diff options
Diffstat (limited to 'arch/x86/mm/pgtable.c')
| -rw-r--r-- | arch/x86/mm/pgtable.c | 38 |
1 files changed, 24 insertions, 14 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index c30f981..fb0a9dd 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -566,19 +566,28 @@ void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys, /** * pud_set_huge - setup kernel PUD mapping * - * MTRR can override PAT memory types with 4KiB granularity. Therefore, - * this function does not set up a huge page when the range is covered - * by a non-WB type of MTRR. MTRR_TYPE_INVALID indicates that MTRR are - * disabled. + * MTRRs can override PAT memory types with 4KiB granularity. Therefore, this + * function sets up a huge page only if any of the following conditions are met: + * + * - MTRRs are disabled, or + * + * - MTRRs are enabled and the range is completely covered by a single MTRR, or + * + * - MTRRs are enabled and the corresponding MTRR memory type is WB, which + * has no effect on the requested PAT memory type. + * + * Callers should try to decrease page size (1GB -> 2MB -> 4K) if the bigger + * page mapping attempt fails. * * Returns 1 on success and 0 on failure. */ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot) { - u8 mtrr; + u8 mtrr, uniform; - mtrr = mtrr_type_lookup(addr, addr + PUD_SIZE); - if ((mtrr != MTRR_TYPE_WRBACK) && (mtrr != MTRR_TYPE_INVALID)) + mtrr = mtrr_type_lookup(addr, addr + PUD_SIZE, &uniform); + if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) && + (mtrr != MTRR_TYPE_WRBACK)) return 0; prot = pgprot_4k_2_large(prot); @@ -593,20 +602,21 @@ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot) /** * pmd_set_huge - setup kernel PMD mapping * - * MTRR can override PAT memory types with 4KiB granularity. Therefore, - * this function does not set up a huge page when the range is covered - * by a non-WB type of MTRR. MTRR_TYPE_INVALID indicates that MTRR are - * disabled. + * See text over pud_set_huge() above. * * Returns 1 on success and 0 on failure. */ int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot) { - u8 mtrr; + u8 mtrr, uniform; - mtrr = mtrr_type_lookup(addr, addr + PMD_SIZE); - if ((mtrr != MTRR_TYPE_WRBACK) && (mtrr != MTRR_TYPE_INVALID)) + mtrr = mtrr_type_lookup(addr, addr + PMD_SIZE, &uniform); + if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) && + (mtrr != MTRR_TYPE_WRBACK)) { + pr_warn_once("%s: Cannot satisfy [mem %#010llx-%#010llx] with a huge-page mapping due to MTRR override.\n", + __func__, addr, addr + PMD_SIZE); return 0; + } prot = pgprot_4k_2_large(prot); |
