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Subject[PATCH 3.10 067/143] ARM: 8165/1: alignment: dont break misaligned NEON load/store
Date
3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Robin Murphy <robin.murphy@arm.com>

commit 5ca918e5e3f9df4634077c06585c42bc6a8d699a upstream.

The alignment fixup incorrectly decodes faulting ARM VLDn/VSTn
instructions (where the optional alignment hint is given but incorrect)
as LDR/STR, leading to register corruption. Detect these and correctly
treat them as unhandled, so that userspace gets the fault it expects.

Reported-by: Simon Hosie <simon.hosie@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/arm/mm/alignment.c | 3 +++
1 file changed, 3 insertions(+)

--- a/arch/arm/mm/alignment.c
+++ b/arch/arm/mm/alignment.c
@@ -39,6 +39,7 @@
* This code is not portable to processors with late data abort handling.
*/
#define CODING_BITS(i) (i & 0x0e000000)
+#define COND_BITS(i) (i & 0xf0000000)

#define LDST_I_BIT(i) (i & (1 << 26)) /* Immediate constant */
#define LDST_P_BIT(i) (i & (1 << 24)) /* Preindex */
@@ -812,6 +813,8 @@ do_alignment(unsigned long addr, unsigne
break;

case 0x04000000: /* ldr or str immediate */
+ if (COND_BITS(instr) == 0xf0000000) /* NEON VLDn, VSTn */
+ goto bad;
offset.un = OFFSET_BITS(instr);
handler = do_alignment_ldrstr;
break;



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