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author | Lachlan McIlroy <lachlan@redback.melbourne.sgi.com> | 2008-12-29 16:47:18 +1100 |
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committer | Lachlan McIlroy <lachlan@redback.melbourne.sgi.com> | 2008-12-29 16:47:18 +1100 |
commit | 0a8c5395f90f06d128247844b2515c8bf3f2826b (patch) | |
tree | d95382dcdfa303b99d480c01763d6cb6767fdaca /Documentation/x86/pat.txt | |
parent | 25051158bbed127e8672b43396c71c5eb610e5f1 (diff) | |
parent | 3c92ec8ae91ecf59d88c798301833d7cf83f2179 (diff) | |
download | op-kernel-dev-0a8c5395f90f06d128247844b2515c8bf3f2826b.zip op-kernel-dev-0a8c5395f90f06d128247844b2515c8bf3f2826b.tar.gz |
[XFS] Fix merge failures
Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:
fs/xfs/linux-2.6/xfs_cred.h
fs/xfs/linux-2.6/xfs_globals.h
fs/xfs/linux-2.6/xfs_ioctl.c
fs/xfs/xfs_vnodeops.h
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Diffstat (limited to 'Documentation/x86/pat.txt')
-rw-r--r-- | Documentation/x86/pat.txt | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/Documentation/x86/pat.txt b/Documentation/x86/pat.txt index c93ff5f..cf08c9f 100644 --- a/Documentation/x86/pat.txt +++ b/Documentation/x86/pat.txt @@ -80,6 +80,30 @@ pci proc | -- | -- | WC | | | | | ------------------------------------------------------------------- +Advanced APIs for drivers +------------------------- +A. Exporting pages to users with remap_pfn_range, io_remap_pfn_range, +vm_insert_pfn + +Drivers wanting to export some pages to userspace do it by using mmap +interface and a combination of +1) pgprot_noncached() +2) io_remap_pfn_range() or remap_pfn_range() or vm_insert_pfn() + +With PAT support, a new API pgprot_writecombine is being added. So, drivers can +continue to use the above sequence, with either pgprot_noncached() or +pgprot_writecombine() in step 1, followed by step 2. + +In addition, step 2 internally tracks the region as UC or WC in memtype +list in order to ensure no conflicting mapping. + +Note that this set of APIs only works with IO (non RAM) regions. If driver +wants to export a RAM region, it has to do set_memory_uc() or set_memory_wc() +as step 0 above and also track the usage of those pages and use set_memory_wb() +before the page is freed to free pool. + + + Notes: -- in the above table mean "Not suggested usage for the API". Some of the --'s |