW_CHECKS),y,n) + # Tell gcc to never replace conditional load with a non-conditional one ifdef CONFIG_CC_IS_GCC # gcc-10 renamed --param=allow-store-data-races=0 to @@ -792,6 +864,9 @@ KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH) +KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings +KBUILD_RUSTFLAGS += $(KBUILD_RUSTFLAGS-y) + ifdef CONFIG_CC_IS_CLANG KBUILD_CPPFLAGS += -Qunused-arguments # The kernel builds with '-std=gnu11' so use of GNU extensions is acceptable. @@ -812,12 +887,15 @@ KBUILD_CFLAGS += $(call cc-disable-warning, dangling-pointer) ifdef CONFIG_FRAME_POINTER KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls +KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y else # Some targets (ARM with Thumb2, for example), can't be built with frame # pointers. For those, we don't have FUNCTION_TRACER automatically # select FRAME_POINTER. However, FUNCTION_TRACER adds -pg, and this is # incompatible with -fomit-frame-pointer with current GCC, so we don't use # -fomit-frame-pointer with FUNCTION_TRACER. +# In the Rust target specification, "frame-pointer" is set explicitly +# to "may-omit". ifndef CONFIG_FUNCTION_TRACER KBUILD_CFLAGS += -fomit-frame-pointer endif @@ -882,8 +960,10 @@ ifdef CONFIG_DEBUG_SECTION_MISMATCH KBUILD_CFLAGS += -fno-inline-functions-called-once endif +# `rustc`'s `-Zfunction-sections` applies to data too (as of 1.59.0). ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections +KBUILD_RUSTFLAGS_KERNEL += -Zfunction-sections=y LDFLAGS_vmlinux += --gc-sections endif @@ -1026,10 +1106,11 @@ include $(addprefix $(srctree)/, $(include-y)) # Do not add $(call cc-option,...) below this line. When you build the kernel # from the clean source tree, the GCC plugins do not exist at this point. -# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments +# Add user supplied CPPFLAGS, AFLAGS, CFLAGS and RUSTFLAGS as the last assignments KBUILD_CPPFLAGS += $(KCPPFLAGS) KBUILD_AFLAGS += $(KAFLAGS) KBUILD_CFLAGS += $(KCFLAGS) +KBUILD_RUSTFLAGS += $(KRUSTFLAGS) KBUILD_LDFLAGS_MODULE += --build-id=sha1 LDFLAGS_vmlinux += --build-id=sha1 @@ -1104,6 +1185,7 @@ ifeq ($(KBUILD_EXTMOD),) core-y += kernel/ certs/ mm/ fs/ ipc/ security/ crypto/ core-$(CONFIG_BLOCK) += block/ core-$(CONFIG_IO_URING) += io_uring/ +core-$(CONFIG_RUST) += rust/ vmlinux-dirs := $(patsubst %/,%,$(filter %/, \ $(core-y) $(core-m) $(drivers-y) $(drivers-m) \ @@ -1206,6 +1288,10 @@ prepare0: archprepare # All the preparing.. prepare: prepare0 +ifdef CONFIG_RUST + $(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh -v + $(Q)$(MAKE) $(build)=rust +endif PHONY += remove-stale-files remove-stale-files: @@ -1499,7 +1585,7 @@ endif # CONFIG_MODULES # Directories & files removed with 'make clean' CLEAN_FILES += include/ksym vmlinux.symvers modules-only.symvers \ modules.builtin modules.builtin.modinfo modules.nsdeps \ - compile_commands.json .thinlto-cache + compile_commands.json .thinlto-cache rust/test rust/doc # Directories & files removed with 'make mrproper' MRPROPER_FILES += include/config include/generated \ @@ -1510,7 +1596,8 @@ MRPROPER_FILES += include/config include/generated \ certs/signing_key.pem \ certs/x509.genkey \ vmlinux-gdb.py \ - *.spec + *.spec \ + rust/target.json rust/libmacros.so # clean - Delete most, but leave enough to build external modules # @@ -1535,6 +1622,9 @@ $(mrproper-dirs): mrproper: clean $(mrproper-dirs) $(call cmd,rmfiles) + @find . $(RCS_FIND_IGNORE) \ + \( -name '*.rmeta' \) \ + -type f -print | xargs rm -f # distclean # @@ -1622,6 +1712,24 @@ help: @echo ' kselftest-merge - Merge all the config dependencies of' @echo ' kselftest to existing .config.' @echo '' + @echo 'Rust targets:' + @echo ' rustavailable - Checks whether the Rust toolchain is' + @echo ' available and, if not, explains why.' + @echo ' rustfmt - Reformat all the Rust code in the kernel' + @echo ' rustfmtcheck - Checks if all the Rust code in the kernel' + @echo ' is formatted, printing a diff otherwise.' + @echo ' rustdoc - Generate Rust documentation' + @echo ' (requires kernel .config)' + @echo ' rusttest - Runs the Rust tests' + @echo ' (requires kernel .config; downloads external repos)' + @echo ' rust-analyzer - Generate rust-project.json rust-analyzer support file' + @echo ' (requires kernel .config)' + @echo ' dir/file.[os] - Build specified target only' + @echo ' dir/file.rsi - Build macro expanded source, similar to C preprocessing.' + @echo ' Run with RUSTFMT=n to skip reformatting if needed.' + @echo ' The output is not intended to be compilable.' + @echo ' dir/file.ll - Build the LLVM assembly file' + @echo '' @$(if $(dtstree), \ echo 'Devicetree:'; \ echo '* dtbs - Build device tree blobs for enabled boards'; \ @@ -1694,6 +1802,52 @@ PHONY += $(DOC_TARGETS) $(DOC_TARGETS): $(Q)$(MAKE) $(build)=Documentation $@ + +# Rust targets +# --------------------------------------------------------------------------- + +# "Is Rust available?" target +PHONY += rustavailable +rustavailable: + $(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh -v && echo "Rust is available!" + +# Documentation target +# +# Using the singular to avoid running afoul of `no-dot-config-targets`. +PHONY += rustdoc +rustdoc: prepare + $(Q)$(MAKE) $(build)=rust $@ + +# Testing target +PHONY += rusttest +rusttest: prepare + $(Q)$(MAKE) $(build)=rust $@ + +# Formatting targets +PHONY += rustfmt rustfmtcheck + +# We skip `rust/alloc` since we want to minimize the diff w.r.t. upstream. +# +# We match using absolute paths since `find` does not resolve them +# when matching, which is a problem when e.g. `srctree` is `..`. +# We `grep` afterwards in order to remove the directory entry itself. +rustfmt: + $(Q)find $(abs_srctree) -type f -name '*.rs' \ + -o -path $(abs_srctree)/rust/alloc -prune \ + -o -path $(abs_objtree)/rust/test -prune \ + | grep -Fv $(abs_srctree)/rust/alloc \ + | grep -Fv $(abs_objtree)/rust/test \ + | grep -Fv generated \ + | xargs $(RUSTFMT) $(rustfmt_flags) + +rustfmtcheck: rustfmt_flags = --check +rustfmtcheck: rustfmt + +# IDE support targets +PHONY += rust-analyzer +rust-analyzer: + $(Q)$(MAKE) $(build)=rust $@ + # Misc # --------------------------------------------------------------------------- @@ -1861,7 +2015,7 @@ $(clean-dirs): clean: $(clean-dirs) $(call cmd,rmfiles) @find $(or $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \ - \( -name '*.[aios]' -o -name '*.ko' -o -name '.*.cmd' \ + \( -name '*.[aios]' -o -name '*.rsi' -o -name '*.ko' -o -name '.*.cmd' \ -o -name '*.ko.*' \ -o -name '*.dtb' -o -name '*.dtbo' -o -name '*.dtb.S' -o -name '*.dt.yaml' \ -o -name '*.dwo' -o -name '*.lst' \ diff --git a/arch/Kconfig b/arch/Kconfig index 8b311e400ec1..d9b4ae0fc805 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -355,6 +355,12 @@ config HAVE_RSEQ This symbol should be selected by an architecture if it supports an implementation of restartable sequences. +config HAVE_RUST + bool + help + This symbol should be selected by an architecture if it + supports Rust. + config HAVE_FUNCTION_ARG_ACCESS_API bool help diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 4f2a819fd60a..50b3f6b9502e 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -4,8 +4,12 @@ #ifndef __ASSEMBLY__ +/* + * Skipped when running bindgen due to a libclang issue; + * see https://github.com/rust-lang/rust-bindgen/issues/2244. + */ #if defined(CONFIG_DEBUG_INFO_BTF) && defined(CONFIG_PAHOLE_HAS_BTF_TAG) && \ - __has_attribute(btf_type_tag) + __has_attribute(btf_type_tag) && !defined(__BINDGEN__) # define BTF_TYPE_TAG(value) __attribute__((btf_type_tag(#value))) #else # define BTF_TYPE_TAG(value) /* nothing */ diff --git a/init/Kconfig b/init/Kconfig index 532362fcfe31..a078cb026523 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -60,6 +60,17 @@ config LLD_VERSION default $(ld-version) if LD_IS_LLD default 0 +config RUST_IS_AVAILABLE + def_bool $(success,$(srctree)/scripts/rust_is_available.sh) + help + This shows whether a suitable Rust toolchain is available (found). + + Please see Documentation/rust/quick-start.rst for instructions on how + to satify the build requirements of Rust support. + + In particular, the Makefile target 'rustavailable' is useful to check + why the Rust toolchain is not being detected. + config CC_CAN_LINK bool default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT @@ -147,7 +158,8 @@ config WERROR default COMPILE_TEST help A kernel build should not cause any compiler warnings, and this - enables the '-Werror' flag to enforce that rule by default. + enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags + to enforce that rule by default. However, if you have a new (or very old) compiler with odd and unusual warnings, or you have some architecture with problems, @@ -1899,6 +1911,38 @@ config PROFILING Say Y here to enable the extended profiling support mechanisms used by profilers. +config RUST + bool "Rust support" + depends on HAVE_RUST + depends on RUST_IS_AVAILABLE + depends on !MODVERSIONS + depends on !GCC_PLUGINS + depends on !RANDSTRUCT + depends on !DEBUG_INFO_BTF + select CONSTRUCTORS + help + Enables Rust support in the kernel. + + This allows other Rust-related options, like drivers written in Rust, + to be selected. + + It is also required to be able to load external kernel modules + written in Rust. + + See Documentation/rust/ for more information. + + If unsure, say N. + +config RUSTC_VERSION_TEXT + string + depends on RUST + default $(shell,command -v $(RUSTC) >/dev/null 2>&1 && $(RUSTC) --version || echo n) + +config BINDGEN_VERSION_TEXT + string + depends on RUST + default $(shell,command -v $(BINDGEN) >/dev/null 2>&1 && $(BINDGEN) --version || echo n) + # # Place an empty function call at each tracepoint site. Can be # dynamically changed for a probe function. diff --git a/kernel/configs/rust.config b/kernel/configs/rust.config new file mode 100644 index 000000000000..38a7c5362c9c --- /dev/null +++ b/kernel/configs/rust.config @@ -0,0 +1 @@ +CONFIG_RUST=y diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index d3e5f36bb01e..e62271da937f 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2710,6 +2710,40 @@ config HYPERV_TESTING endmenu # "Kernel Testing and Coverage" +menu "Rust hacking" + +config RUST_DEBUG_ASSERTIONS + bool "Debug assertions" + depends on RUST + help + Enables rustc's `-Cdebug-assertions` codegen option. + + This flag lets you turn `cfg(debug_assertions)` conditional + compilation on or off. This can be used to enable extra debugging + code in development but not in production. For example, it controls + the behavior of the standard library's `debug_assert!` macro. + + Note that this will apply to all Rust code, including `core`. + + If unsure, say N. + +config RUST_OVERFLOW_CHECKS + bool "Overflow checks" + default y + depends on RUST + help + Enables rustc's `-Coverflow-checks` codegen option. + + This flag allows you to control the behavior of runtime integer + overflow. When overflow-checks are enabled, a Rust panic will occur + on overflow. + + Note that this will apply to all Rust code, including `core`. + + If unsure, say Y. + +endmenu # "Rust" + source "Documentation/Kconfig" endmenu # Kernel hacking diff --git a/rust/.gitignore b/rust/.gitignore new file mode 100644 index 000000000000..9bd1af8e05a1 --- /dev/null +++ b/rust/.gitignore @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0 + +target.json +bindings_generated.rs +bindings_helpers_generated.rs +exports_*_generated.h +doc/ +test/ diff --git a/rust/Makefile b/rust/Makefile new file mode 100644 index 000000000000..7700d3853404 --- /dev/null +++ b/rust/Makefile @@ -0,0 +1,381 @@ +# SPDX-License-Identifier: GPL-2.0 + +always-$(CONFIG_RUST) += target.json +no-clean-files += target.json + +obj-$(CONFIG_RUST) += core.o compiler_builtins.o +always-$(CONFIG_RUST) += exports_core_generated.h + +# Missing prototypes are expected in the helpers since these are exported +# for Rust only, thus there is no header nor prototypes. +obj-$(CONFIG_RUST) += helpers.o +CFLAGS_REMOVE_helpers.o = -Wmissing-prototypes -Wmissing-declarations + +always-$(CONFIG_RUST) += libmacros.so +no-clean-files += libmacros.so + +always-$(CONFIG_RUST) += bindings/bindings_generated.rs bindings/bindings_helpers_generated.rs +obj-$(CONFIG_RUST) += alloc.o bindings.o kernel.o +always-$(CONFIG_RUST) += exports_alloc_generated.h exports_bindings_generated.h \ + exports_kernel_generated.h + +obj-$(CONFIG_RUST) += exports.o + +# Avoids running `$(RUSTC)` for the sysroot when it may not be available. +ifdef CONFIG_RUST + +# `$(rust_flags)` is passed in case the user added `--sysroot`. +rustc_sysroot := $(shell $(RUSTC) $(rust_flags) --print sysroot) +rustc_host_target := $(shell $(RUSTC) --version --verbose | grep -F 'host: ' | cut -d' ' -f2) +RUST_LIB_SRC ?= $(rustc_sysroot)/lib/rustlib/src/rust/library + +ifeq ($(quiet),silent_) +cargo_quiet=-q +rust_test_quiet=-q +rustdoc_test_quiet=--test-args -q +else ifeq ($(quiet),quiet_) +rust_test_quiet=-q +rustdoc_test_quiet=--test-args -q +else +cargo_quiet=--verbose +endif + +core-cfgs = \ + --cfg no_fp_fmt_parse + +alloc-cfgs = \ + --cfg no_fmt \ + --cfg no_global_oom_handling \ + --cfg no_macros \ + --cfg no_rc \ + --cfg no_str \ + --cfg no_string \ + --cfg no_sync \ + --cfg no_thin + +quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $< + cmd_rustdoc = \ + OBJTREE=$(abspath $(objtree)) \ + $(RUSTDOC) $(if $(rustdoc_host),$(rust_common_flags),$(rust_flags)) \ + $(rustc_target_flags) -L$(objtree)/$(obj) \ + --output $(objtree)/$(obj)/doc \ + --crate-name $(subst rustdoc-,,$@) \ + @$(objtree)/include/generated/rustc_cfg $< + +# The `html_logo_url` and `html_favicon_url` forms of the `doc` attribute +# can be used to specify a custom logo. However: +# - The given value is used as-is, thus it cannot be relative or a local file +# (unlike the non-custom case) since the generated docs have subfolders. +# - It requires adding it to every crate. +# - It requires changing `core` which comes from the sysroot. +# +# Using `-Zcrate-attr` would solve the last two points, but not the first. +# The https://github.com/rust-lang/rfcs/pull/3226 RFC suggests two new +# command-like flags to solve the issue. Meanwhile, we use the non-custom case +# and then retouch the generated files. +rustdoc: rustdoc-core rustdoc-macros rustdoc-compiler_builtins \ + rustdoc-alloc rustdoc-kernel + $(Q)cp $(srctree)/Documentation/images/logo.svg $(objtree)/$(obj)/doc + $(Q)cp $(srctree)/Documentation/images/COPYING-logo $(objtree)/$(obj)/doc + $(Q)find $(objtree)/$(obj)/doc -name '*.html' -type f -print0 | xargs -0 sed -Ei \ + -e 's:rust-logo\.svg:logo.svg:g' \ + -e 's:rust-logo\.png:logo.svg:g' \ + -e 's:favicon\.svg:logo.svg:g' \ + -e 's:::g' + $(Q)echo '.logo-container > img { object-fit: contain; }' \ + >> $(objtree)/$(obj)/doc/rustdoc.css + +rustdoc-macros: private rustdoc_host = yes +rustdoc-macros: private rustc_target_flags = --crate-type proc-macro \ + --extern proc_macro +rustdoc-macros: $(src)/macros/lib.rs FORCE + $(call if_changed,rustdoc) + +rustdoc-core: private rustc_target_flags = $(core-cfgs) +rustdoc-core: $(RUST_LIB_SRC)/core/src/lib.rs FORCE + $(call if_changed,rustdoc) + +rustdoc-compiler_builtins: $(src)/compiler_builtins.rs rustdoc-core FORCE + $(call if_changed,rustdoc) + +# We need to allow `rustdoc::broken_intra_doc_links` because some +# `no_global_oom_handling` functions refer to non-`no_global_oom_handling` +# functions. Ideally `rustdoc` would have a way to distinguish broken links +# due to things that are "configured out" vs. entirely non-existing ones. +rustdoc-alloc: private rustc_target_flags = $(alloc-cfgs) \ + -Arustdoc::broken_intra_doc_links +rustdoc-alloc: $(src)/alloc/lib.rs rustdoc-core rustdoc-compiler_builtins FORCE + $(call if_changed,rustdoc) + +rustdoc-kernel: private rustc_target_flags = --extern alloc \ + --extern macros=$(objtree)/$(obj)/libmacros.so \ + --extern bindings +rustdoc-kernel: $(src)/kernel/lib.rs rustdoc-core rustdoc-macros \ + rustdoc-compiler_builtins rustdoc-alloc $(obj)/libmacros.so \ + $(obj)/bindings.o FORCE + $(call if_changed,rustdoc) + +quiet_cmd_rustc_test_library = RUSTC TL $< + cmd_rustc_test_library = \ + OBJTREE=$(abspath $(objtree)) \ + $(RUSTC) $(rust_common_flags) \ + @$(objtree)/include/generated/rustc_cfg $(rustc_target_flags) \ + --crate-type $(if $(rustc_test_library_proc),proc-macro,rlib) \ + --out-dir $(objtree)/$(obj)/test --cfg testlib \ + --sysroot $(objtree)/$(obj)/test/sysroot \ + -L$(objtree)/$(obj)/test \ + --crate-name $(subst rusttest-,,$(subst rusttestlib-,,$@)) $< + +rusttestlib-macros: private rustc_target_flags = --extern proc_macro +rusttestlib-macros: private rustc_test_library_proc = yes +rusttestlib-macros: $(src)/macros/lib.rs rusttest-prepare FORCE + $(call if_changed,rustc_test_library) + +rusttestlib-bindings: $(src)/bindings/lib.rs rusttest-prepare FORCE + $(call if_changed,rustc_test_library) + +quiet_cmd_rustdoc_test = RUSTDOC T $< + cmd_rustdoc_test = \ + OBJTREE=$(abspath $(objtree)) \ + $(RUSTDOC) --test $(rust_common_flags) \ + @$(objtree)/include/generated/rustc_cfg \ + $(rustc_target_flags) $(rustdoc_test_target_flags) \ + --sysroot $(objtree)/$(obj)/test/sysroot $(rustdoc_test_quiet) \ + -L$(objtree)/$(obj)/test --output $(objtree)/$(obj)/doc \ + --crate-name $(subst rusttest-,,$@) $< + +# We cannot use `-Zpanic-abort-tests` because some tests are dynamic, +# so for the moment we skip `-Cpanic=abort`. +quiet_cmd_rustc_test = RUSTC T $< + cmd_rustc_test = \ + OBJTREE=$(abspath $(objtree)) \ + $(RUSTC) --test $(rust_common_flags) \ + @$(objtree)/include/generated/rustc_cfg \ + $(rustc_target_flags) --out-dir $(objtree)/$(obj)/test \ + --sysroot $(objtree)/$(obj)/test/sysroot \ + -L$(objtree)/$(obj)/test \ + --crate-name $(subst rusttest-,,$@) $<; \ + $(objtree)/$(obj)/test/$(subst rusttest-,,$@) $(rust_test_quiet) \ + $(rustc_test_run_flags) + +rusttest: rusttest-macros rusttest-kernel + +# This prepares a custom sysroot with our custom `alloc` instead of +# the standard one. +# +# This requires several hacks: +# - Unlike `core` and `alloc`, `std` depends on more than a dozen crates, +# including third-party crates that need to be downloaded, plus custom +# `build.rs` steps. Thus hardcoding things here is not maintainable. +# - `cargo` knows how to build the standard library, but it is an unstable +# feature so far (`-Zbuild-std`). +# - `cargo` only considers the use case of building the standard library +# to use it in a given package. Thus we need to create a dummy package +# and pick the generated libraries from there. +# - Since we only keep a subset of upstream `alloc` in-tree, we need +# to recreate it on the fly by putting our sources on top. +# - The usual ways of modifying the dependency graph in `cargo` do not seem +# to apply for the `-Zbuild-std` steps, thus we have to mislead it +# by modifying the sources in the sysroot. +# - To avoid messing with the user's Rust installation, we create a clone +# of the sysroot. However, `cargo` ignores `RUSTFLAGS` in the `-Zbuild-std` +# steps, thus we use a wrapper binary passed via `RUSTC` to pass the flag. +# +# In the future, we hope to avoid the whole ordeal by either: +# - Making the `test` crate not depend on `std` (either improving upstream +# or having our own custom crate). +# - Making the tests run in kernel space (requires the previous point). +# - Making `std` and friends be more like a "normal" crate, so that +# `-Zbuild-std` and related hacks are not needed. +quiet_cmd_rustsysroot = RUSTSYSROOT + cmd_rustsysroot = \ + rm -rf $(objtree)/$(obj)/test; \ + mkdir -p $(objtree)/$(obj)/test; \ + cp -a $(rustc_sysroot) $(objtree)/$(obj)/test/sysroot; \ + cp -r $(srctree)/$(src)/alloc/* \ + $(objtree)/$(obj)/test/sysroot/lib/rustlib/src/rust/library/alloc/src; \ + echo '\#!/bin/sh' > $(objtree)/$(obj)/test/rustc_sysroot; \ + echo "$(RUSTC) --sysroot=$(abspath $(objtree)/$(obj)/test/sysroot) \"\$$@\"" \ + >> $(objtree)/$(obj)/test/rustc_sysroot; \ + chmod u+x $(objtree)/$(obj)/test/rustc_sysroot; \ + $(CARGO) -q new $(objtree)/$(obj)/test/dummy; \ + RUSTC=$(objtree)/$(obj)/test/rustc_sysroot $(CARGO) $(cargo_quiet) \ + test -Zbuild-std --target $(rustc_host_target) \ + --manifest-path $(objtree)/$(obj)/test/dummy/Cargo.toml; \ + rm $(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib/*; \ + cp $(objtree)/$(obj)/test/dummy/target/$(rustc_host_target)/debug/deps/* \ + $(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib + +rusttest-prepare: FORCE + $(call if_changed,rustsysroot) + +rusttest-macros: private rustc_target_flags = --extern proc_macro +rusttest-macros: private rustdoc_test_target_flags = --crate-type proc-macro +rusttest-macros: $(src)/macros/lib.rs rusttest-prepare FORCE + $(call if_changed,rustc_test) + $(call if_changed,rustdoc_test) + +rusttest-kernel: private rustc_target_flags = --extern alloc \ + --extern macros --extern bindings +rusttest-kernel: $(src)/kernel/lib.rs rusttest-prepare \ + rusttestlib-macros rusttestlib-bindings FORCE + $(call if_changed,rustc_test) + $(call if_changed,rustc_test_library) + +filechk_rust_target = $(objtree)/scripts/generate_rust_target < $< + +$(obj)/target.json: $(objtree)/include/config/auto.conf FORCE + $(call filechk,rust_target) + +ifdef CONFIG_CC_IS_CLANG +bindgen_c_flags = $(c_flags) +else +# bindgen relies on libclang to parse C. Ideally, bindgen would support a GCC +# plugin backend and/or the Clang driver would be perfectly compatible with GCC. +# +# For the moment, here we are tweaking the flags on the fly. This is a hack, +# and some kernel configurations may not work (e.g. `GCC_PLUGIN_RANDSTRUCT` +# if we end up using one of those structs). +bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \ + -mskip-rax-setup -mgeneral-regs-only -msign-return-address=% \ + -mindirect-branch=thunk-extern -mindirect-branch-register \ + -mfunction-return=thunk-extern -mrecord-mcount -mabi=lp64 \ + -mindirect-branch-cs-prefix -mstack-protector-guard% -mtraceback=no \ + -mno-pointers-to-nested-functions -mno-string \ + -mno-strict-align -mstrict-align \ + -fconserve-stack -falign-jumps=% -falign-loops=% \ + -femit-struct-debug-baseonly -fno-ipa-cp-clone -fno-ipa-sra \ + -fno-partial-inlining -fplugin-arg-arm_ssp_per_task_plugin-% \ + -fno-reorder-blocks -fno-allow-store-data-races -fasan-shadow-offset=% \ + -fzero-call-used-regs=% -fno-stack-clash-protection \ + -fno-inline-functions-called-once \ + --param=% --param asan-% + +# Derived from `scripts/Makefile.clang`. +BINDGEN_TARGET_x86 := x86_64-linux-gnu +BINDGEN_TARGET := $(BINDGEN_TARGET_$(SRCARCH)) + +# All warnings are inhibited since GCC builds are very experimental, +# many GCC warnings are not supported by Clang, they may only appear in +# some configurations, with new GCC versions, etc. +bindgen_extra_c_flags = -w --target=$(BINDGEN_TARGET) + +bindgen_c_flags = $(filter-out $(bindgen_skip_c_flags), $(c_flags)) \ + $(bindgen_extra_c_flags) +endif + +ifdef CONFIG_LTO +bindgen_c_flags_lto = $(filter-out $(CC_FLAGS_LTO), $(bindgen_c_flags)) +else +bindgen_c_flags_lto = $(bindgen_c_flags) +endif + +bindgen_c_flags_final = $(bindgen_c_flags_lto) -D__BINDGEN__ + +quiet_cmd_bindgen = BINDGEN $@ + cmd_bindgen = \ + $(BINDGEN) $< $(bindgen_target_flags) \ + --use-core --with-derive-default --ctypes-prefix core::ffi --no-layout-tests \ + --no-debug '.*' \ + --size_t-is-usize -o $@ -- $(bindgen_c_flags_final) -DMODULE \ + $(bindgen_target_cflags) $(bindgen_target_extra) + +$(obj)/bindings/bindings_generated.rs: private bindgen_target_flags = \ + $(shell grep -v '^\#\|^$$' $(srctree)/$(src)/bindgen_parameters) +$(obj)/bindings/bindings_generated.rs: $(src)/bindings/bindings_helper.h \ + $(src)/bindgen_parameters FORCE + $(call if_changed_dep,bindgen) + +# See `CFLAGS_REMOVE_helpers.o` above. In addition, Clang on C does not warn +# with `-Wmissing-declarations` (unlike GCC), so it is not strictly needed here +# given it is `libclang`; but for consistency, future Clang changes and/or +# a potential future GCC backend for `bindgen`, we disable it too. +$(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_flags = \ + --blacklist-type '.*' --whitelist-var '' \ + --whitelist-function 'rust_helper_.*' +$(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_cflags = \ + -I$(objtree)/$(obj) -Wno-missing-prototypes -Wno-missing-declarations +$(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_extra = ; \ + sed -Ei 's/pub fn rust_helper_([a-zA-Z0-9_]*)/#[link_name="rust_helper_\1"]\n pub fn \1/g' $@ +$(obj)/bindings/bindings_helpers_generated.rs: $(src)/helpers.c FORCE + $(call if_changed_dep,bindgen) + +quiet_cmd_exports = EXPORTS $@ + cmd_exports = \ + $(NM) -p --defined-only $< \ + | grep -E ' (T|R|D) ' | cut -d ' ' -f 3 \ + | xargs -Isymbol \ + echo 'EXPORT_SYMBOL_RUST_GPL(symbol);' > $@ + +$(obj)/exports_core_generated.h: $(obj)/core.o FORCE + $(call if_changed,exports) + +$(obj)/exports_alloc_generated.h: $(obj)/alloc.o FORCE + $(call if_changed,exports) + +$(obj)/exports_bindings_generated.h: $(obj)/bindings.o FORCE + $(call if_changed,exports) + +$(obj)/exports_kernel_generated.h: $(obj)/kernel.o FORCE + $(call if_changed,exports) + +quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@ + cmd_rustc_procmacro = \ + $(RUSTC_OR_CLIPPY) $(rust_common_flags) \ + --emit=dep-info,link --extern proc_macro \ + --crate-type proc-macro --out-dir $(objtree)/$(obj) \ + --crate-name $(patsubst lib%.so,%,$(notdir $@)) $<; \ + mv $(objtree)/$(obj)/$(patsubst lib%.so,%,$(notdir $@)).d $(depfile); \ + sed -i '/^\#/d' $(depfile) + +# Procedural macros can only be used with the `rustc` that compiled it. +# Therefore, to get `libmacros.so` automatically recompiled when the compiler +# version changes, we add `core.o` as a dependency (even if it is not needed). +$(obj)/libmacros.so: $(src)/macros/lib.rs $(obj)/core.o FORCE + $(call if_changed_dep,rustc_procmacro) + +quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L $@ + cmd_rustc_library = \ + OBJTREE=$(abspath $(objtree)) \ + $(if $(skip_clippy),$(RUSTC),$(RUSTC_OR_CLIPPY)) \ + $(filter-out $(skip_flags),$(rust_flags) $(rustc_target_flags)) \ + --emit=dep-info,obj,metadata --crate-type rlib \ + --out-dir $(objtree)/$(obj) -L$(objtree)/$(obj) \ + --crate-name $(patsubst %.o,%,$(notdir $@)) $<; \ + mv $(objtree)/$(obj)/$(patsubst %.o,%,$(notdir $@)).d $(depfile); \ + sed -i '/^\#/d' $(depfile) \ + $(if $(rustc_objcopy),;$(OBJCOPY) $(rustc_objcopy) $@) + +rust-analyzer: + $(Q)$(srctree)/scripts/generate_rust_analyzer.py $(srctree) $(objtree) \ + $(RUST_LIB_SRC) > $(objtree)/rust-project.json + +$(obj)/core.o: private skip_clippy = 1 +$(obj)/core.o: private skip_flags = -Dunreachable_pub +$(obj)/core.o: private rustc_target_flags = $(core-cfgs) +$(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs $(obj)/target.json FORCE + $(call if_changed_dep,rustc_library) + +$(obj)/compiler_builtins.o: private rustc_objcopy = -w -W '__*' +$(obj)/compiler_builtins.o: $(src)/compiler_builtins.rs $(obj)/core.o FORCE + $(call if_changed_dep,rustc_library) + +$(obj)/alloc.o: private skip_clippy = 1 +$(obj)/alloc.o: private skip_flags = -Dunreachable_pub +$(obj)/alloc.o: private rustc_target_flags = $(alloc-cfgs) +$(obj)/alloc.o: $(src)/alloc/lib.rs $(obj)/compiler_builtins.o FORCE + $(call if_changed_dep,rustc_library) + +$(obj)/bindings.o: $(src)/bindings/lib.rs \ + $(obj)/compiler_builtins.o \ + $(obj)/bindings/bindings_generated.rs \ + $(obj)/bindings/bindings_helpers_generated.rs FORCE + $(call if_changed_dep,rustc_library) + +$(obj)/kernel.o: private rustc_target_flags = --extern alloc \ + --extern macros --extern bindings +$(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/alloc.o \ + $(obj)/libmacros.so $(obj)/bindings.o FORCE + $(call if_changed_dep,rustc_library) + +endif # CONFIG_RUST diff --git a/rust/bindgen_parameters b/rust/bindgen_parameters new file mode 100644 index 000000000000..be4963bf7203 --- /dev/null +++ b/rust/bindgen_parameters @@ -0,0 +1,21 @@ +# SPDX-License-Identifier: GPL-2.0 + +--opaque-type xregs_state +--opaque-type desc_struct +--opaque-type arch_lbr_state +--opaque-type local_apic + +# Packed type cannot transitively contain a `#[repr(align)]` type. +--opaque-type x86_msi_data +--opaque-type x86_msi_addr_lo + +# `try` is a reserved keyword since Rust 2018; solved in `bindgen` v0.59.2, +# commit 2aed6b021680 ("context: Escape the try keyword properly"). +--opaque-type kunit_try_catch + +# If SMP is disabled, `arch_spinlock_t` is defined as a ZST which triggers a Rust +# warning. We don't need to peek into it anyway. +--opaque-type spinlock + +# `seccomp`'s comment gets understood as a doctest +--no-doc-comments diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include index a0ccceb22cf8..274125307ebd 100644 --- a/scripts/Kconfig.include +++ b/scripts/Kconfig.include @@ -36,12 +36,12 @@ ld-option = $(success,$(LD) -v $(1)) as-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) -c -x assembler -o /dev/null -) # check if $(CC) and $(LD) exist -$(error-if,$(failure,command -v $(CC)),compiler '$(CC)' not found) +$(error-if,$(failure,command -v $(CC)),C compiler '$(CC)' not found) $(error-if,$(failure,command -v $(LD)),linker '$(LD)' not found) -# Get the compiler name, version, and error out if it is not supported. +# Get the C compiler name, version, and error out if it is not supported. cc-info := $(shell,$(srctree)/scripts/cc-version.sh $(CC)) -$(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this compiler is not supported.) +$(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this C compiler is not supported.) cc-name := $(shell,set -- $(cc-info) && echo $1) cc-version := $(shell,set -- $(cc-info) && echo $2) diff --git a/scripts/Makefile b/scripts/Makefile index f084f08ed176..1575af84d557 100644 --- a/scripts/Makefile +++ b/scripts/Makefile @@ -10,6 +10,9 @@ hostprogs-always-$(CONFIG_BUILDTIME_TABLE_SORT) += sorttable hostprogs-always-$(CONFIG_ASN1) += asn1_compiler hostprogs-always-$(CONFIG_MODULE_SIG_FORMAT) += sign-file hostprogs-always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE) += insert-sys-cert +hostprogs-always-$(CONFIG_RUST) += generate_rust_target + +generate_rust_target-rust := y HOSTCFLAGS_sorttable.o = -I$(srctree)/tools/include HOSTLDLIBS_sorttable = -lpthread diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 784f46d41959..27be77c0d6d8 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -26,6 +26,7 @@ EXTRA_CPPFLAGS := EXTRA_LDFLAGS := asflags-y := ccflags-y := +rustflags-y := cppflags-y := ldflags-y := @@ -271,6 +272,65 @@ quiet_cmd_cc_lst_c = MKLST $@ $(obj)/%.lst: $(src)/%.c FORCE $(call if_changed_dep,cc_lst_c) +# Compile Rust sources (.rs) +# --------------------------------------------------------------------------- + +rust_allowed_features := core_ffi_c + +rust_common_cmd = \ + RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \ + -Zallow-features=$(rust_allowed_features) \ + -Zcrate-attr=no_std \ + -Zcrate-attr='feature($(rust_allowed_features))' \ + --extern alloc --extern kernel \ + --crate-type rlib --out-dir $(obj) -L $(objtree)/rust/ \ + --crate-name $(basename $(notdir $@)) + +rust_handle_depfile = \ + mv $(obj)/$(basename $(notdir $@)).d $(depfile); \ + sed -i '/^\#/d' $(depfile) + +# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit +# will be used. We explicitly request `-Ccodegen-units=1` in any case, and +# the compiler shows a warning if it is not 1. However, if we ever stop +# requesting it explicitly and we start using some other `--emit` that does not +# imply it (and for which codegen is performed), then we would be out of sync, +# i.e. the outputs we would get for the different single targets (e.g. `.ll`) +# would not match each other. + +quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ + cmd_rustc_o_rs = \ + $(rust_common_cmd) --emit=dep-info,obj $<; \ + $(rust_handle_depfile) + +$(obj)/%.o: $(src)/%.rs FORCE + $(call if_changed_dep,rustc_o_rs) + +quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ + cmd_rustc_rsi_rs = \ + $(rust_common_cmd) --emit=dep-info -Zunpretty=expanded $< >$@; \ + command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@; \ + $(rust_handle_depfile) + +$(obj)/%.rsi: $(src)/%.rs FORCE + $(call if_changed_dep,rustc_rsi_rs) + +quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ + cmd_rustc_s_rs = \ + $(rust_common_cmd) --emit=dep-info,asm $<; \ + $(rust_handle_depfile) + +$(obj)/%.s: $(src)/%.rs FORCE + $(call if_changed_dep,rustc_s_rs) + +quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ + cmd_rustc_ll_rs = \ + $(rust_common_cmd) --emit=dep-info,llvm-ir $<; \ + $(rust_handle_depfile) + +$(obj)/%.ll: $(src)/%.rs FORCE + $(call if_changed_dep,rustc_ll_rs) + # Compile assembler sources (.S) # --------------------------------------------------------------------------- diff --git a/scripts/Makefile.debug b/scripts/Makefile.debug index 8cf1cb22dd93..332c486f705f 100644 --- a/scripts/Makefile.debug +++ b/scripts/Makefile.debug @@ -1,4 +1,6 @@ DEBUG_CFLAGS := +DEBUG_RUSTFLAGS := + debug-flags-y := -g ifdef CONFIG_DEBUG_INFO_SPLIT @@ -17,9 +19,12 @@ KBUILD_AFLAGS += $(debug-flags-y) ifdef CONFIG_DEBUG_INFO_REDUCED DEBUG_CFLAGS += -fno-var-tracking +DEBUG_RUSTFLAGS += -Cdebuginfo=1 ifdef CONFIG_CC_IS_GCC DEBUG_CFLAGS += -femit-struct-debug-baseonly endif +else +DEBUG_RUSTFLAGS += -Cdebuginfo=2 endif ifdef CONFIG_DEBUG_INFO_COMPRESSED @@ -30,3 +35,6 @@ endif KBUILD_CFLAGS += $(DEBUG_CFLAGS) export DEBUG_CFLAGS + +KBUILD_RUSTFLAGS += $(DEBUG_RUSTFLAGS) +export DEBUG_RUSTFLAGS diff --git a/scripts/Makefile.host b/scripts/Makefile.host index 278b4d6ac945..da133780b751 100644 --- a/scripts/Makefile.host +++ b/scripts/Makefile.host @@ -22,6 +22,8 @@ $(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE # to preprocess a data file. # # Both C and C++ are supported, but preferred language is C for such utilities. +# Rust is also supported, but it may only be used in scenarios where a Rust +# toolchain is required to be available (e.g. when `CONFIG_RUST` is enabled). # # Sample syntax (see Documentation/kbuild/makefiles.rst for reference) # hostprogs := bin2hex @@ -37,15 +39,20 @@ $(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE # qconf-objs := menu.o # Will compile qconf as a C++ program, and menu as a C program. # They are linked as C++ code to the executable qconf +# +# hostprogs := target +# target-rust := y +# Will compile `target` as a Rust program, using `target.rs` as the crate root. +# The crate may consist of several source files. # C code # Executables compiled from a single .c file host-csingle := $(foreach m,$(hostprogs), \ - $(if $($(m)-objs)$($(m)-cxxobjs),,$(m))) + $(if $($(m)-objs)$($(m)-cxxobjs)$($(m)-rust),,$(m))) # C executables linked based on several .o files host-cmulti := $(foreach m,$(hostprogs),\ - $(if $($(m)-cxxobjs),,$(if $($(m)-objs),$(m)))) + $(if $($(m)-cxxobjs)$($(m)-rust),,$(if $($(m)-objs),$(m)))) # Object (.o) files compiled from .c files host-cobjs := $(sort $(foreach m,$(hostprogs),$($(m)-objs))) @@ -58,11 +65,17 @@ host-cxxmulti := $(foreach m,$(hostprogs),$(if $($(m)-cxxobjs),$(m))) # C++ Object (.o) files compiled from .cc files host-cxxobjs := $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs))) +# Rust code +# Executables compiled from a single Rust crate (which may consist of +# one or more .rs files) +host-rust := $(foreach m,$(hostprogs),$(if $($(m)-rust),$(m))) + host-csingle := $(addprefix $(obj)/,$(host-csingle)) host-cmulti := $(addprefix $(obj)/,$(host-cmulti)) host-cobjs := $(addprefix $(obj)/,$(host-cobjs)) host-cxxmulti := $(addprefix $(obj)/,$(host-cxxmulti)) host-cxxobjs := $(addprefix $(obj)/,$(host-cxxobjs)) +host-rust := $(addprefix $(obj)/,$(host-rust)) ##### # Handle options to gcc. Support building with separate output directory @@ -71,6 +84,8 @@ _hostc_flags = $(KBUILD_HOSTCFLAGS) $(HOST_EXTRACFLAGS) \ $(HOSTCFLAGS_$(target-stem).o) _hostcxx_flags = $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \ $(HOSTCXXFLAGS_$(target-stem).o) +_hostrust_flags = $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \ + $(HOSTRUSTFLAGS_$(target-stem)) # $(objtree)/$(obj) for including generated headers from checkin source files ifeq ($(KBUILD_EXTMOD),) @@ -82,6 +97,7 @@ endif hostc_flags = -Wp,-MMD,$(depfile) $(_hostc_flags) hostcxx_flags = -Wp,-MMD,$(depfile) $(_hostcxx_flags) +hostrust_flags = $(_hostrust_flags) ##### # Compile programs on the host @@ -128,5 +144,17 @@ quiet_cmd_host-cxxobjs = HOSTCXX $@ $(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE $(call if_changed_dep,host-cxxobjs) +# Create executable from a single Rust crate (which may consist of +# one or more `.rs` files) +# host-rust -> Executable +quiet_cmd_host-rust = HOSTRUSTC $@ + cmd_host-rust = \ + $(HOSTRUSTC) $(hostrust_flags) --emit=dep-info,link \ + --out-dir=$(obj)/ $<; \ + mv $(obj)/$(target-stem).d $(depfile); \ + sed -i '/^\#/d' $(depfile) +$(host-rust): $(obj)/%: $(src)/%.rs FORCE + $(call if_changed_dep,host-rust) + targets += $(host-csingle) $(host-cmulti) $(host-cobjs) \ - $(host-cxxmulti) $(host-cxxobjs) + $(host-cxxmulti) $(host-cxxobjs) $(host-rust) diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 3fb6a99e78c4..c88b98b5dc44 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -8,6 +8,7 @@ ldflags-y += $(EXTRA_LDFLAGS) # flags that take effect in current and sub directories KBUILD_AFLAGS += $(subdir-asflags-y) KBUILD_CFLAGS += $(subdir-ccflags-y) +KBUILD_RUSTFLAGS += $(subdir-rustflags-y) # Figure out what we need to build from the various variables # =========================================================================== @@ -128,6 +129,10 @@ _c_flags = $(filter-out $(CFLAGS_REMOVE_$(target-stem).o), \ $(filter-out $(ccflags-remove-y), \ $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(ccflags-y)) \ $(CFLAGS_$(target-stem).o)) +_rust_flags = $(filter-out $(RUSTFLAGS_REMOVE_$(target-stem).o), \ + $(filter-out $(rustflags-remove-y), \ + $(KBUILD_RUSTFLAGS) $(rustflags-y)) \ + $(RUSTFLAGS_$(target-stem).o)) _a_flags = $(filter-out $(AFLAGS_REMOVE_$(target-stem).o), \ $(filter-out $(asflags-remove-y), \ $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(asflags-y)) \ @@ -202,6 +207,11 @@ modkern_cflags = \ $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \ $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL) $(modfile_flags)) +modkern_rustflags = \ + $(if $(part-of-module), \ + $(KBUILD_RUSTFLAGS_MODULE) $(RUSTFLAGS_MODULE), \ + $(KBUILD_RUSTFLAGS_KERNEL) $(RUSTFLAGS_KERNEL)) + modkern_aflags = $(if $(part-of-module), \ $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE), \ $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)) @@ -211,6 +221,8 @@ c_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \ $(_c_flags) $(modkern_cflags) \ $(basename_flags) $(modname_flags) +rust_flags = $(_rust_flags) $(modkern_rustflags) @$(objtree)/include/generated/rustc_cfg + a_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \ $(_a_flags) $(modkern_aflags) diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal index 35100e981f4a..9a1fa6aa30fe 100644 --- a/scripts/Makefile.modfinal +++ b/scripts/Makefile.modfinal @@ -39,11 +39,13 @@ quiet_cmd_ld_ko_o = LD [M] $@ quiet_cmd_btf_ko = BTF [M] $@ cmd_btf_ko = \ - if [ -f vmlinux ]; then \ + if [ ! -f vmlinux ]; then \ + printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \ + elif [ -n "$(CONFIG_RUST)" ] && $(srctree)/scripts/is_rust_module.sh $@; then \ + printf "Skipping BTF generation for %s because it's a Rust module\n" $@ 1>&2; \ + else \ LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) --btf_base vmlinux $@; \ $(RESOLVE_BTFIDS) -b vmlinux $@; \ - else \ - printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \ fi; # Same as newer-prereqs, but allows to exclude specified extra dependencies diff --git a/scripts/cc-version.sh b/scripts/cc-version.sh index f1952c522466..2401c86fcf53 100755 --- a/scripts/cc-version.sh +++ b/scripts/cc-version.sh @@ -1,13 +1,13 @@ #!/bin/sh # SPDX-License-Identifier: GPL-2.0 # -# Print the compiler name and its version in a 5 or 6-digit form. +# Print the C compiler name and its version in a 5 or 6-digit form. # Also, perform the minimum version check. set -e -# Print the compiler name and some version components. -get_compiler_info() +# Print the C compiler name and some version components. +get_c_compiler_info() { cat <<- EOF | "$@" -E -P -x c - 2>/dev/null #if defined(__clang__) @@ -32,7 +32,7 @@ get_canonical_version() # $@ instead of $1 because multiple words might be given, e.g. CC="ccache gcc". orig_args="$@" -set -- $(get_compiler_info "$@") +set -- $(get_c_compiler_info "$@") name=$1 @@ -52,7 +52,7 @@ ICC) min_version=$($min_tool_version icc) ;; *) - echo "$orig_args: unknown compiler" >&2 + echo "$orig_args: unknown C compiler" >&2 exit 1 ;; esac @@ -62,7 +62,7 @@ min_cversion=$(get_canonical_version $min_version) if [ "$cversion" -lt "$min_cversion" ]; then echo >&2 "***" - echo >&2 "*** Compiler is too old." + echo >&2 "*** C compiler is too old." echo >&2 "*** Your $name version: $version" echo >&2 "*** Minimum $name version: $min_version" echo >&2 "***" diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c index c4340c90e172..b7c9f1dd5e42 100644 --- a/scripts/kconfig/confdata.c +++ b/scripts/kconfig/confdata.c @@ -216,6 +216,13 @@ static const char *conf_get_autoheader_name(void) return name ? name : "include/generated/autoconf.h"; } +static const char *conf_get_rustccfg_name(void) +{ + char *name = getenv("KCONFIG_RUSTCCFG"); + + return name ? name : "include/generated/rustc_cfg"; +} + static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p) { char *p2; @@ -605,6 +612,9 @@ static const struct comment_style comment_style_c = { static void conf_write_heading(FILE *fp, const struct comment_style *cs) { + if (!cs) + return; + fprintf(fp, "%s\n", cs->prefix); fprintf(fp, "%s Automatically generated file; DO NOT EDIT.\n", @@ -745,6 +755,65 @@ static void print_symbol_for_c(FILE *fp, struct symbol *sym) free(escaped); } +static void print_symbol_for_rustccfg(FILE *fp, struct symbol *sym) +{ + const char *val; + const char *val_prefix = ""; + char *val_prefixed = NULL; + size_t val_prefixed_len; + char *escaped = NULL; + + if (sym->type == S_UNKNOWN) + return; + + val = sym_get_string_value(sym); + + switch (sym->type) { + case S_BOOLEAN: + case S_TRISTATE: + /* + * We do not care about disabled ones, i.e. no need for + * what otherwise are "comments" in other printers. + */ + if (*val == 'n') + return; + + /* + * To have similar functionality to the C macro `IS_ENABLED()` + * we provide an empty `--cfg CONFIG_X` here in both `y` + * and `m` cases. + * + * Then, the common `fprintf()` below will also give us + * a `--cfg CONFIG_X="y"` or `--cfg CONFIG_X="m"`, which can + * be used as the equivalent of `IS_BUILTIN()`/`IS_MODULE()`. + */ + fprintf(fp, "--cfg=%s%s\n", CONFIG_, sym->name); + break; + case S_HEX: + if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X')) + val_prefix = "0x"; + break; + default: + break; + } + + if (strlen(val_prefix) > 0) { + val_prefixed_len = strlen(val) + strlen(val_prefix) + 1; + val_prefixed = xmalloc(val_prefixed_len); + snprintf(val_prefixed, val_prefixed_len, "%s%s", val_prefix, val); + val = val_prefixed; + } + + /* All values get escaped: the `--cfg` option only takes strings */ + escaped = escape_string_value(val); + val = escaped; + + fprintf(fp, "--cfg=%s%s=%s\n", CONFIG_, sym->name, val); + + free(escaped); + free(val_prefixed); +} + /* * Write out a minimal config. * All values that has default values are skipped as this is redundant. @@ -1132,6 +1201,12 @@ int conf_write_autoconf(int overwrite) if (ret) return ret; + ret = __conf_write_autoconf(conf_get_rustccfg_name(), + print_symbol_for_rustccfg, + NULL); + if (ret) + return ret; + /* * Create include/config/auto.conf. This must be the last step because * Kbuild has a dependency on auto.conf and this marks the successful -- cgit v1.2.3 From 094981352ce27bc36018c009d07ddf974c9725f5 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Thu, 4 Aug 2022 12:16:44 +0200 Subject: x86: enable initial Rust support Note that only x86_64 is covered and not all features nor mitigations are handled, but it is enough as a starting point and showcases the basics needed to add Rust support for a new architecture. Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: David Gow Signed-off-by: David Gow Signed-off-by: Miguel Ojeda --- Documentation/rust/arch-support.rst | 1 + arch/x86/Kconfig | 1 + arch/x86/Makefile | 10 ++++++++++ scripts/generate_rust_target.rs | 15 +++++++++++++-- 4 files changed, 25 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/Documentation/rust/arch-support.rst b/Documentation/rust/arch-support.rst index 1152e0fbdad0..6982b63775da 100644 --- a/Documentation/rust/arch-support.rst +++ b/Documentation/rust/arch-support.rst @@ -15,4 +15,5 @@ support corresponds to ``S`` values in the ``MAINTAINERS`` file. ============ ================ ============================================== Architecture Level of support Constraints ============ ================ ============================================== +``x86`` Maintained ``x86_64`` only. ============ ================ ============================================== diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f9920f1341c8..3ca198742b10 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -257,6 +257,7 @@ config X86 select HAVE_STATIC_CALL_INLINE if HAVE_OBJTOOL select HAVE_PREEMPT_DYNAMIC_CALL select HAVE_RSEQ + select HAVE_RUST if X86_64 select HAVE_SYSCALL_TRACEPOINTS select HAVE_UACCESS_VALIDATION if HAVE_OBJTOOL select HAVE_UNSTABLE_SCHED_CLOCK diff --git a/arch/x86/Makefile b/arch/x86/Makefile index bafbd905e6e7..2d7e640674c6 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -68,6 +68,7 @@ export BITS # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383 # KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx +KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2 ifeq ($(CONFIG_X86_KERNEL_IBT),y) # @@ -155,8 +156,17 @@ else cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic KBUILD_CFLAGS += $(cflags-y) + rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8 + rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona + rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2 + rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom + rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic + KBUILD_RUSTFLAGS += $(rustflags-y) + KBUILD_CFLAGS += -mno-red-zone KBUILD_CFLAGS += -mcmodel=kernel + KBUILD_RUSTFLAGS += -Cno-redzone=y + KBUILD_RUSTFLAGS += -Ccode-model=kernel endif # diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs index 7256c9606cf0..3c6cbe2b278d 100644 --- a/scripts/generate_rust_target.rs +++ b/scripts/generate_rust_target.rs @@ -148,8 +148,19 @@ fn main() { let mut ts = TargetSpec::new(); // `llvm-target`s are taken from `scripts/Makefile.clang`. - if cfg.has("DUMMY_ARCH") { - ts.push("arch", "dummy_arch"); + if cfg.has("X86_64") { + ts.push("arch", "x86_64"); + ts.push( + "data-layout", + "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128", + ); + let mut features = "-3dnow,-3dnowa,-mmx,+soft-float".to_string(); + if cfg.has("RETPOLINE") { + features += ",+retpoline-external-thunk"; + } + ts.push("features", features); + ts.push("llvm-target", "x86_64-linux-gnu"); + ts.push("target-pointer-width", "64"); } else { panic!("Unsupported architecture"); } -- cgit v1.2.3 From f4bf1cd4ac9c8c4610b687e49a1ba691ab286235 Mon Sep 17 00:00:00 2001 From: Jonathan Corbet Date: Tue, 27 Sep 2022 10:05:57 -0600 Subject: docs: move asm-annotations.rst into core-api This one file should not really be in the top-level documentation directory. core-api/ may not be a perfect fit but seems to be best, so move it there. Adjust a couple of internal document references to make them location-independent, and point checkpatch.pl at the new location. Cc: Jiri Slaby Cc: Joe Perches Reviewed-by: David Vernet Acked-by: Jani Nikula Signed-off-by: Jonathan Corbet Acked-by: Randy Dunlap Link: https://lore.kernel.org/r/20220927160559.97154-6-corbet@lwn.net Signed-off-by: Jonathan Corbet --- Documentation/asm-annotations.rst | 221 ---------------------------- Documentation/core-api/asm-annotations.rst | 222 +++++++++++++++++++++++++++++ Documentation/core-api/index.rst | 1 + Documentation/index.rst | 8 -- scripts/checkpatch.pl | 2 +- 5 files changed, 224 insertions(+), 230 deletions(-) delete mode 100644 Documentation/asm-annotations.rst create mode 100644 Documentation/core-api/asm-annotations.rst (limited to 'scripts') diff --git a/Documentation/asm-annotations.rst b/Documentation/asm-annotations.rst deleted file mode 100644 index a64f2ca469d4..000000000000 --- a/Documentation/asm-annotations.rst +++ /dev/null @@ -1,221 +0,0 @@ -Assembler Annotations -===================== - -Copyright (c) 2017-2019 Jiri Slaby - -This document describes the new macros for annotation of data and code in -assembly. In particular, it contains information about ``SYM_FUNC_START``, -``SYM_FUNC_END``, ``SYM_CODE_START``, and similar. - -Rationale ---------- -Some code like entries, trampolines, or boot code needs to be written in -assembly. The same as in C, such code is grouped into functions and -accompanied with data. Standard assemblers do not force users into precisely -marking these pieces as code, data, or even specifying their length. -Nevertheless, assemblers provide developers with such annotations to aid -debuggers throughout assembly. On top of that, developers also want to mark -some functions as *global* in order to be visible outside of their translation -units. - -Over time, the Linux kernel has adopted macros from various projects (like -``binutils``) to facilitate such annotations. So for historic reasons, -developers have been using ``ENTRY``, ``END``, ``ENDPROC``, and other -annotations in assembly. Due to the lack of their documentation, the macros -are used in rather wrong contexts at some locations. Clearly, ``ENTRY`` was -intended to denote the beginning of global symbols (be it data or code). -``END`` used to mark the end of data or end of special functions with -*non-standard* calling convention. In contrast, ``ENDPROC`` should annotate -only ends of *standard* functions. - -When these macros are used correctly, they help assemblers generate a nice -object with both sizes and types set correctly. For example, the result of -``arch/x86/lib/putuser.S``:: - - Num: Value Size Type Bind Vis Ndx Name - 25: 0000000000000000 33 FUNC GLOBAL DEFAULT 1 __put_user_1 - 29: 0000000000000030 37 FUNC GLOBAL DEFAULT 1 __put_user_2 - 32: 0000000000000060 36 FUNC GLOBAL DEFAULT 1 __put_user_4 - 35: 0000000000000090 37 FUNC GLOBAL DEFAULT 1 __put_user_8 - -This is not only important for debugging purposes. When there are properly -annotated objects like this, tools can be run on them to generate more useful -information. In particular, on properly annotated objects, ``objtool`` can be -run to check and fix the object if needed. Currently, ``objtool`` can report -missing frame pointer setup/destruction in functions. It can also -automatically generate annotations for :doc:`ORC unwinder ` -for most code. Both of these are especially important to support reliable -stack traces which are in turn necessary for :doc:`Kernel live patching -`. - -Caveat and Discussion ---------------------- -As one might realize, there were only three macros previously. That is indeed -insufficient to cover all the combinations of cases: - -* standard/non-standard function -* code/data -* global/local symbol - -There was a discussion_ and instead of extending the current ``ENTRY/END*`` -macros, it was decided that brand new macros should be introduced instead:: - - So how about using macro names that actually show the purpose, instead - of importing all the crappy, historic, essentially randomly chosen - debug symbol macro names from the binutils and older kernels? - -.. _discussion: https://lore.kernel.org/r/20170217104757.28588-1-jslaby@suse.cz - -Macros Description ------------------- - -The new macros are prefixed with the ``SYM_`` prefix and can be divided into -three main groups: - -1. ``SYM_FUNC_*`` -- to annotate C-like functions. This means functions with - standard C calling conventions. For example, on x86, this means that the - stack contains a return address at the predefined place and a return from - the function can happen in a standard way. When frame pointers are enabled, - save/restore of frame pointer shall happen at the start/end of a function, - respectively, too. - - Checking tools like ``objtool`` should ensure such marked functions conform - to these rules. The tools can also easily annotate these functions with - debugging information (like *ORC data*) automatically. - -2. ``SYM_CODE_*`` -- special functions called with special stack. Be it - interrupt handlers with special stack content, trampolines, or startup - functions. - - Checking tools mostly ignore checking of these functions. But some debug - information still can be generated automatically. For correct debug data, - this code needs hints like ``UNWIND_HINT_REGS`` provided by developers. - -3. ``SYM_DATA*`` -- obviously data belonging to ``.data`` sections and not to - ``.text``. Data do not contain instructions, so they have to be treated - specially by the tools: they should not treat the bytes as instructions, - nor assign any debug information to them. - -Instruction Macros -~~~~~~~~~~~~~~~~~~ -This section covers ``SYM_FUNC_*`` and ``SYM_CODE_*`` enumerated above. - -``objtool`` requires that all code must be contained in an ELF symbol. Symbol -names that have a ``.L`` prefix do not emit symbol table entries. ``.L`` -prefixed symbols can be used within a code region, but should be avoided for -denoting a range of code via ``SYM_*_START/END`` annotations. - -* ``SYM_FUNC_START`` and ``SYM_FUNC_START_LOCAL`` are supposed to be **the - most frequent markings**. They are used for functions with standard calling - conventions -- global and local. Like in C, they both align the functions to - architecture specific ``__ALIGN`` bytes. There are also ``_NOALIGN`` variants - for special cases where developers do not want this implicit alignment. - - ``SYM_FUNC_START_WEAK`` and ``SYM_FUNC_START_WEAK_NOALIGN`` markings are - also offered as an assembler counterpart to the *weak* attribute known from - C. - - All of these **shall** be coupled with ``SYM_FUNC_END``. First, it marks - the sequence of instructions as a function and computes its size to the - generated object file. Second, it also eases checking and processing such - object files as the tools can trivially find exact function boundaries. - - So in most cases, developers should write something like in the following - example, having some asm instructions in between the macros, of course:: - - SYM_FUNC_START(memset) - ... asm insns ... - SYM_FUNC_END(memset) - - In fact, this kind of annotation corresponds to the now deprecated ``ENTRY`` - and ``ENDPROC`` macros. - -* ``SYM_FUNC_ALIAS``, ``SYM_FUNC_ALIAS_LOCAL``, and ``SYM_FUNC_ALIAS_WEAK`` can - be used to define multiple names for a function. The typical use is:: - - SYM_FUNC_START(__memset) - ... asm insns ... - SYN_FUNC_END(__memset) - SYM_FUNC_ALIAS(memset, __memset) - - In this example, one can call ``__memset`` or ``memset`` with the same - result, except the debug information for the instructions is generated to - the object file only once -- for the non-``ALIAS`` case. - -* ``SYM_CODE_START`` and ``SYM_CODE_START_LOCAL`` should be used only in - special cases -- if you know what you are doing. This is used exclusively - for interrupt handlers and similar where the calling convention is not the C - one. ``_NOALIGN`` variants exist too. The use is the same as for the ``FUNC`` - category above:: - - SYM_CODE_START_LOCAL(bad_put_user) - ... asm insns ... - SYM_CODE_END(bad_put_user) - - Again, every ``SYM_CODE_START*`` **shall** be coupled by ``SYM_CODE_END``. - - To some extent, this category corresponds to deprecated ``ENTRY`` and - ``END``. Except ``END`` had several other meanings too. - -* ``SYM_INNER_LABEL*`` is used to denote a label inside some - ``SYM_{CODE,FUNC}_START`` and ``SYM_{CODE,FUNC}_END``. They are very similar - to C labels, except they can be made global. An example of use:: - - SYM_CODE_START(ftrace_caller) - /* save_mcount_regs fills in first two parameters */ - ... - - SYM_INNER_LABEL(ftrace_caller_op_ptr, SYM_L_GLOBAL) - /* Load the ftrace_ops into the 3rd parameter */ - ... - - SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) - call ftrace_stub - ... - retq - SYM_CODE_END(ftrace_caller) - -Data Macros -~~~~~~~~~~~ -Similar to instructions, there is a couple of macros to describe data in the -assembly. - -* ``SYM_DATA_START`` and ``SYM_DATA_START_LOCAL`` mark the start of some data - and shall be used in conjunction with either ``SYM_DATA_END``, or - ``SYM_DATA_END_LABEL``. The latter adds also a label to the end, so that - people can use ``lstack`` and (local) ``lstack_end`` in the following - example:: - - SYM_DATA_START_LOCAL(lstack) - .skip 4096 - SYM_DATA_END_LABEL(lstack, SYM_L_LOCAL, lstack_end) - -* ``SYM_DATA`` and ``SYM_DATA_LOCAL`` are variants for simple, mostly one-line - data:: - - SYM_DATA(HEAP, .long rm_heap) - SYM_DATA(heap_end, .long rm_stack) - - In the end, they expand to ``SYM_DATA_START`` with ``SYM_DATA_END`` - internally. - -Support Macros -~~~~~~~~~~~~~~ -All the above reduce themselves to some invocation of ``SYM_START``, -``SYM_END``, or ``SYM_ENTRY`` at last. Normally, developers should avoid using -these. - -Further, in the above examples, one could see ``SYM_L_LOCAL``. There are also -``SYM_L_GLOBAL`` and ``SYM_L_WEAK``. All are intended to denote linkage of a -symbol marked by them. They are used either in ``_LABEL`` variants of the -earlier macros, or in ``SYM_START``. - - -Overriding Macros -~~~~~~~~~~~~~~~~~ -Architecture can also override any of the macros in their own -``asm/linkage.h``, including macros specifying the type of a symbol -(``SYM_T_FUNC``, ``SYM_T_OBJECT``, and ``SYM_T_NONE``). As every macro -described in this file is surrounded by ``#ifdef`` + ``#endif``, it is enough -to define the macros differently in the aforementioned architecture-dependent -header. diff --git a/Documentation/core-api/asm-annotations.rst b/Documentation/core-api/asm-annotations.rst new file mode 100644 index 000000000000..bc514ed59887 --- /dev/null +++ b/Documentation/core-api/asm-annotations.rst @@ -0,0 +1,222 @@ +Assembler Annotations +===================== + +Copyright (c) 2017-2019 Jiri Slaby + +This document describes the new macros for annotation of data and code in +assembly. In particular, it contains information about ``SYM_FUNC_START``, +``SYM_FUNC_END``, ``SYM_CODE_START``, and similar. + +Rationale +--------- +Some code like entries, trampolines, or boot code needs to be written in +assembly. The same as in C, such code is grouped into functions and +accompanied with data. Standard assemblers do not force users into precisely +marking these pieces as code, data, or even specifying their length. +Nevertheless, assemblers provide developers with such annotations to aid +debuggers throughout assembly. On top of that, developers also want to mark +some functions as *global* in order to be visible outside of their translation +units. + +Over time, the Linux kernel has adopted macros from various projects (like +``binutils``) to facilitate such annotations. So for historic reasons, +developers have been using ``ENTRY``, ``END``, ``ENDPROC``, and other +annotations in assembly. Due to the lack of their documentation, the macros +are used in rather wrong contexts at some locations. Clearly, ``ENTRY`` was +intended to denote the beginning of global symbols (be it data or code). +``END`` used to mark the end of data or end of special functions with +*non-standard* calling convention. In contrast, ``ENDPROC`` should annotate +only ends of *standard* functions. + +When these macros are used correctly, they help assemblers generate a nice +object with both sizes and types set correctly. For example, the result of +``arch/x86/lib/putuser.S``:: + + Num: Value Size Type Bind Vis Ndx Name + 25: 0000000000000000 33 FUNC GLOBAL DEFAULT 1 __put_user_1 + 29: 0000000000000030 37 FUNC GLOBAL DEFAULT 1 __put_user_2 + 32: 0000000000000060 36 FUNC GLOBAL DEFAULT 1 __put_user_4 + 35: 0000000000000090 37 FUNC GLOBAL DEFAULT 1 __put_user_8 + +This is not only important for debugging purposes. When there are properly +annotated objects like this, tools can be run on them to generate more useful +information. In particular, on properly annotated objects, ``objtool`` can be +run to check and fix the object if needed. Currently, ``objtool`` can report +missing frame pointer setup/destruction in functions. It can also +automatically generate annotations for the ORC unwinder +(Documentation/x86/orc-unwinder.rst) +for most code. Both of these are especially important to support reliable +stack traces which are in turn necessary for kernel live patching +(Documentation/livepatch/livepatch.rst). + +Caveat and Discussion +--------------------- +As one might realize, there were only three macros previously. That is indeed +insufficient to cover all the combinations of cases: + +* standard/non-standard function +* code/data +* global/local symbol + +There was a discussion_ and instead of extending the current ``ENTRY/END*`` +macros, it was decided that brand new macros should be introduced instead:: + + So how about using macro names that actually show the purpose, instead + of importing all the crappy, historic, essentially randomly chosen + debug symbol macro names from the binutils and older kernels? + +.. _discussion: https://lore.kernel.org/r/20170217104757.28588-1-jslaby@suse.cz + +Macros Description +------------------ + +The new macros are prefixed with the ``SYM_`` prefix and can be divided into +three main groups: + +1. ``SYM_FUNC_*`` -- to annotate C-like functions. This means functions with + standard C calling conventions. For example, on x86, this means that the + stack contains a return address at the predefined place and a return from + the function can happen in a standard way. When frame pointers are enabled, + save/restore of frame pointer shall happen at the start/end of a function, + respectively, too. + + Checking tools like ``objtool`` should ensure such marked functions conform + to these rules. The tools can also easily annotate these functions with + debugging information (like *ORC data*) automatically. + +2. ``SYM_CODE_*`` -- special functions called with special stack. Be it + interrupt handlers with special stack content, trampolines, or startup + functions. + + Checking tools mostly ignore checking of these functions. But some debug + information still can be generated automatically. For correct debug data, + this code needs hints like ``UNWIND_HINT_REGS`` provided by developers. + +3. ``SYM_DATA*`` -- obviously data belonging to ``.data`` sections and not to + ``.text``. Data do not contain instructions, so they have to be treated + specially by the tools: they should not treat the bytes as instructions, + nor assign any debug information to them. + +Instruction Macros +~~~~~~~~~~~~~~~~~~ +This section covers ``SYM_FUNC_*`` and ``SYM_CODE_*`` enumerated above. + +``objtool`` requires that all code must be contained in an ELF symbol. Symbol +names that have a ``.L`` prefix do not emit symbol table entries. ``.L`` +prefixed symbols can be used within a code region, but should be avoided for +denoting a range of code via ``SYM_*_START/END`` annotations. + +* ``SYM_FUNC_START`` and ``SYM_FUNC_START_LOCAL`` are supposed to be **the + most frequent markings**. They are used for functions with standard calling + conventions -- global and local. Like in C, they both align the functions to + architecture specific ``__ALIGN`` bytes. There are also ``_NOALIGN`` variants + for special cases where developers do not want this implicit alignment. + + ``SYM_FUNC_START_WEAK`` and ``SYM_FUNC_START_WEAK_NOALIGN`` markings are + also offered as an assembler counterpart to the *weak* attribute known from + C. + + All of these **shall** be coupled with ``SYM_FUNC_END``. First, it marks + the sequence of instructions as a function and computes its size to the + generated object file. Second, it also eases checking and processing such + object files as the tools can trivially find exact function boundaries. + + So in most cases, developers should write something like in the following + example, having some asm instructions in between the macros, of course:: + + SYM_FUNC_START(memset) + ... asm insns ... + SYM_FUNC_END(memset) + + In fact, this kind of annotation corresponds to the now deprecated ``ENTRY`` + and ``ENDPROC`` macros. + +* ``SYM_FUNC_ALIAS``, ``SYM_FUNC_ALIAS_LOCAL``, and ``SYM_FUNC_ALIAS_WEAK`` can + be used to define multiple names for a function. The typical use is:: + + SYM_FUNC_START(__memset) + ... asm insns ... + SYN_FUNC_END(__memset) + SYM_FUNC_ALIAS(memset, __memset) + + In this example, one can call ``__memset`` or ``memset`` with the same + result, except the debug information for the instructions is generated to + the object file only once -- for the non-``ALIAS`` case. + +* ``SYM_CODE_START`` and ``SYM_CODE_START_LOCAL`` should be used only in + special cases -- if you know what you are doing. This is used exclusively + for interrupt handlers and similar where the calling convention is not the C + one. ``_NOALIGN`` variants exist too. The use is the same as for the ``FUNC`` + category above:: + + SYM_CODE_START_LOCAL(bad_put_user) + ... asm insns ... + SYM_CODE_END(bad_put_user) + + Again, every ``SYM_CODE_START*`` **shall** be coupled by ``SYM_CODE_END``. + + To some extent, this category corresponds to deprecated ``ENTRY`` and + ``END``. Except ``END`` had several other meanings too. + +* ``SYM_INNER_LABEL*`` is used to denote a label inside some + ``SYM_{CODE,FUNC}_START`` and ``SYM_{CODE,FUNC}_END``. They are very similar + to C labels, except they can be made global. An example of use:: + + SYM_CODE_START(ftrace_caller) + /* save_mcount_regs fills in first two parameters */ + ... + + SYM_INNER_LABEL(ftrace_caller_op_ptr, SYM_L_GLOBAL) + /* Load the ftrace_ops into the 3rd parameter */ + ... + + SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) + call ftrace_stub + ... + retq + SYM_CODE_END(ftrace_caller) + +Data Macros +~~~~~~~~~~~ +Similar to instructions, there is a couple of macros to describe data in the +assembly. + +* ``SYM_DATA_START`` and ``SYM_DATA_START_LOCAL`` mark the start of some data + and shall be used in conjunction with either ``SYM_DATA_END``, or + ``SYM_DATA_END_LABEL``. The latter adds also a label to the end, so that + people can use ``lstack`` and (local) ``lstack_end`` in the following + example:: + + SYM_DATA_START_LOCAL(lstack) + .skip 4096 + SYM_DATA_END_LABEL(lstack, SYM_L_LOCAL, lstack_end) + +* ``SYM_DATA`` and ``SYM_DATA_LOCAL`` are variants for simple, mostly one-line + data:: + + SYM_DATA(HEAP, .long rm_heap) + SYM_DATA(heap_end, .long rm_stack) + + In the end, they expand to ``SYM_DATA_START`` with ``SYM_DATA_END`` + internally. + +Support Macros +~~~~~~~~~~~~~~ +All the above reduce themselves to some invocation of ``SYM_START``, +``SYM_END``, or ``SYM_ENTRY`` at last. Normally, developers should avoid using +these. + +Further, in the above examples, one could see ``SYM_L_LOCAL``. There are also +``SYM_L_GLOBAL`` and ``SYM_L_WEAK``. All are intended to denote linkage of a +symbol marked by them. They are used either in ``_LABEL`` variants of the +earlier macros, or in ``SYM_START``. + + +Overriding Macros +~~~~~~~~~~~~~~~~~ +Architecture can also override any of the macros in their own +``asm/linkage.h``, including macros specifying the type of a symbol +(``SYM_T_FUNC``, ``SYM_T_OBJECT``, and ``SYM_T_NONE``). As every macro +described in this file is surrounded by ``#ifdef`` + ``#endif``, it is enough +to define the macros differently in the aforementioned architecture-dependent +header. diff --git a/Documentation/core-api/index.rst b/Documentation/core-api/index.rst index dc95df462eea..f5d8e3779fe8 100644 --- a/Documentation/core-api/index.rst +++ b/Documentation/core-api/index.rst @@ -23,6 +23,7 @@ it. printk-formats printk-index symbol-namespaces + asm-annotations Data structures and low-level utilities ======================================= diff --git a/Documentation/index.rst b/Documentation/index.rst index da80c584133c..5a700548ae82 100644 --- a/Documentation/index.rst +++ b/Documentation/index.rst @@ -89,14 +89,6 @@ platform firmwares. devicetree/index -Architecture-agnostic documentation ------------------------------------ - -.. toctree:: - :maxdepth: 1 - - asm-annotations - Architecture-specific documentation ----------------------------------- diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 79e759aac543..812af52f97d2 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -3751,7 +3751,7 @@ sub process { if ($realfile =~ /\.S$/ && $line =~ /^\+\s*(?:[A-Z]+_)?SYM_[A-Z]+_(?:START|END)(?:_[A-Z_]+)?\s*\(\s*\.L/) { WARN("AVOID_L_PREFIX", - "Avoid using '.L' prefixed local symbol names for denoting a range of code via 'SYM_*_START/END' annotations; see Documentation/asm-annotations.rst\n" . $herecurr); + "Avoid using '.L' prefixed local symbol names for denoting a range of code via 'SYM_*_START/END' annotations; see Documentation/core-api/asm-annotations.rst\n" . $herecurr); } # check we are in a valid source file C or perl if not then ignore this hunk -- cgit v1.2.3 From 69d517e6e21099f81efbd39e47874649ae575804 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Fri, 23 Sep 2022 13:34:25 +0200 Subject: checkpatch: warn on usage of VM_BUG_ON() and other BUG variants checkpatch does not point out that VM_BUG_ON() and friends should be avoided, however, Linus notes: VM_BUG_ON() has the exact same semantics as BUG_ON. It is literally no different, the only difference is "we can make the code smaller because these are less important". [1] So let's warn on VM_BUG_ON() and other BUG variants as well. While at it, make it clearer that the kernel really shouldn't be crashed. As there are some subsystem BUG macros that actually don't end up crashing the kernel -- for example, KVM_BUG_ON() -- exclude these manually. [1] https://lore.kernel.org/r/CAHk-=wg40EAZofO16Eviaj7mfqDhZ2gVEbvfsMf6gYzspRjYvw@mail.gmail.com Signed-off-by: David Hildenbrand Link: https://lore.kernel.org/r/20220923113426.52871-3-david@redhat.com Signed-off-by: Jonathan Corbet --- scripts/checkpatch.pl | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'scripts') diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 812af52f97d2..4aa09e0cb86a 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -4695,12 +4695,12 @@ sub process { } } -# avoid BUG() or BUG_ON() - if ($line =~ /\b(?:BUG|BUG_ON)\b/) { +# do not use BUG() or variants + if ($line =~ /\b(?!AA_|BUILD_|DCCP_|IDA_|KVM_|RWLOCK_|snd_|SPIN_)(?:[a-zA-Z_]*_)?BUG(?:_ON)?(?:_[A-Z_]+)?\s*\(/) { my $msg_level = \&WARN; $msg_level = \&CHK if ($file); &{$msg_level}("AVOID_BUG", - "Avoid crashing the kernel - try using WARN_ON & recovery code rather than BUG() or BUG_ON()\n" . $herecurr); + "Do not crash the kernel unless it is absolutely unavoidable--use WARN_ON_ONCE() plus recovery code (if feasible) instead of BUG() or variants\n" . $herecurr); } # avoid LINUX_VERSION_CODE -- cgit v1.2.3 From 2120635108b35ecad9c59c8b44f6cbdf4f98214e Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Fri, 30 Sep 2022 20:33:10 +0000 Subject: Makefile.extrawarn: Move -Wcast-function-type-strict to W=1 We enable -Wcast-function-type globally in the kernel to warn about mismatching types in function pointer casts. Compilers currently warn only about ABI incompability with this flag, but Clang 16 will enable a stricter version of the check by default that checks for an exact type match. This will be very noisy in the kernel, so disable -Wcast-function-type-strict without W=1 until the new warnings have been addressed. Cc: stable@vger.kernel.org Link: https://reviews.llvm.org/D134831 Link: https://github.com/ClangBuiltLinux/linux/issues/1724 Suggested-by: Nathan Chancellor Signed-off-by: Sami Tolvanen Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220930203310.4010564-1-samitolvanen@google.com --- scripts/Makefile.extrawarn | 1 + 1 file changed, 1 insertion(+) (limited to 'scripts') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 0621c39a3955..20df48637373 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -52,6 +52,7 @@ KBUILD_CFLAGS += -Wno-sign-compare KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast) KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare KBUILD_CFLAGS += $(call cc-disable-warning, unaligned-access) +KBUILD_CFLAGS += $(call cc-disable-warning, cast-function-type-strict) endif endif -- cgit v1.2.3