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ARM: 8165/1: alignment: don't break misaligned NEON load/store

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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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Robin Murphy 2014-09-25 11:56:19 +01:00 committed by Russell King
parent 2c553ac19e
commit 5ca918e5e3
1 changed files with 3 additions and 0 deletions
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3
arch/arm/mm/alignment.c
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@ -41,6 +41,7 @@
* 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 */
@ -821,6 +822,8 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
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;