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/* 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_CPU_HAS_ASID
void check_and_switch_context(struct mm_struct *mm, struct task_struct *tsk);
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)
{
if (unlikely(mm->context.vmalloc_seq != init_mm.context.vmalloc_seq))
__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 */
static inline int
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
return 0;
}
#endif /* CONFIG_CPU_HAS_ASID */
#define destroy_context(mm) do { } while(0)
#define activate_mm(prev,next) switch_mm(prev, next, NULL)
/*
* This is called when "tsk" is about to enter lazy TLB mode.
*
* mm: describes the currently active mm context
* tsk: task which is entering lazy tlb
* cpu: cpu number which is entering lazy tlb
*
* tsk->mm will be NULL
*/
static inline void
enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
{
}
/*
* 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
}
#define deactivate_mm(tsk,mm) do { } while (0)
#endif
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