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authorHeiko Carstens <heiko.carstens@de.ibm.com>2009-08-31 14:43:35 +0200
committerIngo Molnar <mingo@elte.hu>2009-08-31 18:08:49 +0200
commit0ee000e5e8fa2e5c760250be0d78d5906e3eb94b (patch)
tree7c3d253b2e6d89bdae8c1fbe86baa17b080efcce
parentf159ee782990aacb5494738c98f13a2aa61dbb4a (diff)
locking, m68k: Calculate thread_info offset with asm offset
m68k has the thread_info structure embedded in its task struct. Therefore its not possible to implement current_thread_info() by looking at the stack pointer and do some simple calculations like most other architectures do it. To return the thread_info pointer for a task two defines are used. This works until the spinlock function bodies get moved into an own header file and CONFIG_SPINLOCK_DEBUG is turned on. That results into this compile error: In file included from include/linux/spinlock.h:378, from include/linux/seqlock.h:29, from include/linux/time.h:8, from include/linux/timex.h:56, from include/linux/sched.h:54, from arch/m68k/kernel/asm-offsets.c:12: include/linux/spinlock_api_smp.h: In function '__spin_unlock_irq': include/linux/spinlock_api_smp.h:371: error: 'current' undeclared (first use in this function) include/linux/spinlock_api_smp.h:371: error: (Each undeclared identifier is reported only once include/linux/spinlock_api_smp.h:371: error: for each function it appears in.) Including asm/current.h to asm-offsets.c wouldn't help since the definition of struct task is needed. So we end up with ugly header file include dependencies. To solve this calculate the offset of the thread_info structure into the task struct in asm-offsets.h and use the offset in task_thread_info(). This works just like it does for IA64 as well. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Horst Hartmann <horsth@linux.vnet.ibm.com> Cc: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: David Miller <davem@davemloft.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: <linux-arch@vger.kernel.org> LKML-Reference: <20090831124417.329662275@de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/m68k/include/asm/thread_info_mm.h11
-rw-r--r--arch/m68k/kernel/asm-offsets.c5
2 files changed, 15 insertions, 1 deletions
diff --git a/arch/m68k/include/asm/thread_info_mm.h b/arch/m68k/include/asm/thread_info_mm.h
index 6ea5c33b3c5..b6da3882be9 100644
--- a/arch/m68k/include/asm/thread_info_mm.h
+++ b/arch/m68k/include/asm/thread_info_mm.h
@@ -1,6 +1,10 @@
#ifndef _ASM_M68K_THREAD_INFO_H
#define _ASM_M68K_THREAD_INFO_H
+#ifndef ASM_OFFSETS_C
+#include <asm/asm-offsets.h>
+#endif
+#include <asm/current.h>
#include <asm/types.h>
#include <asm/page.h>
@@ -31,7 +35,12 @@ struct thread_info {
#define init_thread_info (init_task.thread.info)
#define init_stack (init_thread_union.stack)
-#define task_thread_info(tsk) (&(tsk)->thread.info)
+#ifdef ASM_OFFSETS_C
+#define task_thread_info(tsk) ((struct thread_info *) NULL)
+#else
+#define task_thread_info(tsk) ((struct thread_info *)((char *)tsk+TASK_TINFO))
+#endif
+
#define task_stack_page(tsk) ((tsk)->stack)
#define current_thread_info() task_thread_info(current)
diff --git a/arch/m68k/kernel/asm-offsets.c b/arch/m68k/kernel/asm-offsets.c
index 0cffab8d244..25d6b721522 100644
--- a/arch/m68k/kernel/asm-offsets.c
+++ b/arch/m68k/kernel/asm-offsets.c
@@ -8,6 +8,8 @@
* #defines from the assembly-language output.
*/
+#define ASM_OFFSETS_C
+
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
@@ -27,6 +29,9 @@ int main(void)
DEFINE(TASK_INFO, offsetof(struct task_struct, thread.info));
DEFINE(TASK_MM, offsetof(struct task_struct, mm));
DEFINE(TASK_ACTIVE_MM, offsetof(struct task_struct, active_mm));
+#ifdef CONFIG_MMU
+ DEFINE(TASK_TINFO, offsetof(struct task_struct, thread.info));
+#endif
/* offsets into the thread struct */
DEFINE(THREAD_KSP, offsetof(struct thread_struct, ksp));