perf: Factorize trace events raw sample buffer operations
Introduce ftrace_perf_buf_prepare() and ftrace_perf_buf_submit() to
gather the common code that operates on raw events sampling buffer.
This cleans up redundant code between regular trace events, syscall
events and kprobe events.
Changelog v1->v2:
- Rename function name as per Masami and Frederic's suggestion
- Add __kprobes for ftrace_perf_buf_prepare() and make
ftrace_perf_buf_submit() inline as per Masami's suggestion
- Export ftrace_perf_buf_prepare since modules will use it
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <4B60E92D.9000808@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profile.c
index 9e25573..f0d6930 100644
--- a/kernel/trace/trace_event_profile.c
+++ b/kernel/trace/trace_event_profile.c
@@ -6,14 +6,12 @@
*/
#include <linux/module.h>
+#include <linux/kprobes.h>
#include "trace.h"
-char *perf_trace_buf;
-EXPORT_SYMBOL_GPL(perf_trace_buf);
-
-char *perf_trace_buf_nmi;
-EXPORT_SYMBOL_GPL(perf_trace_buf_nmi);
+static char *perf_trace_buf;
+static char *perf_trace_buf_nmi;
typedef typeof(char [FTRACE_MAX_PROFILE_SIZE]) perf_trace_t ;
@@ -120,3 +118,47 @@
}
mutex_unlock(&event_mutex);
}
+
+__kprobes void *ftrace_perf_buf_prepare(int size, unsigned short type,
+ int *rctxp, unsigned long *irq_flags)
+{
+ struct trace_entry *entry;
+ char *trace_buf, *raw_data;
+ int pc, cpu;
+
+ pc = preempt_count();
+
+ /* Protect the per cpu buffer, begin the rcu read side */
+ local_irq_save(*irq_flags);
+
+ *rctxp = perf_swevent_get_recursion_context();
+ if (*rctxp < 0)
+ goto err_recursion;
+
+ cpu = smp_processor_id();
+
+ if (in_nmi())
+ trace_buf = rcu_dereference(perf_trace_buf_nmi);
+ else
+ trace_buf = rcu_dereference(perf_trace_buf);
+
+ if (!trace_buf)
+ goto err;
+
+ raw_data = per_cpu_ptr(trace_buf, cpu);
+
+ /* zero the dead bytes from align to not leak stack to user */
+ *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
+
+ entry = (struct trace_entry *)raw_data;
+ tracing_generic_entry_update(entry, *irq_flags, pc);
+ entry->type = type;
+
+ return raw_data;
+err:
+ perf_swevent_put_recursion_context(*rctxp);
+err_recursion:
+ local_irq_restore(*irq_flags);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(ftrace_perf_buf_prepare);
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index d6266ca..2e28ee3 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1243,14 +1243,10 @@
struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
struct ftrace_event_call *call = &tp->call;
struct kprobe_trace_entry *entry;
- struct trace_entry *ent;
- int size, __size, i, pc, __cpu;
+ int size, __size, i;
unsigned long irq_flags;
- char *trace_buf;
- char *raw_data;
int rctx;
- pc = preempt_count();
__size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
size = ALIGN(__size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
@@ -1258,45 +1254,16 @@
"profile buffer not large enough"))
return 0;
- /*
- * Protect the non nmi buffer
- * This also protects the rcu read side
- */
- local_irq_save(irq_flags);
+ entry = ftrace_perf_buf_prepare(size, call->id, &rctx, &irq_flags);
+ if (!entry)
+ return 0;
- rctx = perf_swevent_get_recursion_context();
- if (rctx < 0)
- goto end_recursion;
-
- __cpu = smp_processor_id();
-
- if (in_nmi())
- trace_buf = rcu_dereference(perf_trace_buf_nmi);
- else
- trace_buf = rcu_dereference(perf_trace_buf);
-
- if (!trace_buf)
- goto end;
-
- raw_data = per_cpu_ptr(trace_buf, __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;
-
- tracing_generic_entry_update(ent, irq_flags, pc);
- ent->type = call->id;
entry->nargs = tp->nr_args;
entry->ip = (unsigned long)kp->addr;
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);
-end:
- perf_swevent_put_recursion_context(rctx);
-end_recursion:
- local_irq_restore(irq_flags);
+ ftrace_perf_buf_submit(entry, size, rctx, entry->ip, 1, irq_flags);
return 0;
}
@@ -1308,14 +1275,10 @@
struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
struct ftrace_event_call *call = &tp->call;
struct kretprobe_trace_entry *entry;
- struct trace_entry *ent;
- int size, __size, i, pc, __cpu;
+ int size, __size, i;
unsigned long irq_flags;
- char *trace_buf;
- char *raw_data;
int rctx;
- pc = preempt_count();
__size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
size = ALIGN(__size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
@@ -1323,46 +1286,17 @@
"profile buffer not large enough"))
return 0;
- /*
- * Protect the non nmi buffer
- * This also protects the rcu read side
- */
- local_irq_save(irq_flags);
+ entry = ftrace_perf_buf_prepare(size, call->id, &rctx, &irq_flags);
+ if (!entry)
+ return 0;
- rctx = perf_swevent_get_recursion_context();
- if (rctx < 0)
- goto end_recursion;
-
- __cpu = smp_processor_id();
-
- if (in_nmi())
- trace_buf = rcu_dereference(perf_trace_buf_nmi);
- else
- trace_buf = rcu_dereference(perf_trace_buf);
-
- if (!trace_buf)
- goto end;
-
- raw_data = per_cpu_ptr(trace_buf, __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;
-
- tracing_generic_entry_update(ent, irq_flags, pc);
- ent->type = call->id;
entry->nargs = tp->nr_args;
entry->func = (unsigned long)tp->rp.kp.addr;
entry->ret_ip = (unsigned long)ri->ret_addr;
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);
-end:
- perf_swevent_put_recursion_context(rctx);
-end_recursion:
- local_irq_restore(irq_flags);
+ ftrace_perf_buf_submit(entry, size, rctx, entry->ret_ip, 1, irq_flags);
return 0;
}
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index f694f66..4e332b9 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -433,12 +433,9 @@
struct syscall_metadata *sys_data;
struct syscall_trace_enter *rec;
unsigned long flags;
- char *trace_buf;
- char *raw_data;
int syscall_nr;
int rctx;
int size;
- int cpu;
syscall_nr = syscall_get_nr(current, regs);
if (!test_bit(syscall_nr, enabled_prof_enter_syscalls))
@@ -457,37 +454,15 @@
"profile buffer not large enough"))
return;
- /* Protect the per cpu buffer, begin the rcu read side */
- local_irq_save(flags);
+ rec = (struct syscall_trace_enter *)ftrace_perf_buf_prepare(size,
+ sys_data->enter_event->id, &rctx, &flags);
+ if (!rec)
+ return;
- rctx = perf_swevent_get_recursion_context();
- if (rctx < 0)
- goto end_recursion;
-
- cpu = smp_processor_id();
-
- trace_buf = rcu_dereference(perf_trace_buf);
-
- if (!trace_buf)
- goto end;
-
- raw_data = per_cpu_ptr(trace_buf, cpu);
-
- /* zero the dead bytes from align to not leak stack to user */
- *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
-
- rec = (struct syscall_trace_enter *) raw_data;
- tracing_generic_entry_update(&rec->ent, 0, 0);
- rec->ent.type = sys_data->enter_event->id;
rec->nr = syscall_nr;
syscall_get_arguments(current, regs, 0, sys_data->nb_args,
(unsigned long *)&rec->args);
- perf_tp_event(sys_data->enter_event->id, 0, 1, rec, size);
-
-end:
- perf_swevent_put_recursion_context(rctx);
-end_recursion:
- local_irq_restore(flags);
+ ftrace_perf_buf_submit(rec, size, rctx, 0, 1, flags);
}
int prof_sysenter_enable(struct ftrace_event_call *call)
@@ -531,11 +506,8 @@
struct syscall_trace_exit *rec;
unsigned long flags;
int syscall_nr;
- char *trace_buf;
- char *raw_data;
int rctx;
int size;
- int cpu;
syscall_nr = syscall_get_nr(current, regs);
if (!test_bit(syscall_nr, enabled_prof_exit_syscalls))
@@ -557,38 +529,15 @@
"exit event has grown above profile buffer size"))
return;
- /* Protect the per cpu buffer, begin the rcu read side */
- local_irq_save(flags);
+ rec = (struct syscall_trace_exit *)ftrace_perf_buf_prepare(size,
+ sys_data->exit_event->id, &rctx, &flags);
+ if (!rec)
+ return;
- rctx = perf_swevent_get_recursion_context();
- if (rctx < 0)
- goto end_recursion;
-
- cpu = smp_processor_id();
-
- trace_buf = rcu_dereference(perf_trace_buf);
-
- if (!trace_buf)
- goto end;
-
- raw_data = per_cpu_ptr(trace_buf, cpu);
-
- /* zero the dead bytes from align to not leak stack to user */
- *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
-
- rec = (struct syscall_trace_exit *)raw_data;
-
- tracing_generic_entry_update(&rec->ent, 0, 0);
- rec->ent.type = sys_data->exit_event->id;
rec->nr = syscall_nr;
rec->ret = syscall_get_return_value(current, regs);
- perf_tp_event(sys_data->exit_event->id, 0, 1, rec, size);
-
-end:
- perf_swevent_put_recursion_context(rctx);
-end_recursion:
- local_irq_restore(flags);
+ ftrace_perf_buf_submit(rec, size, rctx, 0, 1, flags);
}
int prof_sysexit_enable(struct ftrace_event_call *call)