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authorLinus Torvalds <torvalds@linux-foundation.org>2011-03-25 17:52:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-25 17:52:22 -0700
commit94df491c4a01b39d81279a68386158eb02656712 (patch)
treeba431d9d74f11a7117883df54908ea39e4ef7c5c /kernel/kallsyms.c
parent26ff6801f751cd47e44c2e9507ec08b447f2d2b9 (diff)
parent29096202176ceaa5016a17ea2dd1aea19a4e90e2 (diff)
downloadlwn-94df491c4a01b39d81279a68386158eb02656712.tar.gz
lwn-94df491c4a01b39d81279a68386158eb02656712.zip
Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: futex: Fix WARN_ON() test for UP WARN_ON_SMP(): Allow use in if() statements on UP x86, dumpstack: Use %pB format specifier for stack trace vsprintf: Introduce %pB format specifier lockdep: Remove unused 'factor' variable from lockdep_stats_show()
Diffstat (limited to 'kernel/kallsyms.c')
-rw-r--r--kernel/kallsyms.c44
1 files changed, 41 insertions, 3 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index a56aa58b9cb0..079f1d39a8b8 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -342,13 +342,15 @@ int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
}
/* Look up a kernel symbol and return it in a text buffer. */
-int sprint_symbol(char *buffer, unsigned long address)
+static int __sprint_symbol(char *buffer, unsigned long address,
+ int symbol_offset)
{
char *modname;
const char *name;
unsigned long offset, size;
int len;
+ address += symbol_offset;
name = kallsyms_lookup(address, &size, &offset, &modname, buffer);
if (!name)
return sprintf(buffer, "0x%lx", address);
@@ -357,17 +359,53 @@ int sprint_symbol(char *buffer, unsigned long address)
strcpy(buffer, name);
len = strlen(buffer);
buffer += len;
+ offset -= symbol_offset;
if (modname)
- len += sprintf(buffer, "+%#lx/%#lx [%s]",
- offset, size, modname);
+ len += sprintf(buffer, "+%#lx/%#lx [%s]", offset, size, modname);
else
len += sprintf(buffer, "+%#lx/%#lx", offset, size);
return len;
}
+
+/**
+ * sprint_symbol - Look up a kernel symbol and return it in a text buffer
+ * @buffer: buffer to be stored
+ * @address: address to lookup
+ *
+ * This function looks up a kernel symbol with @address and stores its name,
+ * offset, size and module name to @buffer if possible. If no symbol was found,
+ * just saves its @address as is.
+ *
+ * This function returns the number of bytes stored in @buffer.
+ */
+int sprint_symbol(char *buffer, unsigned long address)
+{
+ return __sprint_symbol(buffer, address, 0);
+}
+
EXPORT_SYMBOL_GPL(sprint_symbol);
+/**
+ * sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
+ * @buffer: buffer to be stored
+ * @address: address to lookup
+ *
+ * This function is for stack backtrace and does the same thing as
+ * sprint_symbol() but with modified/decreased @address. If there is a
+ * tail-call to the function marked "noreturn", gcc optimized out code after
+ * the call so that the stack-saved return address could point outside of the
+ * caller. This function ensures that kallsyms will find the original caller
+ * by decreasing @address.
+ *
+ * This function returns the number of bytes stored in @buffer.
+ */
+int sprint_backtrace(char *buffer, unsigned long address)
+{
+ return __sprint_symbol(buffer, address, -1);
+}
+
/* Look up a kernel symbol and print it to the kernel messages. */
void __print_symbol(const char *fmt, unsigned long address)
{