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 7 /* 8 * For v7 SMP cores running a preemptible kernel we may be pre-empted 9 * during a TLB maintenance operation, so execute an inner-shareable dsb 10 * to ensure that the maintenance completes in case we migrate to another 11 * CPU. 12 */ 13 #if defined(CONFIG_PREEMPTION) && defined(CONFIG_SMP) && defined(CONFIG_CPU_V7) 14 #define __complete_pending_tlbi() dsb(ish) 15 #else 16 #define __complete_pending_tlbi() 17 #endif 18 19 /* 20 * switch_to(prev, next) should switch from task `prev' to `next' 21 * `prev' will never be the same as `next'. schedule() itself 22 * contains the memory barrier to tell GCC not to cache `current'. 23 */ 24 extern struct task_struct *__switch_to(struct task_struct *, struct thread_info *, struct thread_info *); 25 26 static inline void set_ti_cpu(struct task_struct *p) 27 { 28 #ifdef CONFIG_THREAD_INFO_IN_TASK 29 /* 30 * The core code no longer maintains the thread_info::cpu field once 31 * CONFIG_THREAD_INFO_IN_TASK is in effect, but we rely on it for 32 * raw_smp_processor_id(), which cannot access struct task_struct* 33 * directly for reasons of circular #inclusion hell. 34 */ 35 task_thread_info(p)->cpu = task_cpu(p); 36 #endif 37 } 38 39 #define switch_to(prev,next,last) \ 40 do { \ 41 __complete_pending_tlbi(); \ 42 set_ti_cpu(next); \ 43 if (IS_ENABLED(CONFIG_CURRENT_POINTER_IN_TPIDRURO)) \ 44 __this_cpu_write(__entry_task, next); \ 45 last = __switch_to(prev,task_thread_info(prev), task_thread_info(next)); \ 46 } while (0) 47 48 #endif /* __ASM_ARM_SWITCH_TO_H */ 49