From: Heiko Carstens Date: Mon, 31 Aug 2009 12:43:35 +0000 (+0200) Subject: locking, m68k: Calculate thread_info offset with asm offset X-Git-Tag: v2.6.32-rc1~726^2~5 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=0ee000e5e8fa2e5c760250be0d78d5906e3eb94b;p=linux-block.git 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 Acked-by: Peter Zijlstra Cc: Arnd Bergmann Cc: Nick Piggin Cc: Martin Schwidefsky Cc: Horst Hartmann Cc: Christian Ehrhardt Cc: Andrew Morton Cc: Linus Torvalds Cc: David Miller Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Geert Uytterhoeven Cc: Roman Zippel Cc: LKML-Reference: <20090831124417.329662275@de.ibm.com> Signed-off-by: Ingo Molnar --- diff --git a/arch/m68k/include/asm/thread_info_mm.h b/arch/m68k/include/asm/thread_info_mm.h index 6ea5c33b3c56..b6da3882be9b 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 +#endif +#include #include #include @@ -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 0cffab8d2440..25d6b721522e 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 #include #include @@ -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));