https://github.com/torvalds/linux
Tip revision: d07f6ca923ea0927a1024dfccafc5b53b61cfecc authored by Linus Torvalds on 16 May 2021, 22:27:44 UTC
Linux 5.13-rc2
Linux 5.13-rc2
Tip revision: d07f6ca
pci-dma.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/dma-map-ops.h>
#include <linux/dma-direct.h>
#include <linux/iommu.h>
#include <linux/dmar.h>
#include <linux/export.h>
#include <linux/memblock.h>
#include <linux/gfp.h>
#include <linux/pci.h>
#include <asm/proto.h>
#include <asm/dma.h>
#include <asm/iommu.h>
#include <asm/gart.h>
#include <asm/x86_init.h>
#include <asm/iommu_table.h>
static bool disable_dac_quirk __read_mostly;
const struct dma_map_ops *dma_ops;
EXPORT_SYMBOL(dma_ops);
#ifdef CONFIG_IOMMU_DEBUG
int panic_on_overflow __read_mostly = 1;
int force_iommu __read_mostly = 1;
#else
int panic_on_overflow __read_mostly = 0;
int force_iommu __read_mostly = 0;
#endif
int iommu_merge __read_mostly = 0;
int no_iommu __read_mostly;
/* Set this to 1 if there is a HW IOMMU in the system */
int iommu_detected __read_mostly = 0;
extern struct iommu_table_entry __iommu_table[], __iommu_table_end[];
void __init pci_iommu_alloc(void)
{
struct iommu_table_entry *p;
sort_iommu_table(__iommu_table, __iommu_table_end);
check_iommu_entries(__iommu_table, __iommu_table_end);
for (p = __iommu_table; p < __iommu_table_end; p++) {
if (p && p->detect && p->detect() > 0) {
p->flags |= IOMMU_DETECTED;
if (p->early_init)
p->early_init();
if (p->flags & IOMMU_FINISH_IF_DETECTED)
break;
}
}
}
/*
* See <Documentation/x86/x86_64/boot-options.rst> for the iommu kernel
* parameter documentation.
*/
static __init int iommu_setup(char *p)
{
iommu_merge = 1;
if (!p)
return -EINVAL;
while (*p) {
if (!strncmp(p, "off", 3))
no_iommu = 1;
/* gart_parse_options has more force support */
if (!strncmp(p, "force", 5))
force_iommu = 1;
if (!strncmp(p, "noforce", 7)) {
iommu_merge = 0;
force_iommu = 0;
}
if (!strncmp(p, "biomerge", 8)) {
iommu_merge = 1;
force_iommu = 1;
}
if (!strncmp(p, "panic", 5))
panic_on_overflow = 1;
if (!strncmp(p, "nopanic", 7))
panic_on_overflow = 0;
if (!strncmp(p, "merge", 5)) {
iommu_merge = 1;
force_iommu = 1;
}
if (!strncmp(p, "nomerge", 7))
iommu_merge = 0;
if (!strncmp(p, "forcesac", 8))
pr_warn("forcesac option ignored.\n");
if (!strncmp(p, "allowdac", 8))
pr_warn("allowdac option ignored.\n");
if (!strncmp(p, "nodac", 5))
pr_warn("nodac option ignored.\n");
if (!strncmp(p, "usedac", 6)) {
disable_dac_quirk = true;
return 1;
}
#ifdef CONFIG_SWIOTLB
if (!strncmp(p, "soft", 4))
swiotlb = 1;
#endif
if (!strncmp(p, "pt", 2))
iommu_set_default_passthrough(true);
if (!strncmp(p, "nopt", 4))
iommu_set_default_translated(true);
gart_parse_options(p);
p += strcspn(p, ",");
if (*p == ',')
++p;
}
return 0;
}
early_param("iommu", iommu_setup);
static int __init pci_iommu_init(void)
{
struct iommu_table_entry *p;
x86_init.iommu.iommu_init();
for (p = __iommu_table; p < __iommu_table_end; p++) {
if (p && (p->flags & IOMMU_DETECTED) && p->late_init)
p->late_init();
}
return 0;
}
/* Must execute after PCI subsystem */
rootfs_initcall(pci_iommu_init);
#ifdef CONFIG_PCI
/* Many VIA bridges seem to corrupt data for DAC. Disable it here */
static int via_no_dac_cb(struct pci_dev *pdev, void *data)
{
pdev->dev.bus_dma_limit = DMA_BIT_MASK(32);
return 0;
}
static void via_no_dac(struct pci_dev *dev)
{
if (!disable_dac_quirk) {
dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
pci_walk_bus(dev->subordinate, via_no_dac_cb, NULL);
}
}
DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);
#endif