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>
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@ -933,6 +933,11 @@ int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
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{
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pgprot_t sect_prot = __pgprot(PUD_TYPE_SECT |
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pgprot_val(mk_sect_prot(prot)));
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/* ioremap_page_range doesn't honour BBM */
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if (pud_present(READ_ONCE(*pudp)))
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return 0;
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BUG_ON(phys & ~PUD_MASK);
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set_pud(pudp, pfn_pud(__phys_to_pfn(phys), sect_prot));
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return 1;
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@ -942,6 +947,11 @@ int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
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{
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pgprot_t sect_prot = __pgprot(PMD_TYPE_SECT |
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pgprot_val(mk_sect_prot(prot)));
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/* ioremap_page_range doesn't honour BBM */
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if (pmd_present(READ_ONCE(*pmdp)))
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return 0;
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BUG_ON(phys & ~PMD_MASK);
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set_pmd(pmdp, pfn_pmd(__phys_to_pfn(phys), sect_prot));
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return 1;
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