Re: [PATCH] x86/mm: fix regression with huge pages on PAE

From: Ingo Molnar
Date: Thu Nov 12 2015 - 02:49:05 EST



* Borislav Petkov <bp@xxxxxxxxx> wrote:

> --- a/arch/x86/include/asm/pgtable_types.h
> +++ b/arch/x86/include/asm/pgtable_types.h
> @@ -279,17 +279,14 @@ static inline pmdval_t native_pmd_val(pmd_t pmd)
> static inline pudval_t pud_pfn_mask(pud_t pud)
> {
> if (native_pud_val(pud) & _PAGE_PSE)
> - return PUD_PAGE_MASK & PHYSICAL_PAGE_MASK;
> + return ~((1ULL << PUD_SHIFT) - 1) & PHYSICAL_PAGE_MASK;
> else
> return PTE_PFN_MASK;
> }

> static inline pmdval_t pmd_pfn_mask(pmd_t pmd)
> {
> if (native_pmd_val(pmd) & _PAGE_PSE)
> - return PMD_PAGE_MASK & PHYSICAL_PAGE_MASK;
> + return ~((1ULL << PMD_SHIFT) - 1) & PHYSICAL_PAGE_MASK;
> else
> return PTE_PFN_MASK;
> }

So instead of uglifying the code, why not fix the real bug: change the
PMD_PAGE_MASK/PUD_PAGE_MASK definitions to be 64-bit everywhere?

Thanks,

Ingo
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