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Commit e7dbfe34 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt
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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: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 06aeaaea

arch/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -76,6 +76,15 @@ config OPTPROBES 
	depends on KPROBES && HAVE_OPTPROBES

	depends on !PREEMPT



config KPROBES_ON_FTRACE

	def_bool y

	depends on KPROBES && HAVE_KPROBES_ON_FTRACE

	depends on DYNAMIC_FTRACE_WITH_REGS

	help

	 If function tracer is enabled and the arch supports full

	 passing of pt_regs to function tracing, then kprobes can

	 optimize on top of function tracing.



config UPROBES

	bool "Transparent user-space probes (EXPERIMENTAL)"

	depends on UPROBE_EVENT && PERF_EVENTS
@@ -158,6 +167,9 @@ config HAVE_KRETPROBES 
config HAVE_OPTPROBES

	bool



config HAVE_KPROBES_ON_FTRACE

	bool



config HAVE_NMI_WATCHDOG

	bool

#

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ config X86 
	select HAVE_DMA_CONTIGUOUS if !SWIOTLB

	select HAVE_KRETPROBES

	select HAVE_OPTPROBES

	select HAVE_KPROBES_ON_FTRACE

	select HAVE_FTRACE_MCOUNT_RECORD

	select HAVE_FENTRY if X86_64

	select HAVE_C_RECORDMCOUNT

arch/x86/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -67,6 +67,7 @@ obj-$(CONFIG_KEXEC) += relocate_kernel_$(BITS).o crash.o 
obj-$(CONFIG_CRASH_DUMP)	+= crash_dump_$(BITS).o

obj-$(CONFIG_KPROBES)		+= kprobes.o

obj-$(CONFIG_OPTPROBES)		+= kprobes-opt.o

obj-$(CONFIG_KPROBES_ON_FTRACE)	+= kprobes-ftrace.o

obj-$(CONFIG_MODULES)		+= module.o

obj-$(CONFIG_DOUBLEFAULT) 	+= doublefault_32.o

obj-$(CONFIG_KGDB)		+= kgdb.o

arch/x86/kernel/kprobes-common.h

+11 −0
Original line number Diff line number Diff line
@@ -99,4 +99,15 @@ static inline unsigned long __recover_optprobed_insn(kprobe_opcode_t *buf, unsig 
	return addr;

}

#endif



#ifdef CONFIG_KPROBES_ON_FTRACE

extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs,

			   struct kprobe_ctlblk *kcb);

#else

static inline int skip_singlestep(struct kprobe *p, struct pt_regs *regs,

				  struct kprobe_ctlblk *kcb)

{

	return 0;

}

#endif

#endif

arch/x86/kernel/kprobes-ftrace.c

0 → 100644
+93 −0
Original line number Diff line number Diff line 
/*

 * Dynamic Ftrace based Kprobes Optimization

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

 *

 * Copyright (C) Hitachi Ltd., 2012

 */

#include <linux/kprobes.h>

#include <linux/ptrace.h>

#include <linux/hardirq.h>

#include <linux/preempt.h>

#include <linux/ftrace.h>



#include "kprobes-common.h"



static int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,

			     struct kprobe_ctlblk *kcb)

{

	/*

	 * Emulate singlestep (and also recover regs->ip)

	 * as if there is a 5byte nop

	 */

	regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;

	if (unlikely(p->post_handler)) {

		kcb->kprobe_status = KPROBE_HIT_SSDONE;

		p->post_handler(p, regs, 0);

	}

	__this_cpu_write(current_kprobe, NULL);

	return 1;

}



int __kprobes skip_singlestep(struct kprobe *p, struct pt_regs *regs,

			      struct kprobe_ctlblk *kcb)

{

	if (kprobe_ftrace(p))

		return __skip_singlestep(p, regs, kcb);

	else

		return 0;

}



/* Ftrace callback handler for kprobes */

void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,

				     struct ftrace_ops *ops, struct pt_regs *regs)

{

	struct kprobe *p;

	struct kprobe_ctlblk *kcb;

	unsigned long flags;



	/* Disable irq for emulating a breakpoint and avoiding preempt */

	local_irq_save(flags);



	p = get_kprobe((kprobe_opcode_t *)ip);

	if (unlikely(!p) || kprobe_disabled(p))

		goto end;



	kcb = get_kprobe_ctlblk();

	if (kprobe_running()) {

		kprobes_inc_nmissed_count(p);

	} else {

		/* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */

		regs->ip = ip + sizeof(kprobe_opcode_t);



		__this_cpu_write(current_kprobe, p);

		kcb->kprobe_status = KPROBE_HIT_ACTIVE;

		if (!p->pre_handler || !p->pre_handler(p, regs))

			__skip_singlestep(p, regs, kcb);

		/*

		 * If pre_handler returns !0, it sets regs->ip and

		 * resets current kprobe.

		 */

	}

end:

	local_irq_restore(flags);

}



int __kprobes arch_prepare_kprobe_ftrace(struct kprobe *p)

{

	p->ainsn.insn = NULL;

	p->ainsn.boostable = -1;

	return 0;

}