1 // SPDX-License-Identifier: GPL-2.0
2 #define DEBUG
3
4 #include <linux/wait.h>
5 #include <linux/ptrace.h>
6
7 #include <asm/spu.h>
8 #include <asm/spu_priv1.h>
9 #include <asm/io.h>
10 #include <asm/unistd.h>
11
12 #include "spufs.h"
13
14 /* interrupt-level stop callback function. */
spufs_stop_callback(struct spu * spu,int irq)15 void spufs_stop_callback(struct spu *spu, int irq)
16 {
17 struct spu_context *ctx = spu->ctx;
18
19 /*
20 * It should be impossible to preempt a context while an exception
21 * is being processed, since the context switch code is specially
22 * coded to deal with interrupts ... But, just in case, sanity check
23 * the context pointer. It is OK to return doing nothing since
24 * the exception will be regenerated when the context is resumed.
25 */
26 if (ctx) {
27 /* Copy exception arguments into module specific structure */
28 switch(irq) {
29 case 0 :
30 ctx->csa.class_0_pending = spu->class_0_pending;
31 ctx->csa.class_0_dar = spu->class_0_dar;
32 break;
33 case 1 :
34 ctx->csa.class_1_dsisr = spu->class_1_dsisr;
35 ctx->csa.class_1_dar = spu->class_1_dar;
36 break;
37 case 2 :
38 break;
39 }
40
41 /* ensure that the exception status has hit memory before a
42 * thread waiting on the context's stop queue is woken */
43 smp_wmb();
44
45 wake_up_all(&ctx->stop_wq);
46 }
47 }
48
spu_stopped(struct spu_context * ctx,u32 * stat)49 int spu_stopped(struct spu_context *ctx, u32 *stat)
50 {
51 u64 dsisr;
52 u32 stopped;
53
54 stopped = SPU_STATUS_INVALID_INSTR | SPU_STATUS_SINGLE_STEP |
55 SPU_STATUS_STOPPED_BY_HALT | SPU_STATUS_STOPPED_BY_STOP;
56
57 top:
58 *stat = ctx->ops->status_read(ctx);
59 if (*stat & stopped) {
60 /*
61 * If the spu hasn't finished stopping, we need to
62 * re-read the register to get the stopped value.
63 */
64 if (*stat & SPU_STATUS_RUNNING)
65 goto top;
66 return 1;
67 }
68
69 if (test_bit(SPU_SCHED_NOTIFY_ACTIVE, &ctx->sched_flags))
70 return 1;
71
72 dsisr = ctx->csa.class_1_dsisr;
73 if (dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED))
74 return 1;
75
76 if (ctx->csa.class_0_pending)
77 return 1;
78
79 return 0;
80 }
81
spu_setup_isolated(struct spu_context * ctx)82 static int spu_setup_isolated(struct spu_context *ctx)
83 {
84 int ret;
85 u64 __iomem *mfc_cntl;
86 u64 sr1;
87 u32 status;
88 unsigned long timeout;
89 const u32 status_loading = SPU_STATUS_RUNNING
90 | SPU_STATUS_ISOLATED_STATE | SPU_STATUS_ISOLATED_LOAD_STATUS;
91
92 ret = -ENODEV;
93 if (!isolated_loader)
94 goto out;
95
96 /*
97 * We need to exclude userspace access to the context.
98 *
99 * To protect against memory access we invalidate all ptes
100 * and make sure the pagefault handlers block on the mutex.
101 */
102 spu_unmap_mappings(ctx);
103
104 mfc_cntl = &ctx->spu->priv2->mfc_control_RW;
105
106 /* purge the MFC DMA queue to ensure no spurious accesses before we
107 * enter kernel mode */
108 timeout = jiffies + HZ;
109 out_be64(mfc_cntl, MFC_CNTL_PURGE_DMA_REQUEST);
110 while ((in_be64(mfc_cntl) & MFC_CNTL_PURGE_DMA_STATUS_MASK)
111 != MFC_CNTL_PURGE_DMA_COMPLETE) {
112 if (time_after(jiffies, timeout)) {
113 printk(KERN_ERR "%s: timeout flushing MFC DMA queue\n",
114 __func__);
115 ret = -EIO;
116 goto out;
117 }
118 cond_resched();
119 }
120
121 /* clear purge status */
122 out_be64(mfc_cntl, 0);
123
124 /* put the SPE in kernel mode to allow access to the loader */
125 sr1 = spu_mfc_sr1_get(ctx->spu);
126 sr1 &= ~MFC_STATE1_PROBLEM_STATE_MASK;
127 spu_mfc_sr1_set(ctx->spu, sr1);
128
129 /* start the loader */
130 ctx->ops->signal1_write(ctx, (unsigned long)isolated_loader >> 32);
131 ctx->ops->signal2_write(ctx,
132 (unsigned long)isolated_loader & 0xffffffff);
133
134 ctx->ops->runcntl_write(ctx,
135 SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
136
137 ret = 0;
138 timeout = jiffies + HZ;
139 while (((status = ctx->ops->status_read(ctx)) & status_loading) ==
140 status_loading) {
141 if (time_after(jiffies, timeout)) {
142 printk(KERN_ERR "%s: timeout waiting for loader\n",
143 __func__);
144 ret = -EIO;
145 goto out_drop_priv;
146 }
147 cond_resched();
148 }
149
150 if (!(status & SPU_STATUS_RUNNING)) {
151 /* If isolated LOAD has failed: run SPU, we will get a stop-and
152 * signal later. */
153 pr_debug("%s: isolated LOAD failed\n", __func__);
154 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
155 ret = -EACCES;
156 goto out_drop_priv;
157 }
158
159 if (!(status & SPU_STATUS_ISOLATED_STATE)) {
160 /* This isn't allowed by the CBEA, but check anyway */
161 pr_debug("%s: SPU fell out of isolated mode?\n", __func__);
162 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_STOP);
163 ret = -EINVAL;
164 goto out_drop_priv;
165 }
166
167 out_drop_priv:
168 /* Finished accessing the loader. Drop kernel mode */
169 sr1 |= MFC_STATE1_PROBLEM_STATE_MASK;
170 spu_mfc_sr1_set(ctx->spu, sr1);
171
172 out:
173 return ret;
174 }
175
spu_run_init(struct spu_context * ctx,u32 * npc)176 static int spu_run_init(struct spu_context *ctx, u32 *npc)
177 {
178 unsigned long runcntl = SPU_RUNCNTL_RUNNABLE;
179 int ret;
180
181 spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
182
183 /*
184 * NOSCHED is synchronous scheduling with respect to the caller.
185 * The caller waits for the context to be loaded.
186 */
187 if (ctx->flags & SPU_CREATE_NOSCHED) {
188 if (ctx->state == SPU_STATE_SAVED) {
189 ret = spu_activate(ctx, 0);
190 if (ret)
191 return ret;
192 }
193 }
194
195 /*
196 * Apply special setup as required.
197 */
198 if (ctx->flags & SPU_CREATE_ISOLATE) {
199 if (!(ctx->ops->status_read(ctx) & SPU_STATUS_ISOLATED_STATE)) {
200 ret = spu_setup_isolated(ctx);
201 if (ret)
202 return ret;
203 }
204
205 /*
206 * If userspace has set the runcntrl register (eg, to
207 * issue an isolated exit), we need to re-set it here
208 */
209 runcntl = ctx->ops->runcntl_read(ctx) &
210 (SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
211 if (runcntl == 0)
212 runcntl = SPU_RUNCNTL_RUNNABLE;
213 } else {
214 unsigned long privcntl;
215
216 if (test_thread_flag(TIF_SINGLESTEP))
217 privcntl = SPU_PRIVCNTL_MODE_SINGLE_STEP;
218 else
219 privcntl = SPU_PRIVCNTL_MODE_NORMAL;
220
221 ctx->ops->privcntl_write(ctx, privcntl);
222 ctx->ops->npc_write(ctx, *npc);
223 }
224
225 ctx->ops->runcntl_write(ctx, runcntl);
226
227 if (ctx->flags & SPU_CREATE_NOSCHED) {
228 spuctx_switch_state(ctx, SPU_UTIL_USER);
229 } else {
230
231 if (ctx->state == SPU_STATE_SAVED) {
232 ret = spu_activate(ctx, 0);
233 if (ret)
234 return ret;
235 } else {
236 spuctx_switch_state(ctx, SPU_UTIL_USER);
237 }
238 }
239
240 set_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
241 return 0;
242 }
243
spu_run_fini(struct spu_context * ctx,u32 * npc,u32 * status)244 static int spu_run_fini(struct spu_context *ctx, u32 *npc,
245 u32 *status)
246 {
247 int ret = 0;
248
249 spu_del_from_rq(ctx);
250
251 *status = ctx->ops->status_read(ctx);
252 *npc = ctx->ops->npc_read(ctx);
253
254 spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
255 clear_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
256 spu_switch_log_notify(NULL, ctx, SWITCH_LOG_EXIT, *status);
257 spu_release(ctx);
258
259 if (signal_pending(current))
260 ret = -ERESTARTSYS;
261
262 return ret;
263 }
264
265 /*
266 * SPU syscall restarting is tricky because we violate the basic
267 * assumption that the signal handler is running on the interrupted
268 * thread. Here instead, the handler runs on PowerPC user space code,
269 * while the syscall was called from the SPU.
270 * This means we can only do a very rough approximation of POSIX
271 * signal semantics.
272 */
spu_handle_restartsys(struct spu_context * ctx,long * spu_ret,unsigned int * npc)273 static int spu_handle_restartsys(struct spu_context *ctx, long *spu_ret,
274 unsigned int *npc)
275 {
276 int ret;
277
278 switch (*spu_ret) {
279 case -ERESTARTSYS:
280 case -ERESTARTNOINTR:
281 /*
282 * Enter the regular syscall restarting for
283 * sys_spu_run, then restart the SPU syscall
284 * callback.
285 */
286 *npc -= 8;
287 ret = -ERESTARTSYS;
288 break;
289 case -ERESTARTNOHAND:
290 case -ERESTART_RESTARTBLOCK:
291 /*
292 * Restart block is too hard for now, just return -EINTR
293 * to the SPU.
294 * ERESTARTNOHAND comes from sys_pause, we also return
295 * -EINTR from there.
296 * Assume that we need to be restarted ourselves though.
297 */
298 *spu_ret = -EINTR;
299 ret = -ERESTARTSYS;
300 break;
301 default:
302 printk(KERN_WARNING "%s: unexpected return code %ld\n",
303 __func__, *spu_ret);
304 ret = 0;
305 }
306 return ret;
307 }
308
spu_process_callback(struct spu_context * ctx)309 static int spu_process_callback(struct spu_context *ctx)
310 {
311 struct spu_syscall_block s;
312 u32 ls_pointer, npc;
313 void __iomem *ls;
314 long spu_ret;
315 int ret;
316
317 /* get syscall block from local store */
318 npc = ctx->ops->npc_read(ctx) & ~3;
319 ls = (void __iomem *)ctx->ops->get_ls(ctx);
320 ls_pointer = in_be32(ls + npc);
321 if (ls_pointer > (LS_SIZE - sizeof(s)))
322 return -EFAULT;
323 memcpy_fromio(&s, ls + ls_pointer, sizeof(s));
324
325 /* do actual syscall without pinning the spu */
326 ret = 0;
327 spu_ret = -ENOSYS;
328 npc += 4;
329
330 if (s.nr_ret < NR_syscalls) {
331 spu_release(ctx);
332 /* do actual system call from here */
333 spu_ret = spu_sys_callback(&s);
334 if (spu_ret <= -ERESTARTSYS) {
335 ret = spu_handle_restartsys(ctx, &spu_ret, &npc);
336 }
337 mutex_lock(&ctx->state_mutex);
338 if (ret == -ERESTARTSYS)
339 return ret;
340 }
341
342 /* need to re-get the ls, as it may have changed when we released the
343 * spu */
344 ls = (void __iomem *)ctx->ops->get_ls(ctx);
345
346 /* write result, jump over indirect pointer */
347 memcpy_toio(ls + ls_pointer, &spu_ret, sizeof(spu_ret));
348 ctx->ops->npc_write(ctx, npc);
349 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
350 return ret;
351 }
352
spufs_run_spu(struct spu_context * ctx,u32 * npc,u32 * event)353 long spufs_run_spu(struct spu_context *ctx, u32 *npc, u32 *event)
354 {
355 int ret;
356 u32 status;
357
358 if (mutex_lock_interruptible(&ctx->run_mutex))
359 return -ERESTARTSYS;
360
361 ctx->event_return = 0;
362
363 ret = spu_acquire(ctx);
364 if (ret)
365 goto out_unlock;
366
367 spu_enable_spu(ctx);
368
369 spu_update_sched_info(ctx);
370
371 ret = spu_run_init(ctx, npc);
372 if (ret) {
373 spu_release(ctx);
374 goto out;
375 }
376
377 do {
378 ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, &status));
379 if (unlikely(ret)) {
380 /*
381 * This is nasty: we need the state_mutex for all the
382 * bookkeeping even if the syscall was interrupted by
383 * a signal. ewww.
384 */
385 mutex_lock(&ctx->state_mutex);
386 break;
387 }
388 if (unlikely(test_and_clear_bit(SPU_SCHED_NOTIFY_ACTIVE,
389 &ctx->sched_flags))) {
390 if (!(status & SPU_STATUS_STOPPED_BY_STOP))
391 continue;
392 }
393
394 spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
395
396 if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
397 (status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
398 ret = spu_process_callback(ctx);
399 if (ret)
400 break;
401 status &= ~SPU_STATUS_STOPPED_BY_STOP;
402 }
403 ret = spufs_handle_class1(ctx);
404 if (ret)
405 break;
406
407 ret = spufs_handle_class0(ctx);
408 if (ret)
409 break;
410
411 if (signal_pending(current))
412 ret = -ERESTARTSYS;
413 } while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
414 SPU_STATUS_STOPPED_BY_HALT |
415 SPU_STATUS_SINGLE_STEP)));
416
417 spu_disable_spu(ctx);
418 ret = spu_run_fini(ctx, npc, &status);
419 spu_yield(ctx);
420
421 if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
422 (((status >> SPU_STOP_STATUS_SHIFT) & 0x3f00) == 0x2100))
423 ctx->stats.libassist++;
424
425 if ((ret == 0) ||
426 ((ret == -ERESTARTSYS) &&
427 ((status & SPU_STATUS_STOPPED_BY_HALT) ||
428 (status & SPU_STATUS_SINGLE_STEP) ||
429 ((status & SPU_STATUS_STOPPED_BY_STOP) &&
430 (status >> SPU_STOP_STATUS_SHIFT != 0x2104)))))
431 ret = status;
432
433 /* Note: we don't need to force_sig SIGTRAP on single-step
434 * since we have TIF_SINGLESTEP set, thus the kernel will do
435 * it upon return from the syscall anyway.
436 */
437 if (unlikely(status & SPU_STATUS_SINGLE_STEP))
438 ret = -ERESTARTSYS;
439
440 else if (unlikely((status & SPU_STATUS_STOPPED_BY_STOP)
441 && (status >> SPU_STOP_STATUS_SHIFT) == 0x3fff)) {
442 force_sig(SIGTRAP);
443 ret = -ERESTARTSYS;
444 }
445
446 out:
447 *event = ctx->event_return;
448 out_unlock:
449 mutex_unlock(&ctx->run_mutex);
450 return ret;
451 }
452