Extend print_symbol capability TRY #2

PATCH In review Robert Peterson 3 participants 3 messages Mar 6, 2007

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Robert Peterson

author

2007-03-06 00:05 UTC #0 lore raw

PATCH 1/1 Extend print_symbol capability TRY #2

This is try #2 for this patch, with corrections based on feedback. It is the same as the previous patch except:
(1) The function has been renamed from lookup_symbol to sprint_symbol
as requested by Paulo Marques.
(2) I fixed the "return NULL;" to "return;" as pointed out by Paulo Marques
for the case where the kallsyms function is not selected in .config
(3) I changed EXPORT_SYMBOL to EXPORT_SYMBOL_GPL as
requested by Roman Zippel. (Andrew, I thought you said you changed this,
but I didn't see it in mm1).

I hope this patch attaches with proper spacing and without word wrap. If it doesn't, my apologies (I'm using Thunderbird, but suggestions welcome).

Original comment:

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).

Signed-off-by Robert Peterson <[email protected]>

---

 include/linux/kallsyms.h |   10 ++++++++++
 kernel/kallsyms.c        |   21 ++++++++++++++-------
 2 files changed, 24 insertions(+), 7 deletions(-)

include/linux/kallsyms.h +10 -0

index 1cebcbc..3bb4136 100644
@@ -7,6 +7,8 @@
 
 
 #define KSYM_NAME_LEN 127
+#define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN +	\
+			 2*(BITS_PER_LONG*3/10) + MODULE_NAME_LEN + 1)
 
 #ifdef CONFIG_KALLSYMS
 /* Lookup the address for a symbol. Returns 0 if not found. */

@@ -22,6 +24,9 @@ const char *kallsyms_lookup(unsigned long addr,
 			    unsigned long *offset,
 			    char **modname, char *namebuf);
 
+/* Look up a kernel symbol and return it in a text buffer. */
+extern void sprint_symbol(unsigned long addr, char *buffer);
+
 /* Replace "%s" in format with address, if found */
 extern void __print_symbol(const char *fmt, unsigned long address);

@@ -47,6 +52,11 @@ static inline const char *kallsyms_lookup(unsigned long addr,
 	return NULL;
 }
 
+static inline void sprint_symbol(unsigned long addr, char *buffer)
+{
+	return;
+}
+
 /* Stupid that this does nothing, but I didn't create this mess. */
 #define __print_symbol(fmt, addr)
 #endif /*CONFIG_KALLSYMS*/

kernel/kallsyms.c +14 -7

index 6f294ff..775d5e4 100644
@@ -267,20 +267,17 @@ 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. */
+void sprint_symbol(unsigned long addr, char *buffer)
 {
 	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);
 
+	name = kallsyms_lookup(addr, &size, &offset, &modname, namebuf);
 	if (!name)
-		sprintf(buffer, "0x%lx", address);
+		sprintf(buffer, "0x%lx", addr);
 	else {
 		if (modname)
 			sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset,

@@ -288,6 +285,15 @@ void __print_symbol(const char *fmt, unsigned long address)
 		else
 			sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
 	}
+}
+
+/* Replace "%s" in format with address, or returns -errno. */
+void __print_symbol(const char *fmt, unsigned long address)
+{
+	char buffer[KSYM_SYMBOL_LEN];
+
+	sprint_symbol(address, buffer);
+
 	printk(fmt, buffer);
 }

@@ -452,3 +458,4 @@ static int __init kallsyms_init(void)
 __initcall(kallsyms_init);
 
 EXPORT_SYMBOL(__print_symbol);
+EXPORT_SYMBOL_GPL(sprint_symbol);

Randy Dunlap

2007-03-06 01:41 UTC #1 lore raw

Quoted 23 lines · On Mon, 05 Mar 2007 18:03:59 -0600 Robert Peterson wrote:

This is try #2 for this patch, with corrections based on feedback. It is the same as the previous patch except:
(1) The function has been renamed from lookup_symbol to sprint_symbol as requested by Paulo Marques.
(2) I fixed the "return NULL;" to "return;" as pointed out by Paulo Marques for the case where the kallsyms function is not selected in .config
(3) I changed EXPORT_SYMBOL to EXPORT_SYMBOL_GPL as
requested by Roman Zippel. (Andrew, I thought you said you changed this, but I didn't see it in mm1).
I hope this patch attaches with proper spacing and without word wrap. If it doesn't, my apologies (I'm using Thunderbird, but suggestions welcome).
Original comment:
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).

Quoted 2 lines

Signed-off-by Robert Peterson <[email protected]>
---

argh, attachment, harder to review/comment on....

I had commented on this comment, but you seem to have missed it.

+/* Replace "%s" in format with address, or returns -errno. */ +void __print_symbol(const char *fmt, unsigned long address) +{

This function does not "returns -errno" at all.

---
~Randy

using tbird for inline patches:
http://mbligh.org/linuxdocs/Email/Clients/Thunderbird

Andrew Morton

2007-03-06 01:54 UTC #2 lore raw

Quoted 36 lines · On Mon, 5 Mar 2007 17:37:56 -0800 Randy Dunlap <[email protected]> wrote:

Quoted 23 lines · On Mon, 05 Mar 2007 18:03:59 -0600 Robert Peterson wrote:
This is try #2 for this patch, with corrections based on feedback. It is the same as the previous patch except:
(1) The function has been renamed from lookup_symbol to sprint_symbol as requested by Paulo Marques.
(2) I fixed the "return NULL;" to "return;" as pointed out by Paulo Marques for the case where the kallsyms function is not selected in .config
(3) I changed EXPORT_SYMBOL to EXPORT_SYMBOL_GPL as
requested by Roman Zippel. (Andrew, I thought you said you changed this, but I didn't see it in mm1).
I hope this patch attaches with proper spacing and without word wrap. If it doesn't, my apologies (I'm using Thunderbird, but suggestions welcome).
Original comment:
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).
Quoted 2 lines
Signed-off-by Robert Peterson <[email protected]>
---
argh, attachment, harder to review/comment on....
I had commented on this comment, but you seem to have missed it.
kernel/kallsyms.c +3 -0
+/* Replace "%s" in format with address, or returns -errno. */
+void __print_symbol(const char *fmt, unsigned long address)
+{

Quoted 1 line

This function does not "returns -errno" at all.

I think the arguments to sprint_symbol() are backwards. Would prefer

sprint_symbol(char *buffer, unsigned long addr)

like all the other print-into-a-buffer functions.