vsprintf: add binary printf

Impact: add new APIs for binary trace printk infrastructure

vbin_printf(): write args to binary buffer, string is copied
when "%s" is occurred.

bstr_printf(): read from binary buffer for args and format a string

[fweisbec@gmail.com: rebase]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1236356510-8381-2-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/string.h

@@ -10,6 +10,7 @@
 #include <linux/compiler.h>	/* for inline */
 #include <linux/types.h>	/* for size_t */
 #include <linux/stddef.h>	/* for NULL */
+#include <stdarg.h>
 
 extern char *strndup_user(const char __user *, long);
 
@@ -111,6 +112,12 @@ extern void argv_free(char **argv);
 
 extern bool sysfs_streq(const char *s1, const char *s2);
 
+#ifdef CONFIG_BINARY_PRINTF
+int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
+int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
+int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
+#endif
+
 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
 			const void *from, size_t available);
 

lib/Kconfig

@@ -2,6 +2,9 @@
 # Library configuration
 #
 
+config BINARY_PRINTF
+	def_bool n
+
 menu "Library routines"
 
 config BITREVERSE