linux/arch/riscv/kernel/compat_vdso, branch master

Makefile: remove redundant tool coverage variables

2024-05-14T14:35:48Z

Now Kbuild provides reasonable defaults for objtool, sanitizers, and profilers. Remove redundant variables. Note: This commit changes the coverage for some objects: - include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV - include arch/sparc/vdso/vdso-image-*.o into UBSAN - include arch/sparc/vdso/vma.o into UBSAN - include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV - include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV - include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV - include arch/x86/entry/vdso/vma.o into GCOV, KCOV - include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV I believe these are positive effects because all of them are kernel space objects. Signed-off-by: Masahiro Yamada Reviewed-by: Kees Cook Tested-by: Roberto Sassu

kbuild: use $(src) instead of $(srctree)/$(src) for source directory

2024-05-09T19:34:52Z

Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for checked-in source files. It is merely a convention without any functional difference. In fact, $(obj) and $(src) are exactly the same, as defined in scripts/Makefile.build: src := $(obj) When the kernel is built in a separate output directory, $(src) does not accurately reflect the source directory location. While Kbuild resolves this discrepancy by specifying VPATH=$(srctree) to search for source files, it does not cover all cases. For example, when adding a header search path for local headers, -I$(srctree)/$(src) is typically passed to the compiler. This introduces inconsistency between upstream and downstream Makefiles because $(src) is used instead of $(srctree)/$(src) for the latter. To address this inconsistency, this commit changes the semantics of $(src) so that it always points to the directory in the source tree. Going forward, the variables used in Makefiles will have the following meanings: $(obj) - directory in the object tree $(src) - directory in the source tree (changed by this commit) $(objtree) - the top of the kernel object tree $(srctree) - the top of the kernel source tree Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced with $(src). Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier

riscv: compat_vdso: align VDSOAS build log

2024-03-27T14:08:38Z

Add one more space after "VDSOAS" for better alignment in the build log. [Before] LDS arch/riscv/kernel/compat_vdso/compat_vdso.lds VDSOAS arch/riscv/kernel/compat_vdso/rt_sigreturn.o VDSOAS arch/riscv/kernel/compat_vdso/getcpu.o VDSOAS arch/riscv/kernel/compat_vdso/flush_icache.o VDSOAS arch/riscv/kernel/compat_vdso/note.o VDSOLD arch/riscv/kernel/compat_vdso/compat_vdso.so.dbg VDSOSYM include/generated/compat_vdso-offsets.h [After] LDS arch/riscv/kernel/compat_vdso/compat_vdso.lds VDSOAS arch/riscv/kernel/compat_vdso/rt_sigreturn.o VDSOAS arch/riscv/kernel/compat_vdso/getcpu.o VDSOAS arch/riscv/kernel/compat_vdso/flush_icache.o VDSOAS arch/riscv/kernel/compat_vdso/note.o VDSOLD arch/riscv/kernel/compat_vdso/compat_vdso.so.dbg VDSOSYM include/generated/compat_vdso-offsets.h Signed-off-by: Masahiro Yamada Reviewed-by: Alexandre Ghiti Link: https://lore.kernel.org/r/20231117125843.1058553-1-masahiroy@kernel.org Signed-off-by: Palmer Dabbelt

kbuild: unify vdso_install rules

2023-10-28T12:09:02Z

Currently, there is no standard implementation for vdso_install, leading to various issues: 1. Code duplication Many architectures duplicate similar code just for copying files to the install destination. Some architectures (arm, sparc, x86) create build-id symlinks, introducing more code duplication. 2. Unintended updates of in-tree build artifacts The vdso_install rule depends on the vdso files to install. It may update in-tree build artifacts. This can be problematic, as explained in commit 19514fc665ff ("arm, kbuild: make "make install" not depend on vmlinux"). 3. Broken code in some architectures Makefile code is often copied from one architecture to another without proper adaptation. 'make vdso_install' for parisc does not work. 'make vdso_install' for s390 installs vdso64, but not vdso32. To address these problems, this commit introduces a generic vdso_install rule. Architectures that support vdso_install need to define vdso-install-y in arch/*/Makefile. vdso-install-y lists the files to install. For example, arch/x86/Makefile looks like this: vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg vdso-install-$(CONFIG_X86_32) += arch/x86/entry/vdso/vdso32.so.dbg vdso-install-$(CONFIG_IA32_EMULATION) += arch/x86/entry/vdso/vdso32.so.dbg These files will be installed to $(MODLIB)/vdso/ with the .dbg suffix, if exists, stripped away. vdso-install-y can optionally take the second field after the colon separator. This is needed because some architectures install a vdso file as a different base name. The following is a snippet from arch/arm64/Makefile. vdso-install-$(CONFIG_COMPAT_VDSO) += arch/arm64/kernel/vdso32/vdso.so.dbg:vdso32.so This will rename vdso.so.dbg to vdso32.so during installation. If such architectures change their implementation so that the base names match, this workaround will go away. Signed-off-by: Masahiro Yamada Acked-by: Sven Schnelle # s390 Reviewed-by: Nicolas Schier Reviewed-by: Guo Ren Acked-by: Helge Deller # parisc Acked-by: Catalin Marinas Acked-by: Russell King (Oracle)

riscv: Handle zicsr/zifencei issue between gcc and binutils

2023-08-16T14:39:38Z

Binutils-2.38 and GCC-12.1.0 bumped[0][1] the default ISA spec to the newer 20191213 version which moves some instructions from the I extension to the Zicsr and Zifencei extensions. So if one of the binutils and GCC exceeds that version, we should explicitly specifying Zicsr and Zifencei via -march to cope with the new changes. but this only occurs when binutils >= 2.36 and GCC >= 11.1.0. It's a different story when binutils < 2.36. binutils-2.36 supports the Zifencei extension[2] and splits Zifencei and Zicsr from I[3]. GCC-11.1.0 is particular[4] because it add support Zicsr and Zifencei extension for -march. binutils-2.35 does not support the Zifencei extension, and does not need to specify Zicsr and Zifencei when working with GCC >= 12.1.0. To make our lives easier, let's relax the check to binutils >= 2.36 in CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI. For the other two cases, where clang < 17 or GCC < 11.1.0, we will deal with them in CONFIG_TOOLCHAIN_NEEDS_OLD_ISA_SPEC. For more information, please refer to: commit 6df2a016c0c8 ("riscv: fix build with binutils 2.38") commit e89c2e815e76 ("riscv: Handle zicsr/zifencei issues between clang and binutils") Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc [0] Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd [1] Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=5a1b31e1e1cee6e9f1c92abff59cdcfff0dddf30 [2] Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=729a53530e86972d1143553a415db34e6e01d5d2 [3] Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=b03be74bad08c382da47e048007a78fa3fb4ef49 [4] Link: https://lore.kernel.org/all/20230308220842.1231003-1-conor@kernel.org Link: https://lore.kernel.org/all/20230223220546.52879-1-conor@kernel.org Reviewed-by: Conor Dooley Acked-by: Guo Ren Cc: Signed-off-by: Mingzheng Xing Link: https://lore.kernel.org/r/20230809165648.21071-1-xingmingzheng@iscas.ac.cn Signed-off-by: Palmer Dabbelt

Merge tag 'riscv-for-linus-6.4-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2023-04-28T23:55:39Z

Pull RISC-V updates from Palmer Dabbelt: - Support for runtime detection of the Svnapot extension - Support for Zicboz when clearing pages - We've moved to GENERIC_ENTRY - Support for !MMU on rv32 systems - The linear region is now mapped via huge pages - Support for building relocatable kernels - Support for the hwprobe interface - Various fixes and cleanups throughout the tree * tag 'riscv-for-linus-6.4-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (57 commits) RISC-V: hwprobe: Explicity check for -1 in vdso init RISC-V: hwprobe: There can only be one first riscv: Allow to downgrade paging mode from the command line dt-bindings: riscv: add sv57 mmu-type RISC-V: hwprobe: Remove __init on probe_vendor_features() riscv: Use --emit-relocs in order to move .rela.dyn in init riscv: Check relocations at compile time powerpc: Move script to check relocations at compile time in scripts/ riscv: Introduce CONFIG_RELOCATABLE riscv: Move .rela.dyn outside of init to avoid empty relocations riscv: Prepare EFI header for relocatable kernels riscv: Unconditionnally select KASAN_VMALLOC if KASAN riscv: Fix ptdump when KASAN is enabled riscv: Fix EFI stub usage of KASAN instrumented strcmp function riscv: Move DTB_EARLY_BASE_VA to the kernel address space riscv: Rework kasan population functions riscv: Split early and final KASAN population functions riscv: Use PUD/P4D/PGD pages for the linear mapping riscv: Move the linear mapping creation in its own function riscv: Get rid of riscv_pfn_base variable ...

RISC-V: Add hwprobe vDSO function and data

2023-04-18T22:48:18Z

Add a vDSO function __vdso_riscv_hwprobe, which can sit in front of the riscv_hwprobe syscall and answer common queries. We stash a copy of static answers for the "all CPUs" case in the vDSO data page. This data is private to the vDSO, so we can decide later to change what's stored there or under what conditions we defer to the syscall. Currently all data can be discovered at boot, so the vDSO function answers all queries when the cpumask is set to the "all CPUs" hint. There's also a boolean in the data that lets the vDSO function know that all CPUs are the same. In that case, the vDSO will also answer queries for arbitrary CPU masks in addition to the "all CPUs" hint. Signed-off-by: Evan Green Link: https://lore.kernel.org/r/20230407231103.2622178-7-evan@rivosinc.com Signed-off-by: Palmer Dabbelt

RISC-V: Stop emitting attributes

2023-03-06T23:55:25Z

The RISC-V ELF attributes don't contain any useful information. New toolchains ignore them, but they frequently trip up various older/mixed toolchains. So just turn them off. Tested-by: Conor Dooley Link: https://lore.kernel.org/r/20230223224605.6995-1-palmer@rivosinc.com Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt

riscv: compat: vdso: Add COMPAT_VDSO base code implementation

2022-04-26T20:36:53Z

There is no vgettimeofday supported in rv32 that makes simple to generate rv32 vdso code which only needs riscv64 compiler. Other architectures need change compiler or -m (machine parameter) to support vdso32 compiling. If rv32 support vgettimeofday (which cause C compile) in future, we would add CROSS_COMPILE to support that makes more requirement on compiler enviornment. linux-rv64/arch/riscv/kernel/compat_vdso/compat_vdso.so.dbg: file format elf64-littleriscv Disassembly of section .text: 0000000000000800 <__vdso_rt_sigreturn>: 800: 08b00893 li a7,139 804: 00000073 ecall 808: 0000 unimp ... 000000000000080c <__vdso_getcpu>: 80c: 0a800893 li a7,168 810: 00000073 ecall 814: 8082 ret ... 0000000000000818 <__vdso_flush_icache>: 818: 10300893 li a7,259 81c: 00000073 ecall 820: 8082 ret linux-rv32/arch/riscv/kernel/vdso/vdso.so.dbg: file format elf32-littleriscv Disassembly of section .text: 00000800 <__vdso_rt_sigreturn>: 800: 08b00893 li a7,139 804: 00000073 ecall 808: 0000 unimp ... 0000080c <__vdso_getcpu>: 80c: 0a800893 li a7,168 810: 00000073 ecall 814: 8082 ret ... 00000818 <__vdso_flush_icache>: 818: 10300893 li a7,259 81c: 00000073 ecall 820: 8082 ret Finally, reuse all *.S from vdso in compat_vdso that makes implementation clear and readable. Signed-off-by: Guo Ren Signed-off-by: Guo Ren Tested-by: Heiko Stuebner Link: https://lore.kernel.org/r/20220405071314.3225832-17-guoren@kernel.org Signed-off-by: Palmer Dabbelt