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 kmap_prot		PAGE_KERNEL
14
15#define flush_cache_kmaps() \
16	do { \
17		if (cache_is_vivt()) \
18			flush_cache_all(); \
19	} while (0)
20
21extern pte_t *pkmap_page_table;
22
23extern void *kmap_high(struct page *page);
24extern void kunmap_high(struct page *page);
25
26/*
27 * The reason for kmap_high_get() is to ensure that the currently kmap'd
28 * page usage count does not decrease to zero while we're using its
29 * existing virtual mapping in an atomic context.  With a VIVT cache this
30 * is essential to do, but with a VIPT cache this is only an optimization
31 * so not to pay the price of establishing a second mapping if an existing
32 * one can be used.  However, on platforms without hardware TLB maintenance
33 * broadcast, we simply cannot use ARCH_NEEDS_KMAP_HIGH_GET at all since
34 * the locking involved must also disable IRQs which is incompatible with
35 * the IPI mechanism used by global TLB operations.
36 */
37#define ARCH_NEEDS_KMAP_HIGH_GET
38#if defined(CONFIG_SMP) && defined(CONFIG_CPU_TLB_V6)
39#undef ARCH_NEEDS_KMAP_HIGH_GET
40#if defined(CONFIG_HIGHMEM) && defined(CONFIG_CPU_CACHE_VIVT)
41#error "The sum of features in your kernel config cannot be supported together"
42#endif
43#endif
44
45/*
46 * Needed to be able to broadcast the TLB invalidation for kmap.
47 */
48#ifdef CONFIG_ARM_ERRATA_798181
49#undef ARCH_NEEDS_KMAP_HIGH_GET
50#endif
51
52#ifdef ARCH_NEEDS_KMAP_HIGH_GET
53extern void *kmap_high_get(struct page *page);
54#else
55static inline void *kmap_high_get(struct page *page)
56{
57	return NULL;
58}
59#endif
60
61/*
62 * The following functions are already defined by <linux/highmem.h>
63 * when CONFIG_HIGHMEM is not set.
64 */
65#ifdef CONFIG_HIGHMEM
66extern void *kmap(struct page *page);
67extern void kunmap(struct page *page);
68extern void *kmap_atomic(struct page *page);
69extern void __kunmap_atomic(void *kvaddr);
70extern void *kmap_atomic_pfn(unsigned long pfn);
71#endif
72
73#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 kmap_prot		PAGE_KERNEL
14
15#define flush_cache_kmaps() \
16	do { \
17		if (cache_is_vivt()) \
18			flush_cache_all(); \
19	} while (0)
20
21extern pte_t *pkmap_page_table;
22
23extern void *kmap_high(struct page *page);
24extern void kunmap_high(struct page *page);
25
26/*
27 * The reason for kmap_high_get() is to ensure that the currently kmap'd
28 * page usage count does not decrease to zero while we're using its
29 * existing virtual mapping in an atomic context.  With a VIVT cache this
30 * is essential to do, but with a VIPT cache this is only an optimization
31 * so not to pay the price of establishing a second mapping if an existing
32 * one can be used.  However, on platforms without hardware TLB maintenance
33 * broadcast, we simply cannot use ARCH_NEEDS_KMAP_HIGH_GET at all since
34 * the locking involved must also disable IRQs which is incompatible with
35 * the IPI mechanism used by global TLB operations.
36 */
37#define ARCH_NEEDS_KMAP_HIGH_GET
38#if defined(CONFIG_SMP) && defined(CONFIG_CPU_TLB_V6)
39#undef ARCH_NEEDS_KMAP_HIGH_GET
40#if defined(CONFIG_HIGHMEM) && defined(CONFIG_CPU_CACHE_VIVT)
41#error "The sum of features in your kernel config cannot be supported together"
42#endif
43#endif
44
45/*
46 * Needed to be able to broadcast the TLB invalidation for kmap.
47 */
48#ifdef CONFIG_ARM_ERRATA_798181
49#undef ARCH_NEEDS_KMAP_HIGH_GET
50#endif
51
52#ifdef ARCH_NEEDS_KMAP_HIGH_GET
53extern void *kmap_high_get(struct page *page);
54#else
55static inline void *kmap_high_get(struct page *page)
56{
57	return NULL;
58}
59#endif
60
61/*
62 * The following functions are already defined by <linux/highmem.h>
63 * when CONFIG_HIGHMEM is not set.
64 */
65#ifdef CONFIG_HIGHMEM
66extern void *kmap(struct page *page);
67extern void kunmap(struct page *page);
68extern void *kmap_atomic(struct page *page);
69extern void __kunmap_atomic(void *kvaddr);
70extern void *kmap_atomic_pfn(unsigned long pfn);
71#endif
72
73#endif