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_flush_tlb(unsigned long addr)
  17 {
  18         flush_tlb_one(addr);
  19 }
  20 EXPORT_SYMBOL(kmap_flush_tlb);
  21
  22 EXPORT_SYMBOL(kmap);
  23
  24 void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
  25 {
  26         unsigned long vaddr;
  27         int idx, type;
  28
  29         type = kmap_atomic_idx_push();
  30         idx = type + KM_TYPE_NR*smp_processor_id();
  31         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
  32 #ifdef CONFIG_DEBUG_HIGHMEM
  33         BUG_ON(!pte_none(*(kmap_pte - idx)));
  34 #endif
  35         set_pte(kmap_pte-idx, mk_pte(page, prot));
  36         flush_tlb_one((unsigned long)vaddr);
  37
  38         return (void *)vaddr;
  39 }
  40 EXPORT_SYMBOL(kmap_atomic_high_prot);
  41
  42 void kunmap_atomic_high(void *kvaddr)
  43 {
  44         unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
  45         int idx;
  46
  47         if (vaddr < FIXADDR_START)
  48                 return;
  49
  50 #ifdef CONFIG_DEBUG_HIGHMEM
  51         idx = KM_TYPE_NR*smp_processor_id() + kmap_atomic_idx();
  52
  53         BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
  54
  55         pte_clear(&init_mm, vaddr, kmap_pte - idx);
  56         flush_tlb_one(vaddr);
  57 #else
  58         (void) idx; /* to kill a warning */
  59 #endif
  60         kmap_atomic_idx_pop();
  61 }
  62 EXPORT_SYMBOL(kunmap_atomic_high);
  63
  64 /*
  65  * This is the same as kmap_atomic() but can map memory that doesn't
  66  * have a struct page associated with it.
  67  */
  68 void *kmap_atomic_pfn(unsigned long pfn)
  69 {
  70         unsigned long vaddr;
  71         int idx, type;
  72
  73         pagefault_disable();
  74
  75         type = kmap_atomic_idx_push();
  76         idx = type + KM_TYPE_NR*smp_processor_id();
  77         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
  78         set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
  79         flush_tlb_one(vaddr);
  80
  81         return (void *) vaddr;
  82 }
  83
  84 static void __init kmap_pages_init(void)
  85 {
  86         unsigned long vaddr;
  87         pgd_t *pgd;
  88         pmd_t *pmd;
  89         pud_t *pud;
  90         pte_t *pte;
  91
  92         vaddr = PKMAP_BASE;
  93         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
  94
  95         pgd = swapper_pg_dir + pgd_index(vaddr);
  96         pud = (pud_t *)pgd;
  97         pmd = pmd_offset(pud, vaddr);
  98         pte = pte_offset_kernel(pmd, vaddr);
  99         pkmap_page_table = pte;
 100 }
 101
 102 void __init kmap_init(void)
 103 {
 104         unsigned long vaddr;
 105
 106         kmap_pages_init();
 107
 108         vaddr = __fix_to_virt(FIX_KMAP_BEGIN);
 109
 110         kmap_pte = pte_offset_kernel((pmd_t *)pgd_offset_k(vaddr), vaddr);
 111 }