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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2016-03-08 21:09:29 +0700
committerWill Deacon <will.deacon@arm.com>2016-03-09 14:57:08 +0000
commit36e5cd6b897e17d03008f81e075625d8e43e52d0 (patch)
tree31025889d29f888bac40ab90b8efb92eef962304
parentf6cede5b49e822ebc41a099fe41ab4989f64e2cb (diff)
downloadlinux-36e5cd6b897e17d03008f81e075625d8e43e52d0.tar.gz
arm64: account for sparsemem section alignment when choosing vmemmap offset
Commit dfd55ad85e4a ("arm64: vmemmap: use virtual projection of linear
region") fixed an issue where the struct page array would overflow into the
adjacent virtual memory region if system RAM was placed so high up in
physical memory that its addresses were not representable in the build time
configured virtual address size.

However, the fix failed to take into account that the vmemmap region needs
to be relatively aligned with respect to the sparsemem section size, so that
a sequence of page structs corresponding with a sparsemem section in the
linear region appears naturally aligned in the vmemmap region.

So round up vmemmap to sparsemem section size. Since this essentially moves
the projection of the linear region up in memory, also revert the reduction
of the size of the vmemmap region.

Cc: <stable@vger.kernel.org>
Fixes: dfd55ad85e4a ("arm64: vmemmap: use virtual projection of linear region")
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: David Daney <david.daney@cavium.com>
Tested-by: Robert Richter <rrichter@cavium.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
-rw-r--r--arch/arm64/include/asm/pgtable.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index f50608674580..819aff5d593f 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -40,7 +40,7 @@
  * VMALLOC_END: extends to the available space below vmmemmap, PCI I/O space,
  *	fixed mappings and modules
  */
-#define VMEMMAP_SIZE		ALIGN((1UL << (VA_BITS - PAGE_SHIFT - 1)) * sizeof(struct page), PUD_SIZE)
+#define VMEMMAP_SIZE		ALIGN((1UL << (VA_BITS - PAGE_SHIFT)) * sizeof(struct page), PUD_SIZE)
 
 #ifndef CONFIG_KASAN
 #define VMALLOC_START		(VA_START)
@@ -52,7 +52,8 @@
 #define VMALLOC_END		(PAGE_OFFSET - PUD_SIZE - VMEMMAP_SIZE - SZ_64K)
 
 #define VMEMMAP_START		(VMALLOC_END + SZ_64K)
-#define vmemmap			((struct page *)VMEMMAP_START - (memstart_addr >> PAGE_SHIFT))
+#define vmemmap			((struct page *)VMEMMAP_START - \
+				 SECTION_ALIGN_DOWN(memstart_addr >> PAGE_SHIFT))
 
 #define FIRST_USER_ADDRESS	0UL