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| author |   venkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com> | 2008-08-20 16:45:52 -0700 |
|---|---|---|
| committer |   Ingo Molnar <mingo@elte.hu> | 2008-08-21 13:27:33 +0200 |
| commit | 28df82ebab79c6a2b4295dd94fd8de88196a49df (patch) | |
| tree | e206038eea131a943b08590b8440d6119875ff00 /arch/x86 | |
| parent | x86: PAT proper tracking of set_memory_uc and friends (diff) | |
| download | linux-dev-28df82ebab79c6a2b4295dd94fd8de88196a49df.tar.xz linux-dev-28df82ebab79c6a2b4295dd94fd8de88196a49df.zip | |
devmem, x86: PAT Change /dev/mem mmap with O_SYNC to use UC_MINUS
All kernel mappings like ioremap(), etc uses UC_MINUS as the type. /dev/mem
mappings with /dev/mem being opened with O_SYNC however was using UC,
resulting in a conflict with /dev/mem mmap failing. This seems to be
affecting some apps (one being flashrom) which are using O_SYNC and which were
working before.
Switch /dev/mem with O_SYNC also to UC_MINUS.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/mm/pat.c | 17 |
1 files changed, 5 insertions, 12 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index bb6e8a267bfe..2a50e0fa64a5 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -390,14 +390,6 @@ int free_memtype(u64 start, u64 end) } -/* - * /dev/mem mmap interface. The memtype used for mapping varies: - * - Use UC for mappings with O_SYNC flag - * - Without O_SYNC flag, if there is any conflict in reserve_memtype, - * inherit the memtype from existing mapping. - * - Else use UC_MINUS memtype (for backward compatibility with existing - * X drivers. - */ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, unsigned long size, pgprot_t vma_prot) { @@ -435,14 +427,14 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, unsigned long size, pgprot_t *vma_prot) { u64 offset = ((u64) pfn) << PAGE_SHIFT; - unsigned long flags = _PAGE_CACHE_UC_MINUS; + unsigned long flags = -1; int retval; if (!range_is_allowed(pfn, size)) return 0; if (file->f_flags & O_SYNC) { - flags = _PAGE_CACHE_UC; + flags = _PAGE_CACHE_UC_MINUS; } #ifdef CONFIG_X86_32 @@ -465,13 +457,14 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, #endif /* - * With O_SYNC, we can only take UC mapping. Fail if we cannot. + * With O_SYNC, we can only take UC_MINUS mapping. Fail if we cannot. + * * Without O_SYNC, we want to get * - WB for WB-able memory and no other conflicting mappings * - UC_MINUS for non-WB-able memory with no other conflicting mappings * - Inherit from confliting mappings otherwise */ - if (flags != _PAGE_CACHE_UC_MINUS) { + if (flags != -1) { retval = reserve_memtype(offset, offset + size, flags, NULL); } else { retval = reserve_memtype(offset, offset + size, -1, &flags); |