diff options
| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2019-04-26 16:23:37 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-05-03 01:20:26 +1000 |
| commit | da3a3b0a0e38377c98946420acdc7d4ca38cff47 (patch) | |
| tree | 56962be152c3046b9e791ff5a9867da9b4a0ba7c /arch/powerpc/mm/kasan | |
| parent | 215b823707ce4e8e52b106915f70357fa474c669 (diff) | |
powerpc/32s: map kasan zero shadow with PAGE_READONLY instead of PAGE_KERNEL_RO
For hash32, the zero shadow page gets mapped with PAGE_READONLY instead
of PAGE_KERNEL_RO, because the PP bits don't provide a RO kernel, so
PAGE_KERNEL_RO is equivalent to PAGE_KERNEL. By using PAGE_READONLY,
the page is RO for both kernel and user, but this is not a security issue
as it contains only zeroes.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm/kasan')
| -rw-r--r-- | arch/powerpc/mm/kasan/kasan_init_32.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c index ba8361487075..0d62be3cba47 100644 --- a/arch/powerpc/mm/kasan/kasan_init_32.c +++ b/arch/powerpc/mm/kasan/kasan_init_32.c @@ -39,7 +39,10 @@ static int kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_ if (!new) return -ENOMEM; - kasan_populate_pte(new, PAGE_KERNEL_RO); + if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) + kasan_populate_pte(new, PAGE_READONLY); + else + kasan_populate_pte(new, PAGE_KERNEL_RO); pmd_populate_kernel(&init_mm, pmd, new); } return 0; @@ -84,7 +87,10 @@ static int __ref kasan_init_region(void *start, size_t size) static void __init kasan_remap_early_shadow_ro(void) { - kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL_RO); + if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) + kasan_populate_pte(kasan_early_shadow_pte, PAGE_READONLY); + else + kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL_RO); flush_tlb_kernel_range(KASAN_SHADOW_START, KASAN_SHADOW_END); } |