[08/16] ARM: 7939/1: traps: fix opcode endianness when read from user memory

Message ID 1418797379-107848-9-git-send-email-shengyong1@huawei.com
State New
Headers show

Commit Message

Sheng Yong Dec. 17, 2014, 6:22 a.m.
From: Taras Kondratiuk <taras.kondratiuk@linaro.org>

commit d6cd989477e2fee29ccda257614ef7b2621d0601 upstream

Currently code has an inverted logic: opcode from user memory
is swapped to a proper endianness only in case of read error.
While normally opcode should be swapped only if it was read
correctly from user memory.

Reviewed-by: Victor Kamensky <victor.kamensky@linaro.org>
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Taras Kondratiuk <taras.kondratiuk@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 arch/arm/kernel/traps.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Patch

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index b4fd850..fd250da 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -431,9 +431,10 @@  asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 			instr2 = __mem_to_opcode_thumb16(instr2);
 			instr = __opcode_thumb32_compose(instr, instr2);
 		}
-	} else if (get_user(instr, (u32 __user *)pc)) {
+	} else {
+		if (get_user(instr, (u32 __user *)pc))
+			goto die_sig;
 		instr = __mem_to_opcode_arm(instr);
-		goto die_sig;
 	}
 
 	if (call_undef_hook(regs, instr) == 0)