Re: [PATCH V2 06/10] kasan: Allow arch to overrride kasan shadow offsets

From: Andrey Ryabinin
Date: Thu Aug 27 2015 - 05:48:12 EST


2015-08-26 11:26 GMT+03:00 Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>:
> Some archs may want to provide kasan shadow memory as a constant
> offset from the address. Such arch even though cannot use inline kasan
> support, they can work with outofline kasan support.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> ---
> include/linux/kasan.h | 3 +++
> mm/kasan/kasan.h | 3 +++
> 2 files changed, 6 insertions(+)
>
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index 5486d777b706..e458ca64cdaf 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -15,11 +15,14 @@ struct vm_struct;
> #include <asm/kasan.h>
> #include <linux/sched.h>
>
> +#ifndef kasan_mem_to_shadow
> static inline void *kasan_mem_to_shadow(const void *addr)
> {
> return (void *)((unsigned long)addr >> KASAN_SHADOW_SCALE_SHIFT)
> + KASAN_SHADOW_OFFSET;
> }
> +#define kasan_mem_to_shadow kasan_mem_to_shadow

Again, why we need this define here? I think it should be safe to remove it.

> +#endif
>
> /* Enable reporting bugs after kasan_disable_current() */
> static inline void kasan_enable_current(void)
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index deb547d5a916..c0686f2b1224 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -57,11 +57,14 @@ struct kasan_global {
> void kasan_report_error(struct kasan_access_info *info);
> void kasan_report_user_access(struct kasan_access_info *info);
>
> +#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)
> << KASAN_SHADOW_SCALE_SHIFT);
> }
> +#define kasan_shadow_to_mem kasan_shadow_to_mem

ditto

> +#endif
>
> static inline bool kasan_report_enabled(void)
> {
> --
> 2.5.0
>
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