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ARM: kprobes: Extend arch_specific_insn to add pointer to emulated instruction 

When we come to emulating Thumb instructions then, to interwork
correctly, the code on in the instruction slot must be invoked with a
function pointer which has the least significant bit set. Rather that
set this by hand in every Thumb emulation function we will add a new
field for this purpose to arch_specific_insn, called insn_fn.

This also enables us to seamlessly share emulation functions between ARM
and Thumb code.

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
This commit is contained in:
Jon Medhurst 2011-06-09 14:05:51 +01:00 committed by Tixy
parent c6a7d97d57
commit e2960317d4
2 changed files with 7 additions and 0 deletions
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2
arch/arm/include/asm/kprobes.h
View File

@ -34,6 +34,7 @@ struct kprobe;
typedef void (kprobe_insn_handler_t)(struct kprobe *, struct pt_regs *);
typedef unsigned long (kprobe_check_cc)(unsigned long);
typedef void (kprobe_insn_singlestep_t)(struct kprobe *, struct pt_regs *);
typedef void (kprobe_insn_fn_t)(void);
/* Architecture specific copy of original instruction. */
struct arch_specific_insn {
@ -41,6 +42,7 @@ struct arch_specific_insn {
kprobe_insn_handler_t *insn_handler;
kprobe_check_cc *insn_check_cc;
kprobe_insn_singlestep_t *insn_singlestep;
kprobe_insn_fn_t *insn_fn;
};
struct prev_kprobe {

5
arch/arm/kernel/kprobes.c
View File

@ -51,6 +51,7 @@ 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;
bool thumb;
kprobe_decode_insn_t *decode_insn;
int is;
@ -58,6 +59,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
return -EINVAL;
#ifdef CONFIG_THUMB2_KERNEL
thumb = true;
addr &= ~1; /* Bit 0 would normally be set to indicate Thumb code */
insn = ((u16 *)addr)[0];
if (is_wide_instruction(insn)) {
@ -67,6 +69,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
} else
decode_insn = thumb16_kprobe_decode_insn;
#else /* !CONFIG_THUMB2_KERNEL */
thumb = false;
if (addr & 0x3)
return -EINVAL;
insn = *p->addr;
@ -88,6 +91,8 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
p->ainsn.insn[is] = tmp_insn[is];
flush_insns(p->ainsn.insn,
sizeof(p->ainsn.insn[0]) * MAX_INSN_SIZE);
p->ainsn.insn_fn = (kprobe_insn_fn_t *)
((uintptr_t)p->ainsn.insn | thumb);
break;
case INSN_GOOD_NO_SLOT: /* instruction doesn't need insn slot */