From dd212bd3cbd337f8f3bd6b30929bef5a8c8ba81b Mon Sep 17 00:00:00 2001 From: Jon Medhurst Date: Sun, 3 Jul 2011 14:26:16 +0100 Subject: [PATCH] ARM: kprobes: Decode 32-bit Thumb table branch instructions Signed-off-by: Jon Medhurst Acked-by: Nicolas Pitre --- arch/arm/kernel/kprobes-thumb.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c index 299dc3a33ad2..dfaea25c6069 100644 --- a/arch/arm/kernel/kprobes-thumb.c +++ b/arch/arm/kernel/kprobes-thumb.c @@ -37,6 +37,26 @@ static inline unsigned long __kprobes thumb_probe_pc(struct kprobe *p) return (unsigned long)p->addr - 1 + 4; } +static void __kprobes +t32_simulate_table_branch(struct kprobe *p, struct pt_regs *regs) +{ + kprobe_opcode_t insn = p->opcode; + unsigned long pc = thumb_probe_pc(p); + int rn = (insn >> 16) & 0xf; + int rm = insn & 0xf; + + unsigned long rnv = (rn == 15) ? pc : regs->uregs[rn]; + unsigned long rmv = regs->uregs[rm]; + unsigned int halfwords; + + if (insn & 0x10) + halfwords = ((u16 *)rnv)[rmv]; + else + halfwords = ((u8 *)rnv)[rmv]; + + regs->ARM_pc = pc + 2 * halfwords; +} + static enum kprobe_insn __kprobes t32_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi) { @@ -117,6 +137,11 @@ static const union decode_item t32_table_1110_100x_x1xx[] = { DECODE_EMULATEX (0xff400000, 0xe9400000, t32_emulate_ldrdstrd, REGS(NOPCWB, NOSPPC, NOSPPC, 0, 0)), + /* TBB 1110 1000 1101 xxxx xxxx xxxx 0000 xxxx */ + /* TBH 1110 1000 1101 xxxx xxxx xxxx 0001 xxxx */ + DECODE_SIMULATEX(0xfff000e0, 0xe8d00000, t32_simulate_table_branch, + REGS(NOSP, 0, 0, 0, NOSPPC)), + /* STREX 1110 1000 0100 xxxx xxxx xxxx xxxx xxxx */ /* LDREX 1110 1000 0101 xxxx xxxx xxxx xxxx xxxx */ /* STREXB 1110 1000 1100 xxxx xxxx xxxx 0100 xxxx */ -- 2.39.2