1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * Copyright © 2008 Ingo Molnar 4 */ 5 6#include <asm/iomap.h> 7#include <asm/memtype.h> 8#include <linux/export.h> 9#include <linux/highmem.h> 10 11static int is_io_mapping_possible(resource_size_t base, unsigned long size) 12{ 13#if !defined(CONFIG_X86_PAE) && defined(CONFIG_PHYS_ADDR_T_64BIT) 14 /* There is no way to map greater than 1 << 32 address without PAE */ 15 if (base + size > 0x100000000ULL) 16 return 0; 17#endif 18 return 1; 19} 20 21int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot) 22{ 23 enum page_cache_mode pcm = _PAGE_CACHE_MODE_WC; 24 int ret; 25 26 if (!is_io_mapping_possible(base, size)) 27 return -EINVAL; 28 29 ret = memtype_reserve_io(base, base + size, &pcm); 30 if (ret) 31 return ret; 32 33 *prot = __pgprot(__PAGE_KERNEL | cachemode2protval(pcm)); 34 /* Filter out unsupported __PAGE_KERNEL* bits: */ 35 pgprot_val(*prot) &= __default_kernel_pte_mask; 36 37 return 0; 38} 39EXPORT_SYMBOL_GPL(iomap_create_wc); 40 41void iomap_free(resource_size_t base, unsigned long size) 42{ 43 memtype_free_io(base, base + size); 44} 45EXPORT_SYMBOL_GPL(iomap_free); 46 47void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot) 48{ 49 unsigned long vaddr; 50 int idx, type; 51 52 preempt_disable(); 53 pagefault_disable(); 54 55 type = kmap_atomic_idx_push(); 56 idx = type + KM_TYPE_NR * smp_processor_id(); 57 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); 58 set_pte(kmap_pte - idx, pfn_pte(pfn, prot)); 59 arch_flush_lazy_mmu_mode(); 60 61 return (void *)vaddr; 62} 63 64/* 65 * Map 'pfn' using protections 'prot' 66 */ 67void __iomem * 68iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot) 69{ 70 /* 71 * For non-PAT systems, translate non-WB request to UC- just in 72 * case the caller set the PWT bit to prot directly without using 73 * pgprot_writecombine(). UC- translates to uncached if the MTRR 74 * is UC or WC. UC- gets the real intention, of the user, which is 75 * "WC if the MTRR is WC, UC if you can't do that." 76 */ 77 if (!pat_enabled() && pgprot2cachemode(prot) != _PAGE_CACHE_MODE_WB) 78 prot = __pgprot(__PAGE_KERNEL | 79 cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS)); 80 81 /* Filter out unsupported __PAGE_KERNEL* bits: */ 82 pgprot_val(prot) &= __default_kernel_pte_mask; 83 84 return (void __force __iomem *) kmap_atomic_prot_pfn(pfn, prot); 85} 86EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn); 87 88void 89iounmap_atomic(void __iomem *kvaddr) 90{ 91 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; 92 93 if (vaddr >= __fix_to_virt(FIX_KMAP_END) && 94 vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) { 95 int idx, type; 96 97 type = kmap_atomic_idx(); 98 idx = type + KM_TYPE_NR * smp_processor_id(); 99 100#ifdef CONFIG_DEBUG_HIGHMEM 101 WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); 102#endif 103 /* 104 * Force other mappings to Oops if they'll try to access this 105 * pte without first remap it. Keeping stale mappings around 106 * is a bad idea also, in case the page changes cacheability 107 * attributes or becomes a protected page in a hypervisor. 108 */ 109 kpte_clear_flush(kmap_pte-idx, vaddr); 110 kmap_atomic_idx_pop(); 111 } 112 113 pagefault_enable(); 114 preempt_enable(); 115} 116EXPORT_SYMBOL_GPL(iounmap_atomic); 117