arch/arm/include/asm/switch_to.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_ARM_SWITCH_TO_H
   3 #define __ASM_ARM_SWITCH_TO_H
   4
   5 #include <linux/thread_info.h>
   6 #include <asm/smp_plat.h>
   7
   8 /*
   9  * For v7 SMP cores running a preemptible kernel we may be pre-empted
  10  * during a TLB maintenance operation, so execute an inner-shareable dsb
  11  * to ensure that the maintenance completes in case we migrate to another
  12  * CPU.
  13  */
  14 #if defined(CONFIG_PREEMPTION) && defined(CONFIG_SMP) && defined(CONFIG_CPU_V7)
  15 #define __complete_pending_tlbi()       dsb(ish)
  16 #else
  17 #define __complete_pending_tlbi()
  18 #endif
  19
  20 /*
  21  * switch_to(prev, next) should switch from task `prev' to `next'
  22  * `prev' will never be the same as `next'.  schedule() itself
  23  * contains the memory barrier to tell GCC not to cache `current'.
  24  */
  25 extern struct task_struct *__switch_to(struct task_struct *, struct thread_info *, struct thread_info *);
  26
  27 #define switch_to(prev,next,last)                                       \
  28 do {                                                                    \
  29         __complete_pending_tlbi();                                      \
  30         if (IS_ENABLED(CONFIG_CURRENT_POINTER_IN_TPIDRURO) || is_smp()) \
  31                 __this_cpu_write(__entry_task, next);                   \
  32         last = __switch_to(prev,task_thread_info(prev), task_thread_info(next));        \
  33 } while (0)
  34
  35 #endif /* __ASM_ARM_SWITCH_TO_H */