1 #include <linux/dma-mapping.h> 2 #include <linux/dma-debug.h> 3 #include <linux/dmar.h> 4 #include <linux/bootmem.h> 5 #include <linux/gfp.h> 6 #include <linux/pci.h> 7 #include <linux/kmemleak.h> 8 9 #include <asm/proto.h> 10 #include <asm/dma.h> 11 #include <asm/iommu.h> 12 #include <asm/gart.h> 13 #include <asm/calgary.h> 14 #include <asm/amd_iommu.h> 15 #include <asm/x86_init.h> 16 #include <asm/xen/swiotlb-xen.h> 17 18 static int forbid_dac __read_mostly; 19 20 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 /* Dummy device used for NULL arguments (normally ISA). */ 49 struct device x86_dma_fallback_dev = { 50 .init_name = "fallback device", 51 .coherent_dma_mask = ISA_DMA_BIT_MASK, 52 .dma_mask = &x86_dma_fallback_dev.coherent_dma_mask, 53 }; 54 EXPORT_SYMBOL(x86_dma_fallback_dev); 55 56 /* Number of entries preallocated for DMA-API debugging */ 57 #define PREALLOC_DMA_DEBUG_ENTRIES 32768 58 59 int dma_set_mask(struct device *dev, u64 mask) 60 { 61 if (!dev->dma_mask || !dma_supported(dev, mask)) 62 return -EIO; 63 64 *dev->dma_mask = mask; 65 66 return 0; 67 } 68 EXPORT_SYMBOL(dma_set_mask); 69 70 #if defined(CONFIG_X86_64) && !defined(CONFIG_NUMA) 71 static __initdata void *dma32_bootmem_ptr; 72 static unsigned long dma32_bootmem_size __initdata = (128ULL<<20); 73 74 static int __init parse_dma32_size_opt(char *p) 75 { 76 if (!p) 77 return -EINVAL; 78 dma32_bootmem_size = memparse(p, &p); 79 return 0; 80 } 81 early_param("dma32_size", parse_dma32_size_opt); 82 83 void __init dma32_reserve_bootmem(void) 84 { 85 unsigned long size, align; 86 if (max_pfn <= MAX_DMA32_PFN) 87 return; 88 89 /* 90 * check aperture_64.c allocate_aperture() for reason about 91 * using 512M as goal 92 */ 93 align = 64ULL<<20; 94 size = roundup(dma32_bootmem_size, align); 95 dma32_bootmem_ptr = __alloc_bootmem_nopanic(size, align, 96 512ULL<<20); 97 /* 98 * Kmemleak should not scan this block as it may not be mapped via the 99 * kernel direct mapping. 100 */ 101 kmemleak_ignore(dma32_bootmem_ptr); 102 if (dma32_bootmem_ptr) 103 dma32_bootmem_size = size; 104 else 105 dma32_bootmem_size = 0; 106 } 107 static void __init dma32_free_bootmem(void) 108 { 109 110 if (max_pfn <= MAX_DMA32_PFN) 111 return; 112 113 if (!dma32_bootmem_ptr) 114 return; 115 116 free_bootmem(__pa(dma32_bootmem_ptr), dma32_bootmem_size); 117 118 dma32_bootmem_ptr = NULL; 119 dma32_bootmem_size = 0; 120 } 121 #else 122 void __init dma32_reserve_bootmem(void) 123 { 124 } 125 static void __init dma32_free_bootmem(void) 126 { 127 } 128 129 #endif 130 131 void __init pci_iommu_alloc(void) 132 { 133 /* free the range so iommu could get some range less than 4G */ 134 dma32_free_bootmem(); 135 136 if (pci_xen_swiotlb_detect() || pci_swiotlb_detect()) 137 goto out; 138 139 gart_iommu_hole_init(); 140 141 detect_calgary(); 142 143 detect_intel_iommu(); 144 145 /* needs to be called after gart_iommu_hole_init */ 146 amd_iommu_detect(); 147 out: 148 pci_xen_swiotlb_init(); 149 150 pci_swiotlb_init(); 151 } 152 153 void *dma_generic_alloc_coherent(struct device *dev, size_t size, 154 dma_addr_t *dma_addr, gfp_t flag) 155 { 156 unsigned long dma_mask; 157 struct page *page; 158 dma_addr_t addr; 159 160 dma_mask = dma_alloc_coherent_mask(dev, flag); 161 162 flag |= __GFP_ZERO; 163 again: 164 page = alloc_pages_node(dev_to_node(dev), flag, get_order(size)); 165 if (!page) 166 return NULL; 167 168 addr = page_to_phys(page); 169 if (addr + size > dma_mask) { 170 __free_pages(page, get_order(size)); 171 172 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) { 173 flag = (flag & ~GFP_DMA32) | GFP_DMA; 174 goto again; 175 } 176 177 return NULL; 178 } 179 180 *dma_addr = addr; 181 return page_address(page); 182 } 183 184 /* 185 * See <Documentation/x86_64/boot-options.txt> for the iommu kernel parameter 186 * documentation. 187 */ 188 static __init int iommu_setup(char *p) 189 { 190 iommu_merge = 1; 191 192 if (!p) 193 return -EINVAL; 194 195 while (*p) { 196 if (!strncmp(p, "off", 3)) 197 no_iommu = 1; 198 /* gart_parse_options has more force support */ 199 if (!strncmp(p, "force", 5)) 200 force_iommu = 1; 201 if (!strncmp(p, "noforce", 7)) { 202 iommu_merge = 0; 203 force_iommu = 0; 204 } 205 206 if (!strncmp(p, "biomerge", 8)) { 207 iommu_merge = 1; 208 force_iommu = 1; 209 } 210 if (!strncmp(p, "panic", 5)) 211 panic_on_overflow = 1; 212 if (!strncmp(p, "nopanic", 7)) 213 panic_on_overflow = 0; 214 if (!strncmp(p, "merge", 5)) { 215 iommu_merge = 1; 216 force_iommu = 1; 217 } 218 if (!strncmp(p, "nomerge", 7)) 219 iommu_merge = 0; 220 if (!strncmp(p, "forcesac", 8)) 221 iommu_sac_force = 1; 222 if (!strncmp(p, "allowdac", 8)) 223 forbid_dac = 0; 224 if (!strncmp(p, "nodac", 5)) 225 forbid_dac = 1; 226 if (!strncmp(p, "usedac", 6)) { 227 forbid_dac = -1; 228 return 1; 229 } 230 #ifdef CONFIG_SWIOTLB 231 if (!strncmp(p, "soft", 4)) 232 swiotlb = 1; 233 #endif 234 if (!strncmp(p, "pt", 2)) 235 iommu_pass_through = 1; 236 237 gart_parse_options(p); 238 239 #ifdef CONFIG_CALGARY_IOMMU 240 if (!strncmp(p, "calgary", 7)) 241 use_calgary = 1; 242 #endif /* CONFIG_CALGARY_IOMMU */ 243 244 p += strcspn(p, ","); 245 if (*p == ',') 246 ++p; 247 } 248 return 0; 249 } 250 early_param("iommu", iommu_setup); 251 252 int dma_supported(struct device *dev, u64 mask) 253 { 254 struct dma_map_ops *ops = get_dma_ops(dev); 255 256 #ifdef CONFIG_PCI 257 if (mask > 0xffffffff && forbid_dac > 0) { 258 dev_info(dev, "PCI: Disallowing DAC for device\n"); 259 return 0; 260 } 261 #endif 262 263 if (ops->dma_supported) 264 return ops->dma_supported(dev, mask); 265 266 /* Copied from i386. Doesn't make much sense, because it will 267 only work for pci_alloc_coherent. 268 The caller just has to use GFP_DMA in this case. */ 269 if (mask < DMA_BIT_MASK(24)) 270 return 0; 271 272 /* Tell the device to use SAC when IOMMU force is on. This 273 allows the driver to use cheaper accesses in some cases. 274 275 Problem with this is that if we overflow the IOMMU area and 276 return DAC as fallback address the device may not handle it 277 correctly. 278 279 As a special case some controllers have a 39bit address 280 mode that is as efficient as 32bit (aic79xx). Don't force 281 SAC for these. Assume all masks <= 40 bits are of this 282 type. Normally this doesn't make any difference, but gives 283 more gentle handling of IOMMU overflow. */ 284 if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) { 285 dev_info(dev, "Force SAC with mask %Lx\n", mask); 286 return 0; 287 } 288 289 return 1; 290 } 291 EXPORT_SYMBOL(dma_supported); 292 293 static int __init pci_iommu_init(void) 294 { 295 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); 296 297 #ifdef CONFIG_PCI 298 dma_debug_add_bus(&pci_bus_type); 299 #endif 300 x86_init.iommu.iommu_init(); 301 302 if (swiotlb || xen_swiotlb) { 303 printk(KERN_INFO "PCI-DMA: " 304 "Using software bounce buffering for IO (SWIOTLB)\n"); 305 swiotlb_print_info(); 306 } else 307 swiotlb_free(); 308 309 return 0; 310 } 311 /* Must execute after PCI subsystem */ 312 rootfs_initcall(pci_iommu_init); 313 314 #ifdef CONFIG_PCI 315 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */ 316 317 static __devinit void via_no_dac(struct pci_dev *dev) 318 { 319 if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) { 320 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n"); 321 forbid_dac = 1; 322 } 323 } 324 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac); 325 #endif 326