MIPS: kernel: mips-r2-to-r6-emul: Add R2 emulator for MIPS R6

[cascardo/linux.git] / arch / mips / math-emu / cp1emu.c

diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
index c770617..3c341b0 100644 (file)
--- a/arch/mips/math-emu/cp1emu.c
+++ b/arch/mips/math-emu/cp1emu.c
@@ -48,6 +48,7 @@
 #include <asm/processor.h>
 #include <asm/fpu_emulator.h>
 #include <asm/fpu.h>
+#include <asm/mips-r2-to-r6-emul.h>
 
 #include "ieee754.h"
 
@@ -68,7 +69,7 @@ static int fpux_emu(struct pt_regs *,
 #define modeindex(v) ((v) & FPU_CSR_RM)
 
 /* convert condition code register number to csr bit */
-static const unsigned int fpucondbit[8] = {
+const unsigned int fpucondbit[8] = {
        FPU_CSR_COND0,
        FPU_CSR_COND1,
        FPU_CSR_COND2,
@@ -589,6 +590,31 @@ static int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
                if (NO_R6EMU)
                        break;
        case bgtz_op:
+               /*
+                * Compact branches for R6 for the
+                * bgtz and bgtzl opcodes.
+                * BGTZ  | rs = 0 | rt != 0  == BGTZALC
+                * BGTZ  | rs = rt != 0      == BLTZALC
+                * BGTZ  | rs != 0 | rt != 0 == BLTUC
+                * BGTZL | rs = 0 | rt != 0  == BGTZC
+                * BGTZL | rs = rt != 0      == BLTZC
+                * BGTZL | rs != 0 | rt != 0 == BLTC
+                *
+                * *ZALC varint for BGTZ &&& rt != 0
+                * For real GTZ{,L}, rt is always 0.
+                */
+               if (cpu_has_mips_r6 && insn.i_format.rt) {
+                       if ((insn.i_format.opcode == blez_op) &&
+                           ((!insn.i_format.rs && insn.i_format.rt) ||
+                            (insn.i_format.rs == insn.i_format.rt)))
+                               regs->regs[31] = regs->cp0_epc +
+                                       dec_insn.pc_inc;
+                       *contpc = regs->cp0_epc + dec_insn.pc_inc +
+                               dec_insn.next_pc_inc;
+
+                       return 1;
+               }
+
                if ((long)regs->regs[insn.i_format.rs] > 0)
                        *contpc = regs->cp0_epc +
                                dec_insn.pc_inc +
@@ -598,6 +624,16 @@ 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 cbcond0_op:
+       case cbcond1_op:
+               if (!cpu_has_mips_r6)
+                       break;
+               if (insn.i_format.rt && !insn.i_format.rs)
+                       regs->regs[31] = regs->cp0_epc + 4;
+               *contpc = regs->cp0_epc + dec_insn.pc_inc +
+                       dec_insn.next_pc_inc;
+
+               return 1;
 #ifdef CONFIG_CPU_CAVIUM_OCTEON
        case lwc2_op: /* This is bbit0 on Octeon */
                if ((regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt)) == 0)
@@ -623,6 +659,43 @@ 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;
+       case balc6_op:
+               if (!cpu_has_mips_r6)
+                       break;
+               regs->regs[31] = regs->cp0_epc + 4;
+               *contpc = regs->cp0_epc + dec_insn.pc_inc +
+                       dec_insn.next_pc_inc;
+
+               return 1;
+       case beqzcjic_op:
+               if (!cpu_has_mips_r6)
+                       break;
+               *contpc = regs->cp0_epc + dec_insn.pc_inc +
+                       dec_insn.next_pc_inc;
+
+               return 1;
+       case bnezcjialc_op:
+               if (!cpu_has_mips_r6)
+                       break;
+               if (!insn.i_format.rs)
+                       regs->regs[31] = regs->cp0_epc + 4;
+               *contpc = regs->cp0_epc + dec_insn.pc_inc +
+                       dec_insn.next_pc_inc;
+
+               return 1;
 #endif
        case cop0_op:
        case cop1_op: