LXR linux/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
  12static pte_t *kmap_pte;
  13
  14unsigned long highstart_pfn, highend_pfn;
  15
  16void *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}
  28EXPORT_SYMBOL(kmap);
  29
  30void kunmap(struct page *page)
  31{
  32        BUG_ON(in_interrupt());
  33        if (!PageHighMem(page))
  34                return;
  35        kunmap_high(page);
  36}
  37EXPORT_SYMBOL(kunmap);
  38
  39void *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}
  60EXPORT_SYMBOL(kmap_atomic);
  61
  62void __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();
  81out:
  82        pagefault_enable();
  83        preempt_enable();
  84}
  85EXPORT_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 */
  91void *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
 107struct 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
 120static 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
 138void __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}
 148