arch/s390/include/asm/switch_to.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright IBM Corp. 1999, 2009
   4  *
   5  * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   6  */
   7
   8 #ifndef __ASM_SWITCH_TO_H
   9 #define __ASM_SWITCH_TO_H
  10
  11 #include <linux/thread_info.h>
  12 #include <asm/fpu/api.h>
  13 #include <asm/ptrace.h>
  14 #include <asm/guarded_storage.h>
  15
  16 extern struct task_struct *__switch_to(void *, void *);
  17 extern void update_cr_regs(struct task_struct *task);
  18
  19 static inline void save_access_regs(unsigned int *acrs)
  20 {
  21         typedef struct { int _[NUM_ACRS]; } acrstype;
  22
  23         asm volatile("stam 0,15,%0" : "=Q" (*(acrstype *)acrs));
  24 }
  25
  26 static inline void restore_access_regs(unsigned int *acrs)
  27 {
  28         typedef struct { int _[NUM_ACRS]; } acrstype;
  29
  30         asm volatile("lam 0,15,%0" : : "Q" (*(acrstype *)acrs));
  31 }
  32
  33 #define switch_to(prev, next, last) do {                                \
  34         /* save_fpu_regs() sets the CIF_FPU flag, which enforces        \
  35          * a restore of the floating point / vector registers as        \
  36          * soon as the next task returns to user space                  \
  37          */                                                             \
  38         save_fpu_regs();                                                \
  39         save_access_regs(&prev->thread.acrs[0]);                        \
  40         save_ri_cb(prev->thread.ri_cb);                                 \
  41         save_gs_cb(prev->thread.gs_cb);                                 \
  42         update_cr_regs(next);                                           \
  43         restore_access_regs(&next->thread.acrs[0]);                     \
  44         restore_ri_cb(next->thread.ri_cb, prev->thread.ri_cb);          \
  45         restore_gs_cb(next->thread.gs_cb);                              \
  46         prev = __switch_to(prev, next);                                 \
  47 } while (0)
  48
  49 #endif /* __ASM_SWITCH_TO_H */