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authorDaniel De Graaf <dgdegra@tycho.nsa.gov>2010-08-11 01:02:45 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-11 15:59:12 (GMT)
commitc07fbfd17e614a76b194f371c5331e21e6cffb54 (patch)
tree34bd53668b5b45b344411d49d8acf6d466004428 /drivers/video/fbmem.c
parentdaf695fca877068d7533a1b431b09210e5ad0b6b (diff)
fbmem: VM_IO set, but not propagated
When we setup up the VMA flags for the mmap flag and we end up using the fallback mmap functionality we set the vma->vm_flags |= VM_IO. However we neglect to propagate the flag to the vma->vm_page_prot. This bug was found when Linux kernel was running under Xen. In that scenario, any page that has VM_IO flag to it, means that it MUST be a MMIO/VRAM backend memory , _not_ System RAM. That is what the fbmem.c does: sets VM_IO, ioremaps the region - everything is peachy. Well, not exactly. The vm_page_prot does not get the relevant PTE flags set (_PAGE_IOMAP) which under Xen is a death-kneel to pages that are referencing real physical devices but don't have that flag set. This patch fixes this. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Tested-by: Eamon Walsh <ewalsh@tycho.nsa.gov> Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de> Cc: Dave Airlie <airlied@linux.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/video/fbmem.c')
-rw-r--r--drivers/video/fbmem.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index a8500c6..b066475 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1362,6 +1362,7 @@ fb_mmap(struct file *file, struct vm_area_struct * vma)
vma->vm_pgoff = off >> PAGE_SHIFT;
/* This is an IO map - tell maydump to skip this VMA */
vma->vm_flags |= VM_IO | VM_RESERVED;
+ vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
fb_pgprotect(file, vma, off);
if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
vma->vm_end - vma->vm_start, vma->vm_page_prot))

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