Commit 263e368a authored by Jon Medhurst's avatar Jon Medhurst Committed by Tixy
Browse files

ARM: kprobes: Add load_write_pc() 



This writes a value to PC which was obtained as the result of a
LDR or LDM instruction. For ARMv5T and later this must perform
interworking.

Signed-off-by: default avatarJon Medhurst <tixy@yxit.co.uk>
Acked-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
parent f39ca8b4

arch/arm/kernel/kprobes-common.c

+15 −0
Original line number Diff line number Diff line
@@ -45,9 +45,24 @@ void __init find_str_pc_offset(void) 
#endif /* !find_str_pc_offset */





#ifndef test_load_write_pc_interworking



bool load_write_pc_interworks;



void __init test_load_write_pc_interworking(void)

{

	int arch = cpu_architecture();

	BUG_ON(arch == CPU_ARCH_UNKNOWN);

	load_write_pc_interworks = arch >= CPU_ARCH_ARMv5T;

}



#endif /* !test_load_write_pc_interworking */





void __init arm_kprobe_decode_init(void)

{

	find_str_pc_offset();

	test_load_write_pc_interworking();

}

arch/arm/kernel/kprobes.h

+24 −0
Original line number Diff line number Diff line
@@ -109,6 +109,30 @@ static inline void __kprobes bx_write_pc(long pcv, struct pt_regs *regs) 
	regs->ARM_pc = pcv;

}





#if __LINUX_ARM_ARCH__ >= 6



/* Kernels built for >= ARMv6 should never run on <= ARMv5 hardware, so... */

#define load_write_pc_interworks true

#define test_load_write_pc_interworking()



#else /* __LINUX_ARM_ARCH__ < 6 */



/* We need run-time testing to determine if load_write_pc() should interwork. */

extern bool load_write_pc_interworks;

void __init test_load_write_pc_interworking(void);



#endif



static inline void __kprobes load_write_pc(long pcv, struct pt_regs *regs)

{

	if (load_write_pc_interworks)

		bx_write_pc(pcv, regs);

	else

		regs->ARM_pc = pcv;

}





void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs);

void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs);

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