Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit c412aba2 authored by Jon Medhurst's avatar Jon Medhurst Committed by Nicolas Pitre
Browse files

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: default avatarJon Medhurst <tixy@yxit.co.uk>
Signed-off-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
parent 51468ea9

arch/arm/kernel/kprobes-decode.c

+12 −11
Original line number Diff line number Diff line
@@ -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)