2 * arch/arm/mm/highmem.c -- ARM highmem support
4 * Author: Nicolas Pitre
5 * Created: september 8, 2008
6 * Copyright: Marvell Semiconductors Inc.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
13 #include <linux/module.h>
14 #include <linux/highmem.h>
15 #include <linux/interrupt.h>
16 #include <asm/fixmap.h>
17 #include <asm/cacheflush.h>
18 #include <asm/tlbflush.h>
21 void *kmap(struct page *page)
24 if (!PageHighMem(page))
25 return page_address(page);
26 return kmap_high(page);
30 void kunmap(struct page *page)
32 BUG_ON(in_interrupt());
33 if (!PageHighMem(page))
37 EXPORT_SYMBOL(kunmap);
39 void *kmap_atomic(struct page *page)
47 if (!PageHighMem(page))
48 return page_address(page);
50 #ifdef CONFIG_DEBUG_HIGHMEM
52 * There is no cache coherency issue when non VIVT, so force the
53 * dedicated kmap usage for better debugging purposes in that case.
59 kmap = kmap_high_get(page);
63 type = kmap_atomic_idx_push();
65 idx = type + KM_TYPE_NR * smp_processor_id();
66 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
67 #ifdef CONFIG_DEBUG_HIGHMEM
69 * With debugging enabled, kunmap_atomic forces that entry to 0.
70 * Make sure it was indeed properly unmapped.
72 BUG_ON(!pte_none(get_top_pte(vaddr)));
75 * When debugging is off, kunmap_atomic leaves the previous mapping
76 * in place, so the contained TLB flush ensures the TLB is updated
77 * with the new mapping.
79 set_top_pte(vaddr, mk_pte(page, kmap_prot));
83 EXPORT_SYMBOL(kmap_atomic);
85 void __kunmap_atomic(void *kvaddr)
87 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
90 if (kvaddr >= (void *)FIXADDR_START) {
91 type = kmap_atomic_idx();
92 idx = type + KM_TYPE_NR * smp_processor_id();
95 __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
96 #ifdef CONFIG_DEBUG_HIGHMEM
97 BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
98 set_top_pte(vaddr, __pte(0));
100 (void) idx; /* to kill a warning */
102 kmap_atomic_idx_pop();
103 } else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
104 /* this address was obtained through kmap_high_get() */
105 kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
109 EXPORT_SYMBOL(__kunmap_atomic);
111 void *kmap_atomic_pfn(unsigned long pfn)
118 type = kmap_atomic_idx_push();
119 idx = type + KM_TYPE_NR * smp_processor_id();
120 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
121 #ifdef CONFIG_DEBUG_HIGHMEM
122 BUG_ON(!pte_none(get_top_pte(vaddr)));
124 set_top_pte(vaddr, pfn_pte(pfn, kmap_prot));
126 return (void *)vaddr;
129 struct page *kmap_atomic_to_page(const void *ptr)
131 unsigned long vaddr = (unsigned long)ptr;
133 if (vaddr < FIXADDR_START)
134 return virt_to_page(ptr);
136 return pte_page(get_top_pte(vaddr));