arch/x86/kernel/pci-dma.c

   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