[PATCH -tip 2/3] kprobes/x86: Move ftrace-based kprobe code intokprobes-ftrace.c
From: Masami Hiramatsu
Date: Fri Sep 28 2012 - 04:17:17 EST
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.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
---
arch/Kconfig | 12 +++++
arch/x86/Kconfig | 1
arch/x86/kernel/Makefile | 1
arch/x86/kernel/kprobes-common.h | 11 ++++
arch/x86/kernel/kprobes-ftrace.c | 93 ++++++++++++++++++++++++++++++++++++++
arch/x86/kernel/kprobes.c | 70 +----------------------------
include/linux/kprobes.h | 12 -----
kernel/kprobes.c | 8 ++-
8 files changed, 125 insertions(+), 83 deletions(-)
create mode 100644 arch/x86/kernel/kprobes-ftrace.c
diff --git a/arch/Kconfig b/arch/Kconfig
index ea5feb6..d799de9 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -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
@@ -138,6 +147,9 @@ config HAVE_KRETPROBES
config HAVE_OPTPROBES
bool
+config HAVE_KPROBES_ON_FTRACE
+ bool
+
config HAVE_NMI_WATCHDOG
bool
#
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9570638..8e657ce 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -37,6 +37,7 @@ 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
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 8d7a619..ebef9ad 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -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
diff --git a/arch/x86/kernel/kprobes-common.h b/arch/x86/kernel/kprobes-common.h
index 3230b68..2e9d4b5 100644
--- a/arch/x86/kernel/kprobes-common.h
+++ b/arch/x86/kernel/kprobes-common.h
@@ -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
diff --git a/arch/x86/kernel/kprobes-ftrace.c b/arch/x86/kernel/kprobes-ftrace.c
new file mode 100644
index 0000000..70a81c7
--- /dev/null
+++ b/arch/x86/kernel/kprobes-ftrace.c
@@ -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;
+}
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 57916c0..18114bf 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -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();
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 23755ba..4b6ef4d 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -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);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 098f396..f423c3e 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -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
}
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