0dc016dbd8
This patch introduce kprobeopt for ARM 32. Limitations: - Currently only kernel compiled with ARM ISA is supported. - Offset between probe point and optinsn slot must not larger than 32MiB. Masami Hiramatsu suggests replacing 2 words, it will make things complex. Futher patch can make such optimization. Kprobe opt on ARM is relatively simpler than kprobe opt on x86 because ARM instruction is always 4 bytes aligned and 4 bytes long. This patch replace probed instruction by a 'b', branch to trampoline code and then calls optimized_callback(). optimized_callback() calls opt_pre_handler() to execute kprobe handler. It also emulate/simulate replaced instruction. When unregistering kprobe, the deferred manner of unoptimizer may leave branch instruction before optimizer is called. Different from x86_64, which only copy the probed insn after optprobe_template_end and reexecute them, this patch call singlestep to emulate/simulate the insn directly. Futher patch can optimize this behavior. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Will Deacon <will.deacon@arm.com> Reviewed-by: Jon Medhurst (Tixy) <tixy@linaro.org> Signed-off-by: Jon Medhurst <tixy@linaro.org>
84 lines
2.4 KiB
C
84 lines
2.4 KiB
C
/*
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* arch/arm/include/asm/kprobes.h
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*
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* Copyright (C) 2006, 2007 Motorola Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#ifndef _ARM_KPROBES_H
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#define _ARM_KPROBES_H
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#include <linux/types.h>
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#include <linux/ptrace.h>
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#include <linux/notifier.h>
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#define __ARCH_WANT_KPROBES_INSN_SLOT
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#define MAX_INSN_SIZE 2
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#define flush_insn_slot(p) do { } while (0)
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#define kretprobe_blacklist_size 0
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typedef u32 kprobe_opcode_t;
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struct kprobe;
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#include <asm/probes.h>
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#define arch_specific_insn arch_probes_insn
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struct prev_kprobe {
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struct kprobe *kp;
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unsigned int status;
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};
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/* per-cpu kprobe control block */
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struct kprobe_ctlblk {
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unsigned int kprobe_status;
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struct prev_kprobe prev_kprobe;
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struct pt_regs jprobe_saved_regs;
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char jprobes_stack[MAX_STACK_SIZE];
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};
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void arch_remove_kprobe(struct kprobe *);
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int kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr);
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int kprobe_exceptions_notify(struct notifier_block *self,
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unsigned long val, void *data);
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/* optinsn template addresses */
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extern __visible kprobe_opcode_t optprobe_template_entry;
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extern __visible kprobe_opcode_t optprobe_template_val;
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extern __visible kprobe_opcode_t optprobe_template_call;
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extern __visible kprobe_opcode_t optprobe_template_end;
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extern __visible kprobe_opcode_t optprobe_template_sub_sp;
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extern __visible kprobe_opcode_t optprobe_template_add_sp;
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#define MAX_OPTIMIZED_LENGTH 4
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#define MAX_OPTINSN_SIZE \
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((unsigned long)&optprobe_template_end - \
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(unsigned long)&optprobe_template_entry)
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#define RELATIVEJUMP_SIZE 4
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struct arch_optimized_insn {
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/*
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* copy of the original instructions.
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* Different from x86, ARM kprobe_opcode_t is u32.
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*/
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#define MAX_COPIED_INSN DIV_ROUND_UP(RELATIVEJUMP_SIZE, sizeof(kprobe_opcode_t))
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kprobe_opcode_t copied_insn[MAX_COPIED_INSN];
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/* detour code buffer */
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kprobe_opcode_t *insn;
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/*
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* We always copy one instruction on ARM,
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* so size will always be 4, and unlike x86, there is no
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* need for a size field.
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*/
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};
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#endif /* _ARM_KPROBES_H */
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