diff options
Diffstat (limited to 'arch/mips/kernel/branch.c')
| -rw-r--r-- | arch/mips/kernel/branch.c | 399 |
1 files changed, 388 insertions, 11 deletions
diff --git a/arch/mips/kernel/branch.c b/arch/mips/kernel/branch.c index 4d735d0e58f..7b2df224f04 100644 --- a/arch/mips/kernel/branch.c +++ b/arch/mips/kernel/branch.c @@ -14,10 +14,382 @@ #include <asm/cpu.h> #include <asm/cpu-features.h> #include <asm/fpu.h> +#include <asm/fpu_emulator.h> #include <asm/inst.h> #include <asm/ptrace.h> #include <asm/uaccess.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, 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()) + 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 + * 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. @@ -57,7 +429,7 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, */ case bcond_op: switch (insn.i_format.rt) { - case bltz_op: + case bltz_op: case bltzl_op: if ((long)regs->regs[insn.i_format.rs] < 0) { epc = epc + 4 + (insn.i_format.simmediate << 2); @@ -129,6 +501,8 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 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; /* @@ -139,7 +513,7 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 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.rt == beql_op) + if (insn.i_format.opcode == beql_op) ret = BRANCH_LIKELY_TAKEN; } else epc += 8; @@ -151,7 +525,7 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, 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.rt == bnel_op) + if (insn.i_format.opcode == bnel_op) ret = BRANCH_LIKELY_TAKEN; } else epc += 8; @@ -163,7 +537,7 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, /* 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.rt == bnel_op) + if (insn.i_format.opcode == blezl_op) ret = BRANCH_LIKELY_TAKEN; } else epc += 8; @@ -175,7 +549,7 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, /* 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.rt == bnel_op) + if (insn.i_format.opcode == bgtzl_op) ret = BRANCH_LIKELY_TAKEN; } else epc += 8; @@ -188,7 +562,11 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, case cop1_op: preempt_disable(); if (is_fpu_owner()) - asm volatile("cfc1\t%0,$31" : "=r" (fcr31)); + asm volatile( + ".set push\n" + "\t.set mips1\n" + "\tcfc1\t%0,$31\n" + "\t.set pop" : "=r" (fcr31)); else fcr31 = current->thread.fpu.fcr31; preempt_enable(); @@ -197,8 +575,8 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, bit += (bit != 0); bit += 23; switch (insn.i_format.rt & 3) { - case 0: /* bc1f */ - case 2: /* bc1fl */ + case 0: /* bc1f */ + case 2: /* bc1fl */ if (~fcr31 & (1 << bit)) { epc = epc + 4 + (insn.i_format.simmediate << 2); if (insn.i_format.rt == 2) @@ -208,8 +586,8 @@ int __compute_return_epc_for_insn(struct pt_regs *regs, regs->cp0_epc = epc; break; - case 1: /* bc1t */ - case 3: /* bc1tl */ + case 1: /* bc1t */ + case 3: /* bc1tl */ if (fcr31 & (1 << bit)) { epc = epc + 4 + (insn.i_format.simmediate << 2); if (insn.i_format.rt == 3) @@ -289,5 +667,4 @@ unaligned: printk("%s: unaligned epc - sending SIGBUS.\n", current->comm); force_sig(SIGBUS, current); return -EFAULT; - } |