[PATCH] make CALLER_ADDRx overwriteable

Uwe Kleine-König
2009-02-25T22:16:21Z

The current definition of CALLER_ADDRx isn't suitable for all platforms.
E.g. for ARM __builtin_return_address(N) doesn't work for N > 0 and
AFAIK for powerpc there are no frame pointers needed to have a working
__builtin_return_address. This patch allows defining the CALLER_ADDRx
macros in <asm/ftrace.h> and let these take precedence.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
Hello,

[I resent because vger blocked my mail saying: "Wrong MIME labeling on
8-bit character texts." Steven didn't get it either. I don't know
what's wrong, so I put the patch back into git and format-patch'd it. I
hope this one makes it through. Sorry if you got it twice.]

I think I don't break any architecture with this patch:

$ for arch in $(ls arch/); do if test ! -d arch/$arch; then continue; fi; test -f arch/$arch/include/asm/ftrace.h || test -f include/asm-$arch/ftrace.h || { echo -n "$arch: "; git grep FTRACE arch/$arch | wc -l; } done
alpha: 0
avr32: 0
blackfin: 0
cris: 0
frv: 0
h8300: 0
m32r: 0
m68k: 0
m68knommu: 0
mips: 0
mn10300: 0
parisc: 0
um: 0
xtensa: 0

So all archs that don't have <asm/ftrace.h> seem not to use FTRACE.

Best regards
Uwe

include/linux/ftrace.h | 41 +++++++++++++++++++++--------------------
1 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 847bb3c..9d8d362 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -11,6 +11,8 @@
#include <linux/bitops.h>
#include <linux/sched.h>

+#include <asm/ftrace.h>
+
#ifdef CONFIG_FUNCTION_TRACER

extern int ftrace_enabled;
@@ -103,8 +105,6 @@ struct ftrace_func_command {
};

#ifdef CONFIG_DYNAMIC_FTRACE
-/* asm/ftrace.h must be defined for archs supporting dynamic ftrace */
-#include <asm/ftrace.h>

int ftrace_arch_code_modify_prepare(void);
int ftrace_arch_code_modify_post_process(void);
@@ -282,24 +282,25 @@ static inline void __ftrace_enabled_restore(int enabled)
#endif
}

-#ifdef CONFIG_FRAME_POINTER
-/* TODO: need to fix this for ARM */
-# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
-# define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
-# define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
-# define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
-# define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
-# define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
-# define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
-#else
-# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
-# define CALLER_ADDR1 0UL
-# define CALLER_ADDR2 0UL
-# define CALLER_ADDR3 0UL
-# define CALLER_ADDR4 0UL
-# define CALLER_ADDR5 0UL
-# define CALLER_ADDR6 0UL
-#endif
+#ifndef CALLER_ADDR0
+# ifdef CONFIG_FRAME_POINTER
+# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
+# define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
+# define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
+# define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
+# define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
+# define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
+# define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
+# else
+# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
+# define CALLER_ADDR1 0UL
+# define CALLER_ADDR2 0UL
+# define CALLER_ADDR3 0UL
+# define CALLER_ADDR4 0UL
+# define CALLER_ADDR5 0UL
+# define CALLER_ADDR6 0UL
+# endif
+#endif /* ifndef CALLER_ADDR0 */

#ifdef CONFIG_IRQSOFF_TRACER
extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
--
tg: (db50eec..) t/ftrace/make_CALLER_ADDRx_overwriteable (depends on: tip/master)