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Commit 24371707 authored by Jon Medhurst's avatar Jon Medhurst Committed by Tixy
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ARM: kprobes: Add Thumb instruction decoding stubs 



Extend arch_prepare_kprobe to support probing of Thumb code. For
the actual decoding of Thumb instructions, stub functions are
added which currently just reject the probe.

Signed-off-by: default avatarJon Medhurst <tixy@yxit.co.uk>
Acked-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
parent de419840

arch/arm/kernel/Makefile

+4 −0
Original line number Diff line number Diff line
@@ -38,7 +38,11 @@ obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o 
obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o

obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o

obj-$(CONFIG_KPROBES)		+= kprobes.o kprobes-common.o

ifdef CONFIG_THUMB2_KERNEL

obj-$(CONFIG_KPROBES)		+= kprobes-thumb.o

else

obj-$(CONFIG_KPROBES)		+= kprobes-arm.o

endif

obj-$(CONFIG_ATAGS_PROC)	+= atags.o

obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o

obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o

arch/arm/kernel/kprobes-thumb.c

0 → 100644
+26 −0
Original line number Diff line number Diff line 
/*

 * arch/arm/kernel/kprobes-thumb.c

 *

 * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */



#include <linux/kernel.h>

#include <linux/kprobes.h>



#include "kprobes.h"



enum kprobe_insn __kprobes

thumb16_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)

{

	return INSN_REJECTED;

}



enum kprobe_insn __kprobes

thumb32_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)

{

	return INSN_REJECTED;

}

arch/arm/kernel/kprobes.c

+18 −2
Original line number Diff line number Diff line
@@ -51,16 +51,32 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) 
	kprobe_opcode_t insn;

	kprobe_opcode_t tmp_insn[MAX_INSN_SIZE];

	unsigned long addr = (unsigned long)p->addr;

	kprobe_decode_insn_t *decode_insn;

	int is;



	if (addr & 0x3 || in_exception_text(addr))

	if (in_exception_text(addr))

		return -EINVAL;



#ifdef CONFIG_THUMB2_KERNEL

	addr &= ~1; /* Bit 0 would normally be set to indicate Thumb code */

	insn = ((u16 *)addr)[0];

	if (is_wide_instruction(insn)) {

		insn <<= 16;

		insn |= ((u16 *)addr)[1];

		decode_insn = thumb32_kprobe_decode_insn;

	} else

		decode_insn = thumb16_kprobe_decode_insn;

#else /* !CONFIG_THUMB2_KERNEL */

	if (addr & 0x3)

		return -EINVAL;

	insn = *p->addr;

	decode_insn = arm_kprobe_decode_insn;

#endif



	p->opcode = insn;

	p->ainsn.insn = tmp_insn;



	switch (arm_kprobe_decode_insn(insn, &p->ainsn)) {

	switch ((*decode_insn)(insn, &p->ainsn)) {

	case INSN_REJECTED:	/* not supported */

		return -EINVAL;

arch/arm/kernel/kprobes.h

+13 −0
Original line number Diff line number Diff line
@@ -29,8 +29,21 @@ enum kprobe_insn { 
	INSN_GOOD_NO_SLOT

};



typedef enum kprobe_insn (kprobe_decode_insn_t)(kprobe_opcode_t,

						struct arch_specific_insn *);



#ifdef CONFIG_THUMB2_KERNEL



enum kprobe_insn thumb16_kprobe_decode_insn(kprobe_opcode_t,

						struct arch_specific_insn *);

enum kprobe_insn thumb32_kprobe_decode_insn(kprobe_opcode_t,

						struct arch_specific_insn *);



#else /* !CONFIG_THUMB2_KERNEL */



enum kprobe_insn arm_kprobe_decode_insn(kprobe_opcode_t,

					struct arch_specific_insn *);

#endif



void __init arm_kprobe_decode_init(void);