path: root/mm
diff options
authorvenkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com>2008-12-18 11:41:27 -0800
committerH. Peter Anvin <hpa@zytor.com>2008-12-18 13:30:15 -0800
commit3c8bb73ace6249bd089b70c941440441940e3365 (patch)
tree974c8b86fa68c26daa76e5122bab3cf5651a51dd /mm
parent55dac3a5553b13891f0ae4bbd11920619b5436d4 (diff)
x86: PAT: store vm_pgoff for all linear_over_vma_region mappings - v3
Impact: Code transformation, new functions added should have no effect. Drivers use mmap followed by pgprot_* and remap_pfn_range or vm_insert_pfn, in order to export reserved memory to userspace. Currently, such mappings are not tracked and hence not kept consistent with other mappings (/dev/mem, pci resource, ioremap) for the sme memory, that may exist in the system. The following patchset adds x86 PAT attribute tracking and untracking for pfnmap related APIs. First three patches in the patchset are changing the generic mm code to fit in this tracking. Last four patches are x86 specific to make things work with x86 PAT code. The patchset aso introduces pgprot_writecombine interface, which gives writecombine mapping when enabled, falling back to pgprot_noncached otherwise. This patch: While working on x86 PAT, we faced some hurdles with trackking remap_pfn_range() regions, as we do not have any information to say whether that PFNMAP mapping is linear for the entire vma range or it is smaller granularity regions within the vma. A simple solution to this is to use vm_pgoff as an indicator for linear mapping over the vma region. Currently, remap_pfn_range only sets vm_pgoff for COW mappings. Below patch changes the logic and sets the vm_pgoff irrespective of COW. This will still not be enough for the case where pfn is zero (vma region mapped to physical address zero). But, for all the other cases, we can look at pfnmap VMAs and say whether the mappng is for the entire vma region or not. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'mm')
1 files changed, 3 insertions, 4 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 164951c4730..cef95c8c77f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1575,11 +1575,10 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
* behaviour that some programs depend on. We mark the "original"
* un-COW'ed pages by matching them up with "vma->vm_pgoff".
- if (is_cow_mapping(vma->vm_flags)) {
- if (addr != vma->vm_start || end != vma->vm_end)
- return -EINVAL;
+ if (addr == vma->vm_start && end == vma->vm_end)
vma->vm_pgoff = pfn;
- }
+ else if (is_cow_mapping(vma->vm_flags))
+ return -EINVAL;
vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;