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Commit dd212bd3 authored by Jon Medhurst's avatar Jon Medhurst Committed by Tixy
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ARM: kprobes: Decode 32-bit Thumb table branch instructions 



Signed-off-by: default avatarJon Medhurst <tixy@yxit.co.uk>
Acked-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
parent b48354d3

arch/arm/kernel/kprobes-thumb.c

+25 −0
Original line number Diff line number Diff line
@@ -37,6 +37,26 @@ static inline unsigned long __kprobes thumb_probe_pc(struct kprobe *p) 
	return (unsigned long)p->addr - 1 + 4;

}



static void __kprobes

t32_simulate_table_branch(struct kprobe *p, struct pt_regs *regs)

{

	kprobe_opcode_t insn = p->opcode;

	unsigned long pc = thumb_probe_pc(p);

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

	int rm = insn & 0xf;



	unsigned long rnv = (rn == 15) ? pc : regs->uregs[rn];

	unsigned long rmv = regs->uregs[rm];

	unsigned int halfwords;



	if (insn & 0x10)

		halfwords = ((u16 *)rnv)[rmv];

	else

		halfwords = ((u8 *)rnv)[rmv];



	regs->ARM_pc = pc + 2 * halfwords;

}



static enum kprobe_insn __kprobes

t32_decode_ldmstm(kprobe_opcode_t insn, struct arch_specific_insn *asi)

{
@@ -117,6 +137,11 @@ static const union decode_item t32_table_1110_100x_x1xx[] = { 
	DECODE_EMULATEX	(0xff400000, 0xe9400000, t32_emulate_ldrdstrd,

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



	/* TBB			1110 1000 1101 xxxx xxxx xxxx 0000 xxxx */

	/* TBH			1110 1000 1101 xxxx xxxx xxxx 0001 xxxx */

	DECODE_SIMULATEX(0xfff000e0, 0xe8d00000, t32_simulate_table_branch,

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



	/* STREX		1110 1000 0100 xxxx xxxx xxxx xxxx xxxx */

	/* LDREX		1110 1000 0101 xxxx xxxx xxxx xxxx xxxx */

	/* STREXB		1110 1000 1100 xxxx xxxx xxxx 0100 xxxx */