1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 2017 IBM Corp.
4 */
5
6 #include <linux/hugetlb.h>
7 #include <linux/sched/mm.h>
8 #include <asm/pnv-pci.h>
9 #include <misc/cxllib.h>
10
11 #include "cxl.h"
12
13 #define CXL_INVALID_DRA ~0ull
14 #define CXL_DUMMY_READ_SIZE 128
15 #define CXL_DUMMY_READ_ALIGN 8
16 #define CXL_CAPI_WINDOW_START 0x2000000000000ull
17 #define CXL_CAPI_WINDOW_LOG_SIZE 48
18 #define CXL_XSL_CONFIG_CURRENT_VERSION CXL_XSL_CONFIG_VERSION1
19
20
cxllib_slot_is_supported(struct pci_dev * dev,unsigned long flags)21 bool cxllib_slot_is_supported(struct pci_dev *dev, unsigned long flags)
22 {
23 int rc;
24 u32 phb_index;
25 u64 chip_id, capp_unit_id;
26
27 /* No flags currently supported */
28 if (flags)
29 return false;
30
31 if (!cpu_has_feature(CPU_FTR_HVMODE))
32 return false;
33
34 if (!cxl_is_power9())
35 return false;
36
37 if (cxl_slot_is_switched(dev))
38 return false;
39
40 /* on p9, some pci slots are not connected to a CAPP unit */
41 rc = cxl_calc_capp_routing(dev, &chip_id, &phb_index, &capp_unit_id);
42 if (rc)
43 return false;
44
45 return true;
46 }
47 EXPORT_SYMBOL_GPL(cxllib_slot_is_supported);
48
49 static DEFINE_MUTEX(dra_mutex);
50 static u64 dummy_read_addr = CXL_INVALID_DRA;
51
allocate_dummy_read_buf(void)52 static int allocate_dummy_read_buf(void)
53 {
54 u64 buf, vaddr;
55 size_t buf_size;
56
57 /*
58 * Dummy read buffer is 128-byte long, aligned on a
59 * 256-byte boundary and we need the physical address.
60 */
61 buf_size = CXL_DUMMY_READ_SIZE + (1ull << CXL_DUMMY_READ_ALIGN);
62 buf = (u64) kzalloc(buf_size, GFP_KERNEL);
63 if (!buf)
64 return -ENOMEM;
65
66 vaddr = (buf + (1ull << CXL_DUMMY_READ_ALIGN) - 1) &
67 (~0ull << CXL_DUMMY_READ_ALIGN);
68
69 WARN((vaddr + CXL_DUMMY_READ_SIZE) > (buf + buf_size),
70 "Dummy read buffer alignment issue");
71 dummy_read_addr = virt_to_phys((void *) vaddr);
72 return 0;
73 }
74
cxllib_get_xsl_config(struct pci_dev * dev,struct cxllib_xsl_config * cfg)75 int cxllib_get_xsl_config(struct pci_dev *dev, struct cxllib_xsl_config *cfg)
76 {
77 int rc;
78 u32 phb_index;
79 u64 chip_id, capp_unit_id;
80
81 if (!cpu_has_feature(CPU_FTR_HVMODE))
82 return -EINVAL;
83
84 mutex_lock(&dra_mutex);
85 if (dummy_read_addr == CXL_INVALID_DRA) {
86 rc = allocate_dummy_read_buf();
87 if (rc) {
88 mutex_unlock(&dra_mutex);
89 return rc;
90 }
91 }
92 mutex_unlock(&dra_mutex);
93
94 rc = cxl_calc_capp_routing(dev, &chip_id, &phb_index, &capp_unit_id);
95 if (rc)
96 return rc;
97
98 rc = cxl_get_xsl9_dsnctl(dev, capp_unit_id, &cfg->dsnctl);
99 if (rc)
100 return rc;
101
102 cfg->version = CXL_XSL_CONFIG_CURRENT_VERSION;
103 cfg->log_bar_size = CXL_CAPI_WINDOW_LOG_SIZE;
104 cfg->bar_addr = CXL_CAPI_WINDOW_START;
105 cfg->dra = dummy_read_addr;
106 return 0;
107 }
108 EXPORT_SYMBOL_GPL(cxllib_get_xsl_config);
109
cxllib_switch_phb_mode(struct pci_dev * dev,enum cxllib_mode mode,unsigned long flags)110 int cxllib_switch_phb_mode(struct pci_dev *dev, enum cxllib_mode mode,
111 unsigned long flags)
112 {
113 int rc = 0;
114
115 if (!cpu_has_feature(CPU_FTR_HVMODE))
116 return -EINVAL;
117
118 switch (mode) {
119 case CXL_MODE_PCI:
120 /*
121 * We currently don't support going back to PCI mode
122 * However, we'll turn the invalidations off, so that
123 * the firmware doesn't have to ack them and can do
124 * things like reset, etc.. with no worries.
125 * So always return EPERM (can't go back to PCI) or
126 * EBUSY if we couldn't even turn off snooping
127 */
128 rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_SNOOP_OFF);
129 if (rc)
130 rc = -EBUSY;
131 else
132 rc = -EPERM;
133 break;
134 case CXL_MODE_CXL:
135 /* DMA only supported on TVT1 for the time being */
136 if (flags != CXL_MODE_DMA_TVT1)
137 return -EINVAL;
138 rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_DMA_TVT1);
139 if (rc)
140 return rc;
141 rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_SNOOP_ON);
142 break;
143 default:
144 rc = -EINVAL;
145 }
146 return rc;
147 }
148 EXPORT_SYMBOL_GPL(cxllib_switch_phb_mode);
149
150 /*
151 * When switching the PHB to capi mode, the TVT#1 entry for
152 * the Partitionable Endpoint is set in bypass mode, like
153 * in PCI mode.
154 * Configure the device dma to use TVT#1, which is done
155 * by calling dma_set_mask() with a mask large enough.
156 */
cxllib_set_device_dma(struct pci_dev * dev,unsigned long flags)157 int cxllib_set_device_dma(struct pci_dev *dev, unsigned long flags)
158 {
159 int rc;
160
161 if (flags)
162 return -EINVAL;
163
164 rc = dma_set_mask(&dev->dev, DMA_BIT_MASK(64));
165 return rc;
166 }
167 EXPORT_SYMBOL_GPL(cxllib_set_device_dma);
168
cxllib_get_PE_attributes(struct task_struct * task,unsigned long translation_mode,struct cxllib_pe_attributes * attr)169 int cxllib_get_PE_attributes(struct task_struct *task,
170 unsigned long translation_mode,
171 struct cxllib_pe_attributes *attr)
172 {
173 if (translation_mode != CXL_TRANSLATED_MODE &&
174 translation_mode != CXL_REAL_MODE)
175 return -EINVAL;
176
177 attr->sr = cxl_calculate_sr(false,
178 task == NULL,
179 translation_mode == CXL_REAL_MODE,
180 true);
181 attr->lpid = mfspr(SPRN_LPID);
182 if (task) {
183 struct mm_struct *mm = get_task_mm(task);
184 if (mm == NULL)
185 return -EINVAL;
186 /*
187 * Caller is keeping a reference on mm_users for as long
188 * as XSL uses the memory context
189 */
190 attr->pid = mm->context.id;
191 mmput(mm);
192 attr->tid = task->thread.tidr;
193 } else {
194 attr->pid = 0;
195 attr->tid = 0;
196 }
197 return 0;
198 }
199 EXPORT_SYMBOL_GPL(cxllib_get_PE_attributes);
200
get_vma_info(struct mm_struct * mm,u64 addr,u64 * vma_start,u64 * vma_end,unsigned long * page_size)201 static int get_vma_info(struct mm_struct *mm, u64 addr,
202 u64 *vma_start, u64 *vma_end,
203 unsigned long *page_size)
204 {
205 struct vm_area_struct *vma = NULL;
206 int rc = 0;
207
208 mmap_read_lock(mm);
209
210 vma = find_vma(mm, addr);
211 if (!vma) {
212 rc = -EFAULT;
213 goto out;
214 }
215 *page_size = vma_kernel_pagesize(vma);
216 *vma_start = vma->vm_start;
217 *vma_end = vma->vm_end;
218 out:
219 mmap_read_unlock(mm);
220 return rc;
221 }
222
cxllib_handle_fault(struct mm_struct * mm,u64 addr,u64 size,u64 flags)223 int cxllib_handle_fault(struct mm_struct *mm, u64 addr, u64 size, u64 flags)
224 {
225 int rc;
226 u64 dar, vma_start, vma_end;
227 unsigned long page_size;
228
229 if (mm == NULL)
230 return -EFAULT;
231
232 /*
233 * The buffer we have to process can extend over several pages
234 * and may also cover several VMAs.
235 * We iterate over all the pages. The page size could vary
236 * between VMAs.
237 */
238 rc = get_vma_info(mm, addr, &vma_start, &vma_end, &page_size);
239 if (rc)
240 return rc;
241
242 for (dar = (addr & ~(page_size - 1)); dar < (addr + size);
243 dar += page_size) {
244 if (dar < vma_start || dar >= vma_end) {
245 /*
246 * We don't hold mm->mmap_lock while iterating, since
247 * the lock is required by one of the lower-level page
248 * fault processing functions and it could
249 * create a deadlock.
250 *
251 * It means the VMAs can be altered between 2
252 * loop iterations and we could theoretically
253 * miss a page (however unlikely). But that's
254 * not really a problem, as the driver will
255 * retry access, get another page fault on the
256 * missing page and call us again.
257 */
258 rc = get_vma_info(mm, dar, &vma_start, &vma_end,
259 &page_size);
260 if (rc)
261 return rc;
262 }
263
264 rc = cxl_handle_mm_fault(mm, flags, dar);
265 if (rc)
266 return -EFAULT;
267 }
268 return 0;
269 }
270 EXPORT_SYMBOL_GPL(cxllib_handle_fault);
271