ARM: 6226/1: fix kprobe bug in ldr instruction emulation

From: Bin Yang <bin.yang@marvell.com>

Cc: stable@kernel.org
Signed-off-by: Bin Yang <bin.yang@marvell.com>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 3 insertions, 2 deletions

diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c
index da1f94906a4e..8bccbfa693ff 100644
--- a/arch/arm/kernel/kprobes-decode.c
+++ b/arch/arm/kernel/kprobes-decode.c
@@ -583,13 +583,14 @@ static void __kprobes emulate_ldr(struct kprobe *p, struct pt_regs *regs)
 {
         insn_llret_3arg_fn_t *i_fn = (insn_llret_3arg_fn_t *)&p->ainsn.insn[0];
         kprobe_opcode_t insn = p->opcode;
+        long ppc = (long)p->addr + 8;
         union reg_pair fnr;
         int rd = (insn >> 12) & 0xf;
         int rn = (insn >> 16) & 0xf;
         int rm = insn & 0xf;
         long rdv;
-        long rnv  = regs->uregs[rn];
-        long rmv  = regs->uregs[rm]; /* rm/rmv may be invalid, don't care. */
+        long rnv = (rn == 15) ? ppc : regs->uregs[rn];
+        long rmv = (rm == 15) ? ppc : regs->uregs[rm];
         long cpsr = regs->ARM_cpsr;
 
         fnr.dr = insnslot_llret_3arg_rflags(rnv, 0, rmv, cpsr, i_fn);