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 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 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 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 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 * 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 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