perf/x86: fix sysfs type mismatches

This change switches rapl to use PMU_FORMAT_ATTR, and fixes two other
macros to use device_attribute instead of kobj_attribute to avoid
callback type mismatches that trip indirect call checking with Clang's
Control-Flow Integrity (CFI).
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20201113183126.1239404-1-samitolvanen@google.com

arch/x86/events/intel/cstate.c

@@ -107,14 +107,14 @@
 MODULE_LICENSE("GPL");
 
 #define DEFINE_CSTATE_FORMAT_ATTR(_var, _name, _format)		\
-static ssize_t __cstate_##_var##_show(struct kobject *kobj,	\
-				struct kobj_attribute *attr,	\
+static ssize_t __cstate_##_var##_show(struct device *dev,	\
+				struct device_attribute *attr,	\
 				char *page)			\
 {								\
 	BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE);		\
 	return sprintf(page, _format "\n");			\
 }								\
-static struct kobj_attribute format_attr_##_var =		\
+static struct device_attribute format_attr_##_var =		\
 	__ATTR(_name, 0444, __cstate_##_var##_show, NULL)
 
 static ssize_t cstate_get_attr_cpumask(struct device *dev,

arch/x86/events/intel/uncore.c

@@ -94,8 +94,8 @@ struct pci2phy_map *__find_pci2phy_map(int segment)
 	return map;
 }
 
-ssize_t uncore_event_show(struct kobject *kobj,
-			  struct kobj_attribute *attr, char *buf)
+ssize_t uncore_event_show(struct device *dev,
+			  struct device_attribute *attr, char *buf)
 {
 	struct uncore_event_desc *event =
 		container_of(attr, struct uncore_event_desc, attr);

arch/x86/events/intel/uncore.h

@@ -157,7 +157,7 @@ struct intel_uncore_box {
 #define UNCORE_BOX_FLAG_CFL8_CBOX_MSR_OFFS	2
 
 struct uncore_event_desc {
-	struct kobj_attribute attr;
+	struct device_attribute attr;
 	const char *config;
 };
 
@@ -179,8 +179,8 @@ struct pci2phy_map {
 struct pci2phy_map *__find_pci2phy_map(int segment);
 int uncore_pcibus_to_physid(struct pci_bus *bus);
 
-ssize_t uncore_event_show(struct kobject *kobj,
-			  struct kobj_attribute *attr, char *buf);
+ssize_t uncore_event_show(struct device *dev,
+			  struct device_attribute *attr, char *buf);
 
 static inline struct intel_uncore_pmu *dev_to_uncore_pmu(struct device *dev)
 {
@@ -201,14 +201,14 @@ extern int __uncore_max_dies;
 }
 
 #define DEFINE_UNCORE_FORMAT_ATTR(_var, _name, _format)			\
-static ssize_t __uncore_##_var##_show(struct kobject *kobj,		\
-				struct kobj_attribute *attr,		\
+static ssize_t __uncore_##_var##_show(struct device *dev,		\
+				struct device_attribute *attr,		\
 				char *page)				\
 {									\
 	BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE);			\
 	return sprintf(page, _format "\n");				\
 }									\
-static struct kobj_attribute format_attr_##_var =			\
+static struct device_attribute format_attr_##_var =			\
 	__ATTR(_name, 0444, __uncore_##_var##_show, NULL)
 
 static inline bool uncore_pmc_fixed(int idx)

arch/x86/events/rapl.c

@@ -93,18 +93,6 @@ static const char *const rapl_domain_names[NR_RAPL_DOMAINS] __initconst = {
  * any other bit is reserved
  */
 #define RAPL_EVENT_MASK	0xFFULL
-
-#define DEFINE_RAPL_FORMAT_ATTR(_var, _name, _format)		\
-static ssize_t __rapl_##_var##_show(struct kobject *kobj,	\
-				struct kobj_attribute *attr,	\
-				char *page)			\
-{								\
-	BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE);		\
-	return sprintf(page, _format "\n");			\
-}								\
-static struct kobj_attribute format_attr_##_var =		\
-	__ATTR(_name, 0444, __rapl_##_var##_show, NULL)
-
 #define RAPL_CNTR_WIDTH 32
 
 #define RAPL_EVENT_ATTR_STR(_name, v, str)					\
@@ -441,7 +429,7 @@ static struct attribute_group rapl_pmu_events_group = {
 	.attrs = attrs_empty,
 };
 
-DEFINE_RAPL_FORMAT_ATTR(event, event, "config:0-7");
+PMU_FORMAT_ATTR(event, "config:0-7");
 static struct attribute *rapl_formats_attr[] = {
 	&format_attr_event.attr,
 	NULL,