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1#include <linux/module.h>
2#include <linux/highmem.h>
3#include <linux/sched.h>
4#include <linux/smp.h>
5#include <asm/fixmap.h>
6#include <asm/tlbflush.h>
7
8static pte_t *kmap_pte;
9
10unsigned long highstart_pfn, highend_pfn;
11
12void *kmap(struct page *page)
13{
14 void *addr;
15
16 might_sleep();
17 if (!PageHighMem(page))
18 return page_address(page);
19 addr = kmap_high(page);
20 flush_tlb_one((unsigned long)addr);
21
22 return addr;
23}
24EXPORT_SYMBOL(kmap);
25
26void kunmap(struct page *page)
27{
28 BUG_ON(in_interrupt());
29 if (!PageHighMem(page))
30 return;
31 kunmap_high(page);
32}
33EXPORT_SYMBOL(kunmap);
34
35/*
36 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
37 * no global lock is needed and because the kmap code must perform a global TLB
38 * invalidation when the kmap pool wraps.
39 *
40 * However when holding an atomic kmap is is not legal to sleep, so atomic
41 * kmaps are appropriate for short, tight code paths only.
42 */
43
44void *__kmap_atomic(struct page *page)
45{
46 unsigned long vaddr;
47 int idx, type;
48
49 /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
50 pagefault_disable();
51 if (!PageHighMem(page))
52 return page_address(page);
53
54 type = kmap_atomic_idx_push();
55 idx = type + KM_TYPE_NR*smp_processor_id();
56 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
57#ifdef CONFIG_DEBUG_HIGHMEM
58 BUG_ON(!pte_none(*(kmap_pte - idx)));
59#endif
60 set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL));
61 local_flush_tlb_one((unsigned long)vaddr);
62
63 return (void*) vaddr;
64}
65EXPORT_SYMBOL(__kmap_atomic);
66
67void __kunmap_atomic(void *kvaddr)
68{
69 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
70 int type;
71
72 if (vaddr < FIXADDR_START) { // FIXME
73 pagefault_enable();
74 return;
75 }
76
77 type = kmap_atomic_idx();
78#ifdef CONFIG_DEBUG_HIGHMEM
79 {
80 int idx = type + KM_TYPE_NR * smp_processor_id();
81
82 BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
83
84 /*
85 * force other mappings to Oops if they'll try to access
86 * this pte without first remap it
87 */
88 pte_clear(&init_mm, vaddr, kmap_pte-idx);
89 local_flush_tlb_one(vaddr);
90 }
91#endif
92 kmap_atomic_idx_pop();
93 pagefault_enable();
94}
95EXPORT_SYMBOL(__kunmap_atomic);
96
97/*
98 * This is the same as kmap_atomic() but can map memory that doesn't
99 * have a struct page associated with it.
100 */
101void *kmap_atomic_pfn(unsigned long pfn)
102{
103 unsigned long vaddr;
104 int idx, type;
105
106 pagefault_disable();
107
108 type = kmap_atomic_idx_push();
109 idx = type + KM_TYPE_NR*smp_processor_id();
110 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
111 set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
112 flush_tlb_one(vaddr);
113
114 return (void*) vaddr;
115}
116
117struct page *kmap_atomic_to_page(void *ptr)
118{
119 unsigned long idx, vaddr = (unsigned long)ptr;
120 pte_t *pte;
121
122 if (vaddr < FIXADDR_START)
123 return virt_to_page(ptr);
124
125 idx = virt_to_fix(vaddr);
126 pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
127 return pte_page(*pte);
128}
129
130void __init kmap_init(void)
131{
132 unsigned long kmap_vstart;
133
134 /* cache the first kmap pte */
135 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
136 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
137}
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/compiler.h>
3#include <linux/init.h>
4#include <linux/export.h>
5#include <linux/highmem.h>
6#include <linux/sched.h>
7#include <linux/smp.h>
8#include <asm/fixmap.h>
9#include <asm/tlbflush.h>
10
11static pte_t *kmap_pte;
12
13unsigned long highstart_pfn, highend_pfn;
14
15void *kmap(struct page *page)
16{
17 void *addr;
18
19 might_sleep();
20 if (!PageHighMem(page))
21 return page_address(page);
22 addr = kmap_high(page);
23 flush_tlb_one((unsigned long)addr);
24
25 return addr;
26}
27EXPORT_SYMBOL(kmap);
28
29void kunmap(struct page *page)
30{
31 BUG_ON(in_interrupt());
32 if (!PageHighMem(page))
33 return;
34 kunmap_high(page);
35}
36EXPORT_SYMBOL(kunmap);
37
38/*
39 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
40 * no global lock is needed and because the kmap code must perform a global TLB
41 * invalidation when the kmap pool wraps.
42 *
43 * However when holding an atomic kmap is is not legal to sleep, so atomic
44 * kmaps are appropriate for short, tight code paths only.
45 */
46
47void *kmap_atomic(struct page *page)
48{
49 unsigned long vaddr;
50 int idx, type;
51
52 preempt_disable();
53 pagefault_disable();
54 if (!PageHighMem(page))
55 return page_address(page);
56
57 type = kmap_atomic_idx_push();
58 idx = type + KM_TYPE_NR*smp_processor_id();
59 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
60#ifdef CONFIG_DEBUG_HIGHMEM
61 BUG_ON(!pte_none(*(kmap_pte - idx)));
62#endif
63 set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL));
64 local_flush_tlb_one((unsigned long)vaddr);
65
66 return (void*) vaddr;
67}
68EXPORT_SYMBOL(kmap_atomic);
69
70void __kunmap_atomic(void *kvaddr)
71{
72 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
73 int type __maybe_unused;
74
75 if (vaddr < FIXADDR_START) { // FIXME
76 pagefault_enable();
77 preempt_enable();
78 return;
79 }
80
81 type = kmap_atomic_idx();
82#ifdef CONFIG_DEBUG_HIGHMEM
83 {
84 int idx = type + KM_TYPE_NR * smp_processor_id();
85
86 BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
87
88 /*
89 * force other mappings to Oops if they'll try to access
90 * this pte without first remap it
91 */
92 pte_clear(&init_mm, vaddr, kmap_pte-idx);
93 local_flush_tlb_one(vaddr);
94 }
95#endif
96 kmap_atomic_idx_pop();
97 pagefault_enable();
98 preempt_enable();
99}
100EXPORT_SYMBOL(__kunmap_atomic);
101
102/*
103 * This is the same as kmap_atomic() but can map memory that doesn't
104 * have a struct page associated with it.
105 */
106void *kmap_atomic_pfn(unsigned long pfn)
107{
108 unsigned long vaddr;
109 int idx, type;
110
111 preempt_disable();
112 pagefault_disable();
113
114 type = kmap_atomic_idx_push();
115 idx = type + KM_TYPE_NR*smp_processor_id();
116 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
117 set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
118 flush_tlb_one(vaddr);
119
120 return (void*) vaddr;
121}
122
123void __init kmap_init(void)
124{
125 unsigned long kmap_vstart;
126
127 /* cache the first kmap pte */
128 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
129 kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
130}