perf/x86/intel/pt: Factor out pt_config_start()

PT trace is now enabled at the bottom of the event configuration function that takes care of all configuration bits related to a given event, including the address filter update. This is only needed where the event configuration changes, that is, in ->add()/->start(). In the interrupt path we can use a lighter version that keeps the configuration intact, since it hasn't changed, and only flips the enable bit. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: adrian.hunter@intel.com Cc: mathieu.poirier@linaro.org Link: https://lkml.kernel.org/r/20191025140835.53665-3-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>

Author: virtuoso

arch/x86/events/intel/pt.c

@@ -397,6 +397,20 @@ static bool pt_event_valid(struct perf_event *event)
  * These all are cpu affine and operate on a local PT
  */
 
+static void pt_config_start(struct perf_event *event)
+{
+struct pt *pt = this_cpu_ptr(&pt_ctx);
+u64 ctl = event->hw.config;
+
+ctl |= RTIT_CTL_TRACEEN;
+if (READ_ONCE(pt->vmx_on))
+perf_aux_output_flag(&pt->handle, PERF_AUX_FLAG_PARTIAL);
+else
+wrmsrl(MSR_IA32_RTIT_CTL, ctl);
+
+WRITE_ONCE(event->hw.config, ctl);
+}
+
 /* Address ranges and their corresponding msr configuration registers */
 static const struct pt_address_range {
 unsigned longmsr_a;
@@ -468,7 +482,6 @@ static u64 pt_config_filters(struct perf_event *event)
 
 static void pt_config(struct perf_event *event)
 {
-struct pt *pt = this_cpu_ptr(&pt_ctx);
 u64 reg;
 
 /* First round: clear STATUS, in particular the PSB byte counter. */
@@ -501,10 +514,7 @@ static void pt_config(struct perf_event *event)
 reg |= (event->attr.config & PT_CONFIG_MASK);
 
 event->hw.config = reg;
-if (READ_ONCE(pt->vmx_on))
-perf_aux_output_flag(&pt->handle, PERF_AUX_FLAG_PARTIAL);
-else
-wrmsrl(MSR_IA32_RTIT_CTL, reg);
+pt_config_start(event);
 }
 
 static void pt_config_stop(struct perf_event *event)
@@ -1381,7 +1391,7 @@ void intel_pt_interrupt(void)
 
 pt_config_buffer(topa_to_page(buf->cur)->table, buf->cur_idx,
  buf->output_off);
-pt_config(event);
+pt_config_start(event);
 }
 }