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authorVenki Pallipadi <venkatesh.pallipadi@intel.com>2008-05-09 13:05:19 -0700
committerJesse Barnes <jbarnes@virtuousgeek.org>2008-05-13 09:51:54 -0700
commit77db9885646f8a88214ea482988d41f8f73630f4 (patch)
tree8adc0ff3a373c107a5226ed1afca23c23530f1c4 /arch/x86/pci/i386.c
parent439a7733e8fcbaee39979c10246101565834d6b2 (diff)
x86/PCI: X86_PAT & mprotect
Some versions of X used the mprotect workaround to change caching type from UC to WB, so that it can then use mtrr to program WC for that region [1]. Change the mmap of pci space through /sys or /proc interfaces from UC to UC_MINUS. With this change, X will not need to use mprotect workaround to get WC type since the MTRR mapping type will be honored. The bug in mprotect that clobbers PAT bits is fixed in a follow on patch. So, this X workaround will stop working as well. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'arch/x86/pci/i386.c')
-rw-r--r--arch/x86/pci/i386.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index 8af0f0bae2a..10fb308fded 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -301,15 +301,13 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
prot = pgprot_val(vma->vm_page_prot);
if (pat_wc_enabled && write_combine)
prot |= _PAGE_CACHE_WC;
- else if (pat_wc_enabled)
+ else if (pat_wc_enabled || boot_cpu_data.x86 > 3)
/*
* ioremap() and ioremap_nocache() defaults to UC MINUS for now.
* To avoid attribute conflicts, request UC MINUS here
* aswell.
*/
prot |= _PAGE_CACHE_UC_MINUS;
- else if (boot_cpu_data.x86 > 3)
- prot |= _PAGE_CACHE_UC;
vma->vm_page_prot = __pgprot(prot);