path: root/arch
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authorJames Hogan <james.hogan@imgtec.com>2016-09-07 13:37:01 +0100
committerRalf Baechle <ralf@linux-mips.org>2016-09-21 15:56:10 +0200
commit554af0c396380baf416f54c439b99b495180b2f4 (patch)
tree2f0a0838e7c4fd684846c531d3322fb7355eeb0e /arch
parent08bccf43627e1972035c1fed5b4f570bdbde1b1e (diff)
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 'arch')
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
index 9abe447a4b48..f9dbfb14af33 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;
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)