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>
8 #include <linux/kmemleak.h>
10 #include <asm/proto.h>
12 #include <asm/iommu.h>
14 #include <asm/calgary.h>
15 #include <asm/x86_init.h>
16 #include <asm/iommu_table.h>
18 static int forbid_dac __read_mostly;
20 struct dma_map_ops *dma_ops = &nommu_dma_ops;
21 EXPORT_SYMBOL(dma_ops);
23 static int iommu_sac_force __read_mostly;
25 #ifdef CONFIG_IOMMU_DEBUG
26 int panic_on_overflow __read_mostly = 1;
27 int force_iommu __read_mostly = 1;
29 int panic_on_overflow __read_mostly = 0;
30 int force_iommu __read_mostly = 0;
33 int iommu_merge __read_mostly = 0;
35 int no_iommu __read_mostly;
36 /* Set this to 1 if there is a HW IOMMU in the system */
37 int iommu_detected __read_mostly = 0;
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.
46 int iommu_pass_through __read_mostly;
48 extern struct iommu_table_entry __iommu_table[], __iommu_table_end[];
50 /* Dummy device used for NULL arguments (normally ISA). */
51 struct 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,
56 EXPORT_SYMBOL(x86_dma_fallback_dev);
58 /* Number of entries preallocated for DMA-API debugging */
59 #define PREALLOC_DMA_DEBUG_ENTRIES 65536
61 int dma_set_mask(struct device *dev, u64 mask)
63 if (!dev->dma_mask || !dma_supported(dev, mask))
66 *dev->dma_mask = mask;
70 EXPORT_SYMBOL(dma_set_mask);
72 void __init pci_iommu_alloc(void)
74 struct iommu_table_entry *p;
76 sort_iommu_table(__iommu_table, __iommu_table_end);
77 check_iommu_entries(__iommu_table, __iommu_table_end);
79 for (p = __iommu_table; p < __iommu_table_end; p++) {
80 if (p && p->detect && p->detect() > 0) {
81 p->flags |= IOMMU_DETECTED;
84 if (p->flags & IOMMU_FINISH_IF_DETECTED)
89 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
90 dma_addr_t *dma_addr, gfp_t flag,
91 struct dma_attrs *attrs)
93 unsigned long dma_mask;
95 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
98 dma_mask = dma_alloc_coherent_mask(dev, flag);
103 /* CMA can be used only in the context which permits sleeping */
104 if (flag & __GFP_WAIT) {
105 page = dma_alloc_from_contiguous(dev, count, get_order(size));
106 if (page && page_to_phys(page) + size > dma_mask) {
107 dma_release_from_contiguous(dev, page, count);
113 page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
117 addr = page_to_phys(page);
118 if (addr + size > dma_mask) {
119 __free_pages(page, get_order(size));
121 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
122 flag = (flag & ~GFP_DMA32) | GFP_DMA;
128 memset(page_address(page), 0, size);
130 return page_address(page);
133 void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr,
134 dma_addr_t dma_addr, struct dma_attrs *attrs)
136 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
137 struct page *page = virt_to_page(vaddr);
139 if (!dma_release_from_contiguous(dev, page, count))
140 free_pages((unsigned long)vaddr, get_order(size));
143 bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp)
145 *gfp = dma_alloc_coherent_gfp_flags(*dev, *gfp);
146 *gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
149 *dev = &x86_dma_fallback_dev;
150 if (!is_device_dma_capable(*dev))
155 EXPORT_SYMBOL(arch_dma_alloc_attrs);
158 * See <Documentation/x86/x86_64/boot-options.txt> for the iommu kernel
159 * parameter documentation.
161 static __init int iommu_setup(char *p)
169 if (!strncmp(p, "off", 3))
171 /* gart_parse_options has more force support */
172 if (!strncmp(p, "force", 5))
174 if (!strncmp(p, "noforce", 7)) {
179 if (!strncmp(p, "biomerge", 8)) {
183 if (!strncmp(p, "panic", 5))
184 panic_on_overflow = 1;
185 if (!strncmp(p, "nopanic", 7))
186 panic_on_overflow = 0;
187 if (!strncmp(p, "merge", 5)) {
191 if (!strncmp(p, "nomerge", 7))
193 if (!strncmp(p, "forcesac", 8))
195 if (!strncmp(p, "allowdac", 8))
197 if (!strncmp(p, "nodac", 5))
199 if (!strncmp(p, "usedac", 6)) {
203 #ifdef CONFIG_SWIOTLB
204 if (!strncmp(p, "soft", 4))
207 if (!strncmp(p, "pt", 2))
208 iommu_pass_through = 1;
210 gart_parse_options(p);
212 #ifdef CONFIG_CALGARY_IOMMU
213 if (!strncmp(p, "calgary", 7))
215 #endif /* CONFIG_CALGARY_IOMMU */
217 p += strcspn(p, ",");
223 early_param("iommu", iommu_setup);
225 int dma_supported(struct device *dev, u64 mask)
227 struct dma_map_ops *ops = get_dma_ops(dev);
230 if (mask > 0xffffffff && forbid_dac > 0) {
231 dev_info(dev, "PCI: Disallowing DAC for device\n");
236 if (ops->dma_supported)
237 return ops->dma_supported(dev, mask);
239 /* Copied from i386. Doesn't make much sense, because it will
240 only work for pci_alloc_coherent.
241 The caller just has to use GFP_DMA in this case. */
242 if (mask < DMA_BIT_MASK(24))
245 /* Tell the device to use SAC when IOMMU force is on. This
246 allows the driver to use cheaper accesses in some cases.
248 Problem with this is that if we overflow the IOMMU area and
249 return DAC as fallback address the device may not handle it
252 As a special case some controllers have a 39bit address
253 mode that is as efficient as 32bit (aic79xx). Don't force
254 SAC for these. Assume all masks <= 40 bits are of this
255 type. Normally this doesn't make any difference, but gives
256 more gentle handling of IOMMU overflow. */
257 if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) {
258 dev_info(dev, "Force SAC with mask %Lx\n", mask);
264 EXPORT_SYMBOL(dma_supported);
266 static int __init pci_iommu_init(void)
268 struct iommu_table_entry *p;
269 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
272 dma_debug_add_bus(&pci_bus_type);
274 x86_init.iommu.iommu_init();
276 for (p = __iommu_table; p < __iommu_table_end; p++) {
277 if (p && (p->flags & IOMMU_DETECTED) && p->late_init)
283 /* Must execute after PCI subsystem */
284 rootfs_initcall(pci_iommu_init);
287 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
289 static void via_no_dac(struct pci_dev *dev)
291 if (forbid_dac == 0) {
292 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
296 DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
297 PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);