kernel-2.6.17-thread_info-buildfix.patch

   1
   2 From: Chuck Ebbert <76306.1226@compuserve.com>
   3
   4 Using C code for current_thread_info() lets the compiler optimize it.
   5 With gcc 4.0.2, kernel is smaller:
   6
   7     text           data     bss     dec     hex filename
   8  3645212         555556  312024 4512792  44dc18 2.6.17-rc6-nb-post/vmlinux
   9  3647276         555556  312024 4514856  44e428 2.6.17-rc6-nb/vmlinux
  10  -------
  11    -2064
  12
  13 Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
  14 Signed-off-by: Andrew Morton <akpm@osdl.org>
  15 ---
  16
  17  include/asm-i386/thread_info.h |   10 ++++------
  18  1 file changed, 4 insertions(+), 6 deletions(-)
  19
  20 diff -puN include/asm-i386/thread_info.h~i386-use-c-code-for-current_thread_info include/asm-i386/thread_info.h
  21 --- a/include/asm-i386/thread_info.h~i386-use-c-code-for-current_thread_info
  22 +++ a/include/asm-i386/thread_info.h
  23 @@ -83,17 +83,15 @@ struct thread_info {
  24  #define init_stack             (init_thread_union.stack)
  25
  26
  27 +/* how to get the current stack pointer from C */
  28 +register unsigned long current_stack_pointer asm("esp") __attribute_used__;
  29 +
  30  /* how to get the thread information struct from C */
  31  static inline struct thread_info *current_thread_info(void)
  32  {
  33 -       struct thread_info *ti;
  34 -       __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~(THREAD_SIZE - 1)));
  35 -       return ti;
  36 +       return (struct thread_info *)(current_stack_pointer & ~(THREAD_SIZE - 1));
  37  }
  38
  39 -/* how to get the current stack pointer from C */
  40 -register unsigned long current_stack_pointer asm("esp") __attribute_used__;
  41 -
  42  /* thread information allocation */
  43  #ifdef CONFIG_DEBUG_STACK_USAGE
  44  #define alloc_thread_info(tsk)                                 \
  45 _