include/asm-x86/system_32.h

   1 #ifndef __ASM_SYSTEM_H
   2 #define __ASM_SYSTEM_H
   3
   4 #include <asm/segment.h>
   5 #include <asm/cpufeature.h>
   6 #include <asm/cmpxchg.h>
   7
   8 #ifdef __KERNEL__
   9 #define AT_VECTOR_SIZE_ARCH 2 /* entries in ARCH_DLINFO */
  10
  11 struct task_struct;     /* one of the stranger aspects of C forward declarations.. */
  12 extern struct task_struct * FASTCALL(__switch_to(struct task_struct *prev, struct task_struct *next));
  13
  14 /*
  15  * Saving eflags is important. It switches not only IOPL between tasks,
  16  * it also protects other tasks from NT leaking through sysenter etc.
  17  */
  18 #define switch_to(prev,next,last) do {                                  \
  19         unsigned long esi,edi;                                          \
  20         asm volatile("pushfl\n\t"               /* Save flags */        \
  21                      "pushl %%ebp\n\t"                                  \
  22                      "movl %%esp,%0\n\t"        /* save ESP */          \
  23                      "movl %5,%%esp\n\t"        /* restore ESP */       \
  24                      "movl $1f,%1\n\t"          /* save EIP */          \
  25                      "pushl %6\n\t"             /* restore EIP */       \
  26                      "jmp __switch_to\n"                                \
  27                      "1:\t"                                             \
  28                      "popl %%ebp\n\t"                                   \
  29                      "popfl"                                            \
  30                      :"=m" (prev->thread.sp),"=m" (prev->thread.ip),    \
  31                       "=a" (last),"=S" (esi),"=D" (edi)                 \
  32                      :"m" (next->thread.sp),"m" (next->thread.ip),      \
  33                       "2" (prev), "d" (next));                          \
  34 } while (0)
  35
  36 #endif  /* __KERNEL__ */
  37
  38
  39 #include <linux/irqflags.h>
  40
  41 /*
  42  * disable hlt during certain critical i/o operations
  43  */
  44 #define HAVE_DISABLE_HLT
  45
  46 #endif