diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h index bb8a19bd5822..e46bdd0097eb 100644 --- a/arch/arm/include/asm/kprobes.h +++ b/arch/arm/include/asm/kprobes.h @@ -39,10 +39,13 @@ typedef u32 kprobe_opcode_t; struct kprobe; typedef void (kprobe_insn_handler_t)(struct kprobe *, struct pt_regs *); +typedef unsigned long (kprobe_check_cc)(unsigned long); + /* Architecture specific copy of original instruction. */ struct arch_specific_insn { kprobe_opcode_t *insn; kprobe_insn_handler_t *insn_handler; + kprobe_check_cc *insn_check_cc; }; struct prev_kprobe { diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c index 3b0cf90cb449..2e84169b9e91 100644 --- a/arch/arm/kernel/kprobes-decode.c +++ b/arch/arm/kernel/kprobes-decode.c @@ -1396,6 +1396,96 @@ space_cccc_111x(kprobe_opcode_t insn, struct arch_specific_insn *asi) return INSN_GOOD; } +static unsigned long __kprobes __check_eq(unsigned long cpsr) +{ + return cpsr & PSR_Z_BIT; +} + +static unsigned long __kprobes __check_ne(unsigned long cpsr) +{ + return (~cpsr) & PSR_Z_BIT; +} + +static unsigned long __kprobes __check_cs(unsigned long cpsr) +{ + return cpsr & PSR_C_BIT; +} + +static unsigned long __kprobes __check_cc(unsigned long cpsr) +{ + return (~cpsr) & PSR_C_BIT; +} + +static unsigned long __kprobes __check_mi(unsigned long cpsr) +{ + return cpsr & PSR_N_BIT; +} + +static unsigned long __kprobes __check_pl(unsigned long cpsr) +{ + return (~cpsr) & PSR_N_BIT; +} + +static unsigned long __kprobes __check_vs(unsigned long cpsr) +{ + return cpsr & PSR_V_BIT; +} + +static unsigned long __kprobes __check_vc(unsigned long cpsr) +{ + return (~cpsr) & PSR_V_BIT; +} + +static unsigned long __kprobes __check_hi(unsigned long cpsr) +{ + cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */ + return cpsr & PSR_C_BIT; +} + +static unsigned long __kprobes __check_ls(unsigned long cpsr) +{ + cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */ + return (~cpsr) & PSR_C_BIT; +} + +static unsigned long __kprobes __check_ge(unsigned long cpsr) +{ + cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */ + return (~cpsr) & PSR_N_BIT; +} + +static unsigned long __kprobes __check_lt(unsigned long cpsr) +{ + cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */ + return cpsr & PSR_N_BIT; +} + +static unsigned long __kprobes __check_gt(unsigned long cpsr) +{ + unsigned long temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */ + temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */ + return (~temp) & PSR_N_BIT; +} + +static unsigned long __kprobes __check_le(unsigned long cpsr) +{ + unsigned long temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */ + temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */ + return temp & PSR_N_BIT; +} + +static unsigned long __kprobes __check_al(unsigned long cpsr) +{ + return true; +} + +static kprobe_check_cc * const condition_checks[16] = { + &__check_eq, &__check_ne, &__check_cs, &__check_cc, + &__check_mi, &__check_pl, &__check_vs, &__check_vc, + &__check_hi, &__check_ls, &__check_ge, &__check_lt, + &__check_gt, &__check_le, &__check_al, &__check_al +}; + /* Return: * INSN_REJECTED If instruction is one not allowed to kprobe, * INSN_GOOD If instruction is supported and uses instruction slot, @@ -1411,6 +1501,7 @@ space_cccc_111x(kprobe_opcode_t insn, struct arch_specific_insn *asi) enum kprobe_insn __kprobes arm_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi) { + asi->insn_check_cc = condition_checks[insn>>28]; asi->insn[1] = KPROBE_RETURN_INSTRUCTION; if ((insn & 0xf0000000) == 0xf0000000) { diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c index 2ba7deb3072e..1656c87501c0 100644 --- a/arch/arm/kernel/kprobes.c +++ b/arch/arm/kernel/kprobes.c @@ -134,7 +134,8 @@ static void __kprobes singlestep(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { regs->ARM_pc += 4; - p->ainsn.insn_handler(p, regs); + if (p->ainsn.insn_check_cc(regs->ARM_cpsr)) + p->ainsn.insn_handler(p, regs); } /*