#include <linux/kprobes.h>
#include "trace.h"
-DEFINE_PER_CPU(struct pt_regs, perf_trace_regs);
-EXPORT_PER_CPU_SYMBOL_GPL(perf_trace_regs);
-
EXPORT_SYMBOL_GPL(perf_arch_fetch_caller_regs);
-static char *perf_trace_buf;
-static char *perf_trace_buf_nmi;
+static char *perf_trace_buf[4];
-typedef typeof(char [PERF_MAX_TRACE_SIZE]) perf_trace_t ;
+/*
+ * Force it to be aligned to unsigned long to avoid misaligned accesses
+ * suprises
+ */
+typedef typeof(unsigned long [PERF_MAX_TRACE_SIZE / sizeof(unsigned long)])
+ perf_trace_t;
/* Count the events in use (per event id, not per instance) */
static int total_ref_count;
-static int perf_trace_event_enable(struct ftrace_event_call *event)
+static int perf_trace_event_enable(struct ftrace_event_call *event, void *data)
{
- char *buf;
int ret = -ENOMEM;
- if (event->perf_refcount++ > 0)
+ if (event->perf_refcount++ > 0) {
+ event->perf_data = NULL;
return 0;
+ }
if (!total_ref_count) {
- buf = (char *)alloc_percpu(perf_trace_t);
- if (!buf)
- goto fail_buf;
+ char *buf;
+ int i;
- rcu_assign_pointer(perf_trace_buf, buf);
+ for (i = 0; i < 4; i++) {
+ buf = (char *)alloc_percpu(perf_trace_t);
+ if (!buf)
+ goto fail_buf;
- buf = (char *)alloc_percpu(perf_trace_t);
- if (!buf)
- goto fail_buf_nmi;
-
- rcu_assign_pointer(perf_trace_buf_nmi, buf);
+ rcu_assign_pointer(perf_trace_buf[i], buf);
+ }
}
ret = event->perf_event_enable(event);
if (!ret) {
+ event->perf_data = data;
total_ref_count++;
return 0;
}
-fail_buf_nmi:
+fail_buf:
if (!total_ref_count) {
- free_percpu(perf_trace_buf_nmi);
- free_percpu(perf_trace_buf);
- perf_trace_buf_nmi = NULL;
- perf_trace_buf = NULL;
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ free_percpu(perf_trace_buf[i]);
+ perf_trace_buf[i] = NULL;
+ }
}
-fail_buf:
event->perf_refcount--;
return ret;
}
-int perf_trace_enable(int event_id)
+int perf_trace_enable(int event_id, void *data)
{
struct ftrace_event_call *event;
int ret = -EINVAL;
list_for_each_entry(event, &ftrace_events, list) {
if (event->id == event_id && event->perf_event_enable &&
try_module_get(event->mod)) {
- ret = perf_trace_event_enable(event);
+ ret = perf_trace_event_enable(event, data);
break;
}
}
static void perf_trace_event_disable(struct ftrace_event_call *event)
{
- char *buf, *nmi_buf;
-
if (--event->perf_refcount > 0)
return;
event->perf_event_disable(event);
if (!--total_ref_count) {
- buf = perf_trace_buf;
- rcu_assign_pointer(perf_trace_buf, NULL);
+ char *buf[4];
+ int i;
- nmi_buf = perf_trace_buf_nmi;
- rcu_assign_pointer(perf_trace_buf_nmi, NULL);
+ for (i = 0; i < 4; i++) {
+ buf[i] = perf_trace_buf[i];
+ rcu_assign_pointer(perf_trace_buf[i], NULL);
+ }
/*
* Ensure every events in profiling have finished before
*/
synchronize_sched();
- free_percpu(buf);
- free_percpu(nmi_buf);
+ for (i = 0; i < 4; i++)
+ free_percpu(buf[i]);
}
}
}
__kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
- int *rctxp, unsigned long *irq_flags)
+ struct pt_regs *regs, int *rctxp)
{
struct trace_entry *entry;
char *trace_buf, *raw_data;
- int pc, cpu;
+ int pc;
- pc = preempt_count();
+ BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
- /* Protect the per cpu buffer, begin the rcu read side */
- local_irq_save(*irq_flags);
+ pc = preempt_count();
*rctxp = perf_swevent_get_recursion_context();
if (*rctxp < 0)
goto err_recursion;
- cpu = smp_processor_id();
-
- if (in_nmi())
- trace_buf = rcu_dereference_sched(perf_trace_buf_nmi);
- else
- trace_buf = rcu_dereference_sched(perf_trace_buf);
-
+ trace_buf = rcu_dereference_sched(perf_trace_buf[*rctxp]);
if (!trace_buf)
goto err;
- raw_data = per_cpu_ptr(trace_buf, cpu);
+ raw_data = per_cpu_ptr(trace_buf, smp_processor_id());
/* zero the dead bytes from align to not leak stack to user */
- *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
+ memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64));
entry = (struct trace_entry *)raw_data;
- tracing_generic_entry_update(entry, *irq_flags, pc);
+ tracing_generic_entry_update(entry, regs->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(perf_trace_buf_prepare);