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;
103 struct page *page = NULL;
104 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
107 dma_mask = dma_alloc_coherent_mask(dev, flag);
111 if (!(flag & GFP_ATOMIC))
112 page = dma_alloc_from_contiguous(dev, count, get_order(size));
114 page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
118 addr = page_to_phys(page);
119 if (addr + size > dma_mask) {
120 __free_pages(page, get_order(size));
122 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
123 flag = (flag & ~GFP_DMA32) | GFP_DMA;
131 return page_address(page);
134 void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr,
135 dma_addr_t dma_addr, struct dma_attrs *attrs)
137 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
138 struct page *page = virt_to_page(vaddr);
140 if (!dma_release_from_contiguous(dev, page, count))
141 free_pages((unsigned long)vaddr, get_order(size));
145 * See <Documentation/x86/x86_64/boot-options.txt> for the iommu kernel
146 * parameter documentation.
148 static __init int iommu_setup(char *p)
156 if (!strncmp(p, "off", 3))
158 /* gart_parse_options has more force support */
159 if (!strncmp(p, "force", 5))
161 if (!strncmp(p, "noforce", 7)) {
166 if (!strncmp(p, "biomerge", 8)) {
170 if (!strncmp(p, "panic", 5))
171 panic_on_overflow = 1;
172 if (!strncmp(p, "nopanic", 7))
173 panic_on_overflow = 0;
174 if (!strncmp(p, "merge", 5)) {
178 if (!strncmp(p, "nomerge", 7))
180 if (!strncmp(p, "forcesac", 8))
182 if (!strncmp(p, "allowdac", 8))
184 if (!strncmp(p, "nodac", 5))
186 if (!strncmp(p, "usedac", 6)) {
190 #ifdef CONFIG_SWIOTLB
191 if (!strncmp(p, "soft", 4))
194 if (!strncmp(p, "pt", 2))
195 iommu_pass_through = 1;
196 if (!strncmp(p, "group_mf", 8))
199 gart_parse_options(p);
201 #ifdef CONFIG_CALGARY_IOMMU
202 if (!strncmp(p, "calgary", 7))
204 #endif /* CONFIG_CALGARY_IOMMU */
206 p += strcspn(p, ",");
212 early_param("iommu", iommu_setup);
214 int dma_supported(struct device *dev, u64 mask)
216 struct dma_map_ops *ops = get_dma_ops(dev);
219 if (mask > 0xffffffff && forbid_dac > 0) {
220 dev_info(dev, "PCI: Disallowing DAC for device\n");
225 if (ops->dma_supported)
226 return ops->dma_supported(dev, mask);
228 /* Copied from i386. Doesn't make much sense, because it will
229 only work for pci_alloc_coherent.
230 The caller just has to use GFP_DMA in this case. */
231 if (mask < DMA_BIT_MASK(24))
234 /* Tell the device to use SAC when IOMMU force is on. This
235 allows the driver to use cheaper accesses in some cases.
237 Problem with this is that if we overflow the IOMMU area and
238 return DAC as fallback address the device may not handle it
241 As a special case some controllers have a 39bit address
242 mode that is as efficient as 32bit (aic79xx). Don't force
243 SAC for these. Assume all masks <= 40 bits are of this
244 type. Normally this doesn't make any difference, but gives
245 more gentle handling of IOMMU overflow. */
246 if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) {
247 dev_info(dev, "Force SAC with mask %Lx\n", mask);
253 EXPORT_SYMBOL(dma_supported);
255 static int __init pci_iommu_init(void)
257 struct iommu_table_entry *p;
258 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
261 dma_debug_add_bus(&pci_bus_type);
263 x86_init.iommu.iommu_init();
265 for (p = __iommu_table; p < __iommu_table_end; p++) {
266 if (p && (p->flags & IOMMU_DETECTED) && p->late_init)
272 /* Must execute after PCI subsystem */
273 rootfs_initcall(pci_iommu_init);
276 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
278 static __devinit void via_no_dac(struct pci_dev *dev)
280 if (forbid_dac == 0) {
281 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
285 DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
286 PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);