X-Git-Url: http://git.osdn.net/view?a=blobdiff_plain;f=arch%2Fmips%2Fkernel%2Fbranch.c;h=cd880b91f0928c40fd3ced0d925ecf48f23bf8b6;hb=f1b44067c19258b7614e3cd09dfe8d8e12ff5895;hp=4d7d99d601cc13219e9d8f9631da6002b3d9df9d;hpb=c32809521de5b31699a33379183848b0c7628f28;p=uclinux-h8%2Flinux.git diff --git a/arch/mips/kernel/branch.c b/arch/mips/kernel/branch.c index 4d7d99d601cc..cd880b91f092 100644 --- a/arch/mips/kernel/branch.c +++ b/arch/mips/kernel/branch.c @@ -399,11 +399,21 @@ int __MIPS16e_compute_return_epc(struct pt_regs *regs) * @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; + unsigned int bit, fcr31, dspcontrol, reg; long epc = regs->cp0_epc; int ret = 0; @@ -417,6 +427,8 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 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; } @@ -429,8 +441,10 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, */ case bcond_op: switch (insn.i_format.rt) { - case bltz_op: 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) @@ -440,8 +454,10 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, regs->cp0_epc = epc; break; - case bgez_op: 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) @@ -453,7 +469,29 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 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) @@ -465,7 +503,29 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 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) @@ -477,7 +537,7 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, case bposge32_op: if (!cpu_has_dsp) - goto sigill; + goto sigill_dsp; dspcontrol = rddsp(0x01); @@ -508,8 +568,10 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, /* * These are conditional and in i_format. */ - case beq_op: 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); @@ -520,8 +582,10 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, regs->cp0_epc = epc; break; - case bne_op: 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); @@ -532,8 +596,31 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, regs->cp0_epc = epc; break; - case blez_op: /* not really i_format */ - case blezl_op: + 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); @@ -544,8 +631,32 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, regs->cp0_epc = epc; break; - case bgtz_op: 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); @@ -560,40 +671,83 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, * And now the FPA/cp1 branch instructions. */ case cop1_op: - 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 + 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 { - 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; + 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; } - break; #ifdef CONFIG_CPU_CAVIUM_OCTEON case lwc2_op: /* This is bbit0 on Octeon */ if ((regs->regs[insn.i_format.rs] & (1ull<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);