mmu_context.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 *  S390 version
  4 *
  5 *  Derived from "include/asm-i386/mmu_context.h"
  6 */
  7
  8#ifndef __S390_MMU_CONTEXT_H
  9#define __S390_MMU_CONTEXT_H
 10
 11#include <asm/pgalloc.h>
 12#include <linux/uaccess.h>
 13#include <linux/mm_types.h>
 14#include <asm/tlbflush.h>
 15#include <asm/ctlreg.h>
 16#include <asm/asce.h>
 17#include <asm-generic/mm_hooks.h>
 18
 19#define init_new_context init_new_context
 20static inline int init_new_context(struct task_struct *tsk,
 21				   struct mm_struct *mm)
 22{
 23	unsigned long asce_type, init_entry;
 24
 25	spin_lock_init(&mm->context.lock);
 26	INIT_LIST_HEAD(&mm->context.gmap_list);
 27	cpumask_clear(&mm->context.cpu_attach_mask);
 28	atomic_set(&mm->context.flush_count, 0);
 29	atomic_set(&mm->context.protected_count, 0);
 30	mm->context.gmap_asce = 0;
 31	mm->context.flush_mm = 0;
 32#ifdef CONFIG_PGSTE
 33	mm->context.has_pgste = 0;
 34	mm->context.uses_skeys = 0;
 35	mm->context.uses_cmm = 0;
 36	mm->context.allow_cow_sharing = 1;
 37	mm->context.allow_gmap_hpage_1m = 0;
 38#endif
 39	switch (mm->context.asce_limit) {
 40	default:
 41		/*
 42		 * context created by exec, the value of asce_limit can
 43		 * only be zero in this case
 44		 */
 45		VM_BUG_ON(mm->context.asce_limit);
 46		/* continue as 3-level task */
 47		mm->context.asce_limit = _REGION2_SIZE;
 48		fallthrough;
 49	case _REGION2_SIZE:
 50		/* forked 3-level task */
 51		init_entry = _REGION3_ENTRY_EMPTY;
 52		asce_type = _ASCE_TYPE_REGION3;
 53		break;
 54	case TASK_SIZE_MAX:
 55		/* forked 5-level task */
 56		init_entry = _REGION1_ENTRY_EMPTY;
 57		asce_type = _ASCE_TYPE_REGION1;
 58		break;
 59	case _REGION1_SIZE:
 60		/* forked 4-level task */
 61		init_entry = _REGION2_ENTRY_EMPTY;
 62		asce_type = _ASCE_TYPE_REGION2;
 63		break;
 64	}
 65	mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
 66			   _ASCE_USER_BITS | asce_type;
 67	crst_table_init((unsigned long *) mm->pgd, init_entry);
 68	return 0;
 69}
 70
 71static inline void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
 72				      struct task_struct *tsk)
 73{
 74	int cpu = smp_processor_id();
 75
 76	if (next == &init_mm)
 77		get_lowcore()->user_asce = s390_invalid_asce;
 78	else
 79		get_lowcore()->user_asce.val = next->context.asce;
 80	cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
 81	/* Clear previous user-ASCE from CR1 and CR7 */
 82	local_ctl_load(1, &s390_invalid_asce);
 83	local_ctl_load(7, &s390_invalid_asce);
 84	if (prev != next)
 85		cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
 86}
 87#define switch_mm_irqs_off switch_mm_irqs_off
 88
 89static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
 90			     struct task_struct *tsk)
 91{
 92	unsigned long flags;
 93
 94	local_irq_save(flags);
 95	switch_mm_irqs_off(prev, next, tsk);
 96	local_irq_restore(flags);
 97}
 98
 99#define finish_arch_post_lock_switch finish_arch_post_lock_switch
100static inline void finish_arch_post_lock_switch(void)
101{
102	struct task_struct *tsk = current;
103	struct mm_struct *mm = tsk->mm;
104	unsigned long flags;
105
106	if (mm) {
107		preempt_disable();
108		while (atomic_read(&mm->context.flush_count))
109			cpu_relax();
110		cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
111		__tlb_flush_mm_lazy(mm);
112		preempt_enable();
113	}
114	local_irq_save(flags);
115	if (test_thread_flag(TIF_ASCE_PRIMARY))
116		local_ctl_load(1, &get_lowcore()->kernel_asce);
117	else
118		local_ctl_load(1, &get_lowcore()->user_asce);
119	local_ctl_load(7, &get_lowcore()->user_asce);
120	local_irq_restore(flags);
121}
122
123#define activate_mm activate_mm
124static inline void activate_mm(struct mm_struct *prev,
125                               struct mm_struct *next)
126{
127	switch_mm_irqs_off(prev, next, current);
128	cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
129	if (test_thread_flag(TIF_ASCE_PRIMARY))
130		local_ctl_load(1, &get_lowcore()->kernel_asce);
131	else
132		local_ctl_load(1, &get_lowcore()->user_asce);
133	local_ctl_load(7, &get_lowcore()->user_asce);
134}
135
136#include <asm-generic/mmu_context.h>
137
138#endif /* __S390_MMU_CONTEXT_H */