ARM: 8052/1: unwind: Fix handling of "Pop r4-r[4+nnn],r14" opcode

The arm EABI states that unwind opcode 10100nnn means pop register r4-4[4+nnn],aditionally there is a similar unwind opcode: 10101nnn which means the same thing plus popping r14. Those two cases are handled by the unwind_exec_pop_r4_to_rN function which checks whether the 4th bit is set and does r14 popping.

However, up until now it has been checking whether the 8th bit was set (mask & 0x80) instead of the 4th (mask & 0x8), a simple to make typo but this meant that we were always popping r14 even if we had the former opcode.

This patch changes the mask so that the 2 unwind opcodes are being handled correctly.

Signed-off-by: Nikolay Borisov <Nikolay.Borisov@arm.com>
Reviewed-by: Anurag Aggarwal <anurag19aggarwal@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index 3c217694ebecb126b23f226688bcc6874b0c8c7b..cb791ac6a0037dfd392622eb5adf24467bcedc37 100644 (file)
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -285,7 +285,7 @@ static int unwind_exec_pop_r4_to_rN(struct unwind_ctrl_block *ctrl,
                if (unwind_pop_register(ctrl, &vsp, reg))
                                return -URC_FAILURE;
 
-       if (insn & 0x80)
+       if (insn & 0x8)
                if (unwind_pop_register(ctrl, &vsp, 14))
                                return -URC_FAILURE;