/* * 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 #include #include #include #include #include #include #include #include #include #include #include /* * 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, current); return epc; } if (cpu_has_mips16) { if (((union mips16e_instruction)inst).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 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()) 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; } 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 * 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, current); 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, current); 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, current); 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 * @returns: -EFAULT on error and forces SIGBUS, 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) { unsigned int bit, fcr31, dspcontrol, reg; long epc = regs->cp0_epc; 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; /* Fall through */ case jr_op: if (NO_R6EMU && insn.r_format.func == jr_op) goto sigill_r6; 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_r6; 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_r6; 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)) { ret = -SIGILL; break; } 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. Lets 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)) { ret = -SIGILL; break; } 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. Lets 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 jal_op: regs->regs[31] = regs->cp0_epc + 8; 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_r6; 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_r6; 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 (NO_R6EMU) goto sigill_r6; 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 (NO_R6EMU) goto sigill_r6; 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; /* * And now the FPA/cp1 branch instructions. */ case cop1_op: if (cpu_has_mips_r6 && ((insn.i_format.rs == bc1eqz_op) || (insn.i_format.rs == bc1nez_op))) { if (!used_math()) { /* First time FPU user */ ret = init_fpu(); if (ret && NO_R6EMU) { ret = -ret; break; } ret = 0; set_used_math(); } lose_fpu(1); /* Save FPU state for the emulator. */ reg = insn.i_format.rt; bit = 0; switch (insn.i_format.rs) { case bc1eqz_op: /* Test bit 0 */ if (get_fpr32(¤t->thread.fpu.fpr[reg], 0) & 0x1) bit = 1; break; case bc1nez_op: /* Test bit 0 */ if (!(get_fpr32(¤t->thread.fpu.fpr[reg], 0) & 0x1)) bit = 1; break; } 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; } #ifdef CONFIG_CPU_CAVIUM_OCTEON case lwc2_op: /* This is bbit0 on Octeon */ if ((regs->regs[insn.i_format.rs] & (1ull<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<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) { ret = -SIGILL; break; } regs->cp0_epc += 8; break; #endif case cbcond0_op: /* Only valid for MIPS R6 */ if (!cpu_has_mips_r6) { ret = -SIGILL; break; } /* Compact branches: bovc, beqc, beqzalc */ if (insn.i_format.rt && !insn.i_format.rs) regs->regs[31] = epc + 4; regs->cp0_epc += 8; break; } return ret; sigill_dsp: printk("%s: DSP branch but not DSP ASE - sending SIGBUS.\n", current->comm); force_sig(SIGBUS, current); return -EFAULT; sigill_r6: pr_info("%s: R2 branch but r2-to-r6 emulator is not preset - sending SIGILL.\n", current->comm); force_sig(SIGILL, current); 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, current); return -EFAULT; } return __compute_return_epc_for_insn(regs, insn); unaligned: printk("%s: unaligned epc - sending SIGBUS.\n", current->comm); force_sig(SIGBUS, current); return -EFAULT; }