arch/parisc/include/asm/tlbflush.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _PARISC_TLBFLUSH_H
   3 #define _PARISC_TLBFLUSH_H
   4
   5 /* TLB flushing routines.... */
   6
   7 #include <linux/mm.h>
   8 #include <linux/sched.h>
   9 #include <asm/mmu_context.h>
  10
  11
  12 /* This is for the serialisation of PxTLB broadcasts.  At least on the
  13  * N class systems, only one PxTLB inter processor broadcast can be
  14  * active at any one time on the Merced bus.  This tlb purge
  15  * synchronisation is fairly lightweight and harmless so we activate
  16  * it on all systems not just the N class.
  17
  18  * It is also used to ensure PTE updates are atomic and consistent
  19  * with the TLB.
  20  */
  21 extern spinlock_t pa_tlb_lock;
  22
  23 #define purge_tlb_start(flags)  spin_lock_irqsave(&pa_tlb_lock, flags)
  24 #define purge_tlb_end(flags)    spin_unlock_irqrestore(&pa_tlb_lock, flags)
  25
  26 extern void flush_tlb_all(void);
  27 extern void flush_tlb_all_local(void *);
  28
  29 #define smp_flush_tlb_all()     flush_tlb_all()
  30
  31 int __flush_tlb_range(unsigned long sid,
  32         unsigned long start, unsigned long end);
  33
  34 #define flush_tlb_range(vma, start, end) \
  35         __flush_tlb_range((vma)->vm_mm->context, start, end)
  36
  37 #define flush_tlb_kernel_range(start, end) \
  38         __flush_tlb_range(0, start, end)
  39
  40 /*
  41  * flush_tlb_mm()
  42  *
  43  * The code to switch to a new context is NOT valid for processes
  44  * which play with the space id's.  Thus, we have to preserve the
  45  * space and just flush the entire tlb.  However, the compilers,
  46  * dynamic linker, etc, do not manipulate space id's, so there
  47  * could be a significant performance benefit in switching contexts
  48  * and not flushing the whole tlb.
  49  */
  50
  51 static inline void flush_tlb_mm(struct mm_struct *mm)
  52 {
  53         BUG_ON(mm == &init_mm); /* Should never happen */
  54
  55 #if 1 || defined(CONFIG_SMP)
  56         /* Except for very small threads, flushing the whole TLB is
  57          * faster than using __flush_tlb_range.  The pdtlb and pitlb
  58          * instructions are very slow because of the TLB broadcast.
  59          * It might be faster to do local range flushes on all CPUs
  60          * on PA 2.0 systems.
  61          */
  62         flush_tlb_all();
  63 #else
  64         /* FIXME: currently broken, causing space id and protection ids
  65          * to go out of sync, resulting in faults on userspace accesses.
  66          * This approach needs further investigation since running many
  67          * small applications (e.g., GCC testsuite) is faster on HP-UX.
  68          */
  69         if (mm) {
  70                 if (mm->context != 0)
  71                         free_sid(mm->context);
  72                 mm->context = alloc_sid();
  73                 if (mm == current->active_mm)
  74                         load_context(mm->context);
  75         }
  76 #endif
  77 }
  78
  79 static inline void flush_tlb_page(struct vm_area_struct *vma,
  80         unsigned long addr)
  81 {
  82         unsigned long flags, sid;
  83
  84         sid = vma->vm_mm->context;
  85         purge_tlb_start(flags);
  86         mtsp(sid, 1);
  87         pdtlb(addr);
  88         if (unlikely(split_tlb))
  89                 pitlb(addr);
  90         purge_tlb_end(flags);
  91 }
  92 #endif