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