2.6.15-rc5-mm2 can't boot on ia64 due to changing on_each_cpu().

Yasunori Goto
2005-12-15T02:38:31Z

Hello.

I met a trouble in 2.6.15-rc5-mm2 on my ia64 box. (Tiger4)
The trouble was kernel panic at early boot time due to calling
strange instruction "break 0" at smp_flush_tlb_all().

I investigated its cause and realized that gcc warned following
messages.
"arch/ia64/kernel/smp.c:228 Warning: function called through a non-
compatible type"
"arch/ia64/kernel/smp.c:228: note: if this code is reached,
the program will abort"
"arch/ia64/kernel/smp.c:251 Warning: function called through a non-
compatible type"
"arch/ia64/kernel/smp.c:251: note: if this code is reached,
the program will abort"

The line 228 and 251 are calling on_each_cpu(). And the last
instruction of this function was "break 0" indeed.

void
smp_flush_tlb_all (void)
{
on_each_cpu((void (*)(void *))local_flush_tlb_all, NULL, 1, 1);
}

void
smp_flush_tlb_mm (struct mm_struct *mm)
{
:
:
*/
on_each_cpu((void (*)(void *))local_finish_flush_tlb_mm, mm, 1, 1);
}

When I removed following patch which is in 2.6.15-rc5-mm2,
which changes on_each_cpu() from static inline function to macro,
then there was no warning, and kernel could boot up.
So, I guess that gcc was not able to solve a bit messy cast
for calling function "local_flush_tlb_all()" due to its change.

Thanks.

--------------------------------------------------------------------------

From: Benjamin LaHaise <bcrl@kvack.org>

An inline function in smp.h introduces messy ordering requirements on
thread_info by way of using an inline function instead of macro. Convert
on_each_cpu to a macro in order to avoid a big include mess.

Signed-off-by: Andrew Morton <akpm@osdl.org>
---

include/linux/smp.h | 25 +++++++++++++------------
1 files changed, 13 insertions(+), 12 deletions(-)

diff -puN include/linux/smp.h~untangle-smph-vs-thread_info include/linux/smp.h
--- 25/include/linux/smp.h~untangle-smph-vs-thread_info Fri Dec 9 15:16:46 2005
+++ 25-akpm/include/linux/smp.h Fri Dec 9 15:16:46 2005
@@ -57,19 +57,20 @@ extern int smp_call_function (void (*fun
int retry, int wait);

/*
- * Call a function on all processors
+ * Call a function on all processors.
+ * This needs to be a macro to allow for arch specific dependances on
+ * sched.h in preempt_*().
*/
-static inline int on_each_cpu(void (*func) (void *info), void *info,
- int retry, int wait)
-{
- int ret = 0;
-
- preempt_disable();
- ret = smp_call_function(func, info, retry, wait);
- func(info);
- preempt_enable();
- return ret;
-}
+#define on_each_cpu(func, info, retry, wait) \
+({ \
+ int _ret = 0; \
+ \
+ preempt_disable(); \
+ _ret = smp_call_function(func, info, retry, wait); \
+ (func)(info); \
+ preempt_enable(); \
+ _ret; \
+})

#define MSG_ALL_BUT_SELF 0x8000 /* Assume <32768 CPU's */
#define MSG_ALL 0x8001
_

--
Yasunori Goto