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| author | Jon Medhurst <tixy@yxit.co.uk> | 2011-04-19 10:52:18 +0100 |
|---|---|---|
| committer | Nicolas Pitre <nicolas.pitre@linaro.org> | 2011-04-28 23:41:00 -0400 |
| commit | 20e8155e24ba5c04558780d0a8da13c39f98c002 (patch) | |
| tree | 27d7bcb62bb4964442a92eb05c2e679c2ea477af /arch/arm | |
| parent | c9836777d5f22e64eefc759d682511560b6d6d78 (diff) | |
| download | lwn-20e8155e24ba5c04558780d0a8da13c39f98c002.tar.gz lwn-20e8155e24ba5c04558780d0a8da13c39f98c002.zip | |
ARM: kprobes: Add emulation of SBFX, UBFX, BFI and BFC instructions
These bit field manipulation instructions occur several thousand
times in an ARMv7 kernel.
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 | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c index a063f152d9b3..6bed8b089af0 100644 --- a/arch/arm/kernel/kprobes-decode.c +++ b/arch/arm/kernel/kprobes-decode.c @@ -672,6 +672,19 @@ emulate_rd12_modify(struct kprobe *p, struct pt_regs *regs) regs->uregs[rd] = insnslot_1arg_rflags(rdv, regs->ARM_cpsr, i_fn); } +static void __kprobes +emulate_rd12rn0_modify(struct kprobe *p, struct pt_regs *regs) +{ + insn_2arg_fn_t *i_fn = (insn_2arg_fn_t *)&p->ainsn.insn[0]; + kprobe_opcode_t insn = p->opcode; + int rd = (insn >> 12) & 0xf; + int rn = insn & 0xf; + long rdv = regs->uregs[rd]; + long rnv = regs->uregs[rn]; + + regs->uregs[rd] = insnslot_2arg_rflags(rdv, rnv, 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]; @@ -870,6 +883,20 @@ prep_emulate_rd12_modify(kprobe_opcode_t insn, struct arch_specific_insn *asi) } static enum kprobe_insn __kprobes +prep_emulate_rd12rn0_modify(kprobe_opcode_t insn, + struct arch_specific_insn *asi) +{ + if (is_r15(insn, 12)) + return INSN_REJECTED; /* Rd is PC */ + + insn &= 0xffff0ff0; /* Rd = r0 */ + insn |= 0x00000001; /* Rn = r1 */ + asi->insn[0] = insn; + asi->insn_handler = emulate_rd12rn0_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)) @@ -1396,6 +1423,21 @@ space_cccc_0111__1(kprobe_opcode_t insn, struct arch_specific_insn *asi) if ((insn & 0x0ff000d0) == 0x075000d0) return prep_emulate_rd16rn12rs8rm0_wflags(insn, asi); + /* SBFX : cccc 0111 101x xxxx xxxx xxxx x101 xxxx : */ + /* UBFX : cccc 0111 111x xxxx xxxx xxxx x101 xxxx : */ + if ((insn & 0x0fa00070) == 0x07a00050) + return prep_emulate_rd12rm0(insn, asi); + + /* BFI : cccc 0111 110x xxxx xxxx xxxx x001 xxxx : */ + /* BFC : cccc 0111 110x xxxx xxxx xxxx x001 1111 : */ + if ((insn & 0x0fe00070) == 0x07c00010) { + + if ((insn & 0x0000000f) == 0x0000000f) + return prep_emulate_rd12_modify(insn, asi); + else + return prep_emulate_rd12rn0_modify(insn, asi); + } + return INSN_REJECTED; } |