| /* SPDX-License-Identifier: GPL-2.0 */ | |
| #ifndef _ASM_HIGHMEM_H | |
| #define _ASM_HIGHMEM_H | |
| #include <asm/kmap_types.h> | |
| #define PKMAP_BASE (PAGE_OFFSET - PMD_SIZE) | |
| #define LAST_PKMAP PTRS_PER_PTE | |
| #define LAST_PKMAP_MASK (LAST_PKMAP - 1) | |
| #define PKMAP_NR(virt) (((virt) - PKMAP_BASE) >> PAGE_SHIFT) | |
| #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) | |
| #define kmap_prot PAGE_KERNEL | |
| #define flush_cache_kmaps() \ | |
| do { \ | |
| if (cache_is_vivt()) \ | |
| flush_cache_all(); \ | |
| } while (0) | |
| extern pte_t *pkmap_page_table; | |
| extern pte_t *fixmap_page_table; | |
| extern void *kmap_high(struct page *page); | |
| extern void kunmap_high(struct page *page); | |
| /* | |
| * The reason for kmap_high_get() is to ensure that the currently kmap'd | |
| * page usage count does not decrease to zero while we're using its | |
| * existing virtual mapping in an atomic context. With a VIVT cache this | |
| * is essential to do, but with a VIPT cache this is only an optimization | |
| * so not to pay the price of establishing a second mapping if an existing | |
| * one can be used. However, on platforms without hardware TLB maintenance | |
| * broadcast, we simply cannot use ARCH_NEEDS_KMAP_HIGH_GET at all since | |
| * the locking involved must also disable IRQs which is incompatible with | |
| * the IPI mechanism used by global TLB operations. | |
| */ | |
| #define ARCH_NEEDS_KMAP_HIGH_GET | |
| #if defined(CONFIG_SMP) && defined(CONFIG_CPU_TLB_V6) | |
| #undef ARCH_NEEDS_KMAP_HIGH_GET | |
| #if defined(CONFIG_HIGHMEM) && defined(CONFIG_CPU_CACHE_VIVT) | |
| #error "The sum of features in your kernel config cannot be supported together" | |
| #endif | |
| #endif | |
| /* | |
| * Needed to be able to broadcast the TLB invalidation for kmap. | |
| */ | |
| #ifdef CONFIG_ARM_ERRATA_798181 | |
| #undef ARCH_NEEDS_KMAP_HIGH_GET | |
| #endif | |
| #ifdef ARCH_NEEDS_KMAP_HIGH_GET | |
| extern void *kmap_high_get(struct page *page); | |
| #else | |
| static inline void *kmap_high_get(struct page *page) | |
| { | |
| return NULL; | |
| } | |
| #endif | |
| /* | |
| * The following functions are already defined by <linux/highmem.h> | |
| * when CONFIG_HIGHMEM is not set. | |
| */ | |
| #ifdef CONFIG_HIGHMEM | |
| extern void *kmap(struct page *page); | |
| extern void kunmap(struct page *page); | |
| extern void *kmap_atomic(struct page *page); | |
| extern void __kunmap_atomic(void *kvaddr); | |
| extern void *kmap_atomic_pfn(unsigned long pfn); | |
| #endif | |
| #endif |