Re: [PATCH] treewide: Remove stringification from __alias macro definition

From: Nathan Chancellor
Date: Fri Oct 30 2020 - 03:40:45 EST

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In reply to: Joe Perches: "[PATCH] treewide: Remove stringification from __alias macro definition"
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On Thu, Oct 29, 2020 at 08:07:31PM -0700, Joe Perches wrote:
> Like the old __section macro, the __alias macro uses macro # stringification
> to create quotes around the symbol name used in the __attribute__.
>
> This can cause differences between gcc and clang when the stringification
> itself contains a quote character. So avoid these differences by always
> using quotes to define the aliased symbol.
>
> Remove the stringification and add quotes and when necessary a stringification
> when existing uses have a ## concatenation.
>
> Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>

Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>

> ---
>
> Unlike the __section macro conversion in commit 33def8498fdd
> ("treewide: Convert macro and uses of __section(foo) to __section("foo")")
> this one was done by hand.
>
> No other use of __alias exists in the kernel.
>
> This patch does _not_ convert any uses of __attribute__((alias("<foo>")))
> so it should not cause any compilation issues.
>
> arch/x86/boot/compressed/string.c | 6 +++---
> arch/x86/include/asm/syscall_wrapper.h | 2 +-
> drivers/firmware/efi/runtime-wrappers.c | 2 +-
> include/linux/compiler_attributes.h | 2 +-
> kernel/kcsan/core.c | 10 +++++-----
> lib/crc32.c | 4 ++--
> lib/crypto/aes.c | 4 ++--
> mm/kasan/generic.c | 8 ++++----
> 8 files changed, 19 insertions(+), 19 deletions(-)
>
> diff --git a/arch/x86/boot/compressed/string.c b/arch/x86/boot/compressed/string.c
> index 81fc1eaa3229..d38b122f51ef 100644
> --- a/arch/x86/boot/compressed/string.c
> +++ b/arch/x86/boot/compressed/string.c
> @@ -75,7 +75,7 @@ void *memcpy(void *dest, const void *src, size_t n)
> }
>
> #ifdef CONFIG_KASAN
> -extern void *__memset(void *s, int c, size_t n) __alias(memset);
> -extern void *__memmove(void *dest, const void *src, size_t n) __alias(memmove);
> -extern void *__memcpy(void *dest, const void *src, size_t n) __alias(memcpy);
> +extern void *__memset(void *s, int c, size_t n) __alias("memset");
> +extern void *__memmove(void *dest, const void *src, size_t n) __alias("memmove");
> +extern void *__memcpy(void *dest, const void *src, size_t n) __alias("memcpy");
> #endif
> diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
> index a84333adeef2..f19d1bbbff3d 100644
> --- a/arch/x86/include/asm/syscall_wrapper.h
> +++ b/arch/x86/include/asm/syscall_wrapper.h
> @@ -69,7 +69,7 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
> long __##abi##_##name(const struct pt_regs *regs); \
> ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \
> long __##abi##_##name(const struct pt_regs *regs) \
> - __alias(__do_##name);
> + __alias("__do_" #name);
>
> #define __SYS_STUBx(abi, name, ...) \
> long __##abi##_##name(const struct pt_regs *regs); \
> diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
> index 1410beaef5c3..14e380ac65d4 100644
> --- a/drivers/firmware/efi/runtime-wrappers.c
> +++ b/drivers/firmware/efi/runtime-wrappers.c
> @@ -162,7 +162,7 @@ static DEFINE_SEMAPHORE(efi_runtime_lock);
> * Expose the EFI runtime lock to the UV platform
> */
> #ifdef CONFIG_X86_UV
> -extern struct semaphore __efi_uv_runtime_lock __alias(efi_runtime_lock);
> +extern struct semaphore __efi_uv_runtime_lock __alias("efi_runtime_lock");
> #endif
>
> /*
> diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
> index ea7b756b1c8f..4819512c9abd 100644
> --- a/include/linux/compiler_attributes.h
> +++ b/include/linux/compiler_attributes.h
> @@ -42,7 +42,7 @@
> /*
> * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-alias-function-attribute
> */
> -#define __alias(symbol) __attribute__((__alias__(#symbol)))
> +#define __alias(symbol) __attribute__((__alias__(symbol)))
>
> /*
> * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-aligned-function-attribute
> diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c
> index 3994a217bde7..465f6cfc317c 100644
> --- a/kernel/kcsan/core.c
> +++ b/kernel/kcsan/core.c
> @@ -814,7 +814,7 @@ EXPORT_SYMBOL(__kcsan_check_access);
> } \
> EXPORT_SYMBOL(__tsan_read##size); \
> void __tsan_unaligned_read##size(void *ptr) \
> - __alias(__tsan_read##size); \
> + __alias("__tsan_read" #size); \
> EXPORT_SYMBOL(__tsan_unaligned_read##size); \
> void __tsan_write##size(void *ptr); \
> void __tsan_write##size(void *ptr) \
> @@ -823,7 +823,7 @@ EXPORT_SYMBOL(__kcsan_check_access);
> } \
> EXPORT_SYMBOL(__tsan_write##size); \
> void __tsan_unaligned_write##size(void *ptr) \
> - __alias(__tsan_write##size); \
> + __alias("__tsan_write" #size); \
> EXPORT_SYMBOL(__tsan_unaligned_write##size); \
> void __tsan_read_write##size(void *ptr); \
> void __tsan_read_write##size(void *ptr) \
> @@ -833,7 +833,7 @@ EXPORT_SYMBOL(__kcsan_check_access);
> } \
> EXPORT_SYMBOL(__tsan_read_write##size); \
> void __tsan_unaligned_read_write##size(void *ptr) \
> - __alias(__tsan_read_write##size); \
> + __alias("__tsan_read_write" #size); \
> EXPORT_SYMBOL(__tsan_unaligned_read_write##size)
>
> DEFINE_TSAN_READ_WRITE(1);
> @@ -877,7 +877,7 @@ EXPORT_SYMBOL(__tsan_write_range);
> } \
> EXPORT_SYMBOL(__tsan_volatile_read##size); \
> void __tsan_unaligned_volatile_read##size(void *ptr) \
> - __alias(__tsan_volatile_read##size); \
> + __alias("__tsan_volatile_read" #size); \
> EXPORT_SYMBOL(__tsan_unaligned_volatile_read##size); \
> void __tsan_volatile_write##size(void *ptr); \
> void __tsan_volatile_write##size(void *ptr) \
> @@ -892,7 +892,7 @@ EXPORT_SYMBOL(__tsan_write_range);
> } \
> EXPORT_SYMBOL(__tsan_volatile_write##size); \
> void __tsan_unaligned_volatile_write##size(void *ptr) \
> - __alias(__tsan_volatile_write##size); \
> + __alias("__tsan_volatile_write" #size); \
> EXPORT_SYMBOL(__tsan_unaligned_volatile_write##size)
>
> DEFINE_TSAN_VOLATILE_READ_WRITE(1);
> diff --git a/lib/crc32.c b/lib/crc32.c
> index 2a68dfd3b96c..373a17aaa432 100644
> --- a/lib/crc32.c
> +++ b/lib/crc32.c
> @@ -206,8 +206,8 @@ u32 __pure __weak __crc32c_le(u32 crc, unsigned char const *p, size_t len)
> EXPORT_SYMBOL(crc32_le);
> EXPORT_SYMBOL(__crc32c_le);
>
> -u32 __pure crc32_le_base(u32, unsigned char const *, size_t) __alias(crc32_le);
> -u32 __pure __crc32c_le_base(u32, unsigned char const *, size_t) __alias(__crc32c_le);
> +u32 __pure crc32_le_base(u32, unsigned char const *, size_t) __alias("crc32_le");
> +u32 __pure __crc32c_le_base(u32, unsigned char const *, size_t) __alias("__crc32c_le");
>
> /*
> * This multiplies the polynomials x and y modulo the given modulus.
> diff --git a/lib/crypto/aes.c b/lib/crypto/aes.c
> index 827fe89922ff..5b80514595c2 100644
> --- a/lib/crypto/aes.c
> +++ b/lib/crypto/aes.c
> @@ -82,8 +82,8 @@ static volatile const u8 __cacheline_aligned aes_inv_sbox[] = {
> 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d,
> };
>
> -extern const u8 crypto_aes_sbox[256] __alias(aes_sbox);
> -extern const u8 crypto_aes_inv_sbox[256] __alias(aes_inv_sbox);
> +extern const u8 crypto_aes_sbox[256] __alias("aes_sbox");
> +extern const u8 crypto_aes_inv_sbox[256] __alias("aes_inv_sbox");
>
> EXPORT_SYMBOL(crypto_aes_sbox);
> EXPORT_SYMBOL(crypto_aes_inv_sbox);
> diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
> index 248264b9cb76..4496f897e4f5 100644
> --- a/mm/kasan/generic.c
> +++ b/mm/kasan/generic.c
> @@ -234,7 +234,7 @@ EXPORT_SYMBOL(__asan_unregister_globals);
> check_memory_region_inline(addr, size, false, _RET_IP_);\
> } \
> EXPORT_SYMBOL(__asan_load##size); \
> - __alias(__asan_load##size) \
> + __alias("__asan_load" #size) \
> void __asan_load##size##_noabort(unsigned long); \
> EXPORT_SYMBOL(__asan_load##size##_noabort); \
> void __asan_store##size(unsigned long addr) \
> @@ -242,7 +242,7 @@ EXPORT_SYMBOL(__asan_unregister_globals);
> check_memory_region_inline(addr, size, true, _RET_IP_); \
> } \
> EXPORT_SYMBOL(__asan_store##size); \
> - __alias(__asan_store##size) \
> + __alias("__asan_store" #size) \
> void __asan_store##size##_noabort(unsigned long); \
> EXPORT_SYMBOL(__asan_store##size##_noabort)
>
> @@ -258,7 +258,7 @@ void __asan_loadN(unsigned long addr, size_t size)
> }
> EXPORT_SYMBOL(__asan_loadN);
>
> -__alias(__asan_loadN)
> +__alias("__asan_loadN")
> void __asan_loadN_noabort(unsigned long, size_t);
> EXPORT_SYMBOL(__asan_loadN_noabort);
>
> @@ -268,7 +268,7 @@ void __asan_storeN(unsigned long addr, size_t size)
> }
> EXPORT_SYMBOL(__asan_storeN);
>
> -__alias(__asan_storeN)
> +__alias("__asan_storeN")
> void __asan_storeN_noabort(unsigned long, size_t);
> EXPORT_SYMBOL(__asan_storeN_noabort);
>
> --
> 2.26.0
>

Next message: Mauro Carvalho Chehab: "[PATCH v2 11/39] docs: kernellog.py: add support for info()"
Previous message: Yunsheng Lin: "Re: [PATCH v2 net] net: sch_generic: aviod concurrent reset and enqueue op for lockless qdisc"
In reply to: Joe Perches: "[PATCH] treewide: Remove stringification from __alias macro definition"
Next in thread: Miguel Ojeda: "Re: [PATCH] treewide: Remove stringification from __alias macro definition"
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