xref: /openbmc/linux/arch/arm/include/asm/switch_to.h (revision 255490f9)
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 */
36