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kasan: define KASAN_MEMORY_PER_SHADOW_PAGE

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Define KASAN_MEMORY_PER_SHADOW_PAGE as (KASAN_GRANULE_SIZE << PAGE_SHIFT),
which is the same as (KASAN_GRANULE_SIZE * PAGE_SIZE) for software modes
that use shadow memory, and use it across KASAN code to simplify it.

Link: https://lkml.kernel.org/r/8329391cfe14b5cffd3decf3b5c535b6ce21eef6.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2020-12-22 12:00:35 -08:00 committed by Linus Torvalds
parent bb359dbcb7
commit affc3f0775
3 changed files with 13 additions and 15 deletions
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10
mm/kasan/init.c
View file

@ -441,9 +441,8 @@ void kasan_remove_zero_shadow(void *start, unsigned long size)
addr = (unsigned long)kasan_mem_to_shadow(start);
end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);
if (WARN_ON((unsigned long)start %
(KASAN_GRANULE_SIZE * PAGE_SIZE)) ||
WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE)))
if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||
WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
return;
for (; addr < end; addr = next) {
@ -476,9 +475,8 @@ int kasan_add_zero_shadow(void *start, unsigned long size)
shadow_start = kasan_mem_to_shadow(start);
shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);
if (WARN_ON((unsigned long)start %
(KASAN_GRANULE_SIZE * PAGE_SIZE)) ||
WARN_ON(size % (KASAN_GRANULE_SIZE * PAGE_SIZE)))
if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||
WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
return -EINVAL;
ret = kasan_populate_early_shadow(shadow_start, shadow_end);

2
mm/kasan/kasan.h
View file

@ -8,6 +8,8 @@
#define KASAN_GRANULE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT)
#define KASAN_GRANULE_MASK (KASAN_GRANULE_SIZE - 1)
#define KASAN_MEMORY_PER_SHADOW_PAGE (KASAN_GRANULE_SIZE << PAGE_SHIFT)
#define KASAN_TAG_KERNEL 0xFF /* native kernel pointers tag */
#define KASAN_TAG_INVALID 0xFE /* inaccessible memory tag */
#define KASAN_TAG_MAX 0xFD /* maximum value for random tags */

16
mm/kasan/shadow.c
View file

@ -161,7 +161,7 @@ static int __meminit kasan_mem_notifier(struct notifier_block *nb,
shadow_end = shadow_start + shadow_size;
if (WARN_ON(mem_data->nr_pages % KASAN_GRANULE_SIZE) ||
WARN_ON(start_kaddr % (KASAN_GRANULE_SIZE << PAGE_SHIFT)))
WARN_ON(start_kaddr % KASAN_MEMORY_PER_SHADOW_PAGE))
return NOTIFY_BAD;
switch (action) {
@ -432,22 +432,20 @@ void kasan_release_vmalloc(unsigned long start, unsigned long end,
unsigned long region_start, region_end;
unsigned long size;
region_start = ALIGN(start, PAGE_SIZE * KASAN_GRANULE_SIZE);
region_end = ALIGN_DOWN(end, PAGE_SIZE * KASAN_GRANULE_SIZE);
region_start = ALIGN(start, KASAN_MEMORY_PER_SHADOW_PAGE);
region_end = ALIGN_DOWN(end, KASAN_MEMORY_PER_SHADOW_PAGE);
free_region_start = ALIGN(free_region_start,
PAGE_SIZE * KASAN_GRANULE_SIZE);
free_region_start = ALIGN(free_region_start, KASAN_MEMORY_PER_SHADOW_PAGE);
if (start != region_start &&
free_region_start < region_start)
region_start -= PAGE_SIZE * KASAN_GRANULE_SIZE;
region_start -= KASAN_MEMORY_PER_SHADOW_PAGE;
free_region_end = ALIGN_DOWN(free_region_end,
PAGE_SIZE * KASAN_GRANULE_SIZE);
free_region_end = ALIGN_DOWN(free_region_end, KASAN_MEMORY_PER_SHADOW_PAGE);
if (end != region_end &&
free_region_end > region_end)
region_end += PAGE_SIZE * KASAN_GRANULE_SIZE;
region_end += KASAN_MEMORY_PER_SHADOW_PAGE;
shadow_start = kasan_mem_to_shadow((void *)region_start);
shadow_end = kasan_mem_to_shadow((void *)region_end);