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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: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu 2012-09-28 17:15:20 +09:00 committed by Steven Rostedt
parent 06aeaaeabf
commit e7dbfe349d
8 changed files with 125 additions and 83 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
arch/Kconfig
View File

@ -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
#

1
arch/x86/Kconfig
View File

@ -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

1
arch/x86/kernel/Makefile
View File

@ -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

11
arch/x86/kernel/kprobes-common.h
View File

@ -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

93
arch/x86/kernel/kprobes-ftrace.c Normal file
View File

@ -0,0 +1,93 @@
/*
* 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;
}

70
arch/x86/kernel/kprobes.c
View File

@ -541,23 +541,6 @@ reenter_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb
return 1;
}
#ifdef KPROBES_CAN_USE_FTRACE
static void __kprobes 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);
}
#endif
/*
* Interrupts are disabled on entry as trap3 is an interrupt gate and they
* remain disabled throughout this function.
@ -616,13 +599,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
} else if (kprobe_running()) {
p = __this_cpu_read(current_kprobe);
if (p->break_handler && p->break_handler(p, regs)) {
#ifdef KPROBES_CAN_USE_FTRACE
if (kprobe_ftrace(p)) {
skip_singlestep(p, regs, kcb);
return 1;
}
#endif
setup_singlestep(p, regs, kcb, 0);
if (!skip_singlestep(p, regs, kcb))
setup_singlestep(p, regs, kcb, 0);
return 1;
}
} /* else: not a kprobe fault; let the kernel handle it */
@ -1075,50 +1053,6 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
return 0;
}
#ifdef KPROBES_CAN_USE_FTRACE
/* 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;
}
#endif
int __init arch_init_kprobes(void)
{
return arch_init_optprobes();

12
include/linux/kprobes.h
View File

@ -49,16 +49,6 @@
#define KPROBE_REENTER 0x00000004
#define KPROBE_HIT_SSDONE 0x00000008
/*
* 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.
*/
#if defined(CONFIG_FUNCTION_TRACER) && defined(ARCH_SUPPORTS_FTRACE_SAVE_REGS) \
&& defined(ARCH_SUPPORTS_KPROBES_ON_FTRACE)
# define KPROBES_CAN_USE_FTRACE
#endif
/* Attach to insert probes on any functions which should be ignored*/
#define __kprobes __attribute__((__section__(".kprobes.text")))
@ -316,7 +306,7 @@ extern int proc_kprobes_optimization_handler(struct ctl_table *table,
#endif
#endif /* CONFIG_OPTPROBES */
#ifdef KPROBES_CAN_USE_FTRACE
#ifdef CONFIG_KPROBES_ON_FTRACE
extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *ops, struct pt_regs *regs);
extern int arch_prepare_kprobe_ftrace(struct kprobe *p);

8
kernel/kprobes.c
View File

@ -919,7 +919,7 @@ static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
}
#endif /* CONFIG_OPTPROBES */
#ifdef KPROBES_CAN_USE_FTRACE
#ifdef CONFIG_KPROBES_ON_FTRACE
static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
.func = kprobe_ftrace_handler,
.flags = FTRACE_OPS_FL_SAVE_REGS,
@ -964,7 +964,7 @@ static void __kprobes disarm_kprobe_ftrace(struct kprobe *p)
(unsigned long)p->addr, 1, 0);
WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret);
}
#else /* !KPROBES_CAN_USE_FTRACE */
#else /* !CONFIG_KPROBES_ON_FTRACE */
#define prepare_kprobe(p) arch_prepare_kprobe(p)
#define arm_kprobe_ftrace(p) do {} while (0)
#define disarm_kprobe_ftrace(p) do {} while (0)
@ -1414,12 +1414,12 @@ static __kprobes int check_kprobe_address_safe(struct kprobe *p,
*/
ftrace_addr = ftrace_location((unsigned long)p->addr);
if (ftrace_addr) {
#ifdef KPROBES_CAN_USE_FTRACE
#ifdef CONFIG_KPROBES_ON_FTRACE
/* Given address is not on the instruction boundary */
if ((unsigned long)p->addr != ftrace_addr)
return -EILSEQ;
p->flags |= KPROBE_FLAG_FTRACE;
#else /* !KPROBES_CAN_USE_FTRACE */
#else /* !CONFIG_KPROBES_ON_FTRACE */
return -EINVAL;
#endif
}