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kasan: initialize shadow to 0xff for tag-based mode

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A tag-based KASAN shadow memory cell contains a memory tag, that
corresponds to the tag in the top byte of the pointer, that points to that
memory.  The native top byte value of kernel pointers is 0xff, so with
tag-based KASAN we need to initialize shadow memory to 0xff.

[cai@lca.pw: arm64: skip kmemleak for KASAN again\
  Link: http://lkml.kernel.org/r/20181226020550.63712-1-cai@lca.pw
Link: http://lkml.kernel.org/r/5cc1b789aad7c99cf4f3ec5b328b147ad53edb40.1544099024.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mark Rutland <mark.rutland@arm.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
2018-12-28 00:30:09 -08:00
committed by Linus Torvalds
parent 9577dd7486
commit 080eb83f54
3 changed files with 22 additions and 3 deletions
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14
arch/arm64/mm/kasan_init.c
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@@ -43,6 +43,14 @@ static phys_addr_t __init kasan_alloc_zeroed_page(int node)
return __pa(p);
}
static phys_addr_t __init kasan_alloc_raw_page(int node)
{
void *p = memblock_alloc_try_nid_raw(PAGE_SIZE, PAGE_SIZE,
__pa(MAX_DMA_ADDRESS),
MEMBLOCK_ALLOC_KASAN, node);
return __pa(p);
}
static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node,
bool early)
{
@@ -92,7 +100,9 @@ static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
do {
phys_addr_t page_phys = early ?
__pa_symbol(kasan_early_shadow_page)
: kasan_alloc_zeroed_page(node);
: kasan_alloc_raw_page(node);
if (!early)
memset(__va(page_phys), KASAN_SHADOW_INIT, PAGE_SIZE);
next = addr + PAGE_SIZE;
set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
} while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)));
@@ -239,7 +249,7 @@ void __init kasan_init(void)
pfn_pte(sym_to_pfn(kasan_early_shadow_page),
PAGE_KERNEL_RO));
memset(kasan_early_shadow_page, 0, PAGE_SIZE);
memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
/* At this point kasan is fully initialized. Enable error messages */