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1#include <linux/dma-mapping.h>
2#include <linux/dma-debug.h>
3#include <linux/dmar.h>
4#include <linux/export.h>
5#include <linux/bootmem.h>
6#include <linux/gfp.h>
7#include <linux/pci.h>
8#include <linux/kmemleak.h>
9
10#include <asm/proto.h>
11#include <asm/dma.h>
12#include <asm/iommu.h>
13#include <asm/gart.h>
14#include <asm/calgary.h>
15#include <asm/x86_init.h>
16#include <asm/iommu_table.h>
17
18static int forbid_dac __read_mostly;
19
20struct dma_map_ops *dma_ops = &nommu_dma_ops;
21EXPORT_SYMBOL(dma_ops);
22
23static int iommu_sac_force __read_mostly;
24
25#ifdef CONFIG_IOMMU_DEBUG
26int panic_on_overflow __read_mostly = 1;
27int force_iommu __read_mostly = 1;
28#else
29int panic_on_overflow __read_mostly = 0;
30int force_iommu __read_mostly = 0;
31#endif
32
33int iommu_merge __read_mostly = 0;
34
35int no_iommu __read_mostly;
36/* Set this to 1 if there is a HW IOMMU in the system */
37int iommu_detected __read_mostly = 0;
38
39/*
40 * This variable becomes 1 if iommu=pt is passed on the kernel command line.
41 * If this variable is 1, IOMMU implementations do no DMA translation for
42 * devices and allow every device to access to whole physical memory. This is
43 * useful if a user wants to use an IOMMU only for KVM device assignment to
44 * guests and not for driver dma translation.
45 */
46int iommu_pass_through __read_mostly;
47
48extern struct iommu_table_entry __iommu_table[], __iommu_table_end[];
49
50/* Dummy device used for NULL arguments (normally ISA). */
51struct device x86_dma_fallback_dev = {
52 .init_name = "fallback device",
53 .coherent_dma_mask = ISA_DMA_BIT_MASK,
54 .dma_mask = &x86_dma_fallback_dev.coherent_dma_mask,
55};
56EXPORT_SYMBOL(x86_dma_fallback_dev);
57
58/* Number of entries preallocated for DMA-API debugging */
59#define PREALLOC_DMA_DEBUG_ENTRIES 65536
60
61void __init pci_iommu_alloc(void)
62{
63 struct iommu_table_entry *p;
64
65 sort_iommu_table(__iommu_table, __iommu_table_end);
66 check_iommu_entries(__iommu_table, __iommu_table_end);
67
68 for (p = __iommu_table; p < __iommu_table_end; p++) {
69 if (p && p->detect && p->detect() > 0) {
70 p->flags |= IOMMU_DETECTED;
71 if (p->early_init)
72 p->early_init();
73 if (p->flags & IOMMU_FINISH_IF_DETECTED)
74 break;
75 }
76 }
77}
78void *dma_generic_alloc_coherent(struct device *dev, size_t size,
79 dma_addr_t *dma_addr, gfp_t flag,
80 unsigned long attrs)
81{
82 unsigned long dma_mask;
83 struct page *page;
84 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
85 dma_addr_t addr;
86
87 dma_mask = dma_alloc_coherent_mask(dev, flag);
88
89 flag &= ~__GFP_ZERO;
90again:
91 page = NULL;
92 /* CMA can be used only in the context which permits sleeping */
93 if (gfpflags_allow_blocking(flag)) {
94 page = dma_alloc_from_contiguous(dev, count, get_order(size));
95 if (page && page_to_phys(page) + size > dma_mask) {
96 dma_release_from_contiguous(dev, page, count);
97 page = NULL;
98 }
99 }
100 /* fallback */
101 if (!page)
102 page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
103 if (!page)
104 return NULL;
105
106 addr = page_to_phys(page);
107 if (addr + size > dma_mask) {
108 __free_pages(page, get_order(size));
109
110 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
111 flag = (flag & ~GFP_DMA32) | GFP_DMA;
112 goto again;
113 }
114
115 return NULL;
116 }
117 memset(page_address(page), 0, size);
118 *dma_addr = addr;
119 return page_address(page);
120}
121
122void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr,
123 dma_addr_t dma_addr, unsigned long attrs)
124{
125 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
126 struct page *page = virt_to_page(vaddr);
127
128 if (!dma_release_from_contiguous(dev, page, count))
129 free_pages((unsigned long)vaddr, get_order(size));
130}
131
132bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp)
133{
134 if (!*dev)
135 *dev = &x86_dma_fallback_dev;
136
137 *gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
138 *gfp = dma_alloc_coherent_gfp_flags(*dev, *gfp);
139
140 if (!is_device_dma_capable(*dev))
141 return false;
142 return true;
143
144}
145EXPORT_SYMBOL(arch_dma_alloc_attrs);
146
147/*
148 * See <Documentation/x86/x86_64/boot-options.txt> for the iommu kernel
149 * parameter documentation.
150 */
151static __init int iommu_setup(char *p)
152{
153 iommu_merge = 1;
154
155 if (!p)
156 return -EINVAL;
157
158 while (*p) {
159 if (!strncmp(p, "off", 3))
160 no_iommu = 1;
161 /* gart_parse_options has more force support */
162 if (!strncmp(p, "force", 5))
163 force_iommu = 1;
164 if (!strncmp(p, "noforce", 7)) {
165 iommu_merge = 0;
166 force_iommu = 0;
167 }
168
169 if (!strncmp(p, "biomerge", 8)) {
170 iommu_merge = 1;
171 force_iommu = 1;
172 }
173 if (!strncmp(p, "panic", 5))
174 panic_on_overflow = 1;
175 if (!strncmp(p, "nopanic", 7))
176 panic_on_overflow = 0;
177 if (!strncmp(p, "merge", 5)) {
178 iommu_merge = 1;
179 force_iommu = 1;
180 }
181 if (!strncmp(p, "nomerge", 7))
182 iommu_merge = 0;
183 if (!strncmp(p, "forcesac", 8))
184 iommu_sac_force = 1;
185 if (!strncmp(p, "allowdac", 8))
186 forbid_dac = 0;
187 if (!strncmp(p, "nodac", 5))
188 forbid_dac = 1;
189 if (!strncmp(p, "usedac", 6)) {
190 forbid_dac = -1;
191 return 1;
192 }
193#ifdef CONFIG_SWIOTLB
194 if (!strncmp(p, "soft", 4))
195 swiotlb = 1;
196#endif
197 if (!strncmp(p, "pt", 2))
198 iommu_pass_through = 1;
199
200 gart_parse_options(p);
201
202#ifdef CONFIG_CALGARY_IOMMU
203 if (!strncmp(p, "calgary", 7))
204 use_calgary = 1;
205#endif /* CONFIG_CALGARY_IOMMU */
206
207 p += strcspn(p, ",");
208 if (*p == ',')
209 ++p;
210 }
211 return 0;
212}
213early_param("iommu", iommu_setup);
214
215int dma_supported(struct device *dev, u64 mask)
216{
217 struct dma_map_ops *ops = get_dma_ops(dev);
218
219#ifdef CONFIG_PCI
220 if (mask > 0xffffffff && forbid_dac > 0) {
221 dev_info(dev, "PCI: Disallowing DAC for device\n");
222 return 0;
223 }
224#endif
225
226 if (ops->dma_supported)
227 return ops->dma_supported(dev, mask);
228
229 /* Copied from i386. Doesn't make much sense, because it will
230 only work for pci_alloc_coherent.
231 The caller just has to use GFP_DMA in this case. */
232 if (mask < DMA_BIT_MASK(24))
233 return 0;
234
235 /* Tell the device to use SAC when IOMMU force is on. This
236 allows the driver to use cheaper accesses in some cases.
237
238 Problem with this is that if we overflow the IOMMU area and
239 return DAC as fallback address the device may not handle it
240 correctly.
241
242 As a special case some controllers have a 39bit address
243 mode that is as efficient as 32bit (aic79xx). Don't force
244 SAC for these. Assume all masks <= 40 bits are of this
245 type. Normally this doesn't make any difference, but gives
246 more gentle handling of IOMMU overflow. */
247 if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) {
248 dev_info(dev, "Force SAC with mask %Lx\n", mask);
249 return 0;
250 }
251
252 return 1;
253}
254EXPORT_SYMBOL(dma_supported);
255
256static int __init pci_iommu_init(void)
257{
258 struct iommu_table_entry *p;
259 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
260
261#ifdef CONFIG_PCI
262 dma_debug_add_bus(&pci_bus_type);
263#endif
264 x86_init.iommu.iommu_init();
265
266 for (p = __iommu_table; p < __iommu_table_end; p++) {
267 if (p && (p->flags & IOMMU_DETECTED) && p->late_init)
268 p->late_init();
269 }
270
271 return 0;
272}
273/* Must execute after PCI subsystem */
274rootfs_initcall(pci_iommu_init);
275
276#ifdef CONFIG_PCI
277/* Many VIA bridges seem to corrupt data for DAC. Disable it here */
278
279static void via_no_dac(struct pci_dev *dev)
280{
281 if (forbid_dac == 0) {
282 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
283 forbid_dac = 1;
284 }
285}
286DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
287 PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);
288#endif
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