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/[email protected]/
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 <[email protected]>
Reviewed-by: Miguel Ojeda <[email protected]>
Suggested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Nick Desaulniers <[email protected]>
---
Changes V1 -> V2:
* s/no_profile/no_profile_instrument_function/
* fix trailing double underscore on GCC 4 define, as per Fangrui+Miguel.
* Pick up Fangrui + Miguel's reviewed-by tag.
* Add link to GCC's doc.
* Fix clang's doc format; will appear once clang-13 is released.
include/linux/compiler_attributes.h | 13 +++++++++++++
include/linux/compiler_types.h | 2 +-
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
index c043b8d2b17b..225511b17223 100644
--- a/include/linux/compiler_attributes.h
+++ b/include/linux/compiler_attributes.h
@@ -33,6 +33,7 @@
# define __GCC4_has_attribute___externally_visible__ 1
# define __GCC4_has_attribute___no_caller_saved_registers__ 0
# define __GCC4_has_attribute___noclone__ 1
+# define __GCC4_has_attribute___no_profile_instrument_function__ 0
# define __GCC4_has_attribute___nonstring__ 0
# define __GCC4_has_attribute___no_sanitize_address__ (__GNUC_MINOR__ >= 8)
# define __GCC4_has_attribute___no_sanitize_undefined__ (__GNUC_MINOR__ >= 9)
@@ -237,6 +238,18 @@
# define __nonstring
#endif
+/*
+ * Optional: only supported since GCC >= 7.1, clang >= 13.0.
+ *
+ * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-no_005fprofile_005finstrument_005ffunction-function-attribute
+ * clang: https://clang.llvm.org/docs/AttributeReference.html#no-profile-instrument-function
+ */
+#if __has_attribute(__no_profile_instrument_function__)
+# define __no_profile __attribute__((__no_profile_instrument_function__))
+#else
+# define __no_profile
+#endif
+
/*
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noreturn-function-attribute
* clang: https://clang.llvm.org/docs/AttributeReference.html#noreturn
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index d29bda7f6ebd..d509169860f1 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -210,7 +210,7 @@ struct ftrace_likely_data {
/* Section for code which can't be instrumented at all */
#define noinstr \
noinline notrace __attribute((__section__(".noinstr.text"))) \
- __no_kcsan __no_sanitize_address
+ __no_kcsan __no_sanitize_address __no_profile
#endif /* __KERNEL__ */
--
2.32.0.288.g62a8d224e6-goog
On 6/21/2021 4:18 PM, 'Nick Desaulniers' via Clang Built Linux wrote:
> 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/[email protected]/
> 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 <[email protected]>
> Reviewed-by: Miguel Ojeda <[email protected]>
> Suggested-by: Peter Zijlstra <[email protected]>
> Signed-off-by: Nick Desaulniers <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
> ---
> Changes V1 -> V2:
> * s/no_profile/no_profile_instrument_function/
> * fix trailing double underscore on GCC 4 define, as per Fangrui+Miguel.
> * Pick up Fangrui + Miguel's reviewed-by tag.
> * Add link to GCC's doc.
> * Fix clang's doc format; will appear once clang-13 is released.
>
> include/linux/compiler_attributes.h | 13 +++++++++++++
> include/linux/compiler_types.h | 2 +-
> 2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
> index c043b8d2b17b..225511b17223 100644
> --- a/include/linux/compiler_attributes.h
> +++ b/include/linux/compiler_attributes.h
> @@ -33,6 +33,7 @@
> # define __GCC4_has_attribute___externally_visible__ 1
> # define __GCC4_has_attribute___no_caller_saved_registers__ 0
> # define __GCC4_has_attribute___noclone__ 1
> +# define __GCC4_has_attribute___no_profile_instrument_function__ 0
> # define __GCC4_has_attribute___nonstring__ 0
> # define __GCC4_has_attribute___no_sanitize_address__ (__GNUC_MINOR__ >= 8)
> # define __GCC4_has_attribute___no_sanitize_undefined__ (__GNUC_MINOR__ >= 9)
> @@ -237,6 +238,18 @@
> # define __nonstring
> #endif
>
> +/*
> + * Optional: only supported since GCC >= 7.1, clang >= 13.0.
> + *
> + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-no_005fprofile_005finstrument_005ffunction-function-attribute
> + * clang: https://clang.llvm.org/docs/AttributeReference.html#no-profile-instrument-function
> + */
> +#if __has_attribute(__no_profile_instrument_function__)
> +# define __no_profile __attribute__((__no_profile_instrument_function__))
> +#else
> +# define __no_profile
> +#endif
> +
> /*
> * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noreturn-function-attribute
> * clang: https://clang.llvm.org/docs/AttributeReference.html#noreturn
> diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
> index d29bda7f6ebd..d509169860f1 100644
> --- a/include/linux/compiler_types.h
> +++ b/include/linux/compiler_types.h
> @@ -210,7 +210,7 @@ struct ftrace_likely_data {
> /* Section for code which can't be instrumented at all */
> #define noinstr \
> noinline notrace __attribute((__section__(".noinstr.text"))) \
> - __no_kcsan __no_sanitize_address
> + __no_kcsan __no_sanitize_address __no_profile
>
> #endif /* __KERNEL__ */
>
>