From 51c2ee6d121ceb31ab8d35aff4ce53007aefb455 Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Mon, 21 Jun 2021 16:18:22 -0700 Subject: [PATCH] Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR We don't want compiler instrumentation to touch noinstr functions, which are annotated with the no_profile_instrument_function function attribute. Add a Kconfig test for this and make GCOV depend on it, and in the future, PGO. If an architecture is using noinstr, it should denote that via this Kconfig value. That makes Kconfigs that depend on noinstr able to express dependencies in an architecturally agnostic way. Cc: Masahiro Yamada Link: https://lore.kernel.org/lkml/YMTn9yjuemKFLbws@hirez.programming.kicks-ass.net/ Link: https://lore.kernel.org/lkml/YMcssV%2Fn5IBGv4f0@hirez.programming.kicks-ass.net/ Suggested-by: Nathan Chancellor Suggested-by: Peter Zijlstra Signed-off-by: Nick Desaulniers Reviewed-by: Peter Oberparleiter Reviewed-by: Nathan Chancellor Acked-by: Mark Rutland Acked-by: Heiko Carstens Acked-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20210621231822.2848305-4-ndesaulniers@google.com --- arch/Kconfig | 7 +++++++ arch/arm64/Kconfig | 1 + arch/s390/Kconfig | 1 + arch/x86/Kconfig | 1 + init/Kconfig | 3 +++ kernel/gcov/Kconfig | 1 + 6 files changed, 14 insertions(+) diff --git a/arch/Kconfig b/arch/Kconfig index c45b770d3579..129df498a8e1 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -285,6 +285,13 @@ config ARCH_THREAD_STACK_ALLOCATOR config ARCH_WANTS_DYNAMIC_TASK_STRUCT bool +config ARCH_WANTS_NO_INSTR + bool + help + An architecture should select this if the noinstr macro is being used on + functions to denote that the toolchain should avoid instrumenting such + functions and is required for correctness. + config ARCH_32BIT_OFF_T bool depends on !64BIT diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 9f1d8566bbf9..39bf982b06f8 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -93,6 +93,7 @@ config ARM64 select ARCH_WANT_FRAME_POINTERS select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36) select ARCH_WANT_LD_ORPHAN_WARN + select ARCH_WANTS_NO_INSTR select ARCH_HAS_UBSAN_SANITIZE_ALL select ARM_AMBA select ARM_ARCH_TIMER diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index b4c7c34069f8..bd60310f33b9 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -117,6 +117,7 @@ config S390 select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF select ARCH_WANTS_DYNAMIC_TASK_STRUCT + select ARCH_WANTS_NO_INSTR select ARCH_WANT_DEFAULT_BPF_JIT select ARCH_WANT_IPC_PARSE_VERSION select BUILDTIME_TABLE_SORT diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 12fa0d7bfa64..268a5dec8b3f 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -113,6 +113,7 @@ config X86 select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH select ARCH_WANT_DEFAULT_BPF_JIT if X86_64 select ARCH_WANTS_DYNAMIC_TASK_STRUCT + select ARCH_WANTS_NO_INSTR select ARCH_WANT_HUGE_PMD_SHARE select ARCH_WANT_LD_ORPHAN_WARN select ARCH_WANTS_THP_SWAP if X86_64 diff --git a/init/Kconfig b/init/Kconfig index 1ea12c64e4c9..31397a7a45fb 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -83,6 +83,9 @@ config TOOLS_SUPPORT_RELR config CC_HAS_ASM_INLINE def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null) +config CC_HAS_NO_PROFILE_FN_ATTR + def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror) + config CONSTRUCTORS bool diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig index 58f87a3092f3..053447183ac5 100644 --- a/kernel/gcov/Kconfig +++ b/kernel/gcov/Kconfig @@ -5,6 +5,7 @@ config GCOV_KERNEL bool "Enable gcov-based kernel profiling" depends on DEBUG_FS depends on !CC_IS_CLANG || CLANG_VERSION >= 110000 + depends on !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR select CONSTRUCTORS default n help