root/arch/powerpc/mm/book3s32/tlb.c

DEFINITIONS

1. flush_hash_entry
2. tlb_flush
3. flush_range
4. flush_tlb_kernel_range
5. flush_tlb_mm
6. flush_tlb_page
7. flush_tlb_range
8. early_init_mmu

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * This file contains the routines for TLB flushing.
   4  * On machines where the MMU uses a hash table to store virtual to
   5  * physical translations, these routines flush entries from the
   6  * hash table also.
   7  *  -- paulus
   8  *
   9  *  Derived from arch/ppc/mm/init.c:
  10  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  11  *
  12  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
  13  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  14  *    Copyright (C) 1996 Paul Mackerras
  15  *
  16  *  Derived from "arch/i386/mm/init.c"
  17  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  18  */
  19 
  20 #include <linux/kernel.h>
  21 #include <linux/mm.h>
  22 #include <linux/init.h>
  23 #include <linux/highmem.h>
  24 #include <linux/pagemap.h>
  25 #include <linux/export.h>
  26 
  27 #include <asm/tlbflush.h>
  28 #include <asm/tlb.h>
  29 
  30 #include <mm/mmu_decl.h>
  31 
  32 /*
  33  * Called when unmapping pages to flush entries from the TLB/hash table.
  34  */
  35 void flush_hash_entry(struct mm_struct *mm, pte_t *ptep, unsigned long addr)
  36 {
  37         unsigned long ptephys;
  38 
  39         if (Hash) {
  40                 ptephys = __pa(ptep) & PAGE_MASK;
  41                 flush_hash_pages(mm->context.id, addr, ptephys, 1);
  42         }
  43 }
  44 EXPORT_SYMBOL(flush_hash_entry);
  45 
  46 /*
  47  * Called at the end of a mmu_gather operation to make sure the
  48  * TLB flush is completely done.
  49  */
  50 void tlb_flush(struct mmu_gather *tlb)
  51 {
  52         if (!Hash) {
  53                 /*
  54                  * 603 needs to flush the whole TLB here since
  55                  * it doesn't use a hash table.
  56                  */
  57                 _tlbia();
  58         }
  59 }
  60 
  61 /*
  62  * TLB flushing:
  63  *
  64  *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
  65  *  - flush_tlb_page(vma, vmaddr) flushes one page
  66  *  - flush_tlb_range(vma, start, end) flushes a range of pages
  67  *  - flush_tlb_kernel_range(start, end) flushes kernel pages
  68  *
  69  * since the hardware hash table functions as an extension of the
  70  * tlb as far as the linux tables are concerned, flush it too.
  71  *    -- Cort
  72  */
  73 
  74 static void flush_range(struct mm_struct *mm, unsigned long start,
  75                         unsigned long end)
  76 {
  77         pmd_t *pmd;
  78         unsigned long pmd_end;
  79         int count;
  80         unsigned int ctx = mm->context.id;
  81 
  82         if (!Hash) {
  83                 _tlbia();
  84                 return;
  85         }
  86         start &= PAGE_MASK;
  87         if (start >= end)
  88                 return;
  89         end = (end - 1) | ~PAGE_MASK;
  90         pmd = pmd_offset(pud_offset(pgd_offset(mm, start), start), start);
  91         for (;;) {
  92                 pmd_end = ((start + PGDIR_SIZE) & PGDIR_MASK) - 1;
  93                 if (pmd_end > end)
  94                         pmd_end = end;
  95                 if (!pmd_none(*pmd)) {
  96                         count = ((pmd_end - start) >> PAGE_SHIFT) + 1;
  97                         flush_hash_pages(ctx, start, pmd_val(*pmd), count);
  98                 }
  99                 if (pmd_end == end)
 100                         break;
 101                 start = pmd_end + 1;
 102                 ++pmd;
 103         }
 104 }
 105 
 106 /*
 107  * Flush kernel TLB entries in the given range
 108  */
 109 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 110 {
 111         flush_range(&init_mm, start, end);
 112 }
 113 EXPORT_SYMBOL(flush_tlb_kernel_range);
 114 
 115 /*
 116  * Flush all the (user) entries for the address space described by mm.
 117  */
 118 void flush_tlb_mm(struct mm_struct *mm)
 119 {
 120         struct vm_area_struct *mp;
 121 
 122         if (!Hash) {
 123                 _tlbia();
 124                 return;
 125         }
 126 
 127         /*
 128          * It is safe to go down the mm's list of vmas when called
 129          * from dup_mmap, holding mmap_sem.  It would also be safe from
 130          * unmap_region or exit_mmap, but not from vmtruncate on SMP -
 131          * but it seems dup_mmap is the only SMP case which gets here.
 132          */
 133         for (mp = mm->mmap; mp != NULL; mp = mp->vm_next)
 134                 flush_range(mp->vm_mm, mp->vm_start, mp->vm_end);
 135 }
 136 EXPORT_SYMBOL(flush_tlb_mm);
 137 
 138 void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
 139 {
 140         struct mm_struct *mm;
 141         pmd_t *pmd;
 142 
 143         if (!Hash) {
 144                 _tlbie(vmaddr);
 145                 return;
 146         }
 147         mm = (vmaddr < TASK_SIZE)? vma->vm_mm: &init_mm;
 148         pmd = pmd_offset(pud_offset(pgd_offset(mm, vmaddr), vmaddr), vmaddr);
 149         if (!pmd_none(*pmd))
 150                 flush_hash_pages(mm->context.id, vmaddr, pmd_val(*pmd), 1);
 151 }
 152 EXPORT_SYMBOL(flush_tlb_page);
 153 
 154 /*
 155  * For each address in the range, find the pte for the address
 156  * and check _PAGE_HASHPTE bit; if it is set, find and destroy
 157  * the corresponding HPTE.
 158  */
 159 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 160                      unsigned long end)
 161 {
 162         flush_range(vma->vm_mm, start, end);
 163 }
 164 EXPORT_SYMBOL(flush_tlb_range);
 165 
 166 void __init early_init_mmu(void)
 167 {
 168 }