| Message ID | 20210621231822.2848305-4-ndesaulniers@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | no_profile fn attr and Kconfig for GCOV+PGO | expand |
On 6/21/2021 4:18 PM, 'Nick Desaulniers' via Clang Built Linux wrote: > 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 PGO and GCOV depend on > it. > > 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 <masahiroy@kernel.org> > Cc: Peter Oberparleiter <oberpar@linux.ibm.com> > 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 <nathan@kernel.org> > Suggested-by: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Small nit below. > --- > Changes V1 -> V2: > * Add ARCH_WANTS_NO_INSTR > * Change depdendencies to be !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR > rather than list architectures explicitly, as per Nathan. > * s/no_profile/no_profile_instrument_function/ > > arch/Kconfig | 7 +++++++ > arch/arm64/Kconfig | 1 + > arch/s390/Kconfig | 1 + > arch/x86/Kconfig | 1 + > init/Kconfig | 3 +++ > kernel/gcov/Kconfig | 1 + > kernel/pgo/Kconfig | 3 ++- > 7 files changed, 16 insertions(+), 1 deletion(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 2b4109b0edee..2113c6b3b801 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 architecure should select this if the noinstr macro is being used on Architecture > + 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 da43fd046149..7d6a44bb9b0e 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -114,6 +114,7 @@ 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 > diff --git a/kernel/pgo/Kconfig b/kernel/pgo/Kconfig > index d2053df1111c..ce7fe04f303d 100644 > --- a/kernel/pgo/Kconfig > +++ b/kernel/pgo/Kconfig > @@ -8,7 +8,8 @@ config PGO_CLANG > bool "Enable clang's PGO-based kernel profiling" > depends on DEBUG_FS > depends on ARCH_SUPPORTS_PGO_CLANG > - depends on CC_IS_CLANG && CLANG_VERSION >= 120000 > + depends on CC_IS_CLANG > + depends on !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR > help > This option enables clang's PGO (Profile Guided Optimization) based > code profiling to better optimize the kernel. >
On Mon, Jun 21, 2021 at 04:18:22PM -0700, Nick Desaulniers wrote: > 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 PGO and GCOV depend on > it. > > 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 <masahiroy@kernel.org> > Cc: Peter Oberparleiter <oberpar@linux.ibm.com> > 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 <nathan@kernel.org> > Suggested-by: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> > --- > Changes V1 -> V2: > * Add ARCH_WANTS_NO_INSTR > * Change depdendencies to be !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR > rather than list architectures explicitly, as per Nathan. > * s/no_profile/no_profile_instrument_function/ > > arch/Kconfig | 7 +++++++ > arch/arm64/Kconfig | 1 + > arch/s390/Kconfig | 1 + > arch/x86/Kconfig | 1 + > init/Kconfig | 3 +++ > kernel/gcov/Kconfig | 1 + > kernel/pgo/Kconfig | 3 ++- > 7 files changed, 16 insertions(+), 1 deletion(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 2b4109b0edee..2113c6b3b801 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 architecure 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 There's also CC_HAS_WORKING_NOSANITIZE_ADDRESS in lib/Kconfig.kasan that might want to be hooked into this, but that can be done separately I suppose.
On Tue, 22 Jun 2021 at 09:26, Peter Zijlstra <peterz@infradead.org> wrote: > > On Mon, Jun 21, 2021 at 04:18:22PM -0700, Nick Desaulniers wrote: > > 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 PGO and GCOV depend on > > it. > > > > 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 <masahiroy@kernel.org> > > Cc: Peter Oberparleiter <oberpar@linux.ibm.com> > > 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 <nathan@kernel.org> > > Suggested-by: Peter Zijlstra <peterz@infradead.org> > > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> > > --- > > Changes V1 -> V2: > > * Add ARCH_WANTS_NO_INSTR > > * Change depdendencies to be !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR > > rather than list architectures explicitly, as per Nathan. > > * s/no_profile/no_profile_instrument_function/ > > > > arch/Kconfig | 7 +++++++ > > arch/arm64/Kconfig | 1 + > > arch/s390/Kconfig | 1 + > > arch/x86/Kconfig | 1 + > > init/Kconfig | 3 +++ > > kernel/gcov/Kconfig | 1 + > > kernel/pgo/Kconfig | 3 ++- > > 7 files changed, 16 insertions(+), 1 deletion(-) > > > > diff --git a/arch/Kconfig b/arch/Kconfig > > index 2b4109b0edee..2113c6b3b801 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 architecure 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 > > There's also CC_HAS_WORKING_NOSANITIZE_ADDRESS in lib/Kconfig.kasan that > might want to be hooked into this, but that can be done separately I > suppose. KASAN already depends on this for all compiler instrumentation modes, not just for 'noinstr' but also to avoid false positives. So it's not just for noinstr's benefit, and we should not weaken the requirement there.
On Mon, Jun 21, 2021 at 04:18:22PM -0700, Nick Desaulniers wrote: > 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 PGO and GCOV depend on > it. > > 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 <masahiroy@kernel.org> > Cc: Peter Oberparleiter <oberpar@linux.ibm.com> > 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 <nathan@kernel.org> > Suggested-by: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> FWIW, this looks good to me: Acked-by: Mark Rutland <mark.rutland@arm.com> Catalin, Will, are you happy iwth the arm64 bit? Thanks, Makr. > --- > Changes V1 -> V2: > * Add ARCH_WANTS_NO_INSTR > * Change depdendencies to be !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR > rather than list architectures explicitly, as per Nathan. > * s/no_profile/no_profile_instrument_function/ > > arch/Kconfig | 7 +++++++ > arch/arm64/Kconfig | 1 + > arch/s390/Kconfig | 1 + > arch/x86/Kconfig | 1 + > init/Kconfig | 3 +++ > kernel/gcov/Kconfig | 1 + > kernel/pgo/Kconfig | 3 ++- > 7 files changed, 16 insertions(+), 1 deletion(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 2b4109b0edee..2113c6b3b801 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 architecure 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 da43fd046149..7d6a44bb9b0e 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -114,6 +114,7 @@ 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 > diff --git a/kernel/pgo/Kconfig b/kernel/pgo/Kconfig > index d2053df1111c..ce7fe04f303d 100644 > --- a/kernel/pgo/Kconfig > +++ b/kernel/pgo/Kconfig > @@ -8,7 +8,8 @@ config PGO_CLANG > bool "Enable clang's PGO-based kernel profiling" > depends on DEBUG_FS > depends on ARCH_SUPPORTS_PGO_CLANG > - depends on CC_IS_CLANG && CLANG_VERSION >= 120000 > + depends on CC_IS_CLANG > + depends on !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR > help > This option enables clang's PGO (Profile Guided Optimization) based > code profiling to better optimize the kernel. > -- > 2.32.0.288.g62a8d224e6-goog >
On Mon, Jun 21, 2021 at 04:18:22PM -0700, Nick Desaulniers wrote: > 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 PGO and GCOV depend on > it. > > 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 <masahiroy@kernel.org> > Cc: Peter Oberparleiter <oberpar@linux.ibm.com> > 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 <nathan@kernel.org> > Suggested-by: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> > --- > Changes V1 -> V2: > * Add ARCH_WANTS_NO_INSTR > * Change depdendencies to be !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR > rather than list architectures explicitly, as per Nathan. > * s/no_profile/no_profile_instrument_function/ > > arch/Kconfig | 7 +++++++ > arch/arm64/Kconfig | 1 + > arch/s390/Kconfig | 1 + > arch/x86/Kconfig | 1 + > init/Kconfig | 3 +++ > kernel/gcov/Kconfig | 1 + > kernel/pgo/Kconfig | 3 ++- > 7 files changed, 16 insertions(+), 1 deletion(-) For s390: Acked-by: Heiko Carstens <hca@linux.ibm.com>
On 22.06.2021 01:18, Nick Desaulniers wrote: > 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 PGO and GCOV depend on > it. > > 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 <masahiroy@kernel.org> > Cc: Peter Oberparleiter <oberpar@linux.ibm.com> > 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 <nathan@kernel.org> > Suggested-by: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Looks good to me - thanks for resolving this problem! Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com> Regards, Peter
On Tue, Jun 22, 2021 at 10:05:40AM +0100, Mark Rutland wrote: > On Mon, Jun 21, 2021 at 04:18:22PM -0700, Nick Desaulniers wrote: > > 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 PGO and GCOV depend on > > it. > > > > 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 <masahiroy@kernel.org> > > Cc: Peter Oberparleiter <oberpar@linux.ibm.com> > > 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 <nathan@kernel.org> > > Suggested-by: Peter Zijlstra <peterz@infradead.org> > > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> > > FWIW, this looks good to me: > > Acked-by: Mark Rutland <mark.rutland@arm.com> > > Catalin, Will, are you happy iwth the arm64 bit? Looks fine to me. Will
diff --git a/arch/Kconfig b/arch/Kconfig index 2b4109b0edee..2113c6b3b801 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 architecure 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 da43fd046149..7d6a44bb9b0e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -114,6 +114,7 @@ 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 diff --git a/kernel/pgo/Kconfig b/kernel/pgo/Kconfig index d2053df1111c..ce7fe04f303d 100644 --- a/kernel/pgo/Kconfig +++ b/kernel/pgo/Kconfig @@ -8,7 +8,8 @@ config PGO_CLANG bool "Enable clang's PGO-based kernel profiling" depends on DEBUG_FS depends on ARCH_SUPPORTS_PGO_CLANG - depends on CC_IS_CLANG && CLANG_VERSION >= 120000 + depends on CC_IS_CLANG + depends on !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR help This option enables clang's PGO (Profile Guided Optimization) based code profiling to better optimize the kernel.
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 PGO and GCOV depend on it. 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 <masahiroy@kernel.org> Cc: Peter Oberparleiter <oberpar@linux.ibm.com> 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 <nathan@kernel.org> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> --- Changes V1 -> V2: * Add ARCH_WANTS_NO_INSTR * Change depdendencies to be !ARCH_WANTS_NO_INSTR || CC_HAS_NO_PROFILE_FN_ATTR rather than list architectures explicitly, as per Nathan. * s/no_profile/no_profile_instrument_function/ arch/Kconfig | 7 +++++++ arch/arm64/Kconfig | 1 + arch/s390/Kconfig | 1 + arch/x86/Kconfig | 1 + init/Kconfig | 3 +++ kernel/gcov/Kconfig | 1 + kernel/pgo/Kconfig | 3 ++- 7 files changed, 16 insertions(+), 1 deletion(-)