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Commit a1a138d0 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Frederic Weisbecker
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tracing/kprobes: Use global event perf buffers in kprobe tracer 



Use new percpu global event buffer instead of stack in kprobe
tracer while tracing through perf.

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20090925182011.10157.60140.stgit@omoto>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent d7a4b414

kernel/trace/trace_kprobe.c

+73 −42
Original line number Diff line number Diff line
@@ -1149,23 +1149,36 @@ static __kprobes int kprobe_profile_func(struct kprobe *kp, 
	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);

	struct ftrace_event_call *call = &tp->call;

	struct kprobe_trace_entry *entry;

	int size, __size, i, pc;

	struct trace_entry *ent;

	int size, __size, i, pc, __cpu;

	unsigned long irq_flags;

	char *raw_data;



	local_save_flags(irq_flags);

	pc = preempt_count();



	__size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);

	size = ALIGN(__size + sizeof(u32), sizeof(u64));

	size -= sizeof(u32);

	if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,

		     "profile buffer not large enough"))

		return 0;



	do {

		char raw_data[size];

		struct trace_entry *ent;

	/*

		 * Zero dead bytes from alignment to avoid stack leak

		 * to userspace

	 * Protect the non nmi buffer

	 * This also protects the rcu read side

	 */

	local_irq_save(irq_flags);

	__cpu = smp_processor_id();



	if (in_nmi())

		raw_data = rcu_dereference(trace_profile_buf_nmi);

	else

		raw_data = rcu_dereference(trace_profile_buf);



	if (!raw_data)

		goto end;



	raw_data = per_cpu_ptr(raw_data, __cpu);

	/* Zero dead bytes from alignment to avoid buffer leak to userspace */

	*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;

	entry = (struct kprobe_trace_entry *)raw_data;

	ent = &entry->ent;
@@ -1177,7 +1190,8 @@ static __kprobes int kprobe_profile_func(struct kprobe *kp, 
	for (i = 0; i < tp->nr_args; i++)

		entry->args[i] = call_fetch(&tp->args[i].fetch, regs);

	perf_tp_event(call->id, entry->ip, 1, entry, size);

	} while (0);

end:

	local_irq_restore(irq_flags);

	return 0;

}
@@ -1188,20 +1202,36 @@ static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri, 
	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);

	struct ftrace_event_call *call = &tp->call;

	struct kretprobe_trace_entry *entry;

	int size, __size, i, pc;

	struct trace_entry *ent;

	int size, __size, i, pc, __cpu;

	unsigned long irq_flags;

	char *raw_data;



	local_save_flags(irq_flags);

	pc = preempt_count();



	__size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);

	size = ALIGN(__size + sizeof(u32), sizeof(u64));

	size -= sizeof(u32);

	if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,

		     "profile buffer not large enough"))

		return 0;



	do {

		char raw_data[size];

		struct trace_entry *ent;

	/*

	 * Protect the non nmi buffer

	 * This also protects the rcu read side

	 */

	local_irq_save(irq_flags);

	__cpu = smp_processor_id();



	if (in_nmi())

		raw_data = rcu_dereference(trace_profile_buf_nmi);

	else

		raw_data = rcu_dereference(trace_profile_buf);



	if (!raw_data)

		goto end;



	raw_data = per_cpu_ptr(raw_data, __cpu);

	/* Zero dead bytes from alignment to avoid buffer leak to userspace */

	*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;

	entry = (struct kretprobe_trace_entry *)raw_data;

	ent = &entry->ent;
@@ -1214,7 +1244,8 @@ static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri, 
	for (i = 0; i < tp->nr_args; i++)

		entry->args[i] = call_fetch(&tp->args[i].fetch, regs);

	perf_tp_event(call->id, entry->ret_ip, 1, entry, size);

	} while (0);

end:

	local_irq_restore(irq_flags);

	return 0;

}