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

 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