linux/arch/x86/kernel/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 <linux/amd-iommu.h>

#include <asm/proto.h>
#include <asm/dma.h>
#include <asm/iommu.h>
#include <asm/gart.h>
#include <asm/x86_init.h>

#include <xen/xen.h>
#include <xen/swiotlb-xen.h>

static bool disable_dac_quirk __read_mostly;

const struct dma_map_ops *dma_ops;
EXPORT_SYMBOL(…);

#ifdef CONFIG_IOMMU_DEBUG
int panic_on_overflow __read_mostly = …;
int force_iommu __read_mostly = …;
#else
int panic_on_overflow __read_mostly = 0;
int force_iommu __read_mostly = 0;
#endif

int iommu_merge __read_mostly = …;

int no_iommu __read_mostly;
/* Set this to 1 if there is a HW IOMMU in the system */
int iommu_detected __read_mostly = …;

#ifdef CONFIG_SWIOTLB
bool x86_swiotlb_enable;
static unsigned int x86_swiotlb_flags;

static void __init pci_swiotlb_detect(void)
{ … }
#else
static inline void __init pci_swiotlb_detect(void)
{
}
#define x86_swiotlb_flags …
#endif /* CONFIG_SWIOTLB */

#ifdef CONFIG_SWIOTLB_XEN
static bool xen_swiotlb_enabled(void)
{ … }

static void __init pci_xen_swiotlb_init(void)
{ … }
#else
static inline void __init pci_xen_swiotlb_init(void)
{
}
#endif /* CONFIG_SWIOTLB_XEN */

void __init pci_iommu_alloc(void)
{ … }

/*
 * See <Documentation/arch/x86/x86_64/boot-options.rst> for the iommu kernel
 * parameter documentation.
 */
static __init int iommu_setup(char *p)
{ … }
early_param(…);

static int __init pci_iommu_init(void)
{ … }
/* 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)
{ … }

static void via_no_dac(struct pci_dev *dev)
{ … }
DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
				PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);
#endif