1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 2014 IBM Corp.
4 */
5
6 #include <linux/module.h>
7 #include <linux/kernel.h>
8 #include <linux/bitmap.h>
9 #include <linux/sched.h>
10 #include <linux/pid.h>
11 #include <linux/fs.h>
12 #include <linux/mm.h>
13 #include <linux/debugfs.h>
14 #include <linux/slab.h>
15 #include <linux/idr.h>
16 #include <linux/sched/mm.h>
17 #include <linux/mmu_context.h>
18 #include <asm/cputable.h>
19 #include <asm/current.h>
20 #include <asm/copro.h>
21
22 #include "cxl.h"
23
24 /*
25 * Allocates space for a CXL context.
26 */
cxl_context_alloc(void)27 struct cxl_context *cxl_context_alloc(void)
28 {
29 return kzalloc(sizeof(struct cxl_context), GFP_KERNEL);
30 }
31
32 /*
33 * Initialises a CXL context.
34 */
cxl_context_init(struct cxl_context * ctx,struct cxl_afu * afu,bool master)35 int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master)
36 {
37 int i;
38
39 ctx->afu = afu;
40 ctx->master = master;
41 ctx->pid = NULL; /* Set in start work ioctl */
42 mutex_init(&ctx->mapping_lock);
43 ctx->mapping = NULL;
44 ctx->tidr = 0;
45 ctx->assign_tidr = false;
46
47 if (cxl_is_power8()) {
48 spin_lock_init(&ctx->sste_lock);
49
50 /*
51 * Allocate the segment table before we put it in the IDR so that we
52 * can always access it when dereferenced from IDR. For the same
53 * reason, the segment table is only destroyed after the context is
54 * removed from the IDR. Access to this in the IOCTL is protected by
55 * Linux filesytem symantics (can't IOCTL until open is complete).
56 */
57 i = cxl_alloc_sst(ctx);
58 if (i)
59 return i;
60 }
61
62 INIT_WORK(&ctx->fault_work, cxl_handle_fault);
63
64 init_waitqueue_head(&ctx->wq);
65 spin_lock_init(&ctx->lock);
66
67 ctx->irq_bitmap = NULL;
68 ctx->pending_irq = false;
69 ctx->pending_fault = false;
70 ctx->pending_afu_err = false;
71
72 INIT_LIST_HEAD(&ctx->irq_names);
73
74 /*
75 * When we have to destroy all contexts in cxl_context_detach_all() we
76 * end up with afu_release_irqs() called from inside a
77 * idr_for_each_entry(). Hence we need to make sure that anything
78 * dereferenced from this IDR is ok before we allocate the IDR here.
79 * This clears out the IRQ ranges to ensure this.
80 */
81 for (i = 0; i < CXL_IRQ_RANGES; i++)
82 ctx->irqs.range[i] = 0;
83
84 mutex_init(&ctx->status_mutex);
85
86 ctx->status = OPENED;
87
88 /*
89 * Allocating IDR! We better make sure everything's setup that
90 * dereferences from it.
91 */
92 mutex_lock(&afu->contexts_lock);
93 idr_preload(GFP_KERNEL);
94 i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0,
95 ctx->afu->num_procs, GFP_NOWAIT);
96 idr_preload_end();
97 mutex_unlock(&afu->contexts_lock);
98 if (i < 0)
99 return i;
100
101 ctx->pe = i;
102 if (cpu_has_feature(CPU_FTR_HVMODE)) {
103 ctx->elem = &ctx->afu->native->spa[i];
104 ctx->external_pe = ctx->pe;
105 } else {
106 ctx->external_pe = -1; /* assigned when attaching */
107 }
108 ctx->pe_inserted = false;
109
110 /*
111 * take a ref on the afu so that it stays alive at-least till
112 * this context is reclaimed inside reclaim_ctx.
113 */
114 cxl_afu_get(afu);
115 return 0;
116 }
117
cxl_context_set_mapping(struct cxl_context * ctx,struct address_space * mapping)118 void cxl_context_set_mapping(struct cxl_context *ctx,
119 struct address_space *mapping)
120 {
121 mutex_lock(&ctx->mapping_lock);
122 ctx->mapping = mapping;
123 mutex_unlock(&ctx->mapping_lock);
124 }
125
cxl_mmap_fault(struct vm_fault * vmf)126 static vm_fault_t cxl_mmap_fault(struct vm_fault *vmf)
127 {
128 struct vm_area_struct *vma = vmf->vma;
129 struct cxl_context *ctx = vma->vm_file->private_data;
130 u64 area, offset;
131 vm_fault_t ret;
132
133 offset = vmf->pgoff << PAGE_SHIFT;
134
135 pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n",
136 __func__, ctx->pe, vmf->address, offset);
137
138 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
139 area = ctx->afu->psn_phys;
140 if (offset >= ctx->afu->adapter->ps_size)
141 return VM_FAULT_SIGBUS;
142 } else {
143 area = ctx->psn_phys;
144 if (offset >= ctx->psn_size)
145 return VM_FAULT_SIGBUS;
146 }
147
148 mutex_lock(&ctx->status_mutex);
149
150 if (ctx->status != STARTED) {
151 mutex_unlock(&ctx->status_mutex);
152 pr_devel("%s: Context not started, failing problem state access\n", __func__);
153 if (ctx->mmio_err_ff) {
154 if (!ctx->ff_page) {
155 ctx->ff_page = alloc_page(GFP_USER);
156 if (!ctx->ff_page)
157 return VM_FAULT_OOM;
158 memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE);
159 }
160 get_page(ctx->ff_page);
161 vmf->page = ctx->ff_page;
162 vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
163 return 0;
164 }
165 return VM_FAULT_SIGBUS;
166 }
167
168 ret = vmf_insert_pfn(vma, vmf->address, (area + offset) >> PAGE_SHIFT);
169
170 mutex_unlock(&ctx->status_mutex);
171
172 return ret;
173 }
174
175 static const struct vm_operations_struct cxl_mmap_vmops = {
176 .fault = cxl_mmap_fault,
177 };
178
179 /*
180 * Map a per-context mmio space into the given vma.
181 */
cxl_context_iomap(struct cxl_context * ctx,struct vm_area_struct * vma)182 int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma)
183 {
184 u64 start = vma->vm_pgoff << PAGE_SHIFT;
185 u64 len = vma->vm_end - vma->vm_start;
186
187 if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
188 if (start + len > ctx->afu->adapter->ps_size)
189 return -EINVAL;
190
191 if (cxl_is_power9()) {
192 /*
193 * Make sure there is a valid problem state
194 * area space for this AFU.
195 */
196 if (ctx->master && !ctx->afu->psa) {
197 pr_devel("AFU doesn't support mmio space\n");
198 return -EINVAL;
199 }
200
201 /* Can't mmap until the AFU is enabled */
202 if (!ctx->afu->enabled)
203 return -EBUSY;
204 }
205 } else {
206 if (start + len > ctx->psn_size)
207 return -EINVAL;
208
209 /* Make sure there is a valid per process space for this AFU */
210 if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) {
211 pr_devel("AFU doesn't support mmio space\n");
212 return -EINVAL;
213 }
214
215 /* Can't mmap until the AFU is enabled */
216 if (!ctx->afu->enabled)
217 return -EBUSY;
218 }
219
220 pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__,
221 ctx->psn_phys, ctx->pe , ctx->master);
222
223 vma->vm_flags |= VM_IO | VM_PFNMAP;
224 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
225 vma->vm_ops = &cxl_mmap_vmops;
226 return 0;
227 }
228
229 /*
230 * Detach a context from the hardware. This disables interrupts and doesn't
231 * return until all outstanding interrupts for this context have completed. The
232 * hardware should no longer access *ctx after this has returned.
233 */
__detach_context(struct cxl_context * ctx)234 int __detach_context(struct cxl_context *ctx)
235 {
236 enum cxl_context_status status;
237
238 mutex_lock(&ctx->status_mutex);
239 status = ctx->status;
240 ctx->status = CLOSED;
241 mutex_unlock(&ctx->status_mutex);
242 if (status != STARTED)
243 return -EBUSY;
244
245 /* Only warn if we detached while the link was OK.
246 * If detach fails when hw is down, we don't care.
247 */
248 WARN_ON(cxl_ops->detach_process(ctx) &&
249 cxl_ops->link_ok(ctx->afu->adapter, ctx->afu));
250 flush_work(&ctx->fault_work); /* Only needed for dedicated process */
251
252 /*
253 * Wait until no further interrupts are presented by the PSL
254 * for this context.
255 */
256 if (cxl_ops->irq_wait)
257 cxl_ops->irq_wait(ctx);
258
259 /* release the reference to the group leader and mm handling pid */
260 put_pid(ctx->pid);
261
262 cxl_ctx_put();
263
264 /* Decrease the attached context count on the adapter */
265 cxl_adapter_context_put(ctx->afu->adapter);
266
267 /* Decrease the mm count on the context */
268 cxl_context_mm_count_put(ctx);
269 if (ctx->mm)
270 mm_context_remove_copro(ctx->mm);
271 ctx->mm = NULL;
272
273 return 0;
274 }
275
276 /*
277 * Detach the given context from the AFU. This doesn't actually
278 * free the context but it should stop the context running in hardware
279 * (ie. prevent this context from generating any further interrupts
280 * so that it can be freed).
281 */
cxl_context_detach(struct cxl_context * ctx)282 void cxl_context_detach(struct cxl_context *ctx)
283 {
284 int rc;
285
286 rc = __detach_context(ctx);
287 if (rc)
288 return;
289
290 afu_release_irqs(ctx, ctx);
291 wake_up_all(&ctx->wq);
292 }
293
294 /*
295 * Detach all contexts on the given AFU.
296 */
cxl_context_detach_all(struct cxl_afu * afu)297 void cxl_context_detach_all(struct cxl_afu *afu)
298 {
299 struct cxl_context *ctx;
300 int tmp;
301
302 mutex_lock(&afu->contexts_lock);
303 idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
304 /*
305 * Anything done in here needs to be setup before the IDR is
306 * created and torn down after the IDR removed
307 */
308 cxl_context_detach(ctx);
309
310 /*
311 * We are force detaching - remove any active PSA mappings so
312 * userspace cannot interfere with the card if it comes back.
313 * Easiest way to exercise this is to unbind and rebind the
314 * driver via sysfs while it is in use.
315 */
316 mutex_lock(&ctx->mapping_lock);
317 if (ctx->mapping)
318 unmap_mapping_range(ctx->mapping, 0, 0, 1);
319 mutex_unlock(&ctx->mapping_lock);
320 }
321 mutex_unlock(&afu->contexts_lock);
322 }
323
reclaim_ctx(struct rcu_head * rcu)324 static void reclaim_ctx(struct rcu_head *rcu)
325 {
326 struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu);
327
328 if (cxl_is_power8())
329 free_page((u64)ctx->sstp);
330 if (ctx->ff_page)
331 __free_page(ctx->ff_page);
332 ctx->sstp = NULL;
333
334 kfree(ctx->irq_bitmap);
335
336 /* Drop ref to the afu device taken during cxl_context_init */
337 cxl_afu_put(ctx->afu);
338
339 kfree(ctx);
340 }
341
cxl_context_free(struct cxl_context * ctx)342 void cxl_context_free(struct cxl_context *ctx)
343 {
344 if (ctx->kernelapi && ctx->mapping)
345 cxl_release_mapping(ctx);
346 mutex_lock(&ctx->afu->contexts_lock);
347 idr_remove(&ctx->afu->contexts_idr, ctx->pe);
348 mutex_unlock(&ctx->afu->contexts_lock);
349 call_rcu(&ctx->rcu, reclaim_ctx);
350 }
351
cxl_context_mm_count_get(struct cxl_context * ctx)352 void cxl_context_mm_count_get(struct cxl_context *ctx)
353 {
354 if (ctx->mm)
355 mmgrab(ctx->mm);
356 }
357
cxl_context_mm_count_put(struct cxl_context * ctx)358 void cxl_context_mm_count_put(struct cxl_context *ctx)
359 {
360 if (ctx->mm)
361 mmdrop(ctx->mm);
362 }
363
