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         struct folio *folio = page_folio(page);
  31         enum fixed_addresses idx;
  32         unsigned long vaddr;
  33
  34         BUG_ON(!test_bit(PG_dcache_clean, &folio->flags));
  35
  36         preempt_disable();
  37         pagefault_disable();
  38
  39         idx = FIX_CMAP_END -
  40                 (((addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1)) +
  41                  (FIX_N_COLOURS * smp_processor_id()));
  42
  43         vaddr = __fix_to_virt(idx);
  44
  45         BUG_ON(!pte_none(*(kmap_coherent_pte - idx)));
  46         set_pte(kmap_coherent_pte - idx, mk_pte(page, PAGE_KERNEL));
  47
  48         return (void *)vaddr;
  49 }
  50
  51 void kunmap_coherent(void *kvaddr)
  52 {
  53         if (kvaddr >= (void *)FIXADDR_START) {
  54                 unsigned long vaddr = (unsigned long)kvaddr & PAGE_MASK;
  55                 enum fixed_addresses idx = __virt_to_fix(vaddr);
  56
  57                 /* XXX.. Kill this later, here for sanity at the moment.. */
  58                 __flush_purge_region((void *)vaddr, PAGE_SIZE);
  59
  60                 pte_clear(&init_mm, vaddr, kmap_coherent_pte - idx);
  61                 local_flush_tlb_one(get_asid(), vaddr);
  62         }
  63
  64         pagefault_enable();
  65         preempt_enable();
  66 }