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-rw-r--r--arch/mips/kernel/branch.c196
1 files changed, 196 insertions, 0 deletions
diff --git a/arch/mips/kernel/branch.c b/arch/mips/kernel/branch.c
index 4d78bf445a9c..84888d9332b9 100644
--- a/arch/mips/kernel/branch.c
+++ b/arch/mips/kernel/branch.c
@@ -48,6 +48,202 @@ int __isa_exception_epc(struct pt_regs *regs)
return epc;
}
+/* (microMIPS) Convert 16-bit register encoding to 32-bit register encoding. */
+static const unsigned int reg16to32map[8] = {16, 17, 2, 3, 4, 5, 6, 7};
+
+int __mm_isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn,
+ unsigned long *contpc)
+{
+ union mips_instruction insn = (union mips_instruction)dec_insn.insn;
+ int bc_false = 0;
+ unsigned int fcr31;
+ unsigned int bit;
+
+ if (!cpu_has_mmips)
+ return 0;
+
+ switch (insn.mm_i_format.opcode) {
+ case mm_pool32a_op:
+ if ((insn.mm_i_format.simmediate & MM_POOL32A_MINOR_MASK) ==
+ mm_pool32axf_op) {
+ switch (insn.mm_i_format.simmediate >>
+ MM_POOL32A_MINOR_SHIFT) {
+ case mm_jalr_op:
+ case mm_jalrhb_op:
+ case mm_jalrs_op:
+ case mm_jalrshb_op:
+ if (insn.mm_i_format.rt != 0) /* Not mm_jr */
+ regs->regs[insn.mm_i_format.rt] =
+ regs->cp0_epc +
+ dec_insn.pc_inc +
+ dec_insn.next_pc_inc;
+ *contpc = regs->regs[insn.mm_i_format.rs];
+ return 1;
+ }
+ }
+ break;
+ case mm_pool32i_op:
+ switch (insn.mm_i_format.rt) {
+ case mm_bltzals_op:
+ case mm_bltzal_op:
+ regs->regs[31] = regs->cp0_epc +
+ dec_insn.pc_inc +
+ dec_insn.next_pc_inc;
+ /* Fall through */
+ case mm_bltz_op:
+ if ((long)regs->regs[insn.mm_i_format.rs] < 0)
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ (insn.mm_i_format.simmediate << 1);
+ else
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ dec_insn.next_pc_inc;
+ return 1;
+ case mm_bgezals_op:
+ case mm_bgezal_op:
+ regs->regs[31] = regs->cp0_epc +
+ dec_insn.pc_inc +
+ dec_insn.next_pc_inc;
+ /* Fall through */
+ case mm_bgez_op:
+ if ((long)regs->regs[insn.mm_i_format.rs] >= 0)
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ (insn.mm_i_format.simmediate << 1);
+ else
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ dec_insn.next_pc_inc;
+ return 1;
+ case mm_blez_op:
+ if ((long)regs->regs[insn.mm_i_format.rs] <= 0)
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ (insn.mm_i_format.simmediate << 1);
+ else
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ dec_insn.next_pc_inc;
+ return 1;
+ case mm_bgtz_op:
+ if ((long)regs->regs[insn.mm_i_format.rs] <= 0)
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ (insn.mm_i_format.simmediate << 1);
+ else
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ dec_insn.next_pc_inc;
+ return 1;
+ case mm_bc2f_op:
+ case mm_bc1f_op:
+ bc_false = 1;
+ /* Fall through */
+ case mm_bc2t_op:
+ case mm_bc1t_op:
+ preempt_disable();
+ if (is_fpu_owner())
+ asm volatile("cfc1\t%0,$31" : "=r" (fcr31));
+ else
+ fcr31 = current->thread.fpu.fcr31;
+ preempt_enable();
+
+ if (bc_false)
+ fcr31 = ~fcr31;
+
+ bit = (insn.mm_i_format.rs >> 2);
+ bit += (bit != 0);
+ bit += 23;
+ if (fcr31 & (1 << bit))
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ (insn.mm_i_format.simmediate << 1);
+ else
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc + dec_insn.next_pc_inc;
+ return 1;
+ }
+ break;
+ case mm_pool16c_op:
+ switch (insn.mm_i_format.rt) {
+ case mm_jalr16_op:
+ case mm_jalrs16_op:
+ regs->regs[31] = regs->cp0_epc +
+ dec_insn.pc_inc + dec_insn.next_pc_inc;
+ /* Fall through */
+ case mm_jr16_op:
+ *contpc = regs->regs[insn.mm_i_format.rs];
+ return 1;
+ }
+ break;
+ case mm_beqz16_op:
+ if ((long)regs->regs[reg16to32map[insn.mm_b1_format.rs]] == 0)
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ (insn.mm_b1_format.simmediate << 1);
+ else
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc + dec_insn.next_pc_inc;
+ return 1;
+ case mm_bnez16_op:
+ if ((long)regs->regs[reg16to32map[insn.mm_b1_format.rs]] != 0)
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ (insn.mm_b1_format.simmediate << 1);
+ else
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc + dec_insn.next_pc_inc;
+ return 1;
+ case mm_b16_op:
+ *contpc = regs->cp0_epc + dec_insn.pc_inc +
+ (insn.mm_b0_format.simmediate << 1);
+ return 1;
+ case mm_beq32_op:
+ if (regs->regs[insn.mm_i_format.rs] ==
+ regs->regs[insn.mm_i_format.rt])
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ (insn.mm_i_format.simmediate << 1);
+ else
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ dec_insn.next_pc_inc;
+ return 1;
+ case mm_bne32_op:
+ if (regs->regs[insn.mm_i_format.rs] !=
+ regs->regs[insn.mm_i_format.rt])
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc +
+ (insn.mm_i_format.simmediate << 1);
+ else
+ *contpc = regs->cp0_epc +
+ dec_insn.pc_inc + dec_insn.next_pc_inc;
+ return 1;
+ case mm_jalx32_op:
+ regs->regs[31] = regs->cp0_epc +
+ dec_insn.pc_inc + dec_insn.next_pc_inc;
+ *contpc = regs->cp0_epc + dec_insn.pc_inc;
+ *contpc >>= 28;
+ *contpc <<= 28;
+ *contpc |= (insn.j_format.target << 2);
+ return 1;
+ case mm_jals32_op:
+ case mm_jal32_op:
+ regs->regs[31] = regs->cp0_epc +
+ dec_insn.pc_inc + dec_insn.next_pc_inc;
+ /* Fall through */
+ case mm_j32_op:
+ *contpc = regs->cp0_epc + dec_insn.pc_inc;
+ *contpc >>= 27;
+ *contpc <<= 27;
+ *contpc |= (insn.j_format.target << 1);
+ set_isa16_mode(*contpc);
+ return 1;
+ }
+ return 0;
+}
+
/*
* Compute return address and emulate branch in microMIPS mode after an
* exception only. It does not handle compact branches/jumps and cannot
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-12 23:56:43 +0000