Re: [PATCH V2] kasan: Cleanup the __HAVE_ARCH_SHADOW_MAP usage

[Andrey Konovalov]

On Tue, Sep 12, 2023 at 5:18 AM Huacai Chen <chenhuacai@xxxxxxxxxxx> wrote:
>
> As Linus suggested, __HAVE_ARCH_XYZ is "stupid" and "having historical
> uses of it doesn't make it good". So migrate __HAVE_ARCH_SHADOW_MAP to
> separate macros named after the respective functions.
>
> Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Reviewed-by: WANG Xuerui <git@xxxxxxxxxx>
> Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> ---
> V2: Update commit messages.
>
>  arch/loongarch/include/asm/kasan.h | 10 ++++++++--
>  include/linux/kasan.h              |  2 +-
>  mm/kasan/kasan.h                   |  8 +++-----
>  3 files changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/arch/loongarch/include/asm/kasan.h b/arch/loongarch/include/asm/kasan.h
> index deeff8158f45..a12ecab37da7 100644
> --- a/arch/loongarch/include/asm/kasan.h
> +++ b/arch/loongarch/include/asm/kasan.h
> @@ -10,8 +10,6 @@
>  #include <asm/io.h>
>  #include <asm/pgtable.h>
>
> -#define __HAVE_ARCH_SHADOW_MAP
> -
>  #define KASAN_SHADOW_SCALE_SHIFT 3
>  #define KASAN_SHADOW_OFFSET    _AC(CONFIG_KASAN_SHADOW_OFFSET, UL)
>
> @@ -68,6 +66,7 @@ static __always_inline bool kasan_arch_is_ready(void)
>         return !kasan_early_stage;
>  }
>
> +#define kasan_mem_to_shadow kasan_mem_to_shadow
>  static inline void *kasan_mem_to_shadow(const void *addr)
>  {
>         if (!kasan_arch_is_ready()) {
> @@ -97,6 +96,7 @@ static inline void *kasan_mem_to_shadow(const void *addr)
>         }
>  }
>
> +#define kasan_shadow_to_mem kasan_shadow_to_mem
>  static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
>  {
>         unsigned long addr = (unsigned long)shadow_addr;
> @@ -119,6 +119,12 @@ static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
>         }
>  }
>
> +#define addr_has_metadata addr_has_metadata
> +static __always_inline bool addr_has_metadata(const void *addr)
> +{
> +       return (kasan_mem_to_shadow((void *)addr) != NULL);
> +}
> +
>  void kasan_init(void);
>  asmlinkage void kasan_early_init(void);
>
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index 3df5499f7936..842623d708c2 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -54,7 +54,7 @@ extern p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D];
>  int kasan_populate_early_shadow(const void *shadow_start,
>                                 const void *shadow_end);
>
> -#ifndef __HAVE_ARCH_SHADOW_MAP
> +#ifndef kasan_mem_to_shadow
>  static inline void *kasan_mem_to_shadow(const void *addr)
>  {
>         return (void *)((unsigned long)addr >> KASAN_SHADOW_SCALE_SHIFT)
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index f70e3d7a602e..d37831b8511c 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -291,7 +291,7 @@ struct kasan_stack_ring {
>
>  #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
>
> -#ifndef __HAVE_ARCH_SHADOW_MAP
> +#ifndef kasan_shadow_to_mem
>  static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
>  {
>         return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET)
> @@ -299,15 +299,13 @@ static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
>  }
>  #endif
>
> +#ifndef addr_has_metadata
>  static __always_inline bool addr_has_metadata(const void *addr)
>  {
> -#ifdef __HAVE_ARCH_SHADOW_MAP
> -       return (kasan_mem_to_shadow((void *)addr) != NULL);
> -#else
>         return (kasan_reset_tag(addr) >=
>                 kasan_shadow_to_mem((void *)KASAN_SHADOW_START));
> -#endif
>  }
> +#endif
>
>  /**
>   * kasan_check_range - Check memory region, and report if invalid access.
> --
> 2.39.3
>

Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxx>

Thanks!