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author | James Hogan <james.hogan@imgtec.com> | 2016-09-07 12:37:01 (GMT) |
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committer | Ralf Baechle <ralf@linux-mips.org> | 2016-09-21 13:56:10 (GMT) |
commit | 554af0c396380baf416f54c439b99b495180b2f4 (patch) | |
tree | 2f0a0838e7c4fd684846c531d3322fb7355eeb0e /certs | |
parent | 08bccf43627e1972035c1fed5b4f570bdbde1b1e (diff) | |
download | linux-554af0c396380baf416f54c439b99b495180b2f4.tar.xz |
MIPS: vDSO: Fix Malta EVA mapping to vDSO page structs
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
Cc: <stable@vger.kernel.org> # 4.4.x-
Patchwork: https://patchwork.linux-mips.org/patch/14229/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'certs')
0 files changed, 0 insertions, 0 deletions