The MIPS R6 JR instruction is an alias to the JALR one, so it may
need emulation for non-R6 userlands.
Signed-off-by: Markos Chandras <markos.chandras@xxxxxxxxxx>
---
arch/mips/include/asm/branch.h | 3 +++
arch/mips/kernel/branch.c | 5 +++++
arch/mips/math-emu/cp1emu.c | 3 +++
3 files changed, 11 insertions(+)
diff --git a/arch/mips/include/asm/branch.h b/arch/mips/include/asm/branch.h
index de781cf54bc7..2894ea58454d 100644
--- a/arch/mips/include/asm/branch.h
+++ b/arch/mips/include/asm/branch.h
@@ -13,6 +13,9 @@
#include <asm/ptrace.h>
#include <asm/inst.h>
+static int mipsr2_emulation = 0;
+#define NO_R6EMU (cpu_has_mips_r6 && !mipsr2_emulation)
+
extern int __isa_exception_epc(struct pt_regs *regs);
extern int __compute_return_epc(struct pt_regs *regs);
extern int __compute_return_epc_for_insn(struct pt_regs *regs,
diff --git a/arch/mips/kernel/branch.c b/arch/mips/kernel/branch.c
index 4d7d99d601cc..9b622ca391d8 100644
--- a/arch/mips/kernel/branch.c
+++ b/arch/mips/kernel/branch.c
@@ -417,6 +417,11 @@ int __compute_return_epc_for_insn(struct pt_regs *regs,
regs->regs[insn.r_format.rd] = epc + 8;
/* Fall through */
case jr_op:
+ if (NO_R6EMU && (insn.r_format.func == jr_op)) {
+ ret = -SIGILL;
+ /* For R6, JR already emulated in jalr_op */
+ break;
+ }
regs->cp0_epc = regs->regs[insn.r_format.rs];
break;
}
diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index 9dfcd7fc1bc3..9707af43913f 100644
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -448,6 +448,9 @@ static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
dec_insn.next_pc_inc;
/* Fall through */
case jr_op:
+ /* For R6, JR already emulated in jalr_op */
+ if (NO_R6EMU && (insn.r_format.opcode == jr_op))
+ break;
*contpc = regs->regs[insn.r_format.rs];
return 1;
}
--
2.2.1
