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| author | James Hogan <james.hogan@imgtec.com> | 2016-09-07 13:37:01 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-30 10:12:46 +0200 |
| commit | 66f93fb33239b69092e9345d8eb1b48ba6a4b931 (patch) | |
| tree | 8656bde06481039b6257794efb0fa1ed3df1b6df /arch | |
| parent | 9ed2d4aceca21fe96bec0750480af3dd955ac3da (diff) | |
| download | linux-stable-66f93fb33239b69092e9345d8eb1b48ba6a4b931.tar.gz linux-stable-66f93fb33239b69092e9345d8eb1b48ba6a4b931.tar.bz2 linux-stable-66f93fb33239b69092e9345d8eb1b48ba6a4b931.zip | |
MIPS: vDSO: Fix Malta EVA mapping to vDSO page structs
commit 554af0c396380baf416f54c439b99b495180b2f4 upstream.
The page structures associated with the vDSO pages in the kernel image
are calculated using virt_to_page(), which uses __pa() under the hood to
find the pfn associated with the virtual address. The vDSO data pointers
however point to kernel symbols, so __pa_symbol() should really be used
instead.
Since there is no equivalent to virt_to_page() which uses __pa_symbol(),
fix init_vdso_image() to work directly with pfns, calculated with
__phys_to_pfn(__pa_symbol(...)).
This issue broke the Malta Enhanced Virtual Addressing (EVA)
configuration which has a non-default implementation of __pa_symbol().
This is because it uses a physical alias so that the kernel executes
from KSeg0 (VA 0x80000000 -> PA 0x00000000), while RAM is provided to
the kernel in the KUSeg range (VA 0x00000000 -> PA 0x80000000) which
uses the same underlying RAM.
Since there are no page structures associated with the low physical
address region, some arbitrary kernel memory would be interpreted as a
page structure for the vDSO pages and badness ensues.
Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14229/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/kernel/vdso.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c index 54e1663ce639..0b30c02a5014 100644 --- a/arch/mips/kernel/vdso.c +++ b/arch/mips/kernel/vdso.c @@ -39,16 +39,16 @@ static struct vm_special_mapping vdso_vvar_mapping = { static void __init init_vdso_image(struct mips_vdso_image *image) { unsigned long num_pages, i; + unsigned long data_pfn; BUG_ON(!PAGE_ALIGNED(image->data)); BUG_ON(!PAGE_ALIGNED(image->size)); num_pages = image->size / PAGE_SIZE; - for (i = 0; i < num_pages; i++) { - image->mapping.pages[i] = - virt_to_page(image->data + (i * PAGE_SIZE)); - } + data_pfn = __phys_to_pfn(__pa_symbol(image->data)); + for (i = 0; i < num_pages; i++) + image->mapping.pages[i] = pfn_to_page(data_pfn + i); } static int __init init_vdso(void) |