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1// SPDX-License-Identifier: GPL-2.0+
2// Copyright 2017 IBM Corp.
3#include <linux/sched/mm.h>
4#include "trace.h"
5#include "ocxl_internal.h"
6
7int ocxl_context_alloc(struct ocxl_context **context, struct ocxl_afu *afu,
8 struct address_space *mapping)
9{
10 int pasid;
11 struct ocxl_context *ctx;
12
13 ctx = kzalloc_obj(*ctx);
14 if (!ctx)
15 return -ENOMEM;
16
17 ctx->afu = afu;
18 mutex_lock(&afu->contexts_lock);
19 pasid = idr_alloc(&afu->contexts_idr, ctx, afu->pasid_base,
20 afu->pasid_base + afu->pasid_max, GFP_KERNEL);
21 if (pasid < 0) {
22 mutex_unlock(&afu->contexts_lock);
23 kfree(ctx);
24 return pasid;
25 }
26 afu->pasid_count++;
27 mutex_unlock(&afu->contexts_lock);
28
29 ctx->pasid = pasid;
30 ctx->status = OPENED;
31 mutex_init(&ctx->status_mutex);
32 ctx->mapping = mapping;
33 mutex_init(&ctx->mapping_lock);
34 init_waitqueue_head(&ctx->events_wq);
35 mutex_init(&ctx->xsl_error_lock);
36 mutex_init(&ctx->irq_lock);
37 idr_init(&ctx->irq_idr);
38 ctx->tidr = 0;
39
40 /*
41 * Keep a reference on the AFU to make sure it's valid for the
42 * duration of the life of the context
43 */
44 ocxl_afu_get(afu);
45 *context = ctx;
46 return 0;
47}
48EXPORT_SYMBOL_GPL(ocxl_context_alloc);
49
50/*
51 * Callback for when a translation fault triggers an error
52 * data: a pointer to the context which triggered the fault
53 * addr: the address that triggered the error
54 * dsisr: the value of the PPC64 dsisr register
55 */
56static void xsl_fault_error(void *data, u64 addr, u64 dsisr)
57{
58 struct ocxl_context *ctx = data;
59
60 mutex_lock(&ctx->xsl_error_lock);
61 ctx->xsl_error.addr = addr;
62 ctx->xsl_error.dsisr = dsisr;
63 ctx->xsl_error.count++;
64 mutex_unlock(&ctx->xsl_error_lock);
65
66 wake_up_all(&ctx->events_wq);
67}
68
69int ocxl_context_attach(struct ocxl_context *ctx, u64 amr, struct mm_struct *mm)
70{
71 int rc;
72 unsigned long pidr = 0;
73 struct pci_dev *dev;
74
75 // Locks both status & tidr
76 mutex_lock(&ctx->status_mutex);
77 if (ctx->status != OPENED) {
78 rc = -EIO;
79 goto out;
80 }
81
82 if (mm)
83 pidr = mm->context.id;
84
85 dev = to_pci_dev(ctx->afu->fn->dev.parent);
86 rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid, pidr, ctx->tidr,
87 amr, pci_dev_id(dev), mm, xsl_fault_error, ctx);
88 if (rc)
89 goto out;
90
91 ctx->status = ATTACHED;
92out:
93 mutex_unlock(&ctx->status_mutex);
94 return rc;
95}
96EXPORT_SYMBOL_GPL(ocxl_context_attach);
97
98static vm_fault_t map_afu_irq(struct vm_area_struct *vma, unsigned long address,
99 u64 offset, struct ocxl_context *ctx)
100{
101 u64 trigger_addr;
102 int irq_id = ocxl_irq_offset_to_id(ctx, offset);
103
104 trigger_addr = ocxl_afu_irq_get_addr(ctx, irq_id);
105 if (!trigger_addr)
106 return VM_FAULT_SIGBUS;
107
108 return vmf_insert_pfn(vma, address, trigger_addr >> PAGE_SHIFT);
109}
110
111static vm_fault_t map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
112 u64 offset, struct ocxl_context *ctx)
113{
114 u64 pp_mmio_addr;
115 int pasid_off;
116 vm_fault_t ret;
117
118 if (offset >= ctx->afu->config.pp_mmio_stride)
119 return VM_FAULT_SIGBUS;
120
121 mutex_lock(&ctx->status_mutex);
122 if (ctx->status != ATTACHED) {
123 mutex_unlock(&ctx->status_mutex);
124 pr_debug("%s: Context not attached, failing mmio mmap\n",
125 __func__);
126 return VM_FAULT_SIGBUS;
127 }
128
129 pasid_off = ctx->pasid - ctx->afu->pasid_base;
130 pp_mmio_addr = ctx->afu->pp_mmio_start +
131 pasid_off * ctx->afu->config.pp_mmio_stride +
132 offset;
133
134 ret = vmf_insert_pfn(vma, address, pp_mmio_addr >> PAGE_SHIFT);
135 mutex_unlock(&ctx->status_mutex);
136 return ret;
137}
138
139static vm_fault_t ocxl_mmap_fault(struct vm_fault *vmf)
140{
141 struct vm_area_struct *vma = vmf->vma;
142 struct ocxl_context *ctx = vma->vm_file->private_data;
143 u64 offset;
144 vm_fault_t ret;
145
146 offset = vmf->pgoff << PAGE_SHIFT;
147 pr_debug("%s: pasid %d address 0x%lx offset 0x%llx\n", __func__,
148 ctx->pasid, vmf->address, offset);
149
150 if (offset < ctx->afu->irq_base_offset)
151 ret = map_pp_mmio(vma, vmf->address, offset, ctx);
152 else
153 ret = map_afu_irq(vma, vmf->address, offset, ctx);
154 return ret;
155}
156
157static const struct vm_operations_struct ocxl_vmops = {
158 .fault = ocxl_mmap_fault,
159};
160
161static int check_mmap_afu_irq(struct ocxl_context *ctx,
162 struct vm_area_struct *vma)
163{
164 int irq_id = ocxl_irq_offset_to_id(ctx, vma->vm_pgoff << PAGE_SHIFT);
165
166 /* only one page */
167 if (vma_pages(vma) != 1)
168 return -EINVAL;
169
170 /* check offset validty */
171 if (!ocxl_afu_irq_get_addr(ctx, irq_id))
172 return -EINVAL;
173
174 /*
175 * trigger page should only be accessible in write mode.
176 *
177 * It's a bit theoretical, as a page mmaped with only
178 * PROT_WRITE is currently readable, but it doesn't hurt.
179 */
180 if ((vma->vm_flags & VM_READ) || (vma->vm_flags & VM_EXEC) ||
181 !(vma->vm_flags & VM_WRITE))
182 return -EINVAL;
183 vm_flags_clear(vma, VM_MAYREAD | VM_MAYEXEC);
184 return 0;
185}
186
187static int check_mmap_mmio(struct ocxl_context *ctx,
188 struct vm_area_struct *vma)
189{
190 if ((vma_pages(vma) + vma->vm_pgoff) >
191 (ctx->afu->config.pp_mmio_stride >> PAGE_SHIFT))
192 return -EINVAL;
193 return 0;
194}
195
196int ocxl_context_mmap(struct ocxl_context *ctx, struct vm_area_struct *vma)
197{
198 int rc;
199
200 if ((vma->vm_pgoff << PAGE_SHIFT) < ctx->afu->irq_base_offset)
201 rc = check_mmap_mmio(ctx, vma);
202 else
203 rc = check_mmap_afu_irq(ctx, vma);
204 if (rc)
205 return rc;
206
207 vm_flags_set(vma, VM_IO | VM_PFNMAP);
208 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
209 vma->vm_ops = &ocxl_vmops;
210 return 0;
211}
212
213int ocxl_context_detach(struct ocxl_context *ctx)
214{
215 struct pci_dev *dev;
216 int afu_control_pos;
217 enum ocxl_context_status status;
218 int rc;
219
220 mutex_lock(&ctx->status_mutex);
221 status = ctx->status;
222 ctx->status = CLOSED;
223 mutex_unlock(&ctx->status_mutex);
224 if (status != ATTACHED)
225 return 0;
226
227 dev = to_pci_dev(ctx->afu->fn->dev.parent);
228 afu_control_pos = ctx->afu->config.dvsec_afu_control_pos;
229
230 mutex_lock(&ctx->afu->afu_control_lock);
231 rc = ocxl_config_terminate_pasid(dev, afu_control_pos, ctx->pasid);
232 mutex_unlock(&ctx->afu->afu_control_lock);
233 trace_ocxl_terminate_pasid(ctx->pasid, rc);
234 if (rc) {
235 /*
236 * If we timeout waiting for the AFU to terminate the
237 * pasid, then it's dangerous to clean up the Process
238 * Element entry in the SPA, as it may be referenced
239 * in the future by the AFU. In which case, we would
240 * checkstop because of an invalid PE access (FIR
241 * register 2, bit 42). So leave the PE
242 * defined. Caller shouldn't free the context so that
243 * PASID remains allocated.
244 *
245 * A link reset will be required to cleanup the AFU
246 * and the SPA.
247 */
248 if (rc == -EBUSY)
249 return rc;
250 }
251 rc = ocxl_link_remove_pe(ctx->afu->fn->link, ctx->pasid);
252 if (rc) {
253 dev_warn(&dev->dev,
254 "Couldn't remove PE entry cleanly: %d\n", rc);
255 }
256 return 0;
257}
258EXPORT_SYMBOL_GPL(ocxl_context_detach);
259
260void ocxl_context_detach_all(struct ocxl_afu *afu)
261{
262 struct ocxl_context *ctx;
263 int tmp;
264
265 mutex_lock(&afu->contexts_lock);
266 idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
267 ocxl_context_detach(ctx);
268 /*
269 * We are force detaching - remove any active mmio
270 * mappings so userspace cannot interfere with the
271 * card if it comes back. Easiest way to exercise
272 * this is to unbind and rebind the driver via sysfs
273 * while it is in use.
274 */
275 mutex_lock(&ctx->mapping_lock);
276 if (ctx->mapping)
277 unmap_mapping_range(ctx->mapping, 0, 0, 1);
278 mutex_unlock(&ctx->mapping_lock);
279 }
280 mutex_unlock(&afu->contexts_lock);
281}
282
283void ocxl_context_free(struct ocxl_context *ctx)
284{
285 mutex_lock(&ctx->afu->contexts_lock);
286 ctx->afu->pasid_count--;
287 idr_remove(&ctx->afu->contexts_idr, ctx->pasid);
288 mutex_unlock(&ctx->afu->contexts_lock);
289
290 ocxl_afu_irq_free_all(ctx);
291 idr_destroy(&ctx->irq_idr);
292 /* reference to the AFU taken in ocxl_context_alloc() */
293 ocxl_afu_put(ctx->afu);
294 kfree(ctx);
295}
296EXPORT_SYMBOL_GPL(ocxl_context_free);