LXR linux/arch/arm/mm/highmem.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * arch/arm/mm/highmem.c -- ARM highmem support
   4 *
   5 * Author:      Nicolas Pitre
   6 * Created:     september 8, 2008
   7 * Copyright:   Marvell Semiconductors Inc.
   8 */
   9
  10#include <linux/module.h>
  11#include <linux/highmem.h>
  12#include <linux/interrupt.h>
  13#include <asm/fixmap.h>
  14#include <asm/cacheflush.h>
  15#include <asm/tlbflush.h>
  16#include "mm.h"
  17
  18static inline void set_fixmap_pte(int idx, pte_t pte)
  19{
  20        unsigned long vaddr = __fix_to_virt(idx);
  21        pte_t *ptep = virt_to_kpte(vaddr);
  22
  23        set_pte_ext(ptep, pte, 0);
  24        local_flush_tlb_kernel_page(vaddr);
  25}
  26
  27static inline pte_t get_fixmap_pte(unsigned long vaddr)
  28{
  29        pte_t *ptep = virt_to_kpte(vaddr);
  30
  31        return *ptep;
  32}
  33
  34void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
  35{
  36        unsigned int idx;
  37        unsigned long vaddr;
  38        void *kmap;
  39        int type;
  40
  41#ifdef CONFIG_DEBUG_HIGHMEM
  42        /*
  43         * There is no cache coherency issue when non VIVT, so force the
  44         * dedicated kmap usage for better debugging purposes in that case.
  45         */
  46        if (!cache_is_vivt())
  47                kmap = NULL;
  48        else
  49#endif
  50                kmap = kmap_high_get(page);
  51        if (kmap)
  52                return kmap;
  53
  54        type = kmap_atomic_idx_push();
  55
  56        idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
  57        vaddr = __fix_to_virt(idx);
  58#ifdef CONFIG_DEBUG_HIGHMEM
  59        /*
  60         * With debugging enabled, kunmap_atomic forces that entry to 0.
  61         * Make sure it was indeed properly unmapped.
  62         */
  63        BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
  64#endif
  65        /*
  66         * When debugging is off, kunmap_atomic leaves the previous mapping
  67         * in place, so the contained TLB flush ensures the TLB is updated
  68         * with the new mapping.
  69         */
  70        set_fixmap_pte(idx, mk_pte(page, prot));
  71
  72        return (void *)vaddr;
  73}
  74EXPORT_SYMBOL(kmap_atomic_high_prot);
  75
  76void kunmap_atomic_high(void *kvaddr)
  77{
  78        unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
  79        int idx, type;
  80
  81        if (kvaddr >= (void *)FIXADDR_START) {
  82                type = kmap_atomic_idx();
  83                idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
  84
  85                if (cache_is_vivt())
  86                        __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
  87#ifdef CONFIG_DEBUG_HIGHMEM
  88                BUG_ON(vaddr != __fix_to_virt(idx));
  89                set_fixmap_pte(idx, __pte(0));
  90#else
  91                (void) idx;  /* to kill a warning */
  92#endif
  93                kmap_atomic_idx_pop();
  94        } else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
  95                /* this address was obtained through kmap_high_get() */
  96                kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
  97        }
  98}
  99EXPORT_SYMBOL(kunmap_atomic_high);
 100
 101void *kmap_atomic_pfn(unsigned long pfn)
 102{
 103        unsigned long vaddr;
 104        int idx, type;
 105        struct page *page = pfn_to_page(pfn);
 106
 107        preempt_disable();
 108        pagefault_disable();
 109        if (!PageHighMem(page))
 110                return page_address(page);
 111
 112        type = kmap_atomic_idx_push();
 113        idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
 114        vaddr = __fix_to_virt(idx);
 115#ifdef CONFIG_DEBUG_HIGHMEM
 116        BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
 117#endif
 118        set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
 119
 120        return (void *)vaddr;
 121}
 122