diff options
Diffstat (limited to 'kernel/arch/x86/mm/iomap_32.c')
| -rw-r--r-- | kernel/arch/x86/mm/iomap_32.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/arch/x86/mm/iomap_32.c b/kernel/arch/x86/mm/iomap_32.c index b2ffa5c7d..dd25dd167 100644 --- a/kernel/arch/x86/mm/iomap_32.c +++ b/kernel/arch/x86/mm/iomap_32.c @@ -84,13 +84,13 @@ void __iomem * iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot) { /* - * For non-PAT systems, promote PAGE_KERNEL_WC to PAGE_KERNEL_UC_MINUS. - * PAGE_KERNEL_WC maps to PWT, which translates to uncached if the - * MTRR is UC or WC. UC_MINUS gets the real intention, of the - * user, which is "WC if the MTRR is WC, UC if you can't do that." + * For non-PAT systems, translate non-WB request to UC- just in + * case the caller set the PWT bit to prot directly without using + * pgprot_writecombine(). UC- translates to uncached if the MTRR + * is UC or WC. UC- gets the real intention, of the user, which is + * "WC if the MTRR is WC, UC if you can't do that." */ - if (!pat_enabled && pgprot_val(prot) == - (__PAGE_KERNEL | cachemode2protval(_PAGE_CACHE_MODE_WC))) + if (!pat_enabled() && pgprot2cachemode(prot) != _PAGE_CACHE_MODE_WB) prot = __pgprot(__PAGE_KERNEL | cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS)); |