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| author | Laura Abbott <labbott@redhat.com> | 2018-05-23 21:43:46 +0300 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2018-05-24 13:19:31 +0300 |
| commit | 82034c23fcbc2389c73d97737f61fa2dd6526413 (patch) | |
| tree | d297bd7683ea4fd6d5e2415f525754628d697c43 /arch/arm64 | |
| parent | cc19846079a70abcfd91b5a0791a5f17d69458a5 (diff) | |
| download | linux-82034c23fcbc2389c73d97737f61fa2dd6526413.tar.xz | |
arm64: Make sure permission updates happen for pmd/pud
Commit 15122ee2c515 ("arm64: Enforce BBM for huge IO/VMAP mappings")
disallowed block mappings for ioremap since that code does not honor
break-before-make. The same APIs are also used for permission updating
though and the extra checks prevent the permission updates from happening,
even though this should be permitted. This results in read-only permissions
not being fully applied. Visibly, this can occasionaly be seen as a failure
on the built in rodata test when the test data ends up in a section or
as an odd RW gap on the page table dump. Fix this by using
pgattr_change_is_safe instead of p*d_present for determining if the
change is permitted.
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Reported-by: Peter Robinson <pbrobinson@gmail.com>
Fixes: 15122ee2c515 ("arm64: Enforce BBM for huge IO/VMAP mappings")
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/mm/mmu.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 2dbb2c9f1ec1..493ff75670ff 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -933,13 +933,15 @@ int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) { pgprot_t sect_prot = __pgprot(PUD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))); + pud_t new_pud = pfn_pud(__phys_to_pfn(phys), sect_prot); - /* ioremap_page_range doesn't honour BBM */ - if (pud_present(READ_ONCE(*pudp))) + /* Only allow permission changes for now */ + if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), + pud_val(new_pud))) return 0; BUG_ON(phys & ~PUD_MASK); - set_pud(pudp, pfn_pud(__phys_to_pfn(phys), sect_prot)); + set_pud(pudp, new_pud); return 1; } @@ -947,13 +949,15 @@ int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) { pgprot_t sect_prot = __pgprot(PMD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))); + pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), sect_prot); - /* ioremap_page_range doesn't honour BBM */ - if (pmd_present(READ_ONCE(*pmdp))) + /* Only allow permission changes for now */ + if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), + pmd_val(new_pmd))) return 0; BUG_ON(phys & ~PMD_MASK); - set_pmd(pmdp, pfn_pmd(__phys_to_pfn(phys), sect_prot)); + set_pmd(pmdp, new_pmd); return 1; } |