summaryrefslogtreecommitdiffstats
path: root/arch/mips/kernel/branch.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--arch/mips/kernel/branch.c908
1 files changed, 908 insertions, 0 deletions
diff --git a/arch/mips/kernel/branch.c b/arch/mips/kernel/branch.c
new file mode 100644
index 000000000..0216ff24c
--- /dev/null
+++ b/arch/mips/kernel/branch.c
@@ -0,0 +1,908 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1996, 97, 2000, 2001 by Ralf Baechle
+ * Copyright (C) 2001 MIPS Technologies, Inc.
+ */
+#include <linux/kernel.h>
+#include <linux/sched/signal.h>
+#include <linux/signal.h>
+#include <linux/export.h>
+#include <asm/branch.h>
+#include <asm/cpu.h>
+#include <asm/cpu-features.h>
+#include <asm/fpu.h>
+#include <asm/fpu_emulator.h>
+#include <asm/inst.h>
+#include <asm/mips-r2-to-r6-emul.h>
+#include <asm/ptrace.h>
+#include <linux/uaccess.h>
+
+#include "probes-common.h"
+
+/*
+ * Calculate and return exception PC in case of branch delay slot
+ * for microMIPS and MIPS16e. It does not clear the ISA mode bit.
+ */
+int __isa_exception_epc(struct pt_regs *regs)
+{
+ unsigned short inst;
+ long epc = regs->cp0_epc;
+
+ /* Calculate exception PC in branch delay slot. */
+ if (__get_user(inst, (u16 __user *) msk_isa16_mode(epc))) {
+ /* This should never happen because delay slot was checked. */
+ force_sig(SIGSEGV);
+ return epc;
+ }
+ if (cpu_has_mips16) {
+ union mips16e_instruction inst_mips16e;
+
+ inst_mips16e.full = inst;
+ if (inst_mips16e.ri.opcode == MIPS16e_jal_op)
+ epc += 4;
+ else
+ epc += 2;
+ } else if (mm_insn_16bit(inst))
+ epc += 2;
+ else
+ epc += 4;
+
+ 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 __maybe_unused bc_false = 0;
+
+ 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;
+ fallthrough;
+ 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;
+ fallthrough;
+ 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;
+#ifdef CONFIG_MIPS_FP_SUPPORT
+ case mm_bc2f_op:
+ case mm_bc1f_op: {
+ unsigned int fcr31;
+ unsigned int bit;
+
+ bc_false = 1;
+ fallthrough;
+ case mm_bc2t_op:
+ case mm_bc1t_op:
+ preempt_disable();
+ if (is_fpu_owner())
+ fcr31 = read_32bit_cp1_register(CP1_STATUS);
+ 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;
+ }
+#endif /* CONFIG_MIPS_FP_SUPPORT */
+ }
+ 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;
+ fallthrough;
+ 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;
+ fallthrough;
+ 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
+ * be used in interrupt context. (Compact branches/jumps do not cause
+ * exceptions.)
+ */
+int __microMIPS_compute_return_epc(struct pt_regs *regs)
+{
+ u16 __user *pc16;
+ u16 halfword;
+ unsigned int word;
+ unsigned long contpc;
+ struct mm_decoded_insn mminsn = { 0 };
+
+ mminsn.micro_mips_mode = 1;
+
+ /* This load never faults. */
+ pc16 = (unsigned short __user *)msk_isa16_mode(regs->cp0_epc);
+ __get_user(halfword, pc16);
+ pc16++;
+ contpc = regs->cp0_epc + 2;
+ word = ((unsigned int)halfword << 16);
+ mminsn.pc_inc = 2;
+
+ if (!mm_insn_16bit(halfword)) {
+ __get_user(halfword, pc16);
+ pc16++;
+ contpc = regs->cp0_epc + 4;
+ mminsn.pc_inc = 4;
+ word |= halfword;
+ }
+ mminsn.insn = word;
+
+ if (get_user(halfword, pc16))
+ goto sigsegv;
+ mminsn.next_pc_inc = 2;
+ word = ((unsigned int)halfword << 16);
+
+ if (!mm_insn_16bit(halfword)) {
+ pc16++;
+ if (get_user(halfword, pc16))
+ goto sigsegv;
+ mminsn.next_pc_inc = 4;
+ word |= halfword;
+ }
+ mminsn.next_insn = word;
+
+ mm_isBranchInstr(regs, mminsn, &contpc);
+
+ regs->cp0_epc = contpc;
+
+ return 0;
+
+sigsegv:
+ force_sig(SIGSEGV);
+ return -EFAULT;
+}
+
+/*
+ * Compute return address and emulate branch in MIPS16e mode after an
+ * exception only. It does not handle compact branches/jumps and cannot
+ * be used in interrupt context. (Compact branches/jumps do not cause
+ * exceptions.)
+ */
+int __MIPS16e_compute_return_epc(struct pt_regs *regs)
+{
+ u16 __user *addr;
+ union mips16e_instruction inst;
+ u16 inst2;
+ u32 fullinst;
+ long epc;
+
+ epc = regs->cp0_epc;
+
+ /* Read the instruction. */
+ addr = (u16 __user *)msk_isa16_mode(epc);
+ if (__get_user(inst.full, addr)) {
+ force_sig(SIGSEGV);
+ return -EFAULT;
+ }
+
+ switch (inst.ri.opcode) {
+ case MIPS16e_extend_op:
+ regs->cp0_epc += 4;
+ return 0;
+
+ /*
+ * JAL and JALX in MIPS16e mode
+ */
+ case MIPS16e_jal_op:
+ addr += 1;
+ if (__get_user(inst2, addr)) {
+ force_sig(SIGSEGV);
+ return -EFAULT;
+ }
+ fullinst = ((unsigned)inst.full << 16) | inst2;
+ regs->regs[31] = epc + 6;
+ epc += 4;
+ epc >>= 28;
+ epc <<= 28;
+ /*
+ * JAL:5 X:1 TARGET[20-16]:5 TARGET[25:21]:5 TARGET[15:0]:16
+ *
+ * ......TARGET[15:0].................TARGET[20:16]...........
+ * ......TARGET[25:21]
+ */
+ epc |=
+ ((fullinst & 0xffff) << 2) | ((fullinst & 0x3e00000) >> 3) |
+ ((fullinst & 0x1f0000) << 7);
+ if (!inst.jal.x)
+ set_isa16_mode(epc); /* Set ISA mode bit. */
+ regs->cp0_epc = epc;
+ return 0;
+
+ /*
+ * J(AL)R(C)
+ */
+ case MIPS16e_rr_op:
+ if (inst.rr.func == MIPS16e_jr_func) {
+
+ if (inst.rr.ra)
+ regs->cp0_epc = regs->regs[31];
+ else
+ regs->cp0_epc =
+ regs->regs[reg16to32[inst.rr.rx]];
+
+ if (inst.rr.l) {
+ if (inst.rr.nd)
+ regs->regs[31] = epc + 2;
+ else
+ regs->regs[31] = epc + 4;
+ }
+ return 0;
+ }
+ break;
+ }
+
+ /*
+ * All other cases have no branch delay slot and are 16-bits.
+ * Branches do not cause an exception.
+ */
+ regs->cp0_epc += 2;
+
+ return 0;
+}
+
+/**
+ * __compute_return_epc_for_insn - Computes the return address and do emulate
+ * branch simulation, if required.
+ *
+ * @regs: Pointer to pt_regs
+ * @insn: branch instruction to decode
+ * Return: -EFAULT on error and forces SIGILL, and on success
+ * returns 0 or BRANCH_LIKELY_TAKEN as appropriate after
+ * evaluating the branch.
+ *
+ * MIPS R6 Compact branches and forbidden slots:
+ * Compact branches do not throw exceptions because they do
+ * not have delay slots. The forbidden slot instruction ($PC+4)
+ * is only executed if the branch was not taken. Otherwise the
+ * forbidden slot is skipped entirely. This means that the
+ * only possible reason to be here because of a MIPS R6 compact
+ * branch instruction is that the forbidden slot has thrown one.
+ * In that case the branch was not taken, so the EPC can be safely
+ * set to EPC + 8.
+ */
+int __compute_return_epc_for_insn(struct pt_regs *regs,
+ union mips_instruction insn)
+{
+ long epc = regs->cp0_epc;
+ unsigned int dspcontrol;
+ int ret = 0;
+
+ switch (insn.i_format.opcode) {
+ /*
+ * jr and jalr are in r_format format.
+ */
+ case spec_op:
+ switch (insn.r_format.func) {
+ case jalr_op:
+ regs->regs[insn.r_format.rd] = epc + 8;
+ fallthrough;
+ case jr_op:
+ if (NO_R6EMU && insn.r_format.func == jr_op)
+ goto sigill_r2r6;
+ regs->cp0_epc = regs->regs[insn.r_format.rs];
+ break;
+ }
+ break;
+
+ /*
+ * This group contains:
+ * bltz_op, bgez_op, bltzl_op, bgezl_op,
+ * bltzal_op, bgezal_op, bltzall_op, bgezall_op.
+ */
+ case bcond_op:
+ switch (insn.i_format.rt) {
+ case bltzl_op:
+ if (NO_R6EMU)
+ goto sigill_r2r6;
+ fallthrough;
+ case bltz_op:
+ if ((long)regs->regs[insn.i_format.rs] < 0) {
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ if (insn.i_format.rt == bltzl_op)
+ ret = BRANCH_LIKELY_TAKEN;
+ } else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+
+ case bgezl_op:
+ if (NO_R6EMU)
+ goto sigill_r2r6;
+ fallthrough;
+ case bgez_op:
+ if ((long)regs->regs[insn.i_format.rs] >= 0) {
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ if (insn.i_format.rt == bgezl_op)
+ ret = BRANCH_LIKELY_TAKEN;
+ } else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+
+ case bltzal_op:
+ case bltzall_op:
+ if (NO_R6EMU && (insn.i_format.rs ||
+ insn.i_format.rt == bltzall_op))
+ goto sigill_r2r6;
+ regs->regs[31] = epc + 8;
+ /*
+ * OK we are here either because we hit a NAL
+ * instruction or because we are emulating an
+ * old bltzal{,l} one. Let's figure out what the
+ * case really is.
+ */
+ if (!insn.i_format.rs) {
+ /*
+ * NAL or BLTZAL with rs == 0
+ * Doesn't matter if we are R6 or not. The
+ * result is the same
+ */
+ regs->cp0_epc += 4 +
+ (insn.i_format.simmediate << 2);
+ break;
+ }
+ /* Now do the real thing for non-R6 BLTZAL{,L} */
+ if ((long)regs->regs[insn.i_format.rs] < 0) {
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ if (insn.i_format.rt == bltzall_op)
+ ret = BRANCH_LIKELY_TAKEN;
+ } else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+
+ case bgezal_op:
+ case bgezall_op:
+ if (NO_R6EMU && (insn.i_format.rs ||
+ insn.i_format.rt == bgezall_op))
+ goto sigill_r2r6;
+ regs->regs[31] = epc + 8;
+ /*
+ * OK we are here either because we hit a BAL
+ * instruction or because we are emulating an
+ * old bgezal{,l} one. Let's figure out what the
+ * case really is.
+ */
+ if (!insn.i_format.rs) {
+ /*
+ * BAL or BGEZAL with rs == 0
+ * Doesn't matter if we are R6 or not. The
+ * result is the same
+ */
+ regs->cp0_epc += 4 +
+ (insn.i_format.simmediate << 2);
+ break;
+ }
+ /* Now do the real thing for non-R6 BGEZAL{,L} */
+ if ((long)regs->regs[insn.i_format.rs] >= 0) {
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ if (insn.i_format.rt == bgezall_op)
+ ret = BRANCH_LIKELY_TAKEN;
+ } else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+
+ case bposge32_op:
+ if (!cpu_has_dsp)
+ goto sigill_dsp;
+
+ dspcontrol = rddsp(0x01);
+
+ if (dspcontrol >= 32) {
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ } else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+ }
+ break;
+
+ /*
+ * These are unconditional and in j_format.
+ */
+ case jalx_op:
+ case jal_op:
+ regs->regs[31] = regs->cp0_epc + 8;
+ fallthrough;
+ case j_op:
+ epc += 4;
+ epc >>= 28;
+ epc <<= 28;
+ epc |= (insn.j_format.target << 2);
+ regs->cp0_epc = epc;
+ if (insn.i_format.opcode == jalx_op)
+ set_isa16_mode(regs->cp0_epc);
+ break;
+
+ /*
+ * These are conditional and in i_format.
+ */
+ case beql_op:
+ if (NO_R6EMU)
+ goto sigill_r2r6;
+ fallthrough;
+ case beq_op:
+ if (regs->regs[insn.i_format.rs] ==
+ regs->regs[insn.i_format.rt]) {
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ if (insn.i_format.opcode == beql_op)
+ ret = BRANCH_LIKELY_TAKEN;
+ } else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+
+ case bnel_op:
+ if (NO_R6EMU)
+ goto sigill_r2r6;
+ fallthrough;
+ case bne_op:
+ if (regs->regs[insn.i_format.rs] !=
+ regs->regs[insn.i_format.rt]) {
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ if (insn.i_format.opcode == bnel_op)
+ ret = BRANCH_LIKELY_TAKEN;
+ } else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+
+ case blezl_op: /* not really i_format */
+ if (!insn.i_format.rt && NO_R6EMU)
+ goto sigill_r2r6;
+ fallthrough;
+ case blez_op:
+ /*
+ * Compact branches for R6 for the
+ * blez and blezl opcodes.
+ * BLEZ | rs = 0 | rt != 0 == BLEZALC
+ * BLEZ | rs = rt != 0 == BGEZALC
+ * BLEZ | rs != 0 | rt != 0 == BGEUC
+ * BLEZL | rs = 0 | rt != 0 == BLEZC
+ * BLEZL | rs = rt != 0 == BGEZC
+ * BLEZL | rs != 0 | rt != 0 == BGEC
+ *
+ * For real BLEZ{,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] = epc + 4;
+ regs->cp0_epc += 8;
+ break;
+ }
+ /* rt field assumed to be zero */
+ if ((long)regs->regs[insn.i_format.rs] <= 0) {
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ if (insn.i_format.opcode == blezl_op)
+ ret = BRANCH_LIKELY_TAKEN;
+ } else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+
+ case bgtzl_op:
+ if (!insn.i_format.rt && NO_R6EMU)
+ goto sigill_r2r6;
+ fallthrough;
+ 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] = epc + 4;
+ regs->cp0_epc += 8;
+ break;
+ }
+
+ /* rt field assumed to be zero */
+ if ((long)regs->regs[insn.i_format.rs] > 0) {
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ if (insn.i_format.opcode == bgtzl_op)
+ ret = BRANCH_LIKELY_TAKEN;
+ } else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+
+#ifdef CONFIG_MIPS_FP_SUPPORT
+ /*
+ * And now the FPA/cp1 branch instructions.
+ */
+ case cop1_op: {
+ unsigned int bit, fcr31, reg;
+
+ if (cpu_has_mips_r6 &&
+ ((insn.i_format.rs == bc1eqz_op) ||
+ (insn.i_format.rs == bc1nez_op))) {
+ if (!init_fp_ctx(current))
+ lose_fpu(1);
+ reg = insn.i_format.rt;
+ bit = get_fpr32(&current->thread.fpu.fpr[reg], 0) & 0x1;
+ if (insn.i_format.rs == bc1eqz_op)
+ bit = !bit;
+ own_fpu(1);
+ if (bit)
+ epc = epc + 4 +
+ (insn.i_format.simmediate << 2);
+ else
+ epc += 8;
+ regs->cp0_epc = epc;
+
+ break;
+ } else {
+
+ preempt_disable();
+ if (is_fpu_owner())
+ fcr31 = read_32bit_cp1_register(CP1_STATUS);
+ else
+ fcr31 = current->thread.fpu.fcr31;
+ preempt_enable();
+
+ bit = (insn.i_format.rt >> 2);
+ bit += (bit != 0);
+ bit += 23;
+ switch (insn.i_format.rt & 3) {
+ case 0: /* bc1f */
+ case 2: /* bc1fl */
+ if (~fcr31 & (1 << bit)) {
+ epc = epc + 4 +
+ (insn.i_format.simmediate << 2);
+ if (insn.i_format.rt == 2)
+ ret = BRANCH_LIKELY_TAKEN;
+ } else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+
+ case 1: /* bc1t */
+ case 3: /* bc1tl */
+ if (fcr31 & (1 << bit)) {
+ epc = epc + 4 +
+ (insn.i_format.simmediate << 2);
+ if (insn.i_format.rt == 3)
+ ret = BRANCH_LIKELY_TAKEN;
+ } else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+ }
+ break;
+ }
+ }
+#endif /* CONFIG_MIPS_FP_SUPPORT */
+
+#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)
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+ case ldc2_op: /* This is bbit032 on Octeon */
+ if ((regs->regs[insn.i_format.rs] &
+ (1ull<<(insn.i_format.rt+32))) == 0)
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+ case swc2_op: /* This is bbit1 on Octeon */
+ if (regs->regs[insn.i_format.rs] & (1ull<<insn.i_format.rt))
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+ case sdc2_op: /* This is bbit132 on Octeon */
+ if (regs->regs[insn.i_format.rs] &
+ (1ull<<(insn.i_format.rt+32)))
+ epc = epc + 4 + (insn.i_format.simmediate << 2);
+ else
+ epc += 8;
+ regs->cp0_epc = epc;
+ break;
+#else
+ case bc6_op:
+ /* Only valid for MIPS R6 */
+ if (!cpu_has_mips_r6)
+ goto sigill_r6;
+ regs->cp0_epc += 8;
+ break;
+ case balc6_op:
+ if (!cpu_has_mips_r6)
+ goto sigill_r6;
+ /* Compact branch: BALC */
+ regs->regs[31] = epc + 4;
+ epc += 4 + (insn.i_format.simmediate << 2);
+ regs->cp0_epc = epc;
+ break;
+ case pop66_op:
+ if (!cpu_has_mips_r6)
+ goto sigill_r6;
+ /* Compact branch: BEQZC || JIC */
+ regs->cp0_epc += 8;
+ break;
+ case pop76_op:
+ if (!cpu_has_mips_r6)
+ goto sigill_r6;
+ /* Compact branch: BNEZC || JIALC */
+ if (!insn.i_format.rs) {
+ /* JIALC: set $31/ra */
+ regs->regs[31] = epc + 4;
+ }
+ regs->cp0_epc += 8;
+ break;
+#endif
+ case pop10_op:
+ case pop30_op:
+ /* Only valid for MIPS R6 */
+ if (!cpu_has_mips_r6)
+ goto sigill_r6;
+ /*
+ * Compact branches:
+ * bovc, beqc, beqzalc, bnvc, bnec, bnezlac
+ */
+ if (insn.i_format.rt && !insn.i_format.rs)
+ regs->regs[31] = epc + 4;
+ regs->cp0_epc += 8;
+ break;
+ }
+
+ return ret;
+
+sigill_dsp:
+ pr_debug("%s: DSP branch but not DSP ASE - sending SIGILL.\n",
+ current->comm);
+ force_sig(SIGILL);
+ return -EFAULT;
+sigill_r2r6:
+ pr_debug("%s: R2 branch but r2-to-r6 emulator is not present - sending SIGILL.\n",
+ current->comm);
+ force_sig(SIGILL);
+ return -EFAULT;
+sigill_r6:
+ pr_debug("%s: R6 branch but no MIPSr6 ISA support - sending SIGILL.\n",
+ current->comm);
+ force_sig(SIGILL);
+ return -EFAULT;
+}
+EXPORT_SYMBOL_GPL(__compute_return_epc_for_insn);
+
+int __compute_return_epc(struct pt_regs *regs)
+{
+ unsigned int __user *addr;
+ long epc;
+ union mips_instruction insn;
+
+ epc = regs->cp0_epc;
+ if (epc & 3)
+ goto unaligned;
+
+ /*
+ * Read the instruction
+ */
+ addr = (unsigned int __user *) epc;
+ if (__get_user(insn.word, addr)) {
+ force_sig(SIGSEGV);
+ return -EFAULT;
+ }
+
+ return __compute_return_epc_for_insn(regs, insn);
+
+unaligned:
+ printk("%s: unaligned epc - sending SIGBUS.\n", current->comm);
+ force_sig(SIGBUS);
+ return -EFAULT;
+}
+
+#if (defined CONFIG_KPROBES) || (defined CONFIG_UPROBES)
+
+int __insn_is_compact_branch(union mips_instruction insn)
+{
+ if (!cpu_has_mips_r6)
+ return 0;
+
+ switch (insn.i_format.opcode) {
+ case blezl_op:
+ case bgtzl_op:
+ case blez_op:
+ case bgtz_op:
+ /*
+ * blez[l] and bgtz[l] opcodes with non-zero rt
+ * are MIPS R6 compact branches
+ */
+ if (insn.i_format.rt)
+ return 1;
+ break;
+ case bc6_op:
+ case balc6_op:
+ case pop10_op:
+ case pop30_op:
+ case pop66_op:
+ case pop76_op:
+ return 1;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__insn_is_compact_branch);
+
+#endif /* CONFIG_KPROBES || CONFIG_UPROBES */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-15 02:34:40 +0000