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;
106 dma_mask = dma_alloc_coherent_mask(dev, flag);
110 page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
114 addr = page_to_phys(page);
115 if (addr + size > dma_mask) {
116 __free_pages(page, get_order(size));
118 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
119 flag = (flag & ~GFP_DMA32) | GFP_DMA;
127 return page_address(page);
131 * See <Documentation/x86/x86_64/boot-options.txt> for the iommu kernel
132 * parameter documentation.
134 static __init int iommu_setup(char *p)
142 if (!strncmp(p, "off", 3))
144 /* gart_parse_options has more force support */
145 if (!strncmp(p, "force", 5))
147 if (!strncmp(p, "noforce", 7)) {
152 if (!strncmp(p, "biomerge", 8)) {
156 if (!strncmp(p, "panic", 5))
157 panic_on_overflow = 1;
158 if (!strncmp(p, "nopanic", 7))
159 panic_on_overflow = 0;
160 if (!strncmp(p, "merge", 5)) {
164 if (!strncmp(p, "nomerge", 7))
166 if (!strncmp(p, "forcesac", 8))
168 if (!strncmp(p, "allowdac", 8))
170 if (!strncmp(p, "nodac", 5))
172 if (!strncmp(p, "usedac", 6)) {
176 #ifdef CONFIG_SWIOTLB
177 if (!strncmp(p, "soft", 4))
180 if (!strncmp(p, "pt", 2))
181 iommu_pass_through = 1;
182 if (!strncmp(p, "group_mf", 8))
185 gart_parse_options(p);
187 #ifdef CONFIG_CALGARY_IOMMU
188 if (!strncmp(p, "calgary", 7))
190 #endif /* CONFIG_CALGARY_IOMMU */
192 p += strcspn(p, ",");
198 early_param("iommu", iommu_setup);
200 int dma_supported(struct device *dev, u64 mask)
202 struct dma_map_ops *ops = get_dma_ops(dev);
205 if (mask > 0xffffffff && forbid_dac > 0) {
206 dev_info(dev, "PCI: Disallowing DAC for device\n");
211 if (ops->dma_supported)
212 return ops->dma_supported(dev, mask);
214 /* Copied from i386. Doesn't make much sense, because it will
215 only work for pci_alloc_coherent.
216 The caller just has to use GFP_DMA in this case. */
217 if (mask < DMA_BIT_MASK(24))
220 /* Tell the device to use SAC when IOMMU force is on. This
221 allows the driver to use cheaper accesses in some cases.
223 Problem with this is that if we overflow the IOMMU area and
224 return DAC as fallback address the device may not handle it
227 As a special case some controllers have a 39bit address
228 mode that is as efficient as 32bit (aic79xx). Don't force
229 SAC for these. Assume all masks <= 40 bits are of this
230 type. Normally this doesn't make any difference, but gives
231 more gentle handling of IOMMU overflow. */
232 if (iommu_sac_force && (mask >= DMA_BIT_MASK(40))) {
233 dev_info(dev, "Force SAC with mask %Lx\n", mask);
239 EXPORT_SYMBOL(dma_supported);
241 static int __init pci_iommu_init(void)
243 struct iommu_table_entry *p;
244 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
247 dma_debug_add_bus(&pci_bus_type);
249 x86_init.iommu.iommu_init();
251 for (p = __iommu_table; p < __iommu_table_end; p++) {
252 if (p && (p->flags & IOMMU_DETECTED) && p->late_init)
258 /* Must execute after PCI subsystem */
259 rootfs_initcall(pci_iommu_init);
262 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
264 static __devinit void via_no_dac(struct pci_dev *dev)
266 if (forbid_dac == 0) {
267 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
271 DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
272 PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);