diff options
| author | Jon Medhurst <tixy@yxit.co.uk> | 2011-04-19 10:52:17 +0100 |
|---|---|---|
| committer | Nicolas Pitre <nicolas.pitre@linaro.org> | 2011-04-28 23:40:59 -0400 |
| commit | c9836777d5f22e64eefc759d682511560b6d6d78 (patch) | |
| tree | 37dbdb0ad5465fd1b290cc4742dd9f380b6f7ed6 /arch/arm | |
| parent | f704a6e25bd07e1381af81f19fb1d123975807b1 (diff) | |
| download | lwn-c9836777d5f22e64eefc759d682511560b6d6d78.tar.gz lwn-c9836777d5f22e64eefc759d682511560b6d6d78.zip | |
ARM: kprobes: Add emulation of MOVW and MOVT instructions
The MOVW and MOVT instructions account for approximately 7% of all
instructions in a ARMv7 kernel as GCC uses them instead of a literal
pool.
Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/kernel/kprobes-decode.c | 30 |
1 files changed, 28 insertions, 2 deletions
diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c index 4715537b490c..a063f152d9b3 100644 --- a/arch/arm/kernel/kprobes-decode.c +++ b/arch/arm/kernel/kprobes-decode.c @@ -661,6 +661,17 @@ static void __kprobes emulate_nop(struct kprobe *p, struct pt_regs *regs) { } +static void __kprobes +emulate_rd12_modify(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 rd = (insn >> 12) & 0xf; + long rdv = regs->uregs[rd]; + + regs->uregs[rd] = insnslot_1arg_rflags(rdv, regs->ARM_cpsr, i_fn); +} + static void __kprobes emulate_rd12rm0(struct kprobe *p, struct pt_regs *regs) { insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0]; @@ -847,6 +858,18 @@ prep_emulate_ldr_str(kprobe_opcode_t insn, struct arch_specific_insn *asi) } static enum kprobe_insn __kprobes +prep_emulate_rd12_modify(kprobe_opcode_t insn, struct arch_specific_insn *asi) +{ + if (is_r15(insn, 12)) + return INSN_REJECTED; /* Rd is PC */ + + insn &= 0xffff0fff; /* Rd = r0 */ + asi->insn[0] = insn; + asi->insn_handler = emulate_rd12_modify; + return INSN_GOOD; +} + +static enum kprobe_insn __kprobes prep_emulate_rd12rm0(kprobe_opcode_t insn, struct arch_specific_insn *asi) { if (is_r15(insn, 12)) @@ -1170,14 +1193,17 @@ space_cccc_000x(kprobe_opcode_t insn, struct arch_specific_insn *asi) static enum kprobe_insn __kprobes space_cccc_001x(kprobe_opcode_t insn, struct arch_specific_insn *asi) { + /* MOVW : cccc 0011 0000 xxxx xxxx xxxx xxxx xxxx */ + /* MOVT : cccc 0011 0100 xxxx xxxx xxxx xxxx xxxx */ + if ((insn & 0x0fb00000) == 0x03000000) + return prep_emulate_rd12_modify(insn, asi); + /* * MSR : cccc 0011 0x10 xxxx xxxx xxxx xxxx xxxx - * Undef : cccc 0011 0100 xxxx xxxx xxxx xxxx xxxx * ALU op with S bit and Rd == 15 : * cccc 001x xxx1 xxxx 1111 xxxx xxxx xxxx */ if ((insn & 0x0fb00000) == 0x03200000 || /* MSR */ - (insn & 0x0ff00000) == 0x03400000 || /* Undef */ (insn & 0x0e10f000) == 0x0210f000) /* ALU s-bit, R15 */ return INSN_REJECTED; |