diff options
Diffstat (limited to 'arch/mips/kernel/branch.c')
-rw-r--r-- | arch/mips/kernel/branch.c | 128 |
1 files changed, 84 insertions, 44 deletions
diff --git a/arch/mips/kernel/branch.c b/arch/mips/kernel/branch.c index 32103cc..4d735d0 100644 --- a/arch/mips/kernel/branch.c +++ b/arch/mips/kernel/branch.c @@ -9,6 +9,7 @@ #include <linux/kernel.h> #include <linux/sched.h> #include <linux/signal.h> +#include <linux/module.h> #include <asm/branch.h> #include <asm/cpu.h> #include <asm/cpu-features.h> @@ -17,28 +18,22 @@ #include <asm/ptrace.h> #include <asm/uaccess.h> -/* - * Compute the return address and do emulate branch simulation, if required. +/** + * __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. */ -int __compute_return_epc(struct pt_regs *regs) +int __compute_return_epc_for_insn(struct pt_regs *regs, + union mips_instruction insn) { - unsigned int __user *addr; unsigned int bit, fcr31, dspcontrol; - 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; - } + long epc = regs->cp0_epc; + int ret = 0; switch (insn.i_format.opcode) { /* @@ -64,18 +59,22 @@ int __compute_return_epc(struct pt_regs *regs) switch (insn.i_format.rt) { case bltz_op: case bltzl_op: - if ((long)regs->regs[insn.i_format.rs] < 0) + if ((long)regs->regs[insn.i_format.rs] < 0) { epc = epc + 4 + (insn.i_format.simmediate << 2); - else + if (insn.i_format.rt == bltzl_op) + ret = BRANCH_LIKELY_TAKEN; + } else epc += 8; regs->cp0_epc = epc; break; case bgez_op: case bgezl_op: - if ((long)regs->regs[insn.i_format.rs] >= 0) + if ((long)regs->regs[insn.i_format.rs] >= 0) { epc = epc + 4 + (insn.i_format.simmediate << 2); - else + if (insn.i_format.rt == bgezl_op) + ret = BRANCH_LIKELY_TAKEN; + } else epc += 8; regs->cp0_epc = epc; break; @@ -83,9 +82,11 @@ int __compute_return_epc(struct pt_regs *regs) case bltzal_op: case bltzall_op: regs->regs[31] = epc + 8; - if ((long)regs->regs[insn.i_format.rs] < 0) + if ((long)regs->regs[insn.i_format.rs] < 0) { epc = epc + 4 + (insn.i_format.simmediate << 2); - else + if (insn.i_format.rt == bltzall_op) + ret = BRANCH_LIKELY_TAKEN; + } else epc += 8; regs->cp0_epc = epc; break; @@ -93,12 +94,15 @@ int __compute_return_epc(struct pt_regs *regs) case bgezal_op: case bgezall_op: regs->regs[31] = epc + 8; - if ((long)regs->regs[insn.i_format.rs] >= 0) + if ((long)regs->regs[insn.i_format.rs] >= 0) { epc = epc + 4 + (insn.i_format.simmediate << 2); - else + 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; @@ -133,9 +137,11 @@ int __compute_return_epc(struct pt_regs *regs) case beq_op: case beql_op: if (regs->regs[insn.i_format.rs] == - regs->regs[insn.i_format.rt]) + regs->regs[insn.i_format.rt]) { epc = epc + 4 + (insn.i_format.simmediate << 2); - else + if (insn.i_format.rt == beql_op) + ret = BRANCH_LIKELY_TAKEN; + } else epc += 8; regs->cp0_epc = epc; break; @@ -143,9 +149,11 @@ int __compute_return_epc(struct pt_regs *regs) case bne_op: case bnel_op: if (regs->regs[insn.i_format.rs] != - regs->regs[insn.i_format.rt]) + regs->regs[insn.i_format.rt]) { epc = epc + 4 + (insn.i_format.simmediate << 2); - else + if (insn.i_format.rt == bnel_op) + ret = BRANCH_LIKELY_TAKEN; + } else epc += 8; regs->cp0_epc = epc; break; @@ -153,9 +161,11 @@ int __compute_return_epc(struct pt_regs *regs) case blez_op: /* not really i_format */ case blezl_op: /* rt field assumed to be zero */ - if ((long)regs->regs[insn.i_format.rs] <= 0) + if ((long)regs->regs[insn.i_format.rs] <= 0) { epc = epc + 4 + (insn.i_format.simmediate << 2); - else + if (insn.i_format.rt == bnel_op) + ret = BRANCH_LIKELY_TAKEN; + } else epc += 8; regs->cp0_epc = epc; break; @@ -163,9 +173,11 @@ int __compute_return_epc(struct pt_regs *regs) case bgtz_op: case bgtzl_op: /* rt field assumed to be zero */ - if ((long)regs->regs[insn.i_format.rs] > 0) + if ((long)regs->regs[insn.i_format.rs] > 0) { epc = epc + 4 + (insn.i_format.simmediate << 2); - else + if (insn.i_format.rt == bnel_op) + ret = BRANCH_LIKELY_TAKEN; + } else epc += 8; regs->cp0_epc = epc; break; @@ -187,18 +199,22 @@ int __compute_return_epc(struct pt_regs *regs) switch (insn.i_format.rt & 3) { case 0: /* bc1f */ case 2: /* bc1fl */ - if (~fcr31 & (1 << bit)) + if (~fcr31 & (1 << bit)) { epc = epc + 4 + (insn.i_format.simmediate << 2); - else + 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)) + if (fcr31 & (1 << bit)) { epc = epc + 4 + (insn.i_format.simmediate << 2); - else + if (insn.i_format.rt == 3) + ret = BRANCH_LIKELY_TAKEN; + } else epc += 8; regs->cp0_epc = epc; break; @@ -239,15 +255,39 @@ int __compute_return_epc(struct pt_regs *regs) #endif } - return 0; + return ret; -unaligned: - printk("%s: unaligned epc - sending SIGBUS.\n", current->comm); +sigill: + printk("%s: DSP branch but not DSP ASE - sending SIGBUS.\n", current->comm); force_sig(SIGBUS, current); return -EFAULT; +} +EXPORT_SYMBOL_GPL(__compute_return_epc_for_insn); -sigill: - printk("%s: DSP branch but not DSP ASE - sending SIGBUS.\n", current->comm); +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; + } |