| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 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 | |
| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 13 | #define flush_cache_kmaps() \ |
| 14 | do { \ |
| 15 | if (cache_is_vivt()) \ |
| 16 | flush_cache_all(); \ |
| 17 | } while (0) |
| 18 | |
| 19 | extern pte_t *pkmap_page_table; |
| 20 | |
| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 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 |
| 48 | extern void *kmap_high_get(struct page *page); |
| 49 | #else |
| 50 | static 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 |
| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 61 | extern void *kmap_atomic_pfn(unsigned long pfn); |
| 62 | #endif |
| 63 | |
| 64 | #endif |