arch/s390/include/asm/switch_to.h

   1 /*
   2  * Copyright IBM Corp. 1999, 2009
   3  *
   4  * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   5  */
   6
   7 #ifndef __ASM_SWITCH_TO_H
   8 #define __ASM_SWITCH_TO_H
   9
  10 #include <linux/thread_info.h>
  11 #include <asm/fpu/api.h>
  12 #include <asm/ptrace.h>
  13
  14 extern struct task_struct *__switch_to(void *, void *);
  15 extern void update_cr_regs(struct task_struct *task);
  16
  17 static inline void save_access_regs(unsigned int *acrs)
  18 {
  19         typedef struct { int _[NUM_ACRS]; } acrstype;
  20
  21         asm volatile("stam 0,15,%0" : "=Q" (*(acrstype *)acrs));
  22 }
  23
  24 static inline void restore_access_regs(unsigned int *acrs)
  25 {
  26         typedef struct { int _[NUM_ACRS]; } acrstype;
  27
  28         asm volatile("lam 0,15,%0" : : "Q" (*(acrstype *)acrs));
  29 }
  30
  31 #define switch_to(prev,next,last) do {                                  \
  32         /* save_fpu_regs() sets the CIF_FPU flag, which enforces        \
  33          * a restore of the floating point / vector registers as        \
  34          * soon as the next task returns to user space                  \
  35          */                                                             \
  36         save_fpu_regs();                                                \
  37         save_access_regs(&prev->thread.acrs[0]);                        \
  38         save_ri_cb(prev->thread.ri_cb);                                 \
  39         update_cr_regs(next);                                           \
  40         restore_access_regs(&next->thread.acrs[0]);                     \
  41         restore_ri_cb(next->thread.ri_cb, prev->thread.ri_cb);          \
  42         prev = __switch_to(prev,next);                                  \
  43 } while (0)
  44
  45 #endif /* __ASM_SWITCH_TO_H */