summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/pci-dma.c
blob: 5dcedad21dffa2a0e5428c599354c37ff1fc84be (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
// SPDX-License-Identifier: GPL-2.0
#include <linux/dma-direct.h>
#include <linux/dma-debug.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