linux/arch/m68k/kernel
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
..
.gitignore m68k: Add vmlinux.lds to .gitignore 2009-01-12 20:56:32 +01:00
asm-offsets.c locking, m68k: Calculate thread_info offset with asm offset 2009-08-31 18:08:49 +02:00
dma.c m68k: Add missing dma_sync_single_range_for_{cpu,device}() 2008-10-14 10:23:27 -07:00
entry.S locking, m68k/asm-offsets: Rename pt_regs offset defines 2009-08-31 18:08:49 +02:00
head.S m68k: convert to use __HEAD and HEAD_TEXT macros. 2009-04-26 09:20:38 -07:00
ints.c m68k: Fix off-by-one in m68k_setup_user_interrupt() 2008-11-15 11:36:06 -08:00
m68k_ksyms.c Generic semaphore implementation 2008-04-17 10:42:34 -04:00
Makefile m68k: remove the dead PCI code 2008-10-14 10:23:27 -07:00
module.c module: cleanup FIXME comments about trimming exception table entries. 2009-06-12 21:47:05 +09:30
module.lds m68k: runtime patching infrastructure 2007-05-31 07:58:13 -07:00
process.c mm: consolidate init_mm definition 2009-06-16 19:47:28 -07:00
ptrace.c Consolidate PTRACE_DETACH 2007-10-16 09:42:49 -07:00
setup.c m68k: Kill several external declarations in source files 2009-01-12 20:56:34 +01:00
signal.c m68k: Wire up sys_restart_syscall 2009-01-12 20:56:43 +01:00
sun3-head.S m68k: arch/m68k/kernel/sun3-head.S needs <linux/init.h> 2009-04-28 16:07:18 -07:00
sys_m68k.c unified (weak) sys_pipe implementation 2008-05-03 13:50:33 -07:00
time.c m68k: Hook up rtc-generic 2009-04-02 01:05:31 +00:00
traps.c ptrace: remove PT_DTRACE from m68k, m68knommu 2009-06-18 13:03:48 -07:00
vmlinux-std.lds m68k: convert to use __HEAD and HEAD_TEXT macros. 2009-04-26 09:20:38 -07:00
vmlinux-sun3.lds m68k: convert to use __HEAD and HEAD_TEXT macros. 2009-04-26 09:20:38 -07:00
vmlinux.lds.S Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00