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ARM: kprobes: Decode 16-bit Thumb PC- and SP-relative address instructions 

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
This commit is contained in:
Jon Medhurst 2011-07-02 16:05:53 +01:00 committed by Tixy
parent f869514282
commit 2f33582904
1 changed files with 33 additions and 0 deletions
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33
arch/arm/kernel/kprobes-thumb.c
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@ -74,6 +74,28 @@ t16_simulate_ldrstr_sp_relative(struct kprobe *p, struct pt_regs *regs)
base[index] = regs->uregs[rt]; base[index] = regs->uregs[rt];
} }
static void __kprobes
t16_simulate_reladr(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
unsigned long base = (insn & 0x800) ? regs->ARM_sp
: (thumb_probe_pc(p) & ~3);
long offset = insn & 0xff;
int rt = (insn >> 8) & 0x7;
regs->uregs[rt] = base + offset * 4;
}
static void __kprobes
t16_simulate_add_sp_imm(struct kprobe *p, struct pt_regs *regs)
{
kprobe_opcode_t insn = p->opcode;
long imm = insn & 0x7f;
if (insn & 0x80) /* SUB */
regs->ARM_sp -= imm * 4;
else /* ADD */
regs->ARM_sp += imm * 4;
}
static unsigned long __kprobes static unsigned long __kprobes
t16_emulate_loregs(struct kprobe *p, struct pt_regs *regs) t16_emulate_loregs(struct kprobe *p, struct pt_regs *regs)
{ {
@ -154,6 +176,10 @@ t16_decode_hiregs(kprobe_opcode_t insn, struct arch_specific_insn *asi)
static const union decode_item t16_table_1011[] = { static const union decode_item t16_table_1011[] = {
/* Miscellaneous 16-bit instructions */ /* Miscellaneous 16-bit instructions */
/* ADD (SP plus immediate) 1011 0000 0xxx xxxx */
/* SUB (SP minus immediate) 1011 0000 1xxx xxxx */
DECODE_SIMULATE (0xff00, 0xb000, t16_simulate_add_sp_imm),
/* /*
* If-Then, and hints * If-Then, and hints
* 1011 1111 xxxx xxxx * 1011 1111 xxxx xxxx
@ -273,6 +299,13 @@ const union decode_item kprobe_decode_thumb16_table[] = {
/* LDR (immediate, Thumb) 1001 1xxx xxxx xxxx */ /* LDR (immediate, Thumb) 1001 1xxx xxxx xxxx */
DECODE_SIMULATE (0xf000, 0x9000, t16_simulate_ldrstr_sp_relative), DECODE_SIMULATE (0xf000, 0x9000, t16_simulate_ldrstr_sp_relative),
/*
* Generate PC-/SP-relative address
* ADR (literal) 1010 0xxx xxxx xxxx
* ADD (SP plus immediate) 1010 1xxx xxxx xxxx
*/
DECODE_SIMULATE (0xf000, 0xa000, t16_simulate_reladr),
/* /*
* Miscellaneous 16-bit instructions * Miscellaneous 16-bit instructions
* 1011 xxxx xxxx xxxx * 1011 xxxx xxxx xxxx