arch/csky/mm/highmem.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
   3
   4 #include <linux/module.h>
   5 #include <linux/highmem.h>
   6 #include <linux/smp.h>
   7 #include <linux/memblock.h>
   8 #include <asm/fixmap.h>
   9 #include <asm/tlbflush.h>
  10 #include <asm/cacheflush.h>
  11
  12 static pte_t *kmap_pte;
  13
  14 unsigned long highstart_pfn, highend_pfn;
  15
  16 void *kmap(struct page *page)
  17 {
  18         void *addr;
  19
  20         might_sleep();
  21         if (!PageHighMem(page))
  22                 return page_address(page);
  23         addr = kmap_high(page);
  24         flush_tlb_one((unsigned long)addr);
  25
  26         return addr;
  27 }
  28 EXPORT_SYMBOL(kmap);
  29
  30 void kunmap(struct page *page)
  31 {
  32         BUG_ON(in_interrupt());
  33         if (!PageHighMem(page))
  34                 return;
  35         kunmap_high(page);
  36 }
  37 EXPORT_SYMBOL(kunmap);
  38
  39 void *kmap_atomic(struct page *page)
  40 {
  41         unsigned long vaddr;
  42         int idx, type;
  43
  44         preempt_disable();
  45         pagefault_disable();
  46         if (!PageHighMem(page))
  47                 return page_address(page);
  48
  49         type = kmap_atomic_idx_push();
  50         idx = type + KM_TYPE_NR*smp_processor_id();
  51         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
  52 #ifdef CONFIG_DEBUG_HIGHMEM
  53         BUG_ON(!pte_none(*(kmap_pte - idx)));
  54 #endif
  55         set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL));
  56         flush_tlb_one((unsigned long)vaddr);
  57
  58         return (void *)vaddr;
  59 }
  60 EXPORT_SYMBOL(kmap_atomic);
  61
  62 void __kunmap_atomic(void *kvaddr)
  63 {
  64         unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
  65         int idx;
  66
  67         if (vaddr < FIXADDR_START)
  68                 goto out;
  69
  70 #ifdef CONFIG_DEBUG_HIGHMEM
  71         idx = KM_TYPE_NR*smp_processor_id() + kmap_atomic_idx();
  72
  73         BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
  74
  75         pte_clear(&init_mm, vaddr, kmap_pte - idx);
  76         flush_tlb_one(vaddr);
  77 #else
  78         (void) idx; /* to kill a warning */
  79 #endif
  80         kmap_atomic_idx_pop();
  81 out:
  82         pagefault_enable();
  83         preempt_enable();
  84 }
  85 EXPORT_SYMBOL(__kunmap_atomic);
  86
  87 /*
  88  * This is the same as kmap_atomic() but can map memory that doesn't
  89  * have a struct page associated with it.
  90  */
  91 void *kmap_atomic_pfn(unsigned long pfn)
  92 {
  93         unsigned long vaddr;
  94         int idx, type;
  95
  96         pagefault_disable();
  97
  98         type = kmap_atomic_idx_push();
  99         idx = type + KM_TYPE_NR*smp_processor_id();
 100         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 101         set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
 102         flush_tlb_one(vaddr);
 103
 104         return (void *) vaddr;
 105 }
 106
 107 struct page *kmap_atomic_to_page(void *ptr)
 108 {
 109         unsigned long idx, vaddr = (unsigned long)ptr;
 110         pte_t *pte;
 111
 112         if (vaddr < FIXADDR_START)
 113                 return virt_to_page(ptr);
 114
 115         idx = virt_to_fix(vaddr);
 116         pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
 117         return pte_page(*pte);
 118 }
 119
 120 static void __init kmap_pages_init(void)
 121 {
 122         unsigned long vaddr;
 123         pgd_t *pgd;
 124         pmd_t *pmd;
 125         pud_t *pud;
 126         pte_t *pte;
 127
 128         vaddr = PKMAP_BASE;
 129         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 130
 131         pgd = swapper_pg_dir + __pgd_offset(vaddr);
 132         pud = (pud_t *)pgd;
 133         pmd = pmd_offset(pud, vaddr);
 134         pte = pte_offset_kernel(pmd, vaddr);
 135         pkmap_page_table = pte;
 136 }
 137
 138 void __init kmap_init(void)
 139 {
 140         unsigned long vaddr;
 141
 142         kmap_pages_init();
 143
 144         vaddr = __fix_to_virt(FIX_KMAP_BEGIN);
 145
 146         kmap_pte = pte_offset_kernel((pmd_t *)pgd_offset_k(vaddr), vaddr);
 147 }