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d08d4e7cd6
Cease using 4KB pages to host two 2KB PTEs. That greatly
simplifies the memory management code at the expense of
page tables memory footprint.
Instead of two PTEs per 4KB page use only upper half of
the parent page for a single PTE. With that the list of
half-used pages pgtable_list becomes unneeded.
Further, the upper byte of the parent page _refcount
counter does not need to be used for fragments tracking
and could be left alone.
Commit 8211dad627 ("s390: add pte_free_defer() for
pgtables sharing page") introduced the use of PageActive
flag to coordinate a deferred free with 2KB page table
fragments tracking. Since there is no tracking anymore,
there is no need for using PageActive flag.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
128 lines
3.4 KiB
C
128 lines
3.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* S390 version
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*
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* Derived from "include/asm-i386/mmu_context.h"
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*/
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#ifndef __S390_MMU_CONTEXT_H
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#define __S390_MMU_CONTEXT_H
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#include <asm/pgalloc.h>
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#include <linux/uaccess.h>
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#include <linux/mm_types.h>
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#include <asm/tlbflush.h>
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#include <asm/ctlreg.h>
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#include <asm-generic/mm_hooks.h>
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#define init_new_context init_new_context
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static inline int init_new_context(struct task_struct *tsk,
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struct mm_struct *mm)
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{
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unsigned long asce_type, init_entry;
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spin_lock_init(&mm->context.lock);
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INIT_LIST_HEAD(&mm->context.gmap_list);
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cpumask_clear(&mm->context.cpu_attach_mask);
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atomic_set(&mm->context.flush_count, 0);
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atomic_set(&mm->context.protected_count, 0);
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mm->context.gmap_asce = 0;
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mm->context.flush_mm = 0;
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#ifdef CONFIG_PGSTE
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mm->context.alloc_pgste = page_table_allocate_pgste ||
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test_thread_flag(TIF_PGSTE) ||
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(current->mm && current->mm->context.alloc_pgste);
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mm->context.has_pgste = 0;
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mm->context.uses_skeys = 0;
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mm->context.uses_cmm = 0;
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mm->context.allow_gmap_hpage_1m = 0;
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#endif
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switch (mm->context.asce_limit) {
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default:
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/*
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* context created by exec, the value of asce_limit can
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* only be zero in this case
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*/
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VM_BUG_ON(mm->context.asce_limit);
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/* continue as 3-level task */
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mm->context.asce_limit = _REGION2_SIZE;
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fallthrough;
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case _REGION2_SIZE:
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/* forked 3-level task */
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init_entry = _REGION3_ENTRY_EMPTY;
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asce_type = _ASCE_TYPE_REGION3;
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break;
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case TASK_SIZE_MAX:
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/* forked 5-level task */
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init_entry = _REGION1_ENTRY_EMPTY;
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asce_type = _ASCE_TYPE_REGION1;
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break;
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case _REGION1_SIZE:
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/* forked 4-level task */
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init_entry = _REGION2_ENTRY_EMPTY;
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asce_type = _ASCE_TYPE_REGION2;
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break;
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}
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mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
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_ASCE_USER_BITS | asce_type;
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crst_table_init((unsigned long *) mm->pgd, init_entry);
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return 0;
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}
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static inline void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
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struct task_struct *tsk)
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{
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int cpu = smp_processor_id();
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if (next == &init_mm)
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S390_lowcore.user_asce = s390_invalid_asce;
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else
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S390_lowcore.user_asce.val = next->context.asce;
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cpumask_set_cpu(cpu, &next->context.cpu_attach_mask);
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/* Clear previous user-ASCE from CR7 */
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local_ctl_load(7, &s390_invalid_asce);
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if (prev != next)
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cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask);
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}
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#define switch_mm_irqs_off switch_mm_irqs_off
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static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
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struct task_struct *tsk)
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{
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unsigned long flags;
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local_irq_save(flags);
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switch_mm_irqs_off(prev, next, tsk);
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local_irq_restore(flags);
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}
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#define finish_arch_post_lock_switch finish_arch_post_lock_switch
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static inline void finish_arch_post_lock_switch(void)
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{
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struct task_struct *tsk = current;
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struct mm_struct *mm = tsk->mm;
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if (mm) {
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preempt_disable();
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while (atomic_read(&mm->context.flush_count))
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cpu_relax();
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cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
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__tlb_flush_mm_lazy(mm);
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preempt_enable();
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}
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local_ctl_load(7, &S390_lowcore.user_asce);
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}
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#define activate_mm activate_mm
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static inline void activate_mm(struct mm_struct *prev,
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struct mm_struct *next)
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{
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switch_mm(prev, next, current);
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cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
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local_ctl_load(7, &S390_lowcore.user_asce);
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}
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#include <asm-generic/mmu_context.h>
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#endif /* __S390_MMU_CONTEXT_H */
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