1 /* SPDX-License-Identifier: GPL-2.0 */ 2 // 3 // Code shared between 32 and 64 bit 4 5 #include <asm/spec-ctrl.h> 6 7 void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p); 8 9 /* 10 * This needs to be inline to optimize for the common case where no extra 11 * work needs to be done. 12 */ 13 static inline void switch_to_extra(struct task_struct *prev, 14 struct task_struct *next) 15 { 16 unsigned long next_tif = read_task_thread_flags(next); 17 unsigned long prev_tif = read_task_thread_flags(prev); 18 19 if (IS_ENABLED(CONFIG_SMP)) { 20 /* 21 * Avoid __switch_to_xtra() invocation when conditional 22 * STIBP is disabled and the only different bit is 23 * TIF_SPEC_IB. For CONFIG_SMP=n TIF_SPEC_IB is not 24 * in the TIF_WORK_CTXSW masks. 25 */ 26 if (!static_branch_likely(&switch_to_cond_stibp)) { 27 prev_tif &= ~_TIF_SPEC_IB; 28 next_tif &= ~_TIF_SPEC_IB; 29 } 30 } 31 32 /* 33 * __switch_to_xtra() handles debug registers, i/o bitmaps, 34 * speculation mitigations etc. 35 */ 36 if (unlikely(next_tif & _TIF_WORK_CTXSW_NEXT || 37 prev_tif & _TIF_WORK_CTXSW_PREV)) 38 __switch_to_xtra(prev, next); 39 } 40