diff options
| author | Will Deacon <will.deacon@arm.com> | 2018-02-21 12:59:27 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2018-02-22 11:25:53 +0000 |
| commit | 15122ee2c515a253b0c66a3e618bc7ebe35105eb (patch) | |
| tree | 930c790bb615babec3527f85fdbbec6628cf938d | |
| parent | 0331365edb1d6ccd6ae68b1038111da85d4c68d1 (diff) | |
| download | linux-15122ee2c515a253b0c66a3e618bc7ebe35105eb.tar.gz | |
arm64: Enforce BBM for huge IO/VMAP mappings
ioremap_page_range doesn't honour break-before-make and attempts to put
down huge mappings (using p*d_set_huge) over the top of pre-existing
table entries. This leads to us leaking page table memory and also gives
rise to TLB conflicts and spurious aborts, which have been seen in
practice on Cortex-A75.
Until this has been resolved, refuse to put block mappings when the
existing entry is found to be present.
Fixes: 324420bf91f60 ("arm64: add support for ioremap() block mappings")
Reported-by: Hanjun Guo <hanjun.guo@linaro.org>
Reported-by: Lei Li <lious.lilei@hisilicon.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/mm/mmu.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 3161b853f29e1d..84a019f5502293 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -933,6 +933,11 @@ 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))); + + /* ioremap_page_range doesn't honour BBM */ + if (pud_present(READ_ONCE(*pudp))) + return 0; + BUG_ON(phys & ~PUD_MASK); set_pud(pudp, pfn_pud(__phys_to_pfn(phys), sect_prot)); return 1; @@ -942,6 +947,11 @@ 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))); + + /* ioremap_page_range doesn't honour BBM */ + if (pmd_present(READ_ONCE(*pmdp))) + return 0; + BUG_ON(phys & ~PMD_MASK); set_pmd(pmdp, pfn_pmd(__phys_to_pfn(phys), sect_prot)); return 1; |