050eef364a
The tlb flushing code uses the mm_users field of the mm_struct to decide if each page table entry needs to be flushed individually with IPTE or if a global flush for the mm_struct is sufficient after all page table updates have been done. The comment for mm_users says "How many users with user space?" but the /proc code increases mm_users after it found the process structure by pid without creating a new user process. Which makes mm_users useless for the decision between the two tlb flusing methods. The current code can be confused to not flush tlb entries by a concurrent access to /proc files if e.g. a fork is in progres. The solution for this problem is to make the tlb flushing logic independent from the mm_users field. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
99 lines
2.9 KiB
C
99 lines
2.9 KiB
C
/*
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* include/asm-s390/mmu_context.h
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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 <asm/uaccess.h>
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#include <asm/tlbflush.h>
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#include <asm-generic/mm_hooks.h>
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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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atomic_set(&mm->context.attach_count, 0);
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mm->context.flush_mm = 0;
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mm->context.asce_bits = _ASCE_TABLE_LENGTH | _ASCE_USER_BITS;
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#ifdef CONFIG_64BIT
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mm->context.asce_bits |= _ASCE_TYPE_REGION3;
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#endif
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if (current->mm->context.alloc_pgste) {
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/*
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* alloc_pgste indicates, that any NEW context will be created
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* with extended page tables. The old context is unchanged. The
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* page table allocation and the page table operations will
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* look at has_pgste to distinguish normal and extended page
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* tables. The only way to create extended page tables is to
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* set alloc_pgste and then create a new context (e.g. dup_mm).
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* The page table allocation is called after init_new_context
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* and if has_pgste is set, it will create extended page
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* tables.
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*/
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mm->context.noexec = 0;
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mm->context.has_pgste = 1;
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mm->context.alloc_pgste = 1;
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} else {
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mm->context.noexec = (user_mode == SECONDARY_SPACE_MODE);
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mm->context.has_pgste = 0;
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mm->context.alloc_pgste = 0;
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}
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mm->context.asce_limit = STACK_TOP_MAX;
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crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
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return 0;
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}
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#define destroy_context(mm) do { } while (0)
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#ifndef __s390x__
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#define LCTL_OPCODE "lctl"
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#else
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#define LCTL_OPCODE "lctlg"
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#endif
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static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
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{
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pgd_t *pgd = mm->pgd;
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S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
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if (user_mode != HOME_SPACE_MODE) {
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/* Load primary space page table origin. */
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pgd = mm->context.noexec ? get_shadow_table(pgd) : pgd;
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S390_lowcore.user_exec_asce = mm->context.asce_bits | __pa(pgd);
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asm volatile(LCTL_OPCODE" 1,1,%0\n"
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: : "m" (S390_lowcore.user_exec_asce) );
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} else
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/* Load home space page table origin. */
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asm volatile(LCTL_OPCODE" 13,13,%0"
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: : "m" (S390_lowcore.user_asce) );
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set_fs(current->thread.mm_segment);
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}
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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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cpumask_set_cpu(smp_processor_id(), mm_cpumask(next));
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update_mm(next, tsk);
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atomic_dec(&prev->context.attach_count);
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WARN_ON(atomic_read(&prev->context.attach_count) < 0);
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atomic_inc(&next->context.attach_count);
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/* Check for TLBs not flushed yet */
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if (next->context.flush_mm)
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__tlb_flush_mm(next);
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}
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#define enter_lazy_tlb(mm,tsk) do { } while (0)
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#define deactivate_mm(tsk,mm) do { } while (0)
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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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}
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#endif /* __S390_MMU_CONTEXT_H */
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