/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *  arch/arm/include/asm/mmu_context.h
 *
 *  Copyright (C) 1996 Russell King.
 *
 *  Changelog:
 *   27-06-1996 RMK     Created
 */
#ifndef __ASM_ARM_MMU_CONTEXT_H
#define __ASM_ARM_MMU_CONTEXT_H

#include <linux/compiler.h>
#include <linux/sched.h>
#include <linux/mm_types.h>
#include <linux/preempt.h>

#include <asm/cacheflush.h>
#include <asm/cachetype.h>
#include <asm/proc-fns.h>
#include <asm/smp_plat.h>
#include <asm-generic/mm_hooks.h>

void __check_vmalloc_seq(struct mm_struct *mm);

#ifdef CONFIG_MMU
static inline void check_vmalloc_seq(struct mm_struct *mm)
{
        if (!IS_ENABLED(CONFIG_ARM_LPAE) &&
            unlikely(atomic_read(&mm->context.vmalloc_seq) !=
                     atomic_read(&init_mm.context.vmalloc_seq)))
                __check_vmalloc_seq(mm);
}
#endif

#ifdef CONFIG_CPU_HAS_ASID

void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk);

#define init_new_context init_new_context
static inline int
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
        atomic64_set(&mm->context.id, 0);
        return 0;
}

#ifdef CONFIG_ARM_ERRATA_798181
void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
                             cpumask_t *mask);
#else  /* !CONFIG_ARM_ERRATA_798181 */
static inline void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm,
                                           cpumask_t *mask)
{
}
#endif /* CONFIG_ARM_ERRATA_798181 */

#else   /* !CONFIG_CPU_HAS_ASID */

#ifdef CONFIG_MMU

static inline void check_and_switch_context(struct mm_struct *mm,
                                            struct task_struct *tsk)
{
        check_vmalloc_seq(mm);

        if (irqs_disabled())
                /*
                 * cpu_switch_mm() needs to flush the VIVT caches. To avoid
                 * high interrupt latencies, defer the call and continue
                 * running with the old mm. Since we only support UP systems
                 * on non-ASID CPUs, the old mm will remain valid until the
                 * finish_arch_post_lock_switch() call.
                 */
                mm->context.switch_pending = 1;
        else
                cpu_switch_mm(mm->pgd, mm);
}

#ifndef MODULE
#define finish_arch_post_lock_switch \
        finish_arch_post_lock_switch
static inline void finish_arch_post_lock_switch(void)
{
        struct mm_struct *mm = current->mm;

        if (mm && mm->context.switch_pending) {
                /*
                 * Preemption must be disabled during cpu_switch_mm() as we
                 * have some stateful cache flush implementations. Check
                 * switch_pending again in case we were preempted and the
                 * switch to this mm was already done.
                 */
                preempt_disable();
                if (mm->context.switch_pending) {
                        mm->context.switch_pending = 0;
                        cpu_switch_mm(mm->pgd, mm);
                }
                preempt_enable_no_resched();
        }
}
#endif /* !MODULE */

#endif  /* CONFIG_MMU */

#endif  /* CONFIG_CPU_HAS_ASID */

#define activate_mm(prev,next)          switch_mm(prev, next, NULL)

/*
 * This is the actual mm switch as far as the scheduler
 * is concerned.  No registers are touched.  We avoid
 * calling the CPU specific function when the mm hasn't
 * actually changed.
 */
static inline void
switch_mm(struct mm_struct *prev, struct mm_struct *next,
          struct task_struct *tsk)
{
#ifdef CONFIG_MMU
        unsigned int cpu = smp_processor_id();

        /*
         * __sync_icache_dcache doesn't broadcast the I-cache invalidation,
         * so check for possible thread migration and invalidate the I-cache
         * if we're new to this CPU.
         */
        if (cache_ops_need_broadcast() &&
            !cpumask_empty(mm_cpumask(next)) &&
            !cpumask_test_cpu(cpu, mm_cpumask(next)))
                __flush_icache_all();

        if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
                check_and_switch_context(next, tsk);
                if (cache_is_vivt())
                        cpumask_clear_cpu(cpu, mm_cpumask(prev));
        }
#endif
}

#ifdef CONFIG_VMAP_STACK
static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
{
        if (mm != &init_mm)
                check_vmalloc_seq(mm);
}
#define enter_lazy_tlb enter_lazy_tlb
#endif

#include <asm-generic/mmu_context.h>

#endif