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1/*
2 * highmem.c: virtual kernel memory mappings for high memory
3 *
4 * Provides kernel-static versions of atomic kmap functions originally
5 * found as inlines in include/asm-sparc/highmem.h. These became
6 * needed as kmap_atomic() and kunmap_atomic() started getting
7 * called from within modules.
8 * -- Tomas Szepe <szepe@pinerecords.com>, September 2002
9 *
10 * But kmap_atomic() and kunmap_atomic() cannot be inlined in
11 * modules because they are loaded with btfixup-ped functions.
12 */
13
14/*
15 * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
16 * gives a more generic (and caching) interface. But kmap_atomic can
17 * be used in IRQ contexts, so in some (very limited) cases we need it.
18 *
19 * XXX This is an old text. Actually, it's good to use atomic kmaps,
20 * provided you remember that they are atomic and not try to sleep
21 * with a kmap taken, much like a spinlock. Non-atomic kmaps are
22 * shared by CPUs, and so precious, and establishing them requires IPI.
23 * Atomic kmaps are lightweight and we may have NCPUS more of them.
24 */
25#include <linux/mm.h>
26#include <linux/highmem.h>
27#include <asm/pgalloc.h>
28#include <asm/cacheflush.h>
29#include <asm/tlbflush.h>
30#include <asm/fixmap.h>
31
32void *__kmap_atomic(struct page *page)
33{
34 unsigned long vaddr;
35 long idx, type;
36
37 /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
38 pagefault_disable();
39 if (!PageHighMem(page))
40 return page_address(page);
41
42 type = kmap_atomic_idx_push();
43 idx = type + KM_TYPE_NR*smp_processor_id();
44 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
45
46/* XXX Fix - Anton */
47#if 0
48 __flush_cache_one(vaddr);
49#else
50 flush_cache_all();
51#endif
52
53#ifdef CONFIG_DEBUG_HIGHMEM
54 BUG_ON(!pte_none(*(kmap_pte-idx)));
55#endif
56 set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
57/* XXX Fix - Anton */
58#if 0
59 __flush_tlb_one(vaddr);
60#else
61 flush_tlb_all();
62#endif
63
64 return (void*) vaddr;
65}
66EXPORT_SYMBOL(__kmap_atomic);
67
68void __kunmap_atomic(void *kvaddr)
69{
70 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
71 int type;
72
73 if (vaddr < FIXADDR_START) { // FIXME
74 pagefault_enable();
75 return;
76 }
77
78 type = kmap_atomic_idx();
79
80#ifdef CONFIG_DEBUG_HIGHMEM
81 {
82 unsigned long idx;
83
84 idx = type + KM_TYPE_NR * smp_processor_id();
85 BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
86
87 /* XXX Fix - Anton */
88#if 0
89 __flush_cache_one(vaddr);
90#else
91 flush_cache_all();
92#endif
93
94 /*
95 * force other mappings to Oops if they'll try to access
96 * this pte without first remap it
97 */
98 pte_clear(&init_mm, vaddr, kmap_pte-idx);
99 /* XXX Fix - Anton */
100#if 0
101 __flush_tlb_one(vaddr);
102#else
103 flush_tlb_all();
104#endif
105 }
106#endif
107
108 kmap_atomic_idx_pop();
109 pagefault_enable();
110}
111EXPORT_SYMBOL(__kunmap_atomic);
112
113/* We may be fed a pagetable here by ptep_to_xxx and others. */
114struct page *kmap_atomic_to_page(void *ptr)
115{
116 unsigned long idx, vaddr = (unsigned long)ptr;
117 pte_t *pte;
118
119 if (vaddr < SRMMU_NOCACHE_VADDR)
120 return virt_to_page(ptr);
121 if (vaddr < PKMAP_BASE)
122 return pfn_to_page(__nocache_pa(vaddr) >> PAGE_SHIFT);
123 BUG_ON(vaddr < FIXADDR_START);
124 BUG_ON(vaddr > FIXADDR_TOP);
125
126 idx = virt_to_fix(vaddr);
127 pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
128 return pte_page(*pte);
129}
1/*
2 * highmem.c: virtual kernel memory mappings for high memory
3 *
4 * Provides kernel-static versions of atomic kmap functions originally
5 * found as inlines in include/asm-sparc/highmem.h. These became
6 * needed as kmap_atomic() and kunmap_atomic() started getting
7 * called from within modules.
8 * -- Tomas Szepe <szepe@pinerecords.com>, September 2002
9 *
10 * But kmap_atomic() and kunmap_atomic() cannot be inlined in
11 * modules because they are loaded with btfixup-ped functions.
12 */
13
14/*
15 * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
16 * gives a more generic (and caching) interface. But kmap_atomic can
17 * be used in IRQ contexts, so in some (very limited) cases we need it.
18 *
19 * XXX This is an old text. Actually, it's good to use atomic kmaps,
20 * provided you remember that they are atomic and not try to sleep
21 * with a kmap taken, much like a spinlock. Non-atomic kmaps are
22 * shared by CPUs, and so precious, and establishing them requires IPI.
23 * Atomic kmaps are lightweight and we may have NCPUS more of them.
24 */
25#include <linux/highmem.h>
26#include <linux/export.h>
27#include <linux/mm.h>
28
29#include <asm/cacheflush.h>
30#include <asm/tlbflush.h>
31#include <asm/pgalloc.h>
32#include <asm/vaddrs.h>
33
34pgprot_t kmap_prot;
35
36static pte_t *kmap_pte;
37
38void __init kmap_init(void)
39{
40 unsigned long address;
41 pmd_t *dir;
42
43 address = __fix_to_virt(FIX_KMAP_BEGIN);
44 dir = pmd_offset(pgd_offset_k(address), address);
45
46 /* cache the first kmap pte */
47 kmap_pte = pte_offset_kernel(dir, address);
48 kmap_prot = __pgprot(SRMMU_ET_PTE | SRMMU_PRIV | SRMMU_CACHE);
49}
50
51void *kmap_atomic(struct page *page)
52{
53 unsigned long vaddr;
54 long idx, type;
55
56 preempt_disable();
57 pagefault_disable();
58 if (!PageHighMem(page))
59 return page_address(page);
60
61 type = kmap_atomic_idx_push();
62 idx = type + KM_TYPE_NR*smp_processor_id();
63 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
64
65/* XXX Fix - Anton */
66#if 0
67 __flush_cache_one(vaddr);
68#else
69 flush_cache_all();
70#endif
71
72#ifdef CONFIG_DEBUG_HIGHMEM
73 BUG_ON(!pte_none(*(kmap_pte-idx)));
74#endif
75 set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
76/* XXX Fix - Anton */
77#if 0
78 __flush_tlb_one(vaddr);
79#else
80 flush_tlb_all();
81#endif
82
83 return (void*) vaddr;
84}
85EXPORT_SYMBOL(kmap_atomic);
86
87void __kunmap_atomic(void *kvaddr)
88{
89 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
90 int type;
91
92 if (vaddr < FIXADDR_START) { // FIXME
93 pagefault_enable();
94 preempt_enable();
95 return;
96 }
97
98 type = kmap_atomic_idx();
99
100#ifdef CONFIG_DEBUG_HIGHMEM
101 {
102 unsigned long idx;
103
104 idx = type + KM_TYPE_NR * smp_processor_id();
105 BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
106
107 /* XXX Fix - Anton */
108#if 0
109 __flush_cache_one(vaddr);
110#else
111 flush_cache_all();
112#endif
113
114 /*
115 * force other mappings to Oops if they'll try to access
116 * this pte without first remap it
117 */
118 pte_clear(&init_mm, vaddr, kmap_pte-idx);
119 /* XXX Fix - Anton */
120#if 0
121 __flush_tlb_one(vaddr);
122#else
123 flush_tlb_all();
124#endif
125 }
126#endif
127
128 kmap_atomic_idx_pop();
129 pagefault_enable();
130 preempt_enable();
131}
132EXPORT_SYMBOL(__kunmap_atomic);