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ARM: kprobes: Add emulation of SBFX, UBFX, BFI and BFC instructions

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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>
This commit is contained in:
Jon Medhurst 2011-04-19 10:52:18 +01:00 committed by Nicolas Pitre
parent c9836777d5
commit 20e8155e24
1 changed files with 42 additions and 0 deletions
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42
arch/arm/kernel/kprobes-decode.c
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@ -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];
@ -869,6 +882,20 @@ prep_emulate_rd12_modify(kprobe_opcode_t insn, struct arch_specific_insn *asi)
return INSN_GOOD;
}
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)
{
@ -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;
}