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authorJon Medhurst <tixy@yxit.co.uk>2011-04-19 10:52:18 +0100
committerNicolas Pitre <nicolas.pitre@linaro.org>2011-04-28 23:41:00 -0400
commit20e8155e24ba5c04558780d0a8da13c39f98c002 (patch)
tree27d7bcb62bb4964442a92eb05c2e679c2ea477af /arch/arm
parentc9836777d5f22e64eefc759d682511560b6d6d78 (diff)
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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.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c
index a063f15..6bed8b0 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;
}