arch/nds32/mm/highmem.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2005-2017 Andes Technology Corporation
   3
   4 #include <linux/export.h>
   5 #include <linux/highmem.h>
   6 #include <linux/sched.h>
   7 #include <linux/smp.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/bootmem.h>
  10 #include <asm/fixmap.h>
  11 #include <asm/tlbflush.h>
  12
  13 void *kmap(struct page *page)
  14 {
  15         unsigned long vaddr;
  16         might_sleep();
  17         if (!PageHighMem(page))
  18                 return page_address(page);
  19         vaddr = (unsigned long)kmap_high(page);
  20         return (void *)vaddr;
  21 }
  22
  23 EXPORT_SYMBOL(kmap);
  24
  25 void kunmap(struct page *page)
  26 {
  27         BUG_ON(in_interrupt());
  28         if (!PageHighMem(page))
  29                 return;
  30         kunmap_high(page);
  31 }
  32
  33 EXPORT_SYMBOL(kunmap);
  34
  35 void *kmap_atomic(struct page *page)
  36 {
  37         unsigned int idx;
  38         unsigned long vaddr, pte;
  39         int type;
  40         pte_t *ptep;
  41
  42         preempt_disable();
  43         pagefault_disable();
  44         if (!PageHighMem(page))
  45                 return page_address(page);
  46
  47         type = kmap_atomic_idx_push();
  48
  49         idx = type + KM_TYPE_NR * smp_processor_id();
  50         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
  51         pte = (page_to_pfn(page) << PAGE_SHIFT) | (PAGE_KERNEL);
  52         ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
  53         set_pte(ptep, pte);
  54
  55         __nds32__tlbop_inv(vaddr);
  56         __nds32__mtsr_dsb(vaddr, NDS32_SR_TLB_VPN);
  57         __nds32__tlbop_rwr(pte);
  58         __nds32__isb();
  59         return (void *)vaddr;
  60 }
  61
  62 EXPORT_SYMBOL(kmap_atomic);
  63
  64 void __kunmap_atomic(void *kvaddr)
  65 {
  66         if (kvaddr >= (void *)FIXADDR_START) {
  67                 unsigned long vaddr = (unsigned long)kvaddr;
  68                 pte_t *ptep;
  69                 kmap_atomic_idx_pop();
  70                 __nds32__tlbop_inv(vaddr);
  71                 __nds32__isb();
  72                 ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
  73                 set_pte(ptep, 0);
  74         }
  75         pagefault_enable();
  76         preempt_enable();
  77 }
  78
  79 EXPORT_SYMBOL(__kunmap_atomic);