From 1e7e47883830aae5e8246a22ca2fc6883c61acdf Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Tue, 18 Aug 2020 15:57:45 +0200 Subject: x86/static_call: Add inline static call implementation for x86-64 Add the inline static call implementation for x86-64. The generated code is identical to the out-of-line case, except we move the trampoline into it's own section. Objtool uses the trampoline naming convention to detect all the call sites. It then annotates those call sites in the .static_call_sites section. During boot (and module init), the call sites are patched to call directly into the destination function. The temporary trampoline is then no longer used. [peterz: merged trampolines, put trampoline in section] Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/20200818135804.864271425@infradead.org --- tools/objtool/objtool.h | 1 + 1 file changed, 1 insertion(+) (limited to 'tools/objtool/objtool.h') diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h index 528028a66816..9a7cd0b88bd8 100644 --- a/tools/objtool/objtool.h +++ b/tools/objtool/objtool.h @@ -16,6 +16,7 @@ struct objtool_file { struct elf *elf; struct list_head insn_list; DECLARE_HASHTABLE(insn_hash, 20); + struct list_head static_call_list; bool ignore_unreachables, c_file, hints, rodata; }; -- cgit v1.2.3 From 6545eb030e6f14cef8793a86312483c788eaee46 Mon Sep 17 00:00:00 2001 From: Julien Thierry Date: Tue, 25 Aug 2020 13:47:39 +0100 Subject: objtool: Move object file loading out of check() Structure objtool_file can be used by different subcommands. In fact it already is, by check and orc. Provide a function that allows to initialize objtool_file, that builtin can call, without relying on check to do the correct setup for them and explicitly hand the objtool_file to them. Reviewed-by: Miroslav Benes Signed-off-by: Julien Thierry Signed-off-by: Josh Poimboeuf --- tools/objtool/builtin-check.c | 7 ++++++- tools/objtool/builtin-orc.c | 8 +++++++- tools/objtool/check.c | 42 +++++++++++++----------------------------- tools/objtool/objtool.c | 30 ++++++++++++++++++++++++++++++ tools/objtool/objtool.h | 4 +++- tools/objtool/weak.c | 4 +--- 6 files changed, 60 insertions(+), 35 deletions(-) (limited to 'tools/objtool/objtool.h') diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 7a44174967b5..0126ec3bb6c9 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -41,6 +41,7 @@ const struct option check_options[] = { int cmd_check(int argc, const char **argv) { const char *objname, *s; + struct objtool_file *file; argc = parse_options(argc, argv, check_options, check_usage, 0); @@ -53,5 +54,9 @@ int cmd_check(int argc, const char **argv) if (s && !s[9]) vmlinux = true; - return check(objname, false); + file = objtool_open_read(objname); + if (!file) + return 1; + + return check(file, false); } diff --git a/tools/objtool/builtin-orc.c b/tools/objtool/builtin-orc.c index b1dfe2007962..3979f275a775 100644 --- a/tools/objtool/builtin-orc.c +++ b/tools/objtool/builtin-orc.c @@ -31,13 +31,19 @@ int cmd_orc(int argc, const char **argv) usage_with_options(orc_usage, check_options); if (!strncmp(argv[0], "gen", 3)) { + struct objtool_file *file; + argc = parse_options(argc, argv, check_options, orc_usage, 0); if (argc != 1) usage_with_options(orc_usage, check_options); objname = argv[0]; - return check(objname, true); + file = objtool_open_read(objname); + if (!file) + return 1; + + return check(file, true); } if (!strcmp(argv[0], "dump")) { diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 75d0cd2f9044..9d4efa3b12ba 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -28,7 +28,6 @@ struct alternative { bool skip_orig; }; -const char *objname; struct cfi_init_state initial_func_cfi; struct instruction *find_insn(struct objtool_file *file, @@ -2909,37 +2908,22 @@ static int validate_reachable_instructions(struct objtool_file *file) return 0; } -static struct objtool_file file; - -int check(const char *_objname, bool orc) +int check(struct objtool_file *file, bool orc) { int ret, warnings = 0; - objname = _objname; - - file.elf = elf_open_read(objname, O_RDWR); - if (!file.elf) - return 1; - - INIT_LIST_HEAD(&file.insn_list); - hash_init(file.insn_hash); - INIT_LIST_HEAD(&file.static_call_list); - file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment"); - file.ignore_unreachables = no_unreachable; - file.hints = false; - arch_initial_func_cfi_state(&initial_func_cfi); - ret = decode_sections(&file); + ret = decode_sections(file); if (ret < 0) goto out; warnings += ret; - if (list_empty(&file.insn_list)) + if (list_empty(&file->insn_list)) goto out; if (vmlinux && !validate_dup) { - ret = validate_vmlinux_functions(&file); + ret = validate_vmlinux_functions(file); if (ret < 0) goto out; @@ -2948,46 +2932,46 @@ int check(const char *_objname, bool orc) } if (retpoline) { - ret = validate_retpoline(&file); + ret = validate_retpoline(file); if (ret < 0) return ret; warnings += ret; } - ret = validate_functions(&file); + ret = validate_functions(file); if (ret < 0) goto out; warnings += ret; - ret = validate_unwind_hints(&file, NULL); + ret = validate_unwind_hints(file, NULL); if (ret < 0) goto out; warnings += ret; if (!warnings) { - ret = validate_reachable_instructions(&file); + ret = validate_reachable_instructions(file); if (ret < 0) goto out; warnings += ret; } - ret = create_static_call_sections(&file); + ret = create_static_call_sections(file); if (ret < 0) goto out; warnings += ret; if (orc) { - ret = create_orc(&file); + ret = create_orc(file); if (ret < 0) goto out; - ret = create_orc_sections(&file); + ret = create_orc_sections(file); if (ret < 0) goto out; } - if (file.elf->changed) { - ret = elf_write(file.elf); + if (file->elf->changed) { + ret = elf_write(file->elf); if (ret < 0) goto out; } diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c index 58fdda510653..9df0cd86d310 100644 --- a/tools/objtool/objtool.c +++ b/tools/objtool/objtool.c @@ -22,6 +22,8 @@ #include #include "builtin.h" +#include "objtool.h" +#include "warn.h" struct cmd_struct { const char *name; @@ -39,6 +41,34 @@ static struct cmd_struct objtool_cmds[] = { bool help; +const char *objname; +static struct objtool_file file; + +struct objtool_file *objtool_open_read(const char *_objname) +{ + if (objname) { + if (strcmp(objname, _objname)) { + WARN("won't handle more than one file at a time"); + return NULL; + } + return &file; + } + objname = _objname; + + file.elf = elf_open_read(objname, O_RDWR); + if (!file.elf) + return NULL; + + INIT_LIST_HEAD(&file.insn_list); + hash_init(file.insn_hash); + INIT_LIST_HEAD(&file.static_call_list); + file.c_file = !vmlinux && find_section_by_name(file.elf, ".comment"); + file.ignore_unreachables = no_unreachable; + file.hints = false; + + return &file; +} + static void cmd_usage(void) { unsigned int i, longest = 0; diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h index 9a7cd0b88bd8..7efc43f22174 100644 --- a/tools/objtool/objtool.h +++ b/tools/objtool/objtool.h @@ -20,7 +20,9 @@ struct objtool_file { bool ignore_unreachables, c_file, hints, rodata; }; -int check(const char *objname, bool orc); +struct objtool_file *objtool_open_read(const char *_objname); + +int check(struct objtool_file *file, bool orc); int orc_dump(const char *objname); int create_orc(struct objtool_file *file); int create_orc_sections(struct objtool_file *file); diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c index 942ea5e8ac36..82698319f008 100644 --- a/tools/objtool/weak.c +++ b/tools/objtool/weak.c @@ -17,9 +17,7 @@ return ENOSYS; \ }) -const char __weak *objname; - -int __weak check(const char *_objname, bool orc) +int __weak check(struct objtool_file *file, bool orc) { UNSUPPORTED("check subcommand"); } -- cgit v1.2.3 From d44becb9decf4438d1e555b1428634964d2e5764 Mon Sep 17 00:00:00 2001 From: Julien Thierry Date: Tue, 25 Aug 2020 13:47:40 +0100 Subject: objtool: Move ORC logic out of check() Now that the objtool_file can be obtained outside of the check function, orc generation builtin no longer requires check to explicitly call its orc related functions. Signed-off-by: Julien Thierry Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf --- tools/objtool/builtin-check.c | 10 +++++++++- tools/objtool/builtin-orc.c | 21 ++++++++++++++++++++- tools/objtool/check.c | 18 +----------------- tools/objtool/objtool.h | 2 +- tools/objtool/weak.c | 2 +- 5 files changed, 32 insertions(+), 21 deletions(-) (limited to 'tools/objtool/objtool.h') diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 0126ec3bb6c9..c6d199bfd0ae 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -42,6 +42,7 @@ int cmd_check(int argc, const char **argv) { const char *objname, *s; struct objtool_file *file; + int ret; argc = parse_options(argc, argv, check_options, check_usage, 0); @@ -58,5 +59,12 @@ int cmd_check(int argc, const char **argv) if (!file) return 1; - return check(file, false); + ret = check(file); + if (ret) + return ret; + + if (file->elf->changed) + return elf_write(file->elf); + + return 0; } diff --git a/tools/objtool/builtin-orc.c b/tools/objtool/builtin-orc.c index 3979f275a775..7b31121fa60b 100644 --- a/tools/objtool/builtin-orc.c +++ b/tools/objtool/builtin-orc.c @@ -32,6 +32,7 @@ int cmd_orc(int argc, const char **argv) if (!strncmp(argv[0], "gen", 3)) { struct objtool_file *file; + int ret; argc = parse_options(argc, argv, check_options, orc_usage, 0); if (argc != 1) @@ -43,7 +44,25 @@ int cmd_orc(int argc, const char **argv) if (!file) return 1; - return check(file, true); + ret = check(file); + if (ret) + return ret; + + if (list_empty(&file->insn_list)) + return 0; + + ret = create_orc(file); + if (ret) + return ret; + + ret = create_orc_sections(file); + if (ret) + return ret; + + if (!file->elf->changed) + return 0; + + return elf_write(file->elf); } if (!strcmp(argv[0], "dump")) { diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 9d4efa3b12ba..4afc2d5465b9 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2908,7 +2908,7 @@ static int validate_reachable_instructions(struct objtool_file *file) return 0; } -int check(struct objtool_file *file, bool orc) +int check(struct objtool_file *file) { int ret, warnings = 0; @@ -2960,22 +2960,6 @@ int check(struct objtool_file *file, bool orc) goto out; warnings += ret; - if (orc) { - ret = create_orc(file); - if (ret < 0) - goto out; - - ret = create_orc_sections(file); - if (ret < 0) - goto out; - } - - if (file->elf->changed) { - ret = elf_write(file->elf); - if (ret < 0) - goto out; - } - out: if (ret < 0) { /* diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h index 7efc43f22174..a635f68a9b09 100644 --- a/tools/objtool/objtool.h +++ b/tools/objtool/objtool.h @@ -22,7 +22,7 @@ struct objtool_file { struct objtool_file *objtool_open_read(const char *_objname); -int check(struct objtool_file *file, bool orc); +int check(struct objtool_file *file); int orc_dump(const char *objname); int create_orc(struct objtool_file *file); int create_orc_sections(struct objtool_file *file); diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c index 82698319f008..29180d599b08 100644 --- a/tools/objtool/weak.c +++ b/tools/objtool/weak.c @@ -17,7 +17,7 @@ return ENOSYS; \ }) -int __weak check(struct objtool_file *file, bool orc) +int __weak check(struct objtool_file *file) { UNSUPPORTED("check subcommand"); } -- cgit v1.2.3 From eda3dc905834dc9c99132f987f77b68cf53a8682 Mon Sep 17 00:00:00 2001 From: Julien Thierry Date: Fri, 4 Sep 2020 16:30:22 +0100 Subject: objtool: Abstract alternative special case handling Some alternatives associated with a specific feature need to be treated in a special way. Since the features and how to treat them vary from one architecture to another, move the special case handling to arch specific code. Reviewed-by: Miroslav Benes Signed-off-by: Julien Thierry Signed-off-by: Josh Poimboeuf --- tools/objtool/arch/x86/Build | 1 + tools/objtool/arch/x86/special.c | 37 +++++++++++++++++++++++++++++++++++++ tools/objtool/objtool.h | 2 ++ tools/objtool/special.c | 32 +++++--------------------------- tools/objtool/special.h | 2 ++ tools/objtool/weak.c | 2 -- 6 files changed, 47 insertions(+), 29 deletions(-) create mode 100644 tools/objtool/arch/x86/special.c (limited to 'tools/objtool/objtool.h') diff --git a/tools/objtool/arch/x86/Build b/tools/objtool/arch/x86/Build index 7c5004008e97..9f7869b5c5e0 100644 --- a/tools/objtool/arch/x86/Build +++ b/tools/objtool/arch/x86/Build @@ -1,3 +1,4 @@ +objtool-y += special.o objtool-y += decode.o inat_tables_script = ../arch/x86/tools/gen-insn-attr-x86.awk diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c new file mode 100644 index 000000000000..823561e4015c --- /dev/null +++ b/tools/objtool/arch/x86/special.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +#include "../../special.h" +#include "../../builtin.h" + +#define X86_FEATURE_POPCNT (4 * 32 + 23) +#define X86_FEATURE_SMAP (9 * 32 + 20) + +void arch_handle_alternative(unsigned short feature, struct special_alt *alt) +{ + switch (feature) { + case X86_FEATURE_SMAP: + /* + * If UACCESS validation is enabled; force that alternative; + * otherwise force it the other way. + * + * What we want to avoid is having both the original and the + * alternative code flow at the same time, in that case we can + * find paths that see the STAC but take the NOP instead of + * CLAC and the other way around. + */ + if (uaccess) + alt->skip_orig = true; + else + alt->skip_alt = true; + break; + case X86_FEATURE_POPCNT: + /* + * It has been requested that we don't validate the !POPCNT + * feature path which is a "very very small percentage of + * machines". + */ + alt->skip_orig = true; + break; + default: + break; + } +} diff --git a/tools/objtool/objtool.h b/tools/objtool/objtool.h index a635f68a9b09..4125d4578b23 100644 --- a/tools/objtool/objtool.h +++ b/tools/objtool/objtool.h @@ -12,6 +12,8 @@ #include "elf.h" +#define __weak __attribute__((weak)) + struct objtool_file { struct elf *elf; struct list_head insn_list; diff --git a/tools/objtool/special.c b/tools/objtool/special.c index b04f395de5de..1a2420febd08 100644 --- a/tools/objtool/special.c +++ b/tools/objtool/special.c @@ -16,9 +16,6 @@ #include "warn.h" #include "arch_special.h" -#define X86_FEATURE_POPCNT (4*32+23) -#define X86_FEATURE_SMAP (9*32+20) - struct special_entry { const char *sec; bool group, jump_or_nop; @@ -54,6 +51,10 @@ struct special_entry entries[] = { {}, }; +void __weak arch_handle_alternative(unsigned short feature, struct special_alt *alt) +{ +} + static int get_alt_entry(struct elf *elf, struct special_entry *entry, struct section *sec, int idx, struct special_alt *alt) @@ -78,30 +79,7 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry, feature = *(unsigned short *)(sec->data->d_buf + offset + entry->feature); - - /* - * It has been requested that we don't validate the !POPCNT - * feature path which is a "very very small percentage of - * machines". - */ - if (feature == X86_FEATURE_POPCNT) - alt->skip_orig = true; - - /* - * If UACCESS validation is enabled; force that alternative; - * otherwise force it the other way. - * - * What we want to avoid is having both the original and the - * alternative code flow at the same time, in that case we can - * find paths that see the STAC but take the NOP instead of - * CLAC and the other way around. - */ - if (feature == X86_FEATURE_SMAP) { - if (uaccess) - alt->skip_orig = true; - else - alt->skip_alt = true; - } + arch_handle_alternative(feature, alt); } orig_reloc = find_reloc_by_dest(elf, sec, offset + entry->orig); diff --git a/tools/objtool/special.h b/tools/objtool/special.h index 35061530e46e..44da89afeda2 100644 --- a/tools/objtool/special.h +++ b/tools/objtool/special.h @@ -28,4 +28,6 @@ struct special_alt { int special_get_alts(struct elf *elf, struct list_head *alts); +void arch_handle_alternative(unsigned short feature, struct special_alt *alt); + #endif /* _SPECIAL_H */ diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c index 29180d599b08..7843e9a7a72f 100644 --- a/tools/objtool/weak.c +++ b/tools/objtool/weak.c @@ -9,8 +9,6 @@ #include #include "objtool.h" -#define __weak __attribute__((weak)) - #define UNSUPPORTED(name) \ ({ \ fprintf(stderr, "error: objtool: " name " not implemented\n"); \ -- cgit v1.2.3