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/module.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 unsigned long flag = _PAGE_CACHE_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, &flag); 43 if (ret) 44 return ret; 45 46 *prot = __pgprot(__PAGE_KERNEL | flag); 47 return 0; 48 } 49 EXPORT_SYMBOL_GPL(iomap_create_wc); 50 51 void 52 iomap_free(resource_size_t base, unsigned long size) 53 { 54 io_free_memtype(base, base + size); 55 } 56 EXPORT_SYMBOL_GPL(iomap_free); 57 58 void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot) 59 { 60 enum fixed_addresses idx; 61 unsigned long vaddr; 62 63 pagefault_disable(); 64 65 debug_kmap_atomic(type); 66 idx = type + KM_TYPE_NR * smp_processor_id(); 67 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); 68 set_pte(kmap_pte - idx, pfn_pte(pfn, prot)); 69 arch_flush_lazy_mmu_mode(); 70 71 return (void *)vaddr; 72 } 73 74 /* 75 * Map 'pfn' using fixed map 'type' and protections 'prot' 76 */ 77 void * 78 iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot) 79 { 80 /* 81 * For non-PAT systems, promote PAGE_KERNEL_WC to PAGE_KERNEL_UC_MINUS. 82 * PAGE_KERNEL_WC maps to PWT, which translates to uncached if the 83 * MTRR is UC or WC. UC_MINUS gets the real intention, of the 84 * user, which is "WC if the MTRR is WC, UC if you can't do that." 85 */ 86 if (!pat_enabled && pgprot_val(prot) == pgprot_val(PAGE_KERNEL_WC)) 87 prot = PAGE_KERNEL_UC_MINUS; 88 89 return kmap_atomic_prot_pfn(pfn, type, prot); 90 } 91 EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn); 92 93 void 94 iounmap_atomic(void *kvaddr, enum km_type type) 95 { 96 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; 97 enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id(); 98 99 /* 100 * Force other mappings to Oops if they'll try to access this pte 101 * without first remap it. Keeping stale mappings around is a bad idea 102 * also, in case the page changes cacheability attributes or becomes 103 * a protected page in a hypervisor. 104 */ 105 if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx)) 106 kpte_clear_flush(kmap_pte-idx, vaddr); 107 108 pagefault_enable(); 109 } 110 EXPORT_SYMBOL_GPL(iounmap_atomic); 111