perf: Adding sysfs group format attribute for pmu device

Adding sysfs group 'format' attribute for pmu device that
contains a syntax description on how to construct raw events.

The event configuration is described in following
struct pefr_event_attr attributes:

  config
  config1
  config2

Each sysfs attribute within the format attribute group,
describes mapping of name and bitfield definition within
one of above attributes.

eg:
  "/sys/...<dev>/format/event" contains "config:0-7"
  "/sys/...<dev>/format/umask" contains "config:8-15"
  "/sys/...<dev>/format/usr"   contains "config:16"

the attribute value syntax is:

  line:      config ':' bits
  config:    'config' | 'config1' | 'config2"
  bits:      bits ',' bit_term | bit_term
  bit_term:  VALUE '-' VALUE | VALUE

Adding format attribute definitions for x86 cpu pmus.

Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-vhdk5y2hyype9j63prymty36@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index bd9f55a5958d..57ae485e80fc 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -550,6 +550,7 @@ struct perf_guest_info_callbacks {
 #include <linux/irq_work.h>
 #include <linux/static_key.h>
 #include <linux/atomic.h>
+#include <linux/sysfs.h>
 #include <asm/local.h>
 
 #define PERF_MAX_STACK_DEPTH            255
@@ -1291,5 +1292,18 @@ do {									\
         register_cpu_notifier(&fn##_nb);                                \
 } while (0)
 
+
+#define PMU_FORMAT_ATTR(_name, _format)                                 \
+static ssize_t                                                          \
+_name##_show(struct device *dev,                                        \
+                               struct device_attribute *attr,           \
+                               char *page)                              \
+{                                                                       \
+        BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE);                     \
+        return sprintf(page, _format "\n");                             \
+}                                                                       \
+                                                                        \
+static struct device_attribute format_attr_##_name = __ATTR_RO(_name)
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_PERF_EVENT_H */