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Commit 41713d13 authored by Jon Medhurst's avatar Jon Medhurst Committed by Nicolas Pitre
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ARM: kprobes: Fix emulation of PLD instructions 



The PLD instructions wasn't being decoded correctly and the emulation
code wasn't adjusting PC correctly.

As the PLD instruction is only a performance hint we emulate it as a
simple nop, and we can broaden the instruction decoding to take into
account newer PLI and PLDW instructions.

Signed-off-by: default avatarJon Medhurst <tixy@yxit.co.uk>
Signed-off-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
parent f0aeb8bf

arch/arm/kernel/kprobes-decode.c

+8 −13
Original line number Diff line number Diff line
@@ -657,14 +657,8 @@ static void __kprobes emulate_none(struct kprobe *p, struct pt_regs *regs) 
	insnslot_0arg_rflags(regs->ARM_cpsr, i_fn);

}



static void __kprobes emulate_rn16(struct kprobe *p, struct pt_regs *regs)

static void __kprobes emulate_nop(struct kprobe *p, struct pt_regs *regs)

{

	insn_1arg_fn_t *i_fn = (insn_1arg_fn_t *)&p->ainsn.insn[0];

	kprobe_opcode_t insn = p->opcode;

	int rn = (insn >> 16) & 0xf;

	long rnv = regs->uregs[rn];



	insnslot_1arg_rflags(rnv, regs->ARM_cpsr, i_fn);

}



static void __kprobes emulate_rd12rm0(struct kprobe *p, struct pt_regs *regs)
@@ -941,12 +935,13 @@ space_1111(kprobe_opcode_t insn, struct arch_specific_insn *asi) 
	    (insn & 0xfe5f0f00) == 0xf84d0500)

		return INSN_REJECTED;



	/* PLD : 1111 01x1 x101 xxxx xxxx xxxx xxxx xxxx : */

	if ((insn & 0xfd700000) == 0xf4500000) {

		insn &= 0xfff0ffff;	/* Rn = r0 */

		asi->insn[0] = insn;

		asi->insn_handler = emulate_rn16;

		return INSN_GOOD;

	/* memory hint : 1111 0100 x001 xxxx xxxx xxxx xxxx xxxx : */

	/* PLDI        : 1111 0100 x101 xxxx xxxx xxxx xxxx xxxx : */

	/* PLDW        : 1111 0101 x001 xxxx xxxx xxxx xxxx xxxx : */

	/* PLD         : 1111 0101 x101 xxxx xxxx xxxx xxxx xxxx : */

	if ((insn & 0xfe300000) == 0xf4100000) {

		asi->insn_handler = emulate_nop;

		return INSN_GOOD_NO_SLOT;

	}



	/* BLX(1) : 1111 101x xxxx xxxx xxxx xxxx xxxx xxxx : */