arch/x86/kernel/pci-dma.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/dma-direct.h>
   3 #include <linux/dma-debug.h>
   4 #include <linux/iommu.h>
   5 #include <linux/dmar.h>
   6 #include <linux/export.h>
   7 #include <linux/memblock.h>
   8 #include <linux/gfp.h>
   9 #include <linux/pci.h>
  10
  11 #include <asm/proto.h>
  12 #include <asm/dma.h>
  13 #include <asm/iommu.h>
  14 #include <asm/gart.h>
  15 #include <asm/x86_init.h>
  16 #include <asm/iommu_table.h>
  17
  18 static bool disable_dac_quirk __read_mostly;
  19
  20 const struct dma_map_ops *dma_ops;
  21 EXPORT_SYMBOL(dma_ops);
  22
  23 #ifdef CONFIG_IOMMU_DEBUG
  24 int panic_on_overflow __read_mostly = 1;
  25 int force_iommu __read_mostly = 1;
  26 #else
  27 int panic_on_overflow __read_mostly = 0;
  28 int force_iommu __read_mostly = 0;
  29 #endif
  30
  31 int iommu_merge __read_mostly = 0;
  32
  33 int no_iommu __read_mostly;
  34 /* Set this to 1 if there is a HW IOMMU in the system */
  35 int iommu_detected __read_mostly = 0;
  36
  37 extern struct iommu_table_entry __iommu_table[], __iommu_table_end[];
  38
  39 void __init pci_iommu_alloc(void)
  40 {
  41         struct iommu_table_entry *p;
  42
  43         sort_iommu_table(__iommu_table, __iommu_table_end);
  44         check_iommu_entries(__iommu_table, __iommu_table_end);
  45
  46         for (p = __iommu_table; p < __iommu_table_end; p++) {
  47                 if (p && p->detect && p->detect() > 0) {
  48                         p->flags |= IOMMU_DETECTED;
  49                         if (p->early_init)
  50                                 p->early_init();
  51                         if (p->flags & IOMMU_FINISH_IF_DETECTED)
  52                                 break;
  53                 }
  54         }
  55 }
  56
  57 /*
  58  * See <Documentation/x86/x86_64/boot-options.rst> for the iommu kernel
  59  * parameter documentation.
  60  */
  61 static __init int iommu_setup(char *p)
  62 {
  63         iommu_merge = 1;
  64
  65         if (!p)
  66                 return -EINVAL;
  67
  68         while (*p) {
  69                 if (!strncmp(p, "off", 3))
  70                         no_iommu = 1;
  71                 /* gart_parse_options has more force support */
  72                 if (!strncmp(p, "force", 5))
  73                         force_iommu = 1;
  74                 if (!strncmp(p, "noforce", 7)) {
  75                         iommu_merge = 0;
  76                         force_iommu = 0;
  77                 }
  78
  79                 if (!strncmp(p, "biomerge", 8)) {
  80                         iommu_merge = 1;
  81                         force_iommu = 1;
  82                 }
  83                 if (!strncmp(p, "panic", 5))
  84                         panic_on_overflow = 1;
  85                 if (!strncmp(p, "nopanic", 7))
  86                         panic_on_overflow = 0;
  87                 if (!strncmp(p, "merge", 5)) {
  88                         iommu_merge = 1;
  89                         force_iommu = 1;
  90                 }
  91                 if (!strncmp(p, "nomerge", 7))
  92                         iommu_merge = 0;
  93                 if (!strncmp(p, "forcesac", 8))
  94                         pr_warn("forcesac option ignored.\n");
  95                 if (!strncmp(p, "allowdac", 8))
  96                         pr_warn("allowdac option ignored.\n");
  97                 if (!strncmp(p, "nodac", 5))
  98                         pr_warn("nodac option ignored.\n");
  99                 if (!strncmp(p, "usedac", 6)) {
 100                         disable_dac_quirk = true;
 101                         return 1;
 102                 }
 103 #ifdef CONFIG_SWIOTLB
 104                 if (!strncmp(p, "soft", 4))
 105                         swiotlb = 1;
 106 #endif
 107                 if (!strncmp(p, "pt", 2))
 108                         iommu_set_default_passthrough(true);
 109                 if (!strncmp(p, "nopt", 4))
 110                         iommu_set_default_translated(true);
 111
 112                 gart_parse_options(p);
 113
 114                 p += strcspn(p, ",");
 115                 if (*p == ',')
 116                         ++p;
 117         }
 118         return 0;
 119 }
 120 early_param("iommu", iommu_setup);
 121
 122 static int __init pci_iommu_init(void)
 123 {
 124         struct iommu_table_entry *p;
 125
 126         x86_init.iommu.iommu_init();
 127
 128         for (p = __iommu_table; p < __iommu_table_end; p++) {
 129                 if (p && (p->flags & IOMMU_DETECTED) && p->late_init)
 130                         p->late_init();
 131         }
 132
 133         return 0;
 134 }
 135 /* Must execute after PCI subsystem */
 136 rootfs_initcall(pci_iommu_init);
 137
 138 #ifdef CONFIG_PCI
 139 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
 140
 141 static int via_no_dac_cb(struct pci_dev *pdev, void *data)
 142 {
 143         pdev->dev.bus_dma_limit = DMA_BIT_MASK(32);
 144         return 0;
 145 }
 146
 147 static void via_no_dac(struct pci_dev *dev)
 148 {
 149         if (!disable_dac_quirk) {
 150                 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
 151                 pci_walk_bus(dev->subordinate, via_no_dac_cb, NULL);
 152         }
 153 }
 154 DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
 155                                 PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);
 156 #endif