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
20 extern 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
49 extern void *kmap_high_get(struct page *page);
50
51 static 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 */
60 static 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) \
70 do { \
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
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