diff options
| -rw-r--r-- | include/linux/compiler_attributes.h | 6 | ||||
| -rw-r--r-- | include/linux/compiler_types.h | 27 | ||||
| -rw-r--r-- | kernel/exit.c | 9 |
3 files changed, 35 insertions, 7 deletions
diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h index 898b3458b24a..b83126452c65 100644 --- a/include/linux/compiler_attributes.h +++ b/include/linux/compiler_attributes.h @@ -76,12 +76,6 @@ #endif /* - * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-cold-function-attribute - * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-cold-label-attribute - */ -#define __cold __attribute__((__cold__)) - -/* * Note the long name. * * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-const-function-attribute diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 7c1afe0f4129..aab34e30128e 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -79,6 +79,33 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { } /* Attributes */ #include <linux/compiler_attributes.h> +#if CONFIG_FUNCTION_ALIGNMENT > 0 +#define __function_aligned __aligned(CONFIG_FUNCTION_ALIGNMENT) +#else +#define __function_aligned +#endif + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-cold-function-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-cold-label-attribute + * + * When -falign-functions=N is in use, we must avoid the cold attribute as + * contemporary versions of GCC drop the alignment for cold functions. Worse, + * GCC can implicitly mark callees of cold functions as cold themselves, so + * it's not sufficient to add __function_aligned here as that will not ensure + * that callees are correctly aligned. + * + * See: + * + * https://lore.kernel.org/lkml/Y77%2FqVgvaJidFpYt@FVFF77S0Q05N + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345#c9 + */ +#if !defined(CONFIG_CC_IS_GCC) || (CONFIG_FUNCTION_ALIGNMENT == 0) +#define __cold __attribute__((__cold__)) +#else +#define __cold +#endif + /* Builtins */ /* diff --git a/kernel/exit.c b/kernel/exit.c index 15dc2ec80c46..c8e0375705f4 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1898,7 +1898,14 @@ bool thread_group_exited(struct pid *pid) } EXPORT_SYMBOL(thread_group_exited); -__weak void abort(void) +/* + * This needs to be __function_aligned as GCC implicitly makes any + * implementation of abort() cold and drops alignment specified by + * -falign-functions=N. + * + * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345#c11 + */ +__weak __function_aligned void abort(void) { BUG(); |