| /* SPDX-License-Identifier: GPL-2.0 */ |
| // |
| // Code shared between 32 and 64 bit |
| |
| #include <asm/spec-ctrl.h> |
| |
| void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p); |
| |
| /* |
| * This needs to be inline to optimize for the common case where no extra |
| * work needs to be done. |
| */ |
| static inline void switch_to_extra(struct task_struct *prev, |
| struct task_struct *next) |
| { |
| unsigned long next_tif = read_task_thread_flags(next); |
| unsigned long prev_tif = read_task_thread_flags(prev); |
| |
| if (IS_ENABLED(CONFIG_SMP)) { |
| /* |
| * Avoid __switch_to_xtra() invocation when conditional |
| * STIBP is disabled and the only different bit is |
| * TIF_SPEC_IB. For CONFIG_SMP=n TIF_SPEC_IB is not |
| * in the TIF_WORK_CTXSW masks. |
| */ |
| if (!static_branch_likely(&switch_to_cond_stibp)) { |
| prev_tif &= ~_TIF_SPEC_IB; |
| next_tif &= ~_TIF_SPEC_IB; |
| } |
| } |
| |
| /* |
| * __switch_to_xtra() handles debug registers, i/o bitmaps, |
| * speculation mitigations etc. |
| */ |
| if (unlikely(next_tif & _TIF_WORK_CTXSW_NEXT || |
| prev_tif & _TIF_WORK_CTXSW_PREV)) |
| __switch_to_xtra(prev, next); |
| } |
