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arm64: kprobes instruction simulation support

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Kprobes needs simulation of instructions that cannot be stepped
from a different memory location, e.g.: those instructions
that uses PC-relative addressing. In simulation, the behaviour
of the instruction is implemented using a copy of pt_regs.

The following instruction categories are simulated:
 - All branching instructions(conditional, register, and immediate)
 - Literal access instructions(load-literal, adr/adrp)

Conditional execution is limited to branching instructions in
ARM v8. If conditions at PSTATE do not match the condition fields
of opcode, the instruction is effectively NOP.

Thanks to Will Cohen for assorted suggested changes.

Signed-off-by: Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>
Signed-off-by: William Cohen <wcohen@redhat.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
[catalin.marinas@arm.com: removed linux/module.h include]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Sandeepa Prabhu
2016-07-08 12:35:51 -04:00
committed by Catalin Marinas
parent 888b3c8720
commit 39a67d49ba
8 changed files with 326 additions and 15 deletions
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5
arch/arm64/include/asm/probes.h
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@@ -15,17 +15,18 @@
#ifndef _ARM_PROBES_H
#define _ARM_PROBES_H
#include <asm/opcodes.h>
struct kprobe;
struct arch_specific_insn;
typedef u32 kprobe_opcode_t;
typedef unsigned long (kprobes_pstate_check_t)(unsigned long);
typedef void (kprobes_handler_t) (u32 opcode, long addr, struct pt_regs *);
/* architecture specific copy of original instruction */
struct arch_specific_insn {
kprobe_opcode_t *insn;
kprobes_pstate_check_t *pstate_cc;
pstate_check_t *pstate_cc;
kprobes_handler_t *handler;
/* restore address after step xol */
unsigned long restore;