From 143fefc8f315cd10e046e6860913c421c3385cb1 Mon Sep 17 00:00:00 2001 From: Markos Chandras Date: Wed, 24 Jun 2015 09:52:01 +0100 Subject: [PATCH] MIPS: Fix erroneous JR emulation for MIPS R6 Commit 5f9f41c474befb4ebbc40b27f65bb7d649241581 ("MIPS: kernel: Prepare the JR instruction for emulation on MIPS R6") added support for emulating the JR instruction on MIPS R6 cores but that introduced a bug which could be triggered when hitting a JALR opcode because the code used the wrong field in the 'r_format' struct to determine the instruction opcode. This lead to crashes because an emulated JALR instruction was treated as a JR one when the R6 emulator was turned off. Fixes: 5f9f41c474be ("MIPS: kernel: Prepare the JR instruction for emulation on MIPS R6") Cc: # 4.0+ Signed-off-by: Markos Chandras Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/10583/ Signed-off-by: Ralf Baechle --- arch/mips/math-emu/cp1emu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c index 00c241ae04ce..712f17a2ecf2 100644 --- a/arch/mips/math-emu/cp1emu.c +++ b/arch/mips/math-emu/cp1emu.c @@ -451,7 +451,7 @@ static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn, /* Fall through */ case jr_op: /* For R6, JR already emulated in jalr_op */ - if (NO_R6EMU && insn.r_format.opcode == jr_op) + if (NO_R6EMU && insn.r_format.func == jr_op) break; *contpc = regs->regs[insn.r_format.rs]; return 1;