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author | venkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com> | 2008-03-19 00:00:20 (GMT) |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-04-24 21:40:47 (GMT) |
commit | f0970c13b6a5b01189aeb196ebb573cf87d95839 (patch) | |
tree | c33836b693ca066c19dc8986165aee5849fbcdd9 /arch | |
parent | e045fb2a988a9a1964059b0d33dbaf18d12f925f (diff) | |
download | linux-fsl-qoriq-f0970c13b6a5b01189aeb196ebb573cf87d95839.tar.xz |
x86: PAT phys_mem_access_prot_allowed for dev/mem mmap
Introduce phys_mem_access_prot_allowed(), which checks whether the mapping
is possible, without any conflicts and returns success or failure based on that.
phys_mem_access_prot() by itself does not allow failure case. This ability
to return error is needed for PAT where we may have aliasing conflicts.
x86 setup __HAVE_PHYS_MEM_ACCESS_PROT and move x86 specific code out of
/dev/mem into arch specific area.
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>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/mm/pat.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 72c0f60..64cc0c1 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -419,3 +419,42 @@ int free_memtype(u64 start, u64 end) return err; } + +/* /dev/mem interface. Use the previous mapping */ +pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, + unsigned long size, pgprot_t vma_prot) +{ + return vma_prot; +} + +int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, + unsigned long size, pgprot_t *vma_prot) +{ + + if (file->f_flags & O_SYNC) { + *vma_prot = pgprot_noncached(*vma_prot); + return 1; + } + +#ifdef CONFIG_X86_32 + /* + * On the PPro and successors, the MTRRs are used to set + * memory types for physical addresses outside main memory, + * so blindly setting UC or PWT on those pages is wrong. + * For Pentiums and earlier, the surround logic should disable + * caching for the high addresses through the KEN pin, but + * we maintain the tradition of paranoia in this code. + */ + if (!pat_wc_enabled && + ! ( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) || + test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) || + test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) || + test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability)) && + (pfn << PAGE_SHIFT) >= __pa(high_memory)) { + *vma_prot = pgprot_noncached(*vma_prot); + return 1; + } +#endif + + return 1; +} |