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

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _ASM_HIGHMEM_H
   3#define _ASM_HIGHMEM_H
   4
   5#include <asm/cachetype.h>
   6#include <asm/fixmap.h>
   7
   8#define PKMAP_BASE              (PAGE_OFFSET - PMD_SIZE)
   9#define LAST_PKMAP              PTRS_PER_PTE
  10#define LAST_PKMAP_MASK         (LAST_PKMAP - 1)
  11#define PKMAP_NR(virt)          (((virt) - PKMAP_BASE) >> PAGE_SHIFT)
  12#define PKMAP_ADDR(nr)          (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  13
  14#define flush_cache_kmaps() \
  15        do { \
  16                if (cache_is_vivt()) \
  17                        flush_cache_all(); \
  18        } while (0)
  19
  20extern pte_t *pkmap_page_table;
  21
  22/*
  23 * The reason for kmap_high_get() is to ensure that the currently kmap'd
  24 * page usage count does not decrease to zero while we're using its
  25 * existing virtual mapping in an atomic context.  With a VIVT cache this
  26 * is essential to do, but with a VIPT cache this is only an optimization
  27 * so not to pay the price of establishing a second mapping if an existing
  28 * one can be used.  However, on platforms without hardware TLB maintenance
  29 * broadcast, we simply cannot use ARCH_NEEDS_KMAP_HIGH_GET at all since
  30 * the locking involved must also disable IRQs which is incompatible with
  31 * the IPI mechanism used by global TLB operations.
  32 */
  33#define ARCH_NEEDS_KMAP_HIGH_GET
  34#if defined(CONFIG_SMP) && defined(CONFIG_CPU_TLB_V6)
  35#undef ARCH_NEEDS_KMAP_HIGH_GET
  36#if defined(CONFIG_HIGHMEM) && defined(CONFIG_CPU_CACHE_VIVT)
  37#error "The sum of features in your kernel config cannot be supported together"
  38#endif
  39#endif
  40
  41/*
  42 * Needed to be able to broadcast the TLB invalidation for kmap.
  43 */
  44#ifdef CONFIG_ARM_ERRATA_798181
  45#undef ARCH_NEEDS_KMAP_HIGH_GET
  46#endif
  47
  48#ifdef ARCH_NEEDS_KMAP_HIGH_GET
  49extern void *kmap_high_get(struct page *page);
  50
  51static inline void *arch_kmap_local_high_get(struct page *page)
  52{
  53        if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM) && !cache_is_vivt())
  54                return NULL;
  55        return kmap_high_get(page);
  56}
  57#define arch_kmap_local_high_get arch_kmap_local_high_get
  58
  59#else /* ARCH_NEEDS_KMAP_HIGH_GET */
  60static inline void *kmap_high_get(struct page *page)
  61{
  62        return NULL;
  63}
  64#endif /* !ARCH_NEEDS_KMAP_HIGH_GET */
  65
  66#define arch_kmap_local_post_map(vaddr, pteval)                         \
  67        local_flush_tlb_kernel_page(vaddr)
  68
  69#define arch_kmap_local_pre_unmap(vaddr)                                \
  70do {                                                                    \
  71        if (cache_is_vivt())                                            \
  72                __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);     \
  73} while (0)
  74
  75#define arch_kmap_local_post_unmap(vaddr)                               \
  76        local_flush_tlb_kernel_page(vaddr)
  77
  78#endif
  79