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Commit 080e0013 authored by Jon Medhurst's avatar Jon Medhurst Committed by Tixy
Browse files

ARM: kprobes: Decode 32-bit Thumb data-processing (shifted register) instructions 



Signed-off-by: default avatarJon Medhurst <tixy@yxit.co.uk>
Acked-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
parent dd212bd3

arch/arm/kernel/kprobes-thumb.c

+93 −0
Original line number Diff line number Diff line
@@ -97,6 +97,33 @@ t32_emulate_ldrdstrd(struct kprobe *p, struct pt_regs *regs) 
	regs->uregs[rt2] = rt2v;

}



static void __kprobes

t32_emulate_rd8rn16rm0_rwflags(struct kprobe *p, struct pt_regs *regs)

{

	kprobe_opcode_t insn = p->opcode;

	int rd = (insn >> 8) & 0xf;

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

	int rm = insn & 0xf;



	register unsigned long rdv asm("r1") = regs->uregs[rd];

	register unsigned long rnv asm("r2") = regs->uregs[rn];

	register unsigned long rmv asm("r3") = regs->uregs[rm];

	unsigned long cpsr = regs->ARM_cpsr;



	__asm__ __volatile__ (

		"msr	cpsr_fs, %[cpsr]	\n\t"

		"blx    %[fn]			\n\t"

		"mrs	%[cpsr], cpsr		\n\t"

		: "=r" (rdv), [cpsr] "=r" (cpsr)

		: "0" (rdv), "r" (rnv), "r" (rmv),

		  "1" (cpsr), [fn] "r" (p->ainsn.insn_fn)

		: "lr", "memory", "cc"

	);



	regs->uregs[rd] = rdv;

	regs->ARM_cpsr = (regs->ARM_cpsr & ~APSR_MASK) | (cpsr & APSR_MASK);

}



static const union decode_item t32_table_1110_100x_x0xx[] = {

	/* Load/store multiple instructions */
@@ -154,6 +181,66 @@ static const union decode_item t32_table_1110_100x_x1xx[] = { 
	DECODE_END

};



static const union decode_item t32_table_1110_101x[] = {

	/* Data-processing (shifted register)				*/



	/* TST			1110 1010 0001 xxxx xxxx 1111 xxxx xxxx */

	/* TEQ			1110 1010 1001 xxxx xxxx 1111 xxxx xxxx */

	DECODE_EMULATEX	(0xff700f00, 0xea100f00, t32_emulate_rd8rn16rm0_rwflags,

						 REGS(NOSPPC, 0, 0, 0, NOSPPC)),



	/* CMN			1110 1011 0001 xxxx xxxx 1111 xxxx xxxx */

	DECODE_OR	(0xfff00f00, 0xeb100f00),

	/* CMP			1110 1011 1011 xxxx xxxx 1111 xxxx xxxx */

	DECODE_EMULATEX	(0xfff00f00, 0xebb00f00, t32_emulate_rd8rn16rm0_rwflags,

						 REGS(NOPC, 0, 0, 0, NOSPPC)),



	/* MOV			1110 1010 010x 1111 xxxx xxxx xxxx xxxx */

	/* MVN			1110 1010 011x 1111 xxxx xxxx xxxx xxxx */

	DECODE_EMULATEX	(0xffcf0000, 0xea4f0000, t32_emulate_rd8rn16rm0_rwflags,

						 REGS(0, 0, NOSPPC, 0, NOSPPC)),



	/* ???			1110 1010 101x xxxx xxxx xxxx xxxx xxxx */

	/* ???			1110 1010 111x xxxx xxxx xxxx xxxx xxxx */

	DECODE_REJECT	(0xffa00000, 0xeaa00000),

	/* ???			1110 1011 001x xxxx xxxx xxxx xxxx xxxx */

	DECODE_REJECT	(0xffe00000, 0xeb200000),

	/* ???			1110 1011 100x xxxx xxxx xxxx xxxx xxxx */

	DECODE_REJECT	(0xffe00000, 0xeb800000),

	/* ???			1110 1011 111x xxxx xxxx xxxx xxxx xxxx */

	DECODE_REJECT	(0xffe00000, 0xebe00000),



	/* ADD/SUB SP, SP, Rm, LSL #0..3				*/

	/*			1110 1011 x0xx 1101 x000 1101 xx00 xxxx */

	DECODE_EMULATEX	(0xff4f7f30, 0xeb0d0d00, t32_emulate_rd8rn16rm0_rwflags,

						 REGS(SP, 0, SP, 0, NOSPPC)),



	/* ADD/SUB SP, SP, Rm, shift					*/

	/*			1110 1011 x0xx 1101 xxxx 1101 xxxx xxxx */

	DECODE_REJECT	(0xff4f0f00, 0xeb0d0d00),



	/* ADD/SUB Rd, SP, Rm, shift					*/

	/*			1110 1011 x0xx 1101 xxxx xxxx xxxx xxxx */

	DECODE_EMULATEX	(0xff4f0000, 0xeb0d0000, t32_emulate_rd8rn16rm0_rwflags,

						 REGS(SP, 0, NOPC, 0, NOSPPC)),



	/* AND			1110 1010 000x xxxx xxxx xxxx xxxx xxxx */

	/* BIC			1110 1010 001x xxxx xxxx xxxx xxxx xxxx */

	/* ORR			1110 1010 010x xxxx xxxx xxxx xxxx xxxx */

	/* ORN			1110 1010 011x xxxx xxxx xxxx xxxx xxxx */

	/* EOR			1110 1010 100x xxxx xxxx xxxx xxxx xxxx */

	/* PKH			1110 1010 110x xxxx xxxx xxxx xxxx xxxx */

	/* ADD			1110 1011 000x xxxx xxxx xxxx xxxx xxxx */

	/* ADC			1110 1011 010x xxxx xxxx xxxx xxxx xxxx */

	/* SBC			1110 1011 011x xxxx xxxx xxxx xxxx xxxx */

	/* SUB			1110 1011 101x xxxx xxxx xxxx xxxx xxxx */

	/* RSB			1110 1011 110x xxxx xxxx xxxx xxxx xxxx */

	DECODE_EMULATEX	(0xfe000000, 0xea000000, t32_emulate_rd8rn16rm0_rwflags,

						 REGS(NOSPPC, 0, NOSPPC, 0, NOSPPC)),



	DECODE_END

};



static const union decode_item t32_table_1111_0xxx___1[] = {

	/* Branches and miscellaneous control				*/
@@ -183,6 +270,12 @@ const union decode_item kprobe_decode_thumb32_table[] = { 
	 */

	DECODE_TABLE	(0xfe400000, 0xe8400000, t32_table_1110_100x_x1xx),



	/*

	 * Data-processing (shifted register)

	 *			1110 101x xxxx xxxx xxxx xxxx xxxx xxxx

	 */

	DECODE_TABLE	(0xfe000000, 0xea000000, t32_table_1110_101x),



	/*

	 * Branches and miscellaneous control

	 *			1111 0xxx xxxx xxxx 1xxx xxxx xxxx xxxx