diff options
authorRobert Peterson <rpeterso@redhat.com>2007-04-30 15:09:48 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-04-30 16:40:39 -0700
commit42e380832a6911c8a3173ee0172fbc0e4864d80b (patch)
parent[UDP]: Do not allow specific bind when wildcard bind exists. (diff)
Extend print_symbol capability
Today's print_symbol function dumps a kernel symbol with printk. This patch extends the functionality of kallsyms.c so that the symbol lookup function may be used without the printk. This is useful for modules that want to dump symbols elsewhere, for example, to debugfs. I intend to use the new function call in the GFS2 file system (which will be a separate patch). [akpm@linux-foundation.org: build fix] [clameter@sgi.com: sprint_symbol should return length of string like sprintf] Signed-off-by: Robert Peterson <rpeterso@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Cc: Sam Ravnborg <sam@ravnborg.org> Acked-by: Paulo Marques <pmarques@grupopie.com> Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2 files changed, 27 insertions, 9 deletions
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 1cebcbc28b47..3e3b92dabe3b 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -7,6 +7,8 @@
#define KSYM_NAME_LEN 127
+#define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN + \
/* Lookup the address for a symbol. Returns 0 if not found. */
@@ -22,7 +24,10 @@ const char *kallsyms_lookup(unsigned long addr,
unsigned long *offset,
char **modname, char *namebuf);
-/* Replace "%s" in format with address, if found */
+/* Look up a kernel symbol and return it in a text buffer. */
+extern int sprint_symbol(char *buffer, unsigned long address);
+/* Look up a kernel symbol and print it to the kernel messages. */
extern void __print_symbol(const char *fmt, unsigned long address);
#else /* !CONFIG_KALLSYMS */
@@ -47,6 +52,12 @@ static inline const char *kallsyms_lookup(unsigned long addr,
return NULL;
+static inline int sprint_symbol(char *buffer, unsigned long addr)
+ *buffer = '\0';
+ return 0;
/* Stupid that this does nothing, but I didn't create this mess. */
#define __print_symbol(fmt, addr)
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 6f294ff4f9ee..5a0de8409739 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -267,27 +267,33 @@ const char *kallsyms_lookup(unsigned long addr,
return NULL;
-/* Replace "%s" in format with address, or returns -errno. */
-void __print_symbol(const char *fmt, unsigned long address)
+/* Look up a kernel symbol and return it in a text buffer. */
+int sprint_symbol(char *buffer, unsigned long address)
char *modname;
const char *name;
unsigned long offset, size;
char namebuf[KSYM_NAME_LEN+1];
- char buffer[sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN +
- 2*(BITS_PER_LONG*3/10) + MODULE_NAME_LEN + 1];
name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);
if (!name)
- sprintf(buffer, "0x%lx", address);
+ return sprintf(buffer, "0x%lx", address);
else {
if (modname)
- sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset,
+ return sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset,
size, modname);
- sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
+ return sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
+/* Look up a kernel symbol and print it to the kernel messages. */
+void __print_symbol(const char *fmt, unsigned long address)
+ char buffer[KSYM_SYMBOL_LEN];
+ sprint_symbol(buffer, address);
printk(fmt, buffer);
@@ -452,3 +458,4 @@ static int __init kallsyms_init(void)