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;
49 * Group multi-function PCI devices into a single device-group for the
50 * iommu_device_group interface. This tells the iommu driver to pretend
51 * it cannot distinguish between functions of a device, exposing only one
52 * group for the device. Useful for disallowing use of individual PCI
53 * functions from userspace drivers.
55 int iommu_group_mf __read_mostly;
57 extern struct iommu_table_entry __iommu_table[], __iommu_table_end[];
59 /* Dummy device used for NULL arguments (normally ISA). */
60 struct device x86_dma_fallback_dev = {
61 .init_name = "fallback device",
62 .coherent_dma_mask = ISA_DMA_BIT_MASK,
63 .dma_mask = &x86_dma_fallback_dev.coherent_dma_mask,
65 EXPORT_SYMBOL(x86_dma_fallback_dev);
67 /* Number of entries preallocated for DMA-API debugging */
68 #define PREALLOC_DMA_DEBUG_ENTRIES 32768
70 int dma_set_mask(struct device *dev, u64 mask)
72 if (!dev->dma_mask || !dma_supported(dev, mask))
75 *dev->dma_mask = mask;
79 EXPORT_SYMBOL(dma_set_mask);
81 void __init pci_iommu_alloc(void)
83 struct iommu_table_entry *p;
85 sort_iommu_table(__iommu_table, __iommu_table_end);
86 check_iommu_entries(__iommu_table, __iommu_table_end);
88 for (p = __iommu_table; p < __iommu_table_end; p++) {
89 if (p && p->detect && p->detect() > 0) {
90 p->flags |= IOMMU_DETECTED;
93 if (p->flags & IOMMU_FINISH_IF_DETECTED)
98 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
99 dma_addr_t *dma_addr, gfp_t flag,
100 struct dma_attrs *attrs)
102 unsigned long dma_mask;
104 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
107 dma_mask = dma_alloc_coherent_mask(dev, flag);
112 if (!(flag & GFP_ATOMIC))
113 page = dma_alloc_from_contiguous(dev, count, get_order(size));
115 page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
119 addr = page_to_phys(page);
120 if (addr + size > dma_mask) {
121 __free_pages(page, get_order(size));
123 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
124 flag = (flag & ~GFP_DMA32) | GFP_DMA;
132 return page_address(page);
135 void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr,
136 dma_addr_t dma_addr, struct dma_attrs *attrs)
138 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
139 struct page *page = virt_to_page(vaddr);
141 if (!dma_release_from_contiguous(dev, page, count))
142 free_pages((unsigned long)vaddr, get_order(size));
146 * See <Documentation/x86/x86_64/boot-options.txt> for the iommu kernel
147 * parameter documentation.
149 static __init int iommu_setup(char *p)
157 if (!strncmp(p, "off", 3))
159 /* gart_parse_options has more force support */
160 if (!strncmp(p, "force", 5))
162 if (!strncmp(p, "noforce", 7)) {
167 if (!strncmp(p, "biomerge", 8)) {
171 if (!strncmp(p, "panic", 5))
172 panic_on_overflow = 1;
173 if (!strncmp(p, "nopanic", 7))
174 panic_on_overflow = 0;
175 if (!strncmp(p, "merge", 5)) {
179 if (!strncmp(p, "nomerge", 7))
181 if (!strncmp(p, "forcesac", 8))
183 if (!strncmp(p, "allowdac", 8))
185 if (!strncmp(p, "nodac", 5))
187 if (!strncmp(p, "usedac", 6)) {
191 #ifdef CONFIG_SWIOTLB
192 if (!strncmp(p, "soft", 4))
195 if (!strncmp(p, "pt", 2))
196 iommu_pass_through = 1;
197 if (!strncmp(p, "group_mf", 8))
200 gart_parse_options(p);
202 #ifdef CONFIG_CALGARY_IOMMU
203 if (!strncmp(p, "calgary", 7))
205 #endif /* CONFIG_CALGARY_IOMMU */
207 p += strcspn(p, ",");
213 early_param("iommu", iommu_setup);
215 int dma_supported(struct device *dev, u64 mask)
217 struct dma_map_ops *ops = get_dma_ops(dev);
220 if (mask > 0xffffffff && forbid_dac > 0) {
221 dev_info(dev, "PCI: Disallowing DAC for device\n");
226 if (ops->dma_supported)
227 return ops->dma_supported(dev, mask);
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))
235 /* Tell the device to use SAC when IOMMU force is on. This
236 allows the driver to use cheaper accesses in some cases.
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
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);
254 EXPORT_SYMBOL(dma_supported);
256 static int __init pci_iommu_init(void)
258 struct iommu_table_entry *p;
259 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
262 dma_debug_add_bus(&pci_bus_type);
264 x86_init.iommu.iommu_init();
266 for (p = __iommu_table; p < __iommu_table_end; p++) {
267 if (p && (p->flags & IOMMU_DETECTED) && p->late_init)
273 /* Must execute after PCI subsystem */
274 rootfs_initcall(pci_iommu_init);
277 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
279 static __devinit void via_no_dac(struct pci_dev *dev)
281 if (forbid_dac == 0) {
282 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
286 DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
287 PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);