1 #include <linux/dma-mapping.h> 2 #include <linux/dma-debug.h> 3 #include <linux/dmar.h> 4 #include <linux/export.h> 5 #include <linux/bootmem.h> 6 #include <linux/gfp.h> 7 #include <linux/pci.h> 8 #include <linux/kmemleak.h> 9 10 #include <asm/proto.h> 11 #include <asm/dma.h> 12 #include <asm/iommu.h> 13 #include <asm/gart.h> 14 #include <asm/calgary.h> 15 #include <asm/x86_init.h> 16 #include <asm/iommu_table.h> 17 18 static int forbid_dac __read_mostly; 19 20 const struct dma_map_ops *dma_ops = &nommu_dma_ops; 21 EXPORT_SYMBOL(dma_ops); 22 23 static int iommu_sac_force __read_mostly; 24 25 #ifdef CONFIG_IOMMU_DEBUG 26 int panic_on_overflow __read_mostly = 1; 27 int force_iommu __read_mostly = 1; 28 #else 29 int panic_on_overflow __read_mostly = 0; 30 int force_iommu __read_mostly = 0; 31 #endif 32 33 int iommu_merge __read_mostly = 0; 34 35 int no_iommu __read_mostly; 36 /* Set this to 1 if there is a HW IOMMU in the system */ 37 int iommu_detected __read_mostly = 0; 38 39 /* 40 * This variable becomes 1 if iommu=pt is passed on the kernel command line. 41 * If this variable is 1, IOMMU implementations do no DMA translation for 42 * devices and allow every device to access to whole physical memory. This is 43 * useful if a user wants to use an IOMMU only for KVM device assignment to 44 * guests and not for driver dma translation. 45 */ 46 int iommu_pass_through __read_mostly; 47 48 extern struct iommu_table_entry __iommu_table[], __iommu_table_end[]; 49 50 /* Dummy device used for NULL arguments (normally ISA). */ 51 struct device x86_dma_fallback_dev = { 52 .init_name = "fallback device", 53 .coherent_dma_mask = ISA_DMA_BIT_MASK, 54 .dma_mask = &x86_dma_fallback_dev.coherent_dma_mask, 55 }; 56 EXPORT_SYMBOL(x86_dma_fallback_dev); 57 58 /* Number of entries preallocated for DMA-API debugging */ 59 #define PREALLOC_DMA_DEBUG_ENTRIES 65536 60 61 void __init pci_iommu_alloc(void) 62 { 63 struct iommu_table_entry *p; 64 65 sort_iommu_table(__iommu_table, __iommu_table_end); 66 check_iommu_entries(__iommu_table, __iommu_table_end); 67 68 for (p = __iommu_table; p < __iommu_table_end; p++) { 69 if (p && p->detect && p->detect() > 0) { 70 p->flags |= IOMMU_DETECTED; 71 if (p->early_init) 72 p->early_init(); 73 if (p->flags & IOMMU_FINISH_IF_DETECTED) 74 break; 75 } 76 } 77 } 78 void *dma_generic_alloc_coherent(struct device *dev, size_t size, 79 dma_addr_t *dma_addr, gfp_t flag, 80 unsigned long attrs) 81 { 82 unsigned long dma_mask; 83 struct page *page; 84 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; 85 dma_addr_t addr; 86 87 dma_mask = dma_alloc_coherent_mask(dev, flag); 88 89 flag &= ~__GFP_ZERO; 90 again: 91 page = NULL; 92 /* CMA can be used only in the context which permits sleeping */ 93 if (gfpflags_allow_blocking(flag)) { 94 page = dma_alloc_from_contiguous(dev, count, get_order(size), 95 flag); 96 if (page && page_to_phys(page) + size > dma_mask) { 97 dma_release_from_contiguous(dev, page, count); 98 page = NULL; 99 } 100 } 101 /* fallback */ 102 if (!page) 103 page = alloc_pages_node(dev_to_node(dev), flag, get_order(size)); 104 if (!page) 105 return NULL; 106 107 addr = page_to_phys(page); 108 if (addr + size > dma_mask) { 109 __free_pages(page, get_order(size)); 110 111 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) { 112 flag = (flag & ~GFP_DMA32) | GFP_DMA; 113 goto again; 114 } 115 116 return NULL; 117 } 118 memset(page_address(page), 0, size); 119 *dma_addr = addr; 120 return page_address(page); 121 } 122 123 void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr, 124 dma_addr_t dma_addr, unsigned long attrs) 125 { 126 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; 127 struct page *page = virt_to_page(vaddr); 128 129 if (!dma_release_from_contiguous(dev, page, count)) 130 free_pages((unsigned long)vaddr, get_order(size)); 131 } 132 133 bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp) 134 { 135 if (!*dev) 136 *dev = &x86_dma_fallback_dev; 137 138 *gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32); 139 *gfp = dma_alloc_coherent_gfp_flags(*dev, *gfp); 140 141 if (!is_device_dma_capable(*dev)) 142 return false; 143 return true; 144 145 } 146 EXPORT_SYMBOL(arch_dma_alloc_attrs); 147 148 /* 149 * See <Documentation/x86/x86_64/boot-options.txt> for the iommu kernel 150 * parameter documentation. 151 */ 152 static __init int iommu_setup(char *p) 153 { 154 iommu_merge = 1; 155 156 if (!p) 157 return -EINVAL; 158 159 while (*p) { 160 if (!strncmp(p, "off", 3)) 161 no_iommu = 1; 162 /* gart_parse_options has more force support */ 163 if (!strncmp(p, "force", 5)) 164 force_iommu = 1; 165 if (!strncmp(p, "noforce", 7)) { 166 iommu_merge = 0; 167 force_iommu = 0; 168 } 169 170 if (!strncmp(p, "biomerge", 8)) { 171 iommu_merge = 1; 172 force_iommu = 1; 173 } 174 if (!strncmp(p, "panic", 5)) 175 panic_on_overflow = 1; 176 if (!strncmp(p, "nopanic", 7)) 177 panic_on_overflow = 0; 178 if (!strncmp(p, "merge", 5)) { 179 iommu_merge = 1; 180 force_iommu = 1; 181 } 182 if (!strncmp(p, "nomerge", 7)) 183 iommu_merge = 0; 184 if (!strncmp(p, "forcesac", 8)) 185 iommu_sac_force = 1; 186 if (!strncmp(p, "allowdac", 8)) 187 forbid_dac = 0; 188 if (!strncmp(p, "nodac", 5)) 189 forbid_dac = 1; 190 if (!strncmp(p, "usedac", 6)) { 191 forbid_dac = -1; 192 return 1; 193 } 194 #ifdef CONFIG_SWIOTLB 195 if (!strncmp(p, "soft", 4)) 196 swiotlb = 1; 197 #endif 198 if (!strncmp(p, "pt", 2)) 199 iommu_pass_through = 1; 200 201 gart_parse_options(p); 202 203 #ifdef CONFIG_CALGARY_IOMMU 204 if (!strncmp(p, "calgary", 7)) 205 use_calgary = 1; 206 #endif /* CONFIG_CALGARY_IOMMU */ 207 208 p += strcspn(p, ","); 209 if (*p == ',') 210 ++p; 211 } 212 return 0; 213 } 214 early_param("iommu", iommu_setup); 215 216 int dma_supported(struct device *dev, u64 mask) 217 { 218 const struct dma_map_ops *ops = get_dma_ops(dev); 219 220 #ifdef CONFIG_PCI 221 if (mask > 0xffffffff && forbid_dac > 0) { 222 dev_info(dev, "PCI: Disallowing DAC for device\n"); 223 return 0; 224 } 225 #endif 226 227 if (ops->dma_supported) 228 return ops->dma_supported(dev, mask); 229 230 /* Copied from i386. Doesn't make much sense, because it will 231 only work for pci_alloc_coherent. 232 The caller just has to use GFP_DMA in this case. */ 233 if (mask < DMA_BIT_MASK(24)) 234 return 0; 235 236 /* Tell the device to use SAC when IOMMU force is on. This 237 allows the driver to use cheaper accesses in some cases. 238 239 Problem with this is that if we overflow the IOMMU area and 240 return DAC as fallback address the device may not handle it 241 correctly. 242 243 As a special case some controllers have a 39bit address 244 mode that is as efficient as 32bit (aic79xx). Don't force 245 SAC for these. Assume all masks <= 40 bits are of this 246 type. Normally this doesn't make any difference, but gives 247 more gentle handling of IOMMU overflow. */ 248 if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) { 249 dev_info(dev, "Force SAC with mask %Lx\n", mask); 250 return 0; 251 } 252 253 return 1; 254 } 255 EXPORT_SYMBOL(dma_supported); 256 257 static int __init pci_iommu_init(void) 258 { 259 struct iommu_table_entry *p; 260 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); 261 262 #ifdef CONFIG_PCI 263 dma_debug_add_bus(&pci_bus_type); 264 #endif 265 x86_init.iommu.iommu_init(); 266 267 for (p = __iommu_table; p < __iommu_table_end; p++) { 268 if (p && (p->flags & IOMMU_DETECTED) && p->late_init) 269 p->late_init(); 270 } 271 272 return 0; 273 } 274 /* Must execute after PCI subsystem */ 275 rootfs_initcall(pci_iommu_init); 276 277 #ifdef CONFIG_PCI 278 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */ 279 280 static void via_no_dac(struct pci_dev *dev) 281 { 282 if (forbid_dac == 0) { 283 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n"); 284 forbid_dac = 1; 285 } 286 } 287 DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, 288 PCI_CLASS_BRIDGE_PCI, 8, via_no_dac); 289 #endif 290