Commit 15122ee2 authored by Will Deacon's avatar Will Deacon Committed by Catalin Marinas

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: 324420bf ("arm64: add support for ioremap() block mappings")
Reported-by: default avatarHanjun Guo <hanjun.guo@linaro.org>
Reported-by: default avatarLei Li <lious.lilei@hisilicon.com>
Acked-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 0331365e
...@@ -933,6 +933,11 @@ int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) ...@@ -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_t sect_prot = __pgprot(PUD_TYPE_SECT |
pgprot_val(mk_sect_prot(prot))); 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); BUG_ON(phys & ~PUD_MASK);
set_pud(pudp, pfn_pud(__phys_to_pfn(phys), sect_prot)); set_pud(pudp, pfn_pud(__phys_to_pfn(phys), sect_prot));
return 1; return 1;
...@@ -942,6 +947,11 @@ int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) ...@@ -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_t sect_prot = __pgprot(PMD_TYPE_SECT |
pgprot_val(mk_sect_prot(prot))); 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); BUG_ON(phys & ~PMD_MASK);
set_pmd(pmdp, pfn_pmd(__phys_to_pfn(phys), sect_prot)); set_pmd(pmdp, pfn_pmd(__phys_to_pfn(phys), sect_prot));
return 1; return 1;
......
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