From c412aba2a1243192a4d53736805a96bdda915608 Mon Sep 17 00:00:00 2001 From: Jon Medhurst Date: Thu, 7 Apr 2011 13:25:16 +0100 Subject: [PATCH] ARM: kprobes: Fix emulation of MRS instruction The MRS instruction should set mode and interrupt bits in the read value so it is simpler to use a new simulation routine (simulate_mrs) rather than some modified emulation. prep_emulate_rd12 is now unused and removed. Signed-off-by: Jon Medhurst Signed-off-by: Nicolas Pitre --- arch/arm/kernel/kprobes-decode.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/arch/arm/kernel/kprobes-decode.c b/arch/arm/kernel/kprobes-decode.c index e5bc576ba3fb..4ab83f4c47cf 100644 --- a/arch/arm/kernel/kprobes-decode.c +++ b/arch/arm/kernel/kprobes-decode.c @@ -451,6 +451,14 @@ static void __kprobes simulate_blx2bx(struct kprobe *p, struct pt_regs *regs) regs->ARM_cpsr |= PSR_T_BIT; } +static void __kprobes simulate_mrs(struct kprobe *p, struct pt_regs *regs) +{ + kprobe_opcode_t insn = p->opcode; + int rd = (insn >> 12) & 0xf; + unsigned long mask = 0xf8ff03df; /* Mask out execution state */ + regs->uregs[rd] = regs->ARM_cpsr & mask; +} + static void __kprobes simulate_ldm1stm1(struct kprobe *p, struct pt_regs *regs) { kprobe_opcode_t insn = p->opcode; @@ -895,15 +903,6 @@ prep_emulate_rd12rm0(kprobe_opcode_t insn, struct arch_specific_insn *asi) return INSN_GOOD; } -static enum kprobe_insn __kprobes -prep_emulate_rd12(kprobe_opcode_t insn, struct arch_specific_insn *asi) -{ - insn &= 0xffff0fff; /* Rd = r0 */ - asi->insn[0] = insn; - asi->insn_handler = emulate_rd12; - return INSN_GOOD; -} - static enum kprobe_insn __kprobes prep_emulate_rd12rn16rm0_wflags(kprobe_opcode_t insn, struct arch_specific_insn *asi) @@ -1035,8 +1034,10 @@ space_cccc_000x(kprobe_opcode_t insn, struct arch_specific_insn *asi) return INSN_REJECTED; /* MRS cpsr : cccc 0001 0000 xxxx xxxx xxxx 0000 xxxx */ - if ((insn & 0x0ff000f0) == 0x01000000) - return prep_emulate_rd12(insn, asi); + if ((insn & 0x0ff000f0) == 0x01000000) { + asi->insn_handler = simulate_mrs; + return INSN_GOOD_NO_SLOT; + } /* SMLALxy : cccc 0001 0100 xxxx xxxx xxxx 1xx0 xxxx */ if ((insn & 0x0ff00090) == 0x01400080)