arch/sh/mm/kmap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * arch/sh/mm/kmap.c
   4  *
   5  * Copyright (C) 1999, 2000, 2002  Niibe Yutaka
   6  * Copyright (C) 2002 - 2009  Paul Mundt
   7  */
   8 #include <linux/mm.h>
   9 #include <linux/init.h>
  10 #include <linux/mutex.h>
  11 #include <linux/fs.h>
  12 #include <linux/highmem.h>
  13 #include <linux/module.h>
  14 #include <asm/mmu_context.h>
  15 #include <asm/cacheflush.h>
  16
  17 static pte_t *kmap_coherent_pte;
  18
  19 void __init kmap_coherent_init(void)
  20 {
  21         unsigned long vaddr;
  22
  23         /* cache the first coherent kmap pte */
  24         vaddr = __fix_to_virt(FIX_CMAP_BEGIN);
  25         kmap_coherent_pte = virt_to_kpte(vaddr);
  26 }
  27
  28 void *kmap_coherent(struct page *page, unsigned long addr)
  29 {
  30         enum fixed_addresses idx;
  31         unsigned long vaddr;
  32
  33         BUG_ON(!test_bit(PG_dcache_clean, &page->flags));
  34
  35         preempt_disable();
  36         pagefault_disable();
  37
  38         idx = FIX_CMAP_END -
  39                 (((addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1)) +
  40                  (FIX_N_COLOURS * smp_processor_id()));
  41
  42         vaddr = __fix_to_virt(idx);
  43
  44         BUG_ON(!pte_none(*(kmap_coherent_pte - idx)));
  45         set_pte(kmap_coherent_pte - idx, mk_pte(page, PAGE_KERNEL));
  46
  47         return (void *)vaddr;
  48 }
  49
  50 void kunmap_coherent(void *kvaddr)
  51 {
  52         if (kvaddr >= (void *)FIXADDR_START) {
  53                 unsigned long vaddr = (unsigned long)kvaddr & PAGE_MASK;
  54                 enum fixed_addresses idx = __virt_to_fix(vaddr);
  55
  56                 /* XXX.. Kill this later, here for sanity at the moment.. */
  57                 __flush_purge_region((void *)vaddr, PAGE_SIZE);
  58
  59                 pte_clear(&init_mm, vaddr, kmap_coherent_pte - idx);
  60                 local_flush_tlb_one(get_asid(), vaddr);
  61         }
  62
  63         pagefault_enable();
  64         preempt_enable();
  65 }