From 8467ca0122e20f3f8e73d34907b8b30461af5d4e Mon Sep 17 00:00:00 2001
From: Markos Chandras <markos.chandras@imgtec.com>
Date: Wed, 26 Nov 2014 13:56:51 +0000
Subject: [PATCH] MIPS: Emulate the new MIPS R6 branch compact (BC) instruction
MIPS R6 uses the <R6 LWC2 opcode for the new BC instruction.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
---
arch/mips/include/uapi/asm/inst.h | 2 +-
arch/mips/kernel/branch.c | 9 +++++++++
arch/mips/math-emu/cp1emu.c | 13 +++++++++++++
3 files changed, 23 insertions(+), 1 deletion(-)
diff --git a/arch/mips/include/uapi/asm/inst.h b/arch/mips/include/uapi/asm/inst.h
index 19d3bc1e65106..9ce5e34b9c648 100644
--- a/arch/mips/include/uapi/asm/inst.h
+++ b/arch/mips/include/uapi/asm/inst.h
@@ -31,7 +31,7 @@ enum major_op {
lbu_op, lhu_op, lwr_op, lwu_op,
sb_op, sh_op, swl_op, sw_op,
sdl_op, sdr_op, swr_op, cache_op,
- ll_op, lwc1_op, lwc2_op, pref_op,
+ ll_op, lwc1_op, lwc2_op, bc6_op = lwc2_op, pref_op,
lld_op, ldc1_op, ldc2_op, ld_op,
sc_op, swc1_op, swc2_op, major_3b_op,
scd_op, sdc1_op, sdc2_op, sd_op
diff --git a/arch/mips/kernel/branch.c b/arch/mips/kernel/branch.c
index cd880b91f0928..1a0a30e16684d 100644
--- a/arch/mips/kernel/branch.c
+++ b/arch/mips/kernel/branch.c
@@ -780,6 +780,15 @@ int __compute_return_epc_for_insn(struct pt_regs *regs,
epc += 8;
regs->cp0_epc = epc;
break;
+#else
+ case bc6_op:
+ /* Only valid for MIPS R6 */
+ if (!cpu_has_mips_r6) {
+ ret = -SIGILL;
+ break;
+ }
+ regs->cp0_epc += 8;
+ break;
#endif
}
diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index d6d67e2a0434d..7f373a2858b54 100644
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -648,6 +648,19 @@ static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
else
*contpc = regs->cp0_epc + 8;
return 1;
+#else
+ case bc6_op:
+ /*
+ * Only valid for MIPS R6 but we can still end up
+ * here from a broken userland so just tell emulator
+ * this is not a branch and let it break later on.
+ */
+ if (!cpu_has_mips_r6)
+ break;
+ *contpc = regs->cp0_epc + dec_insn.pc_inc +
+ dec_insn.next_pc_inc;
+
+ return 1;
#endif
case cop0_op:
case cop1_op:
--
2.30.2