diff options
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/kernel/kprobes-thumb.c | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c index a5bdb2dc39e7..e0289493b4c6 100644 --- a/arch/arm/kernel/kprobes-thumb.c +++ b/arch/arm/kernel/kprobes-thumb.c @@ -187,6 +187,87 @@ t16_decode_hiregs(kprobe_opcode_t insn, struct arch_specific_insn *asi) return INSN_GOOD; } +static void __kprobes +t16_emulate_push(struct kprobe *p, struct pt_regs *regs) +{ + __asm__ __volatile__ ( + "ldr r9, [%[regs], #13*4] \n\t" + "ldr r8, [%[regs], #14*4] \n\t" + "ldmia %[regs], {r0-r7} \n\t" + "blx %[fn] \n\t" + "str r9, [%[regs], #13*4] \n\t" + : + : [regs] "r" (regs), [fn] "r" (p->ainsn.insn_fn) + : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", + "lr", "memory", "cc" + ); +} + +static enum kprobe_insn __kprobes +t16_decode_push(kprobe_opcode_t insn, struct arch_specific_insn *asi) +{ + /* + * To simulate a PUSH we use a Thumb-2 "STMDB R9!, {registers}" + * and call it with R9=SP and LR in the register list represented + * by R8. + */ + ((u16 *)asi->insn)[0] = 0xe929; /* 1st half STMDB R9!,{} */ + ((u16 *)asi->insn)[1] = insn & 0x1ff; /* 2nd half (register list) */ + asi->insn_handler = t16_emulate_push; + return INSN_GOOD; +} + +static void __kprobes +t16_emulate_pop_nopc(struct kprobe *p, struct pt_regs *regs) +{ + __asm__ __volatile__ ( + "ldr r9, [%[regs], #13*4] \n\t" + "ldmia %[regs], {r0-r7} \n\t" + "blx %[fn] \n\t" + "stmia %[regs], {r0-r7} \n\t" + "str r9, [%[regs], #13*4] \n\t" + : + : [regs] "r" (regs), [fn] "r" (p->ainsn.insn_fn) + : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r9", + "lr", "memory", "cc" + ); +} + +static void __kprobes +t16_emulate_pop_pc(struct kprobe *p, struct pt_regs *regs) +{ + register unsigned long pc asm("r8"); + + __asm__ __volatile__ ( + "ldr r9, [%[regs], #13*4] \n\t" + "ldmia %[regs], {r0-r7} \n\t" + "blx %[fn] \n\t" + "stmia %[regs], {r0-r7} \n\t" + "str r9, [%[regs], #13*4] \n\t" + : "=r" (pc) + : [regs] "r" (regs), [fn] "r" (p->ainsn.insn_fn) + : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", "r9", + "lr", "memory", "cc" + ); + + bx_write_pc(pc, regs); +} + +static enum kprobe_insn __kprobes +t16_decode_pop(kprobe_opcode_t insn, struct arch_specific_insn *asi) +{ + /* + * To simulate a POP we use a Thumb-2 "LDMDB R9!, {registers}" + * and call it with R9=SP and PC in the register list represented + * by R8. + */ + ((u16 *)asi->insn)[0] = 0xe8b9; /* 1st half LDMIA R9!,{} */ + ((u16 *)asi->insn)[1] = insn & 0x1ff; /* 2nd half (register list) */ + asi->insn_handler = insn & 0x100 ? t16_emulate_pop_pc + : t16_emulate_pop_nopc; + return INSN_GOOD; +} + static const union decode_item t16_table_1011[] = { /* Miscellaneous 16-bit instructions */ @@ -209,6 +290,11 @@ static const union decode_item t16_table_1011[] = { DECODE_REJECT (0xffc0, 0xba80), DECODE_EMULATE (0xf500, 0xb000, t16_emulate_loregs_rwflags), + /* PUSH 1011 010x xxxx xxxx */ + DECODE_CUSTOM (0xfe00, 0xb400, t16_decode_push), + /* POP 1011 110x xxxx xxxx */ + DECODE_CUSTOM (0xfe00, 0xbc00, t16_decode_pop), + /* * If-Then, and hints * 1011 1111 xxxx xxxx |