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linux/arch/m68k/include/asm/thread_info_mm.h
Heiko Carstens 0ee000e5e8 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>
2009-08-31 18:08:49 +02:00

68 lines
1.9 KiB
C

#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>
struct thread_info {
struct task_struct *task; /* main task structure */
unsigned long flags;
struct exec_domain *exec_domain; /* execution domain */
int preempt_count; /* 0 => preemptable, <0 => BUG */
__u32 cpu; /* should always be 0 on m68k */
struct restart_block restart_block;
};
#define PREEMPT_ACTIVE 0x4000000
#define INIT_THREAD_INFO(tsk) \
{ \
.task = &tsk, \
.exec_domain = &default_exec_domain, \
.preempt_count = INIT_PREEMPT_COUNT, \
.restart_block = { \
.fn = do_no_restart_syscall, \
}, \
}
/* THREAD_SIZE should be 8k, so handle differently for 4k and 8k machines */
#define THREAD_SIZE_ORDER (13 - PAGE_SHIFT)
#define init_thread_info (init_task.thread.info)
#define init_stack (init_thread_union.stack)
#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)
#define __HAVE_THREAD_FUNCTIONS
#define setup_thread_stack(p, org) ({ \
*(struct task_struct **)(p)->stack = (p); \
task_thread_info(p)->task = (p); \
})
#define end_of_stack(p) ((unsigned long *)(p)->stack + 1)
/* entry.S relies on these definitions!
* bits 0-7 are tested at every exception exit
* bits 8-15 are also tested at syscall exit
*/
#define TIF_SIGPENDING 6 /* signal pending */
#define TIF_NEED_RESCHED 7 /* rescheduling necessary */
#define TIF_DELAYED_TRACE 14 /* single step a syscall */
#define TIF_SYSCALL_TRACE 15 /* syscall trace active */
#define TIF_MEMDIE 16
#define TIF_FREEZE 17 /* thread is freezing for suspend */
#endif /* _ASM_M68K_THREAD_INFO_H */