kprobes/x86: Move ftrace-based kprobe code into kprobes-ftrace.c
Split ftrace-based kprobes code from kprobes, and introduce CONFIG_(HAVE_)KPROBES_ON_FTRACE Kconfig flags. For the cleanup reason, this also moves kprobe_ftrace check into skip_singlestep. Link: http://lkml.kernel.org/r/20120928081520.3560.25624.stgit@ltc138.sdl.hitachi.co.jp Cc: Ingo Molnar <mingo@elte.hu> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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12
arch/Kconfig
12
arch/Kconfig
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@ -76,6 +76,15 @@ config OPTPROBES
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depends on KPROBES && HAVE_OPTPROBES
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depends on !PREEMPT
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config KPROBES_ON_FTRACE
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def_bool y
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depends on KPROBES && HAVE_KPROBES_ON_FTRACE
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depends on DYNAMIC_FTRACE_WITH_REGS
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help
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If function tracer is enabled and the arch supports full
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passing of pt_regs to function tracing, then kprobes can
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optimize on top of function tracing.
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config UPROBES
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bool "Transparent user-space probes (EXPERIMENTAL)"
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depends on UPROBE_EVENT && PERF_EVENTS
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@ -158,6 +167,9 @@ config HAVE_KRETPROBES
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config HAVE_OPTPROBES
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bool
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config HAVE_KPROBES_ON_FTRACE
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bool
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config HAVE_NMI_WATCHDOG
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bool
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#
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@ -40,6 +40,7 @@ config X86
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select HAVE_DMA_CONTIGUOUS if !SWIOTLB
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select HAVE_KRETPROBES
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select HAVE_OPTPROBES
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select HAVE_KPROBES_ON_FTRACE
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select HAVE_FTRACE_MCOUNT_RECORD
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select HAVE_FENTRY if X86_64
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select HAVE_C_RECORDMCOUNT
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@ -67,6 +67,7 @@ obj-$(CONFIG_KEXEC) += relocate_kernel_$(BITS).o crash.o
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obj-$(CONFIG_CRASH_DUMP) += crash_dump_$(BITS).o
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obj-$(CONFIG_KPROBES) += kprobes.o
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obj-$(CONFIG_OPTPROBES) += kprobes-opt.o
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obj-$(CONFIG_KPROBES_ON_FTRACE) += kprobes-ftrace.o
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obj-$(CONFIG_MODULES) += module.o
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obj-$(CONFIG_DOUBLEFAULT) += doublefault_32.o
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obj-$(CONFIG_KGDB) += kgdb.o
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@ -99,4 +99,15 @@ static inline unsigned long __recover_optprobed_insn(kprobe_opcode_t *buf, unsig
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return addr;
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}
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#endif
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#ifdef CONFIG_KPROBES_ON_FTRACE
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extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
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struct kprobe_ctlblk *kcb);
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#else
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static inline int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
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struct kprobe_ctlblk *kcb)
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{
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return 0;
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}
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#endif
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#endif
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@ -0,0 +1,93 @@
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/*
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* Dynamic Ftrace based Kprobes Optimization
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright (C) Hitachi Ltd., 2012
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*/
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#include <linux/kprobes.h>
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#include <linux/ptrace.h>
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#include <linux/hardirq.h>
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#include <linux/preempt.h>
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#include <linux/ftrace.h>
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#include "kprobes-common.h"
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static int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
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struct kprobe_ctlblk *kcb)
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{
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/*
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* Emulate singlestep (and also recover regs->ip)
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* as if there is a 5byte nop
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*/
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regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
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if (unlikely(p->post_handler)) {
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kcb->kprobe_status = KPROBE_HIT_SSDONE;
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p->post_handler(p, regs, 0);
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}
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__this_cpu_write(current_kprobe, NULL);
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return 1;
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}
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int __kprobes skip_singlestep(struct kprobe *p, struct pt_regs *regs,
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struct kprobe_ctlblk *kcb)
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{
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if (kprobe_ftrace(p))
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return __skip_singlestep(p, regs, kcb);
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else
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return 0;
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}
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/* Ftrace callback handler for kprobes */
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void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
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struct ftrace_ops *ops, struct pt_regs *regs)
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{
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struct kprobe *p;
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struct kprobe_ctlblk *kcb;
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unsigned long flags;
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/* Disable irq for emulating a breakpoint and avoiding preempt */
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local_irq_save(flags);
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p = get_kprobe((kprobe_opcode_t *)ip);
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if (unlikely(!p) || kprobe_disabled(p))
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goto end;
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kcb = get_kprobe_ctlblk();
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if (kprobe_running()) {
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kprobes_inc_nmissed_count(p);
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} else {
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/* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
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regs->ip = ip + sizeof(kprobe_opcode_t);
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__this_cpu_write(current_kprobe, p);
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kcb->kprobe_status = KPROBE_HIT_ACTIVE;
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if (!p->pre_handler || !p->pre_handler(p, regs))
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__skip_singlestep(p, regs, kcb);
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/*
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* If pre_handler returns !0, it sets regs->ip and
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* resets current kprobe.
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*/
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}
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end:
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local_irq_restore(flags);
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}
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int __kprobes arch_prepare_kprobe_ftrace(struct kprobe *p)
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{
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p->ainsn.insn = NULL;
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p->ainsn.boostable = -1;
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return 0;
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}
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@ -541,23 +541,6 @@ reenter_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb
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return 1;
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}
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#ifdef KPROBES_CAN_USE_FTRACE
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static void __kprobes skip_singlestep(struct kprobe *p, struct pt_regs *regs,
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struct kprobe_ctlblk *kcb)
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{
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/*
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* Emulate singlestep (and also recover regs->ip)
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* as if there is a 5byte nop
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*/
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regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
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if (unlikely(p->post_handler)) {
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kcb->kprobe_status = KPROBE_HIT_SSDONE;
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p->post_handler(p, regs, 0);
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}
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__this_cpu_write(current_kprobe, NULL);
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}
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#endif
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/*
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* Interrupts are disabled on entry as trap3 is an interrupt gate and they
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* remain disabled throughout this function.
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@ -616,13 +599,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
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} else if (kprobe_running()) {
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p = __this_cpu_read(current_kprobe);
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if (p->break_handler && p->break_handler(p, regs)) {
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#ifdef KPROBES_CAN_USE_FTRACE
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if (kprobe_ftrace(p)) {
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skip_singlestep(p, regs, kcb);
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return 1;
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}
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#endif
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setup_singlestep(p, regs, kcb, 0);
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if (!skip_singlestep(p, regs, kcb))
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setup_singlestep(p, regs, kcb, 0);
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return 1;
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}
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} /* else: not a kprobe fault; let the kernel handle it */
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@ -1075,50 +1053,6 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
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return 0;
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}
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#ifdef KPROBES_CAN_USE_FTRACE
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/* Ftrace callback handler for kprobes */
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void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
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struct ftrace_ops *ops, struct pt_regs *regs)
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{
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struct kprobe *p;
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struct kprobe_ctlblk *kcb;
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unsigned long flags;
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/* Disable irq for emulating a breakpoint and avoiding preempt */
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local_irq_save(flags);
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p = get_kprobe((kprobe_opcode_t *)ip);
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if (unlikely(!p) || kprobe_disabled(p))
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goto end;
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kcb = get_kprobe_ctlblk();
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if (kprobe_running()) {
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kprobes_inc_nmissed_count(p);
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} else {
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/* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
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regs->ip = ip + sizeof(kprobe_opcode_t);
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__this_cpu_write(current_kprobe, p);
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kcb->kprobe_status = KPROBE_HIT_ACTIVE;
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if (!p->pre_handler || !p->pre_handler(p, regs))
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skip_singlestep(p, regs, kcb);
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/*
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* If pre_handler returns !0, it sets regs->ip and
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* resets current kprobe.
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*/
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}
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end:
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local_irq_restore(flags);
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}
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int __kprobes arch_prepare_kprobe_ftrace(struct kprobe *p)
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{
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p->ainsn.insn = NULL;
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p->ainsn.boostable = -1;
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return 0;
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}
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#endif
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int __init arch_init_kprobes(void)
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{
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return arch_init_optprobes();
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@ -49,16 +49,6 @@
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#define KPROBE_REENTER 0x00000004
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#define KPROBE_HIT_SSDONE 0x00000008
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/*
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* If function tracer is enabled and the arch supports full
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* passing of pt_regs to function tracing, then kprobes can
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* optimize on top of function tracing.
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*/
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#if defined(CONFIG_FUNCTION_TRACER) && defined(ARCH_SUPPORTS_FTRACE_SAVE_REGS) \
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&& defined(ARCH_SUPPORTS_KPROBES_ON_FTRACE)
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# define KPROBES_CAN_USE_FTRACE
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#endif
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/* Attach to insert probes on any functions which should be ignored*/
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#define __kprobes __attribute__((__section__(".kprobes.text")))
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@ -316,7 +306,7 @@ extern int proc_kprobes_optimization_handler(struct ctl_table *table,
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#endif
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#endif /* CONFIG_OPTPROBES */
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#ifdef KPROBES_CAN_USE_FTRACE
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#ifdef CONFIG_KPROBES_ON_FTRACE
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extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
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struct ftrace_ops *ops, struct pt_regs *regs);
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extern int arch_prepare_kprobe_ftrace(struct kprobe *p);
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@ -919,7 +919,7 @@ static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
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}
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#endif /* CONFIG_OPTPROBES */
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#ifdef KPROBES_CAN_USE_FTRACE
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#ifdef CONFIG_KPROBES_ON_FTRACE
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static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
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.func = kprobe_ftrace_handler,
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.flags = FTRACE_OPS_FL_SAVE_REGS,
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@ -964,7 +964,7 @@ static void __kprobes disarm_kprobe_ftrace(struct kprobe *p)
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(unsigned long)p->addr, 1, 0);
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WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret);
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}
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#else /* !KPROBES_CAN_USE_FTRACE */
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#else /* !CONFIG_KPROBES_ON_FTRACE */
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#define prepare_kprobe(p) arch_prepare_kprobe(p)
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#define arm_kprobe_ftrace(p) do {} while (0)
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#define disarm_kprobe_ftrace(p) do {} while (0)
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@ -1414,12 +1414,12 @@ static __kprobes int check_kprobe_address_safe(struct kprobe *p,
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*/
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ftrace_addr = ftrace_location((unsigned long)p->addr);
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if (ftrace_addr) {
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#ifdef KPROBES_CAN_USE_FTRACE
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#ifdef CONFIG_KPROBES_ON_FTRACE
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/* Given address is not on the instruction boundary */
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if ((unsigned long)p->addr != ftrace_addr)
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return -EILSEQ;
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p->flags |= KPROBE_FLAG_FTRACE;
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#else /* !KPROBES_CAN_USE_FTRACE */
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#else /* !CONFIG_KPROBES_ON_FTRACE */
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return -EINVAL;
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#endif
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}
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