diff mbox series

[-next] treewide: Remove stringification from __alias macro definition

Message ID e9b1ba517f06b81bd24e54c84f5e44d81c27c566.camel@perches.com (mailing list archive)
State New
Headers show
Series [-next] treewide: Remove stringification from __alias macro definition | expand

Commit Message

Joe Perches Oct. 21, 2020, 6:58 p.m. UTC
Like the __section macro, the __alias macro uses
macro # stringification to create quotes around
the section name used in the __attribute__.

Remove the stringification and add quotes or a
stringification to the uses instead.

Signed-off-by: Joe Perches <joe@perches.com>
---

There is a script that might eventually be applied
to convert the __section macro definition and uses
to remove stringification

https://lore.kernel.org/lkml/46f69161e60b802488ba8c8f3f8bbf922aa3b49b.camel@perches.com/
https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/

This patch is intended to create commonality
between the uses of __section and __alias.

 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(-)

Comments

Ard Biesheuvel Oct. 21, 2020, 7:02 p.m. UTC | #1
On Wed, 21 Oct 2020 at 20:58, Joe Perches <joe@perches.com> wrote:
>
> Like the __section macro, the __alias macro uses
> macro # stringification to create quotes around
> the section name used in the __attribute__.
>
> Remove the stringification and add quotes or a
> stringification to the uses instead.
>

Why?

> Signed-off-by: Joe Perches <joe@perches.com>
> ---
>
> There is a script that might eventually be applied
> to convert the __section macro definition and uses
> to remove stringification
>
> https://lore.kernel.org/lkml/46f69161e60b802488ba8c8f3f8bbf922aa3b49b.camel@perches.com/
> https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/
>
> This patch is intended to create commonality
> between the uses of __section and __alias.
>
>  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);
>
>
>
>
>
Joe Perches Oct. 21, 2020, 7:07 p.m. UTC | #2
On Wed, 2020-10-21 at 21:02 +0200, Ard Biesheuvel wrote:
> On Wed, 21 Oct 2020 at 20:58, Joe Perches <joe@perches.com> wrote:
> > Like the __section macro, the __alias macro uses
> > macro # stringification to create quotes around
> > the section name used in the __attribute__.
> > 
> > Remove the stringification and add quotes or a
> > stringification to the uses instead.
> > 
> 
> Why?

Using quotes in __section caused/causes differences
between clang and gcc.

https://lkml.org/lkml/2020/9/29/2187

Using common styles for details like this is good.
Ard Biesheuvel Oct. 21, 2020, 7:09 p.m. UTC | #3
On Wed, 21 Oct 2020 at 21:07, Joe Perches <joe@perches.com> wrote:
>
> On Wed, 2020-10-21 at 21:02 +0200, Ard Biesheuvel wrote:
> > On Wed, 21 Oct 2020 at 20:58, Joe Perches <joe@perches.com> wrote:
> > > Like the __section macro, the __alias macro uses
> > > macro # stringification to create quotes around
> > > the section name used in the __attribute__.
> > >
> > > Remove the stringification and add quotes or a
> > > stringification to the uses instead.
> > >
> >
> > Why?
>
> Using quotes in __section caused/causes differences
> between clang and gcc.
>
> https://lkml.org/lkml/2020/9/29/2187
>
> Using common styles for details like this is good.
>
>

Ah, fair enough.

With this rationale added to the commit log:

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Marco Elver Oct. 21, 2020, 7:20 p.m. UTC | #4
On Wed, 21 Oct 2020 at 20:58, Joe Perches <joe@perches.com> wrote:
>
> Like the __section macro, the __alias macro uses
> macro # stringification to create quotes around
> the section name used in the __attribute__.
>
> Remove the stringification and add quotes or a
> stringification to the uses instead.
>
> Signed-off-by: Joe Perches <joe@perches.com>
> ---
>
> There is a script that might eventually be applied
> to convert the __section macro definition and uses
> to remove stringification
>
> https://lore.kernel.org/lkml/46f69161e60b802488ba8c8f3f8bbf922aa3b49b.camel@perches.com/
> https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/
>
> This patch is intended to create commonality
> between the uses of __section and __alias.
>
>  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(-)

Reviewed-by: Marco Elver <elver@google.com>

for KCSAN and KASAN.

Thank you!

> 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);
>
>
>
>
>
Miguel Ojeda Oct. 21, 2020, 7:23 p.m. UTC | #5
On Wed, Oct 21, 2020 at 9:07 PM Joe Perches <joe@perches.com> wrote:
>
> Using quotes in __section caused/causes differences
> between clang and gcc.

Yeah, it is a good cleanup get.

Thanks!

> https://lkml.org/lkml/2020/9/29/2187

Can you please put this in a Link: like Ard suggested? (and ideally
find the message in lore.kernel.org instead).

Cheers,
Miguel
Nick Desaulniers Oct. 21, 2020, 8:23 p.m. UTC | #6
On Wed, Oct 21, 2020 at 12:07 PM Joe Perches <joe@perches.com> wrote:
>
> On Wed, 2020-10-21 at 21:02 +0200, Ard Biesheuvel wrote:
> > On Wed, 21 Oct 2020 at 20:58, Joe Perches <joe@perches.com> wrote:
> > > Like the __section macro, the __alias macro uses
> > > macro # stringification to create quotes around
> > > the section name used in the __attribute__.
> > >
> > > Remove the stringification and add quotes or a
> > > stringification to the uses instead.
> > >
> >
> > Why?
>
> Using quotes in __section caused/causes differences
> between clang and gcc.
>
> https://lkml.org/lkml/2020/9/29/2187
>
> Using common styles for details like this is good.

Luckily, there's no difference/issue here with alias as there exist
with section: https://godbolt.org/z/eWxc7P
So it's just a stylistic cleanup, not a bugfix.
Acked-by: Nick Desaulniers <ndesaulniers@google.com>

$ grep -rn __attribute__ | grep alias

didn't turn up any other cases that look like they don't use strings.
David Laight Oct. 21, 2020, 9:18 p.m. UTC | #7
From: Ard Biesheuvel
> Sent: 21 October 2020 20:03
> 
> On Wed, 21 Oct 2020 at 20:58, Joe Perches <joe@perches.com> wrote:
> >
> > Like the __section macro, the __alias macro uses
> > macro # stringification to create quotes around
> > the section name used in the __attribute__.
> >
> > Remove the stringification and add quotes or a
> > stringification to the uses instead.
> >
> 
> Why?

It allows the section name be made up of two concatenated strings.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
Peter Zijlstra Oct. 22, 2020, 7:33 a.m. UTC | #8
On Wed, Oct 21, 2020 at 11:58:25AM -0700, Joe Perches wrote:
> Like the __section macro, the __alias macro uses
> macro # stringification to create quotes around
> the section name used in the __attribute__.
> 
> Remove the stringification and add quotes or a
> stringification to the uses instead.

There's a complete lack of rationale for this change.
Joe Perches Oct. 22, 2020, 4:20 p.m. UTC | #9
On Thu, 2020-10-22 at 09:33 +0200, Peter Zijlstra wrote:
> On Wed, Oct 21, 2020 at 11:58:25AM -0700, Joe Perches wrote:
> > Like the __section macro, the __alias macro uses
> > macro # stringification to create quotes around
> > the section name used in the __attribute__.
> > 
> > Remove the stringification and add quotes or a
> > stringification to the uses instead.
> 
> There's a complete lack of rationale for this change.

I'll eventually post V2.
I'm waiting to see if there are more comments.

As I wrote in reply to Ard:

https://lore.kernel.org/lkml/1cecfbfc853b2e71a96ab58661037c28a2f9280e.camel@perches.com/

Using quotes in __section caused/causes differences
between clang and gcc.

https://lkml.org/lkml/2020/9/29/2187

Using common styles for details like this is good.
Ard Biesheuvel Nov. 11, 2020, 7:19 a.m. UTC | #10
(+ Russell)

On Thu, 22 Oct 2020 at 18:20, Joe Perches <joe@perches.com> wrote:
>
> On Thu, 2020-10-22 at 09:33 +0200, Peter Zijlstra wrote:
> > On Wed, Oct 21, 2020 at 11:58:25AM -0700, Joe Perches wrote:
> > > Like the __section macro, the __alias macro uses
> > > macro # stringification to create quotes around
> > > the section name used in the __attribute__.
> > >
> > > Remove the stringification and add quotes or a
> > > stringification to the uses instead.
> >
> > There's a complete lack of rationale for this change.
>
> I'll eventually post V2.
> I'm waiting to see if there are more comments.
>
> As I wrote in reply to Ard:
>
> https://lore.kernel.org/lkml/1cecfbfc853b2e71a96ab58661037c28a2f9280e.camel@perches.com/
>
> Using quotes in __section caused/causes differences
> between clang and gcc.
>
> https://lkml.org/lkml/2020/9/29/2187
>
> Using common styles for details like this is good.
>

This patch is now causing problems in the ARM tree, because some new
uses of __alias() have been queued (for KASAN), and since this is a
non-backwards compatible change, we have to choose between breaking
the maintainer's tree or breaking -next (given that the change has
been pulled in there now)

I am still not convinced we need this change, as I don't see how the
concerns regarding __section apply to __alias. But if we do, can we
please use the same approach, i.e., revert the current patch, and
queue it again after v5.11-rc1 with all new occurrences covered as
well?
Miguel Ojeda Nov. 12, 2020, 9:36 a.m. UTC | #11
On Wed, Nov 11, 2020 at 8:19 AM Ard Biesheuvel <ardb@kernel.org> wrote:
>
> I am still not convinced we need this change, as I don't see how the
> concerns regarding __section apply to __alias. But if we do, can we
> please use the same approach, i.e., revert the current patch, and
> queue it again after v5.11-rc1 with all new occurrences covered as
> well?

In general, it would be nice to move all compiler attributes to use
the `__` syntax, which is independent of compiler vendor, gives us a
level of indirection to modify behavior between compilers and is
shorter/nicer for users.

But it is low priority, so it should go in whenever it causes the
least amount of trouble.

Cheers,
Miguel
diff mbox series

Patch

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);