LXR linux/arch/x86/kernel/pci-dma.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/dma-map-ops.h>
   3#include <linux/dma-direct.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
  18static bool disable_dac_quirk __read_mostly;
  19
  20const struct dma_map_ops *dma_ops;
  21EXPORT_SYMBOL(dma_ops);
  22
  23#ifdef CONFIG_IOMMU_DEBUG
  24int panic_on_overflow __read_mostly = 1;
  25int force_iommu __read_mostly = 1;
  26#else
  27int panic_on_overflow __read_mostly = 0;
  28int force_iommu __read_mostly = 0;
  29#endif
  30
  31int iommu_merge __read_mostly = 0;
  32
  33int no_iommu __read_mostly;
  34/* Set this to 1 if there is a HW IOMMU in the system */
  35int iommu_detected __read_mostly = 0;
  36
  37extern struct iommu_table_entry __iommu_table[], __iommu_table_end[];
  38
  39void __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 */
  61static __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}
 120early_param("iommu", iommu_setup);
 121
 122static 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 */
 136rootfs_initcall(pci_iommu_init);
 137
 138#ifdef CONFIG_PCI
 139/* Many VIA bridges seem to corrupt data for DAC. Disable it here */
 140
 141static 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
 147static 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}
 154DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
 155                                PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);
 156#endif
 157