/* 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);
}