kernel/include/linux/compiler_attributes.h, branch linux-5.14.y

Merge tag 'clang-features-v5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2021-06-30T21:33:25Z

Pull clang feature updates from Kees Cook: - Add CC_HAS_NO_PROFILE_FN_ATTR in preparation for PGO support in the face of the noinstr attribute, paving the way for PGO and fixing GCOV. (Nick Desaulniers) - x86_64 LTO coverage is expanded to 32-bit x86. (Nathan Chancellor) - Small fixes to CFI. (Mark Rutland, Nathan Chancellor) * tag 'clang-features-v5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: qemu_fw_cfg: Make fw_cfg_rev_attr a proper kobj_attribute Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR compiler_attributes.h: cleanups for GCC 4.9+ compiler_attributes.h: define __no_profile, add to noinstr x86, lto: Enable Clang LTO for 32-bit as well CFI: Move function_nocfi() into compiler.h MAINTAINERS: Add Clang CFI section

compiler_attributes.h: cleanups for GCC 4.9+

2021-06-22T18:05:35Z

Since commit 6ec4476ac825 ("Raise gcc version requirement to 4.9") we no longer support building the kernel with GCC 4.8; drop the preprocess checks for __GNUC_MINOR__ version. It's implied that if __GNUC_MAJOR__ is 4, then the only supported version of __GNUC_MINOR__ left is 9. Signed-off-by: Nick Desaulniers Reviewed-by: Nathan Chancellor Acked-by: Peter Zijlstra (Intel) Reviewed-by: Miguel Ojeda Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20210621231822.2848305-3-ndesaulniers@google.com

compiler_attributes.h: define __no_profile, add to noinstr

2021-06-22T18:00:30Z

noinstr implies that we would like the compiler to avoid instrumenting a function. Add support for the compiler attribute no_profile_instrument_function to compiler_attributes.h, then add __no_profile to the definition of noinstr. Link: https://lore.kernel.org/lkml/20210614162018.GD68749@worktop.programming.kicks-ass.net/ Link: https://reviews.llvm.org/D104257 Link: https://reviews.llvm.org/D104475 Link: https://reviews.llvm.org/D104658 Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80223 Reviewed-by: Fangrui Song Reviewed-by: Miguel Ojeda Suggested-by: Peter Zijlstra Signed-off-by: Nick Desaulniers Reviewed-by: Nathan Chancellor Acked-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20210621231822.2848305-2-ndesaulniers@google.com

Compiler Attributes: Add continue in comment

2021-05-12T18:18:46Z

Add "continue;" for switch/case block according to Doc[1] [1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Wei Ming Chen Signed-off-by: Miguel Ojeda

percpu: fix clang modpost section mismatch

2021-02-14T18:15:15Z

pcpu_build_alloc_info() is an __init function that makes a call to cpumask_clear_cpu(). With CONFIG_GCOV_PROFILE_ALL enabled, the inline heuristics are modified and such cpumask_clear_cpu() which is marked inline doesn't get inlined. Because it works on mask in __initdata, modpost throws a section mismatch error. Arnd sent a patch with the flatten attribute as an alternative [2]. I've added it to compiler_attributes.h. modpost complaint: WARNING: modpost: vmlinux.o(.text+0x735425): Section mismatch in reference from the function cpumask_clear_cpu() to the variable .init.data:pcpu_build_alloc_info.mask The function cpumask_clear_cpu() references the variable __initdata pcpu_build_alloc_info.mask. This is often because cpumask_clear_cpu lacks a __initdata annotation or the annotation of pcpu_build_alloc_info.mask is wrong. clang output: mm/percpu.c:2724:5: remark: cpumask_clear_cpu not inlined into pcpu_build_alloc_info because too costly to inline (cost=725, threshold=325) [-Rpass-missed=inline] [1] https://lore.kernel.org/linux-mm/202012220454.9F6Bkz9q-lkp@intel.com/ [2] https://lore.kernel.org/lkml/CAK8P3a2ZWfNeXKSm8K_SUhhwkor17jFo3xApLXjzfPqX0eUDUA@mail.gmail.com/ Reported-by: kernel test robot Cc: Arnd Bergmann Cc: Nick Desaulniers Signed-off-by: Dennis Zhou

Compiler Attributes: remove CONFIG_ENABLE_MUST_CHECK

2020-12-02T12:47:17Z

Revert commit cebc04ba9aeb ("add CONFIG_ENABLE_MUST_CHECK"). A lot of warn_unused_result warnings existed in 2006, but until now they have been fixed thanks to people doing allmodconfig tests. Our goal is to always enable __must_check where appropriate, so this CONFIG option is no longer needed. I see a lot of defconfig (arch/*/configs/*_defconfig) files having: # CONFIG_ENABLE_MUST_CHECK is not set I did not touch them for now since it would be a big churn. If arch maintainers want to clean them up, please go ahead. While I was here, I also moved __must_check to compiler_attributes.h from compiler_types.h Signed-off-by: Masahiro Yamada Acked-by: Jason A. Donenfeld Acked-by: Nathan Chancellor Reviewed-by: Nick Desaulniers [Moved addition in compiler_attributes.h to keep it sorted] Signed-off-by: Miguel Ojeda

treewide: Convert macro and uses of section(foo) to section("foo")

2020-10-25T21:51:49Z

Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl Signed-off-by: Joe Perches Reviewed-by: Nick Desaulniers Reviewed-by: Miguel Ojeda Signed-off-by: Linus Torvalds

Compiler Attributes: fix comment concerning GCC 4.6

2020-08-27T07:53:06Z

GCC 4.6 is not supported anymore, so remove a reference to it, leaving just the part about version prior GCC 5. Signed-off-by: Luc Van Oostenryck Signed-off-by: Miguel Ojeda

Compiler Attributes: remove comment about sparse not supporting __has_attribute

2020-08-27T07:52:37Z

Sparse supports __has_attribute() since 2018-08-31, so the comment is not true anymore but more importantly is rather confusing. So remove it. Signed-off-by: Luc Van Oostenryck Signed-off-by: Miguel Ojeda

Merge tag 'gcc-plugins-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2020-08-04T20:26:06Z

Pull gcc plugin updates from Kees Cook: "Primarily improvements to STACKLEAK from Alexander Popov, along with some additional cleanups. - Update URLs for HTTPS scheme where available (Alexander A. Klimov) - Improve STACKLEAK code generation on x86 (Alexander Popov)" * tag 'gcc-plugins-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: gcc-plugins: Replace HTTP links with HTTPS ones gcc-plugins/stackleak: Add 'verbose' plugin parameter gcc-plugins/stackleak: Use asm instrumentation to avoid useless register saving ARM: vdso: Don't use gcc plugins for building vgettimeofday.c gcc-plugins/stackleak: Don't instrument itself