From 15122ee2c515a253b0c66a3e618bc7ebe35105eb Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 21 Feb 2018 12:59:27 +0000 Subject: 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 Reported-by: Lei Li Acked-by: Ard Biesheuvel Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/mm/mmu.c | 10 ++++++++++ 1 file changed, 10 insertions(+) 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; -- cgit 1.2.3-korg