tracing/user_events: Update user_events ABI from

index 706e1686b5eb..a6621c52ce45 100644
@@ -567,7 +567,7 @@ static int user_event_set_call_visible(struct user_event *user, bool visible)
 	 * to allow user_event files to be less locked down. The extreme case
 	 * being "other" has read/write access to user_events_data/status.
 	 *
-	 * When not locked down, processes may not have have permissions to
+	 * When not locked down, processes may not have permissions to
 	 * add/remove calls themselves to tracefs. We need to temporarily
 	 * switch to root file permission to allow for this scenario.
 	 */

index a6621c52ce45..075d694d20e3 100644
@@ -277,7 +277,7 @@ static int user_event_add_field(struct user_event *user, const char *type,
 	goto add_field;
 
 add_validator:
-	if (strstr(type, "char") != 0)
+	if (strstr(type, "char") != NULL)
 		validator_flags |= VALIDATOR_ENSURE_NULL;
 
 	validator = kmalloc(sizeof(*validator), GFP_KERNEL);

@@ -458,7 +458,7 @@ static const char *user_field_format(const char *type)
 		return "%d";
 	if (strcmp(type, "unsigned char") == 0)
 		return "%u";
-	if (strstr(type, "char[") != 0)
+	if (strstr(type, "char[") != NULL)
 		return "%s";
 
 	/* Unknown, likely struct, allowed treat as 64-bit */

@@ -479,7 +479,7 @@ static bool user_field_is_dyn_string(const char *type, const char **str_func)
 
 	return false;
 check:
-	return strstr(type, "char") != 0;
+	return strstr(type, "char") != NULL;
 }
 
 #define LEN_OR_ZERO (len ? len - pos : 0)

index 075d694d20e3..15edbf6b1e2e 100644
@@ -1245,7 +1245,8 @@ static ssize_t user_events_write(struct file *file, const char __user *ubuf,
 	if (unlikely(*ppos != 0))
 		return -EFAULT;
 
-	if (unlikely(import_single_range(READ, (char *)ubuf, count, &iov, &i)))
+	if (unlikely(import_single_range(WRITE, (char __user *)ubuf,
+					 count, &iov, &i)))
 		return -EFAULT;
 
 	return user_events_write_core(file, &i);

index 15edbf6b1e2e..f9bb7d37d76f 100644
@@ -45,7 +45,6 @@
 #define MAX_EVENT_DESC 512
 #define EVENT_NAME(user_event) ((user_event)->tracepoint.name)
 #define MAX_FIELD_ARRAY_SIZE 1024
-#define MAX_FIELD_ARG_NAME 256
 
 static char *register_page_data;
 

@@ -483,6 +482,48 @@ static bool user_field_is_dyn_string(const char *type, const char **str_func)
 }
 
 #define LEN_OR_ZERO (len ? len - pos : 0)
+static int user_dyn_field_set_string(int argc, const char **argv, int *iout,
+				     char *buf, int len, bool *colon)
+{
+	int pos = 0, i = *iout;
+
+	*colon = false;
+
+	for (; i < argc; ++i) {
+		if (i != *iout)
+			pos += snprintf(buf + pos, LEN_OR_ZERO, " ");
+
+		pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", argv[i]);
+
+		if (strchr(argv[i], ';')) {
+			++i;
+			*colon = true;
+			break;
+		}
+	}
+
+	/* Actual set, advance i */
+	if (len != 0)
+		*iout = i;
+
+	return pos + 1;
+}
+
+static int user_field_set_string(struct ftrace_event_field *field,
+				 char *buf, int len, bool colon)
+{
+	int pos = 0;
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", field->type);
+	pos += snprintf(buf + pos, LEN_OR_ZERO, " ");
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", field->name);
+
+	if (colon)
+		pos += snprintf(buf + pos, LEN_OR_ZERO, ";");
+
+	return pos + 1;
+}
+
 static int user_event_set_print_fmt(struct user_event *user, char *buf, int len)
 {
 	struct ftrace_event_field *field, *next;

@@ -926,49 +967,35 @@ static int user_event_free(struct dyn_event *ev)
 static bool user_field_match(struct ftrace_event_field *field, int argc,
 			     const char **argv, int *iout)
 {
-	char *field_name, *arg_name;
-	int len, pos, i = *iout;
+	char *field_name = NULL, *dyn_field_name = NULL;
 	bool colon = false, match = false;
+	int dyn_len, len;
 
-	if (i >= argc)
+	if (*iout >= argc)
 		return false;
 
-	len = MAX_FIELD_ARG_NAME;
-	field_name = kmalloc(len, GFP_KERNEL);
-	arg_name = kmalloc(len, GFP_KERNEL);
+	dyn_len = user_dyn_field_set_string(argc, argv, iout, dyn_field_name,
+					    0, &colon);
 
-	if (!arg_name || !field_name)
-		goto out;
-
-	pos = 0;
-
-	for (; i < argc; ++i) {
-		if (i != *iout)
-			pos += snprintf(arg_name + pos, len - pos, " ");
+	len = user_field_set_string(field, field_name, 0, colon);
 
-		pos += snprintf(arg_name + pos, len - pos, argv[i]);
-
-		if (strchr(argv[i], ';')) {
-			++i;
-			colon = true;
-			break;
-		}
-	}
+	if (dyn_len != len)
+		return false;
 
-	pos = 0;
+	dyn_field_name = kmalloc(dyn_len, GFP_KERNEL);
+	field_name = kmalloc(len, GFP_KERNEL);
 
-	pos += snprintf(field_name + pos, len - pos, field->type);
-	pos += snprintf(field_name + pos, len - pos, " ");
-	pos += snprintf(field_name + pos, len - pos, field->name);
+	if (!dyn_field_name || !field_name)
+		goto out;
 
-	if (colon)
-		pos += snprintf(field_name + pos, len - pos, ";");
+	user_dyn_field_set_string(argc, argv, iout, dyn_field_name,
+				  dyn_len, &colon);
 
-	*iout = i;
+	user_field_set_string(field, field_name, len, colon);
 
-	match = strcmp(arg_name, field_name) == 0;
+	match = strcmp(dyn_field_name, field_name) == 0;
 out:
-	kfree(arg_name);
+	kfree(dyn_field_name);
 	kfree(field_name);
 
 	return match;

index f9bb7d37d76f..2bcae7abfa81 100644
@@ -14,6 +14,7 @@
 #include <linux/uio.h>
 #include <linux/ioctl.h>
 #include <linux/jhash.h>
+#include <linux/refcount.h>
 #include <linux/trace_events.h>
 #include <linux/tracefs.h>
 #include <linux/types.h>

@@ -57,7 +58,7 @@ static DECLARE_BITMAP(page_bitmap, MAX_EVENTS);
  * within a file a user_event might be created if it does not
  * already exist. These are globally used and their lifetime
  * is tied to the refcnt member. These cannot go away until the
- * refcnt reaches zero.
+ * refcnt reaches one.
  */
 struct user_event {
 	struct tracepoint tracepoint;

@@ -67,7 +68,7 @@ struct user_event {
 	struct hlist_node node;
 	struct list_head fields;
 	struct list_head validators;
-	atomic_t refcnt;
+	refcount_t refcnt;
 	int index;
 	int flags;
 	int min_size;

@@ -105,6 +106,12 @@ static u32 user_event_key(char *name)
 	return jhash(name, strlen(name), 0);
 }
 
+static __always_inline __must_check
+bool user_event_last_ref(struct user_event *user)
+{
+	return refcount_read(&user->refcnt) == 1;
+}
+
 static __always_inline __must_check
 size_t copy_nofault(void *addr, size_t bytes, struct iov_iter *i)
 {

@@ -662,7 +669,7 @@ static struct user_event *find_user_event(char *name, u32 *outkey)
 
 	hash_for_each_possible(register_table, user, node, key)
 		if (!strcmp(EVENT_NAME(user), name)) {
-			atomic_inc(&user->refcnt);
+			refcount_inc(&user->refcnt);
 			return user;
 		}
 

@@ -876,12 +883,12 @@ static int user_event_reg(struct trace_event_call *call,
 
 	return ret;
 inc:
-	atomic_inc(&user->refcnt);
+	refcount_inc(&user->refcnt);
 	update_reg_page_for(user);
 	return 0;
 dec:
 	update_reg_page_for(user);
-	atomic_dec(&user->refcnt);
+	refcount_dec(&user->refcnt);
 	return 0;
 }
 

@@ -907,7 +914,7 @@ static int user_event_create(const char *raw_command)
 	ret = user_event_parse_cmd(name, &user);
 
 	if (!ret)
-		atomic_dec(&user->refcnt);
+		refcount_dec(&user->refcnt);
 
 	mutex_unlock(&reg_mutex);
 

@@ -951,14 +958,14 @@ static bool user_event_is_busy(struct dyn_event *ev)
 {
 	struct user_event *user = container_of(ev, struct user_event, devent);
 
-	return atomic_read(&user->refcnt) != 0;
+	return !user_event_last_ref(user);
 }
 
 static int user_event_free(struct dyn_event *ev)
 {
 	struct user_event *user = container_of(ev, struct user_event, devent);
 
-	if (atomic_read(&user->refcnt) != 0)
+	if (!user_event_last_ref(user))
 		return -EBUSY;
 
 	return destroy_user_event(user);

@@ -1137,8 +1144,8 @@ static int user_event_parse(char *name, char *args, char *flags,
 
 	user->index = index;
 
-	/* Ensure we track ref */
-	atomic_inc(&user->refcnt);
+	/* Ensure we track self ref and caller ref (2) */
+	refcount_set(&user->refcnt, 2);
 
 	dyn_event_init(&user->devent, &user_event_dops);
 	dyn_event_add(&user->devent, &user->call);

@@ -1164,29 +1171,17 @@ static int user_event_parse(char *name, char *args, char *flags,
 static int delete_user_event(char *name)
 {
 	u32 key;
-	int ret;
 	struct user_event *user = find_user_event(name, &key);
 
 	if (!user)
 		return -ENOENT;
 
-	/* Ensure we are the last ref */
-	if (atomic_read(&user->refcnt) != 1) {
-		ret = -EBUSY;
-		goto put_ref;
-	}
-
-	ret = destroy_user_event(user);
+	refcount_dec(&user->refcnt);
 
-	if (ret)
-		goto put_ref;
-
-	return ret;
-put_ref:
-	/* No longer have this ref */
-	atomic_dec(&user->refcnt);
+	if (!user_event_last_ref(user))
+		return -EBUSY;
 
-	return ret;
+	return destroy_user_event(user);
 }
 
 /*

@@ -1314,7 +1309,7 @@ static int user_events_ref_add(struct file *file, struct user_event *user)
 
 	new_refs->events[i] = user;
 
-	atomic_inc(&user->refcnt);
+	refcount_inc(&user->refcnt);
 
 	rcu_assign_pointer(file->private_data, new_refs);
 

@@ -1374,7 +1369,7 @@ static long user_events_ioctl_reg(struct file *file, unsigned long uarg)
 	ret = user_events_ref_add(file, user);
 
 	/* No longer need parse ref, ref_add either worked or not */
-	atomic_dec(&user->refcnt);
+	refcount_dec(&user->refcnt);
 
 	/* Positive number is index and valid */
 	if (ret < 0)

@@ -1464,7 +1459,7 @@ static int user_events_release(struct inode *node, struct file *file)
 		user = refs->events[i];
 
 		if (user)
-			atomic_dec(&user->refcnt);
+			refcount_dec(&user->refcnt);
 	}
 out:
 	file->private_data = NULL;

index 736e05603463..592a3fbed98e 100644
@@ -20,15 +20,6 @@
 #define USER_EVENTS_SYSTEM "user_events"
 #define USER_EVENTS_PREFIX "u:"
 
-/* Bits 0-6 are for known probe types, Bit 7 is for unknown probes */
-#define EVENT_BIT_FTRACE 0
-#define EVENT_BIT_PERF 1
-#define EVENT_BIT_OTHER 7
-
-#define EVENT_STATUS_FTRACE (1 << EVENT_BIT_FTRACE)
-#define EVENT_STATUS_PERF (1 << EVENT_BIT_PERF)
-#define EVENT_STATUS_OTHER (1 << EVENT_BIT_OTHER)
-
 /* Create dynamic location entry within a 32-bit value */
 #define DYN_LOC(offset, size) ((size) << 16 | (offset))
 

@@ -45,12 +36,12 @@ struct user_reg {
 	/* Input: Pointer to string with event name, description and flags */
 	__u64 name_args;
 
-	/* Output: Byte index of the event within the status page */
-	__u32 status_index;
+	/* Output: Bitwise index of the event within the status page */
+	__u32 status_bit;
 
 	/* Output: Index of the event to use when writing data */
 	__u32 write_index;
-};
+} __attribute__((__packed__));
 
 #define DIAG_IOC_MAGIC '*'
 

120 lines not on this page · raw message

index 4f5778e441c0..d06dc24156ec 100644
@@ -12,13 +12,21 @@
 #include <fcntl.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <asm/bitsperlong.h>
+#include <endian.h>
 #include <linux/user_events.h>
 
+#if __BITS_PER_LONG == 64
+#define endian_swap(x) htole64(x)
+#else
+#define endian_swap(x) htole32(x)
+#endif
+
 /* Assumes debugfs is mounted */
 const char *data_file = "/sys/kernel/debug/tracing/user_events_data";
 const char *status_file = "/sys/kernel/debug/tracing/user_events_status";
 
-static int event_status(char **status)
+static int event_status(long **status)
 {
 	int fd = open(status_file, O_RDONLY);
 

@@ -33,7 +41,8 @@ static int event_status(char **status)
 	return 0;
 }
 
-static int event_reg(int fd, const char *command, int *status, int *write)
+static int event_reg(int fd, const char *command, long *index, long *mask,
+		     int *write)
 {
 	struct user_reg reg = {0};
 

@@ -43,7 +52,8 @@ static int event_reg(int fd, const char *command, int *status, int *write)
 	if (ioctl(fd, DIAG_IOCSREG, &reg) == -1)
 		return -1;
 
-	*status = reg.status_index;
+	*index = reg.status_bit / __BITS_PER_LONG;
+	*mask = endian_swap(1L << (reg.status_bit % __BITS_PER_LONG));
 	*write = reg.write_index;
 
 	return 0;

@@ -51,8 +61,9 @@ static int event_reg(int fd, const char *command, int *status, int *write)
 
 int main(int argc, char **argv)
 {
-	int data_fd, status, write;
-	char *status_page;
+	int data_fd, write;
+	long index, mask;
+	long *status_page;
 	struct iovec io[2];
 	__u32 count = 0;
 

@@ -61,7 +72,7 @@ int main(int argc, char **argv)
 
 	data_fd = open(data_file, O_RDWR);
 
-	if (event_reg(data_fd, "test u32 count", &status, &write) == -1)
+	if (event_reg(data_fd, "test u32 count", &index, &mask, &write) == -1)
 		return errno;
 
 	/* Setup iovec */

@@ -75,7 +86,7 @@ int main(int argc, char **argv)
 	getchar();
 
 	/* Check if anyone is listening */
-	if (status_page[status]) {
+	if (status_page[index] & mask) {
 		/* Yep, trace out our data */
 		writev(data_fd, (const struct iovec *)io, 2);
 

120 lines not on this page · raw message

index 26851d51d6bb..8b4c7879d5a7 100644
@@ -35,6 +35,11 @@ static long perf_event_open(struct perf_event_attr *pe, pid_t pid,
 	return syscall(__NR_perf_event_open, pe, pid, cpu, group_fd, flags);
 }
 
+static inline int status_check(char *status_page, int status_bit)
+{
+	return status_page[status_bit >> 3] & (1 << (status_bit & 7));
+}
+
 static int get_id(void)
 {
 	FILE *fp = fopen(id_file, "r");

@@ -120,8 +125,8 @@ TEST_F(user, perf_write) {
 	/* Register should work */
 	ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, &reg));
 	ASSERT_EQ(0, reg.write_index);
-	ASSERT_NE(0, reg.status_index);
-	ASSERT_EQ(0, status_page[reg.status_index]);
+	ASSERT_NE(0, reg.status_bit);
+	ASSERT_EQ(0, status_check(status_page, reg.status_bit));
 
 	/* Id should be there */
 	id = get_id();

@@ -144,7 +149,7 @@ TEST_F(user, perf_write) {
 	ASSERT_NE(MAP_FAILED, perf_page);
 
 	/* Status should be updated */
-	ASSERT_EQ(EVENT_STATUS_PERF, status_page[reg.status_index]);
+	ASSERT_NE(0, status_check(status_page, reg.status_bit));
 
 	event.index = reg.write_index;
 	event.field1 = 0xc001;