LXR linux/arch/microblaze/include/asm/highmem.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * highmem.h: virtual kernel memory mappings for high memory
   4 *
   5 * Used in CONFIG_HIGHMEM systems for memory pages which
   6 * are not addressable by direct kernel virtual addresses.
   7 *
   8 * Copyright (C) 1999 Gerhard Wichert, Siemens AG
   9 *                    Gerhard.Wichert@pdb.siemens.de
  10 *
  11 *
  12 * Redesigned the x86 32-bit VM architecture to deal with
  13 * up to 16 Terabyte physical memory. With current x86 CPUs
  14 * we now support up to 64 Gigabytes physical RAM.
  15 *
  16 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
  17 */
  18#ifndef _ASM_HIGHMEM_H
  19#define _ASM_HIGHMEM_H
  20
  21#ifdef __KERNEL__
  22
  23#include <linux/init.h>
  24#include <linux/interrupt.h>
  25#include <linux/uaccess.h>
  26#include <asm/fixmap.h>
  27
  28extern pte_t *kmap_pte;
  29extern pgprot_t kmap_prot;
  30extern pte_t *pkmap_page_table;
  31
  32/*
  33 * Right now we initialize only a single pte table. It can be extended
  34 * easily, subsequent pte tables have to be allocated in one physical
  35 * chunk of RAM.
  36 */
  37/*
  38 * We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
  39 * table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
  40 * and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
  41 * in case of 16K/64K/256K page sizes.
  42 */
  43
  44#define PKMAP_ORDER     PTE_SHIFT
  45#define LAST_PKMAP      (1 << PKMAP_ORDER)
  46
  47#define PKMAP_BASE      ((FIXADDR_START - PAGE_SIZE * (LAST_PKMAP + 1)) \
  48                                                                & PMD_MASK)
  49
  50#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
  51#define PKMAP_NR(virt)  ((virt - PKMAP_BASE) >> PAGE_SHIFT)
  52#define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  53
  54extern void *kmap_high(struct page *page);
  55extern void kunmap_high(struct page *page);
  56extern void *kmap_atomic_prot(struct page *page, pgprot_t prot);
  57extern void __kunmap_atomic(void *kvaddr);
  58
  59static inline void *kmap(struct page *page)
  60{
  61        might_sleep();
  62        if (!PageHighMem(page))
  63                return page_address(page);
  64        return kmap_high(page);
  65}
  66
  67static inline void kunmap(struct page *page)
  68{
  69        BUG_ON(in_interrupt());
  70        if (!PageHighMem(page))
  71                return;
  72        kunmap_high(page);
  73}
  74
  75static inline void *kmap_atomic(struct page *page)
  76{
  77        return kmap_atomic_prot(page, kmap_prot);
  78}
  79
  80#define flush_cache_kmaps()     { flush_icache(); flush_dcache(); }
  81
  82#endif /* __KERNEL__ */
  83
  84#endif /* _ASM_HIGHMEM_H */
  85