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