diff options
| author | Jon Medhurst <tixy@yxit.co.uk> | 2011-04-06 11:17:11 +0100 |
|---|---|---|
| committer | Nicolas Pitre <nicolas.pitre@linaro.org> | 2011-04-28 23:40:55 -0400 |
| commit | ad111ce46674a473370d302325db8f418ac4fe92 (patch) | |
| tree | f99fc1a1dd357e431f8be4ca0b9784d8ad7797f8 /arch | |
| parent | a539f5d46c868cb1f37b92e62e040b400571aed4 (diff) | |
| download | lwn-ad111ce46674a473370d302325db8f418ac4fe92.tar.gz lwn-ad111ce46674a473370d302325db8f418ac4fe92.zip | |
ARM: kprobes: Fix emulation of CMP, CMN, TST and TEQ instructions.
Probing these instructions was corrupting R0 because the emulation code
didn't account for the fact that they don't write a result to a
register.
Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/kernel/kprobes-decode.c | 55 |
1 files changed, 53 insertions, 2 deletions
diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c index f52fac0c59f0..ee29d3350437 100644 --- a/arch/arm/kernel/kprobes-decode.c +++ b/arch/arm/kernel/kprobes-decode.c @@ -808,6 +808,17 @@ emulate_alu_imm_rwflags(struct kprobe *p, struct pt_regs *regs) } static void __kprobes +emulate_alu_tests_imm(struct kprobe *p, struct pt_regs *regs) +{ + insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0]; + kprobe_opcode_t insn = p->opcode; + int rn = (insn >> 16) & 0xf; + long rnv = (rn == 15) ? (long)p->addr + 8 : regs->uregs[rn]; + + insnslot_1arg_rwflags(rnv, ®s->ARM_cpsr, i_fn); +} + +static void __kprobes emulate_alu_rflags(struct kprobe *p, struct pt_regs *regs) { insn_3arg_fn_t *i_fn = (insn_3arg_fn_t *)&p->ainsn.insn[0]; @@ -843,6 +854,22 @@ emulate_alu_rwflags(struct kprobe *p, struct pt_regs *regs) insnslot_3arg_rwflags(rnv, rmv, rsv, ®s->ARM_cpsr, i_fn); } +static void __kprobes +emulate_alu_tests(struct kprobe *p, struct pt_regs *regs) +{ + insn_3arg_fn_t *i_fn = (insn_3arg_fn_t *)&p->ainsn.insn[0]; + kprobe_opcode_t insn = p->opcode; + long ppc = (long)p->addr + 8; + int rn = (insn >> 16) & 0xf; + int rs = (insn >> 8) & 0xf; /* rs/rsv may be invalid, don't care. */ + int rm = insn & 0xf; + long rnv = (rn == 15) ? ppc : regs->uregs[rn]; + long rmv = (rm == 15) ? ppc : regs->uregs[rm]; + long rsv = regs->uregs[rs]; + + insnslot_3arg_rwflags(rnv, rmv, rsv, ®s->ARM_cpsr, i_fn); +} + static enum kprobe_insn __kprobes prep_emulate_ldr_str(kprobe_opcode_t insn, struct arch_specific_insn *asi) { @@ -1142,8 +1169,20 @@ space_cccc_000x(kprobe_opcode_t insn, struct arch_specific_insn *asi) insn |= 0x00000200; /* Rs = r2 */ } asi->insn[0] = insn; - asi->insn_handler = (insn & (1 << 20)) ? /* S-bit */ + + if ((insn & 0x0f900000) == 0x01100000) { + /* + * TST : cccc 0001 0001 xxxx xxxx xxxx xxxx xxxx + * TEQ : cccc 0001 0011 xxxx xxxx xxxx xxxx xxxx + * CMP : cccc 0001 0101 xxxx xxxx xxxx xxxx xxxx + * CMN : cccc 0001 0111 xxxx xxxx xxxx xxxx xxxx + */ + asi->insn_handler = emulate_alu_tests; + } else { + /* ALU ops which write to Rd */ + asi->insn_handler = (insn & (1 << 20)) ? /* S-bit */ emulate_alu_rwflags : emulate_alu_rflags; + } return INSN_GOOD; } @@ -1170,8 +1209,20 @@ space_cccc_001x(kprobe_opcode_t insn, struct arch_specific_insn *asi) */ insn &= 0xffff0fff; /* Rd = r0 */ asi->insn[0] = insn; - asi->insn_handler = (insn & (1 << 20)) ? /* S-bit */ + + if ((insn & 0x0f900000) == 0x03100000) { + /* + * TST : cccc 0011 0001 xxxx xxxx xxxx xxxx xxxx + * TEQ : cccc 0011 0011 xxxx xxxx xxxx xxxx xxxx + * CMP : cccc 0011 0101 xxxx xxxx xxxx xxxx xxxx + * CMN : cccc 0011 0111 xxxx xxxx xxxx xxxx xxxx + */ + asi->insn_handler = emulate_alu_tests_imm; + } else { + /* ALU ops which write to Rd */ + asi->insn_handler = (insn & (1 << 20)) ? /* S-bit */ emulate_alu_imm_rwflags : emulate_alu_imm_rflags; + } return INSN_GOOD; } |