MIPS: kernel: branch: Do not emulate the branch likelies on MIPS R6

MIPS R6 removed the BLTZL, BGEZL, BLTZAL, BGEZAL, BEQL, BNEL, BLEZL,
BGTZL branch likely instructions so we must not try to emulate them on
MIPS R6 if the R2-to-R6 emulator is not present.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>

1 files changed, 26 insertions, 6 deletions

diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index 9bf82117b4f2..7bbaefe0434d 100644
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -459,12 +459,18 @@ static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
                 switch (insn.i_format.rt) {
                 case bltzal_op:
                 case bltzall_op:
+                        if (NO_R6EMU && (insn.i_format.rs ||
+                            insn.i_format.rt == bltzall_op))
+                                break;
+
                         regs->regs[31] = regs->cp0_epc +
                                 dec_insn.pc_inc +
                                 dec_insn.next_pc_inc;
                         /* Fall through */
-                case bltz_op:
                 case bltzl_op:
+                        if (NO_R6EMU)
+                                break;
+                case bltz_op:
                         if ((long)regs->regs[insn.i_format.rs] < 0)
                                 *contpc = regs->cp0_epc +
                                         dec_insn.pc_inc +
@@ -476,12 +482,18 @@ static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
                         return 1;
                 case bgezal_op:
                 case bgezall_op:
+                        if (NO_R6EMU && (insn.i_format.rs ||
+                            insn.i_format.rt == bgezall_op))
+                                break;
+
                         regs->regs[31] = regs->cp0_epc +
                                 dec_insn.pc_inc +
                                 dec_insn.next_pc_inc;
                         /* Fall through */
-                case bgez_op:
                 case bgezl_op:
+                        if (NO_R6EMU)
+                                break;
+                case bgez_op:
                         if ((long)regs->regs[insn.i_format.rs] >= 0)
                                 *contpc = regs->cp0_epc +
                                         dec_insn.pc_inc +
@@ -508,8 +520,10 @@ static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
                 /* Set microMIPS mode bit: XOR for jalx. */
                 *contpc ^= bit;
                 return 1;
-        case beq_op:
         case beql_op:
+                if (NO_R6EMU)
+                        break;
+        case beq_op:
                 if (regs->regs[insn.i_format.rs] ==
                     regs->regs[insn.i_format.rt])
                         *contpc = regs->cp0_epc +
@@ -520,8 +534,10 @@ static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
                                 dec_insn.pc_inc +
                                 dec_insn.next_pc_inc;
                 return 1;
-        case bne_op:
         case bnel_op:
+                if (NO_R6EMU)
+                        break;
+        case bne_op:
                 if (regs->regs[insn.i_format.rs] !=
                     regs->regs[insn.i_format.rt])
                         *contpc = regs->cp0_epc +
@@ -532,8 +548,10 @@ static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
                                 dec_insn.pc_inc +
                                 dec_insn.next_pc_inc;
                 return 1;
-        case blez_op:
         case blezl_op:
+                if (NO_R6EMU)
+                        break;
+        case blez_op:
                 if ((long)regs->regs[insn.i_format.rs] <= 0)
                         *contpc = regs->cp0_epc +
                                 dec_insn.pc_inc +
@@ -543,8 +561,10 @@ static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
                                 dec_insn.pc_inc +
                                 dec_insn.next_pc_inc;
                 return 1;
-        case bgtz_op:
         case bgtzl_op:
+                if (NO_R6EMU)
+                        break;
+        case bgtz_op:
                 if ((long)regs->regs[insn.i_format.rs] > 0)
                         *contpc = regs->cp0_epc +
                                 dec_insn.pc_inc +