Messages in this thread | | | Date | Thu, 27 Aug 2015 12:46:03 +0300 | Subject | Re: [PATCH V2 05/10] kasan: Enable arch to hook into kasan callbacks. | From | Andrey Ryabinin <> |
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2015-08-26 11:26 GMT+03:00 Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>: > We add enable/disable callbacks in this patch which architecture > can implemement. We will use this in the later patches for architecture > like ppc64, that cannot have early zero page kasan shadow region for the > entire virtual address space. Such architectures also cannot use > inline kasan support. > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> > --- > mm/kasan/kasan.c | 9 +++++++++ > mm/kasan/kasan.h | 15 +++++++++++++++ > 2 files changed, 24 insertions(+) > > diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c > index 7b28e9cdf1c7..e4d33afd0eaf 100644 > --- a/mm/kasan/kasan.c > +++ b/mm/kasan/kasan.c > @@ -43,6 +43,9 @@ static void kasan_poison_shadow(const void *address, size_t size, u8 value) > { > void *shadow_start, *shadow_end; > > + if (!kasan_enabled()) > + return; > +
By the time this function called we already should have shadow, so it should be safe to remove this check.
> shadow_start = kasan_mem_to_shadow(address); > shadow_end = kasan_mem_to_shadow(address + size); > > @@ -51,6 +54,9 @@ static void kasan_poison_shadow(const void *address, size_t size, u8 value) > > void kasan_unpoison_shadow(const void *address, size_t size) > { > + if (!kasan_enabled()) > + return; > +
Ditto.
> kasan_poison_shadow(address, size, 0); > > if (size & KASAN_SHADOW_MASK) { > @@ -238,6 +244,9 @@ static __always_inline void check_memory_region(unsigned long addr, > { > struct kasan_access_info info; > > + if (!kasan_enabled()) > + return; > + > if (unlikely(size == 0)) > return; > > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h > index a6b46cc94907..deb547d5a916 100644 > --- a/mm/kasan/kasan.h > +++ b/mm/kasan/kasan.h > @@ -68,6 +68,21 @@ static inline bool kasan_report_enabled(void) > return !current->kasan_depth; > } > > +#ifndef kasan_enabled > +/* > + * Some archs may want to disable kasan callbacks. > + */ > +static inline bool kasan_enabled(void) > +{ > + return true; > +} > +#define kasan_enabled kasan_enabled
Why we need this define?
> +#else > +#ifdef CONFIG_KASAN_INLINE > +#error "Kasan inline support cannot work with KASAN arch hooks" > +#endif > +#endif > + > void kasan_report(unsigned long addr, size_t size, > bool is_write, unsigned long ip); > > -- > 2.5.0 >
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