1 /*
2 * Copyright © 2008 Ingo Molnar
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
17 */
18
19 #include <asm/iomap.h>
20 #include <asm/pat.h>
21 #include <linux/export.h>
22 #include <linux/highmem.h>
23
is_io_mapping_possible(resource_size_t base,unsigned long size)24 static int is_io_mapping_possible(resource_size_t base, unsigned long size)
25 {
26 #if !defined(CONFIG_X86_PAE) && defined(CONFIG_PHYS_ADDR_T_64BIT)
27 /* There is no way to map greater than 1 << 32 address without PAE */
28 if (base + size > 0x100000000ULL)
29 return 0;
30 #endif
31 return 1;
32 }
33
iomap_create_wc(resource_size_t base,unsigned long size,pgprot_t * prot)34 int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot)
35 {
36 enum page_cache_mode pcm = _PAGE_CACHE_MODE_WC;
37 int ret;
38
39 if (!is_io_mapping_possible(base, size))
40 return -EINVAL;
41
42 ret = io_reserve_memtype(base, base + size, &pcm);
43 if (ret)
44 return ret;
45
46 *prot = __pgprot(__PAGE_KERNEL | cachemode2protval(pcm));
47 /* Filter out unsupported __PAGE_KERNEL* bits: */
48 pgprot_val(*prot) &= __default_kernel_pte_mask;
49
50 return 0;
51 }
52 EXPORT_SYMBOL_GPL(iomap_create_wc);
53
iomap_free(resource_size_t base,unsigned long size)54 void iomap_free(resource_size_t base, unsigned long size)
55 {
56 io_free_memtype(base, base + size);
57 }
58 EXPORT_SYMBOL_GPL(iomap_free);
59
kmap_atomic_prot_pfn(unsigned long pfn,pgprot_t prot)60 void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
61 {
62 unsigned long vaddr;
63 int idx, type;
64
65 preempt_disable();
66 pagefault_disable();
67
68 type = kmap_atomic_idx_push();
69 idx = type + KM_TYPE_NR * smp_processor_id();
70 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
71 set_pte(kmap_pte - idx, pfn_pte(pfn, prot));
72 arch_flush_lazy_mmu_mode();
73
74 return (void *)vaddr;
75 }
76
77 /*
78 * Map 'pfn' using protections 'prot'
79 */
80 void __iomem *
iomap_atomic_prot_pfn(unsigned long pfn,pgprot_t prot)81 iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
82 {
83 /*
84 * For non-PAT systems, translate non-WB request to UC- just in
85 * case the caller set the PWT bit to prot directly without using
86 * pgprot_writecombine(). UC- translates to uncached if the MTRR
87 * is UC or WC. UC- gets the real intention, of the user, which is
88 * "WC if the MTRR is WC, UC if you can't do that."
89 */
90 if (!pat_enabled() && pgprot2cachemode(prot) != _PAGE_CACHE_MODE_WB)
91 prot = __pgprot(__PAGE_KERNEL |
92 cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS));
93
94 /* Filter out unsupported __PAGE_KERNEL* bits: */
95 pgprot_val(prot) &= __default_kernel_pte_mask;
96
97 return (void __force __iomem *) kmap_atomic_prot_pfn(pfn, prot);
98 }
99 EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn);
100
101 void
iounmap_atomic(void __iomem * kvaddr)102 iounmap_atomic(void __iomem *kvaddr)
103 {
104 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
105
106 if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
107 vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
108 int idx, type;
109
110 type = kmap_atomic_idx();
111 idx = type + KM_TYPE_NR * smp_processor_id();
112
113 #ifdef CONFIG_DEBUG_HIGHMEM
114 WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
115 #endif
116 /*
117 * Force other mappings to Oops if they'll try to access this
118 * pte without first remap it. Keeping stale mappings around
119 * is a bad idea also, in case the page changes cacheability
120 * attributes or becomes a protected page in a hypervisor.
121 */
122 kpte_clear_flush(kmap_pte-idx, vaddr);
123 kmap_atomic_idx_pop();
124 }
125
126 pagefault_enable();
127 preempt_enable();
128 }
129 EXPORT_SYMBOL_GPL(iounmap_atomic);
130
