1 #define DEBUG
2
3 #include <linux/wait.h>
4 #include <linux/ptrace.h>
5
6 #include <asm/spu.h>
7 #include <asm/spu_priv1.h>
8 #include <asm/io.h>
9 #include <asm/unistd.h>
10
11 #include "spufs.h"
12
13 /* interrupt-level stop callback function. */
spufs_stop_callback(struct spu * spu,int irq)14 void spufs_stop_callback(struct spu *spu, int irq)
15 {
16 struct spu_context *ctx = spu->ctx;
17
18 /*
19 * It should be impossible to preempt a context while an exception
20 * is being processed, since the context switch code is specially
21 * coded to deal with interrupts ... But, just in case, sanity check
22 * the context pointer. It is OK to return doing nothing since
23 * the exception will be regenerated when the context is resumed.
24 */
25 if (ctx) {
26 /* Copy exception arguments into module specific structure */
27 switch(irq) {
28 case 0 :
29 ctx->csa.class_0_pending = spu->class_0_pending;
30 ctx->csa.class_0_dar = spu->class_0_dar;
31 break;
32 case 1 :
33 ctx->csa.class_1_dsisr = spu->class_1_dsisr;
34 ctx->csa.class_1_dar = spu->class_1_dar;
35 break;
36 case 2 :
37 break;
38 }
39
40 /* ensure that the exception status has hit memory before a
41 * thread waiting on the context's stop queue is woken */
42 smp_wmb();
43
44 wake_up_all(&ctx->stop_wq);
45 }
46 }
47
spu_stopped(struct spu_context * ctx,u32 * stat)48 int spu_stopped(struct spu_context *ctx, u32 *stat)
49 {
50 u64 dsisr;
51 u32 stopped;
52
53 stopped = SPU_STATUS_INVALID_INSTR | SPU_STATUS_SINGLE_STEP |
54 SPU_STATUS_STOPPED_BY_HALT | SPU_STATUS_STOPPED_BY_STOP;
55
56 top:
57 *stat = ctx->ops->status_read(ctx);
58 if (*stat & stopped) {
59 /*
60 * If the spu hasn't finished stopping, we need to
61 * re-read the register to get the stopped value.
62 */
63 if (*stat & SPU_STATUS_RUNNING)
64 goto top;
65 return 1;
66 }
67
68 if (test_bit(SPU_SCHED_NOTIFY_ACTIVE, &ctx->sched_flags))
69 return 1;
70
71 dsisr = ctx->csa.class_1_dsisr;
72 if (dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED))
73 return 1;
74
75 if (ctx->csa.class_0_pending)
76 return 1;
77
78 return 0;
79 }
80
spu_setup_isolated(struct spu_context * ctx)81 static int spu_setup_isolated(struct spu_context *ctx)
82 {
83 int ret;
84 u64 __iomem *mfc_cntl;
85 u64 sr1;
86 u32 status;
87 unsigned long timeout;
88 const u32 status_loading = SPU_STATUS_RUNNING
89 | SPU_STATUS_ISOLATED_STATE | SPU_STATUS_ISOLATED_LOAD_STATUS;
90
91 ret = -ENODEV;
92 if (!isolated_loader)
93 goto out;
94
95 /*
96 * We need to exclude userspace access to the context.
97 *
98 * To protect against memory access we invalidate all ptes
99 * and make sure the pagefault handlers block on the mutex.
100 */
101 spu_unmap_mappings(ctx);
102
103 mfc_cntl = &ctx->spu->priv2->mfc_control_RW;
104
105 /* purge the MFC DMA queue to ensure no spurious accesses before we
106 * enter kernel mode */
107 timeout = jiffies + HZ;
108 out_be64(mfc_cntl, MFC_CNTL_PURGE_DMA_REQUEST);
109 while ((in_be64(mfc_cntl) & MFC_CNTL_PURGE_DMA_STATUS_MASK)
110 != MFC_CNTL_PURGE_DMA_COMPLETE) {
111 if (time_after(jiffies, timeout)) {
112 printk(KERN_ERR "%s: timeout flushing MFC DMA queue\n",
113 __func__);
114 ret = -EIO;
115 goto out;
116 }
117 cond_resched();
118 }
119
120 /* clear purge status */
121 out_be64(mfc_cntl, 0);
122
123 /* put the SPE in kernel mode to allow access to the loader */
124 sr1 = spu_mfc_sr1_get(ctx->spu);
125 sr1 &= ~MFC_STATE1_PROBLEM_STATE_MASK;
126 spu_mfc_sr1_set(ctx->spu, sr1);
127
128 /* start the loader */
129 ctx->ops->signal1_write(ctx, (unsigned long)isolated_loader >> 32);
130 ctx->ops->signal2_write(ctx,
131 (unsigned long)isolated_loader & 0xffffffff);
132
133 ctx->ops->runcntl_write(ctx,
134 SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
135
136 ret = 0;
137 timeout = jiffies + HZ;
138 while (((status = ctx->ops->status_read(ctx)) & status_loading) ==
139 status_loading) {
140 if (time_after(jiffies, timeout)) {
141 printk(KERN_ERR "%s: timeout waiting for loader\n",
142 __func__);
143 ret = -EIO;
144 goto out_drop_priv;
145 }
146 cond_resched();
147 }
148
149 if (!(status & SPU_STATUS_RUNNING)) {
150 /* If isolated LOAD has failed: run SPU, we will get a stop-and
151 * signal later. */
152 pr_debug("%s: isolated LOAD failed\n", __func__);
153 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
154 ret = -EACCES;
155 goto out_drop_priv;
156 }
157
158 if (!(status & SPU_STATUS_ISOLATED_STATE)) {
159 /* This isn't allowed by the CBEA, but check anyway */
160 pr_debug("%s: SPU fell out of isolated mode?\n", __func__);
161 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_STOP);
162 ret = -EINVAL;
163 goto out_drop_priv;
164 }
165
166 out_drop_priv:
167 /* Finished accessing the loader. Drop kernel mode */
168 sr1 |= MFC_STATE1_PROBLEM_STATE_MASK;
169 spu_mfc_sr1_set(ctx->spu, sr1);
170
171 out:
172 return ret;
173 }
174
spu_run_init(struct spu_context * ctx,u32 * npc)175 static int spu_run_init(struct spu_context *ctx, u32 *npc)
176 {
177 unsigned long runcntl = SPU_RUNCNTL_RUNNABLE;
178 int ret;
179
180 spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
181
182 /*
183 * NOSCHED is synchronous scheduling with respect to the caller.
184 * The caller waits for the context to be loaded.
185 */
186 if (ctx->flags & SPU_CREATE_NOSCHED) {
187 if (ctx->state == SPU_STATE_SAVED) {
188 ret = spu_activate(ctx, 0);
189 if (ret)
190 return ret;
191 }
192 }
193
194 /*
195 * Apply special setup as required.
196 */
197 if (ctx->flags & SPU_CREATE_ISOLATE) {
198 if (!(ctx->ops->status_read(ctx) & SPU_STATUS_ISOLATED_STATE)) {
199 ret = spu_setup_isolated(ctx);
200 if (ret)
201 return ret;
202 }
203
204 /*
205 * If userspace has set the runcntrl register (eg, to
206 * issue an isolated exit), we need to re-set it here
207 */
208 runcntl = ctx->ops->runcntl_read(ctx) &
209 (SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
210 if (runcntl == 0)
211 runcntl = SPU_RUNCNTL_RUNNABLE;
212 } else {
213 unsigned long privcntl;
214
215 if (test_thread_flag(TIF_SINGLESTEP))
216 privcntl = SPU_PRIVCNTL_MODE_SINGLE_STEP;
217 else
218 privcntl = SPU_PRIVCNTL_MODE_NORMAL;
219
220 ctx->ops->privcntl_write(ctx, privcntl);
221 ctx->ops->npc_write(ctx, *npc);
222 }
223
224 ctx->ops->runcntl_write(ctx, runcntl);
225
226 if (ctx->flags & SPU_CREATE_NOSCHED) {
227 spuctx_switch_state(ctx, SPU_UTIL_USER);
228 } else {
229
230 if (ctx->state == SPU_STATE_SAVED) {
231 ret = spu_activate(ctx, 0);
232 if (ret)
233 return ret;
234 } else {
235 spuctx_switch_state(ctx, SPU_UTIL_USER);
236 }
237 }
238
239 set_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
240 return 0;
241 }
242
spu_run_fini(struct spu_context * ctx,u32 * npc,u32 * status)243 static int spu_run_fini(struct spu_context *ctx, u32 *npc,
244 u32 *status)
245 {
246 int ret = 0;
247
248 spu_del_from_rq(ctx);
249
250 *status = ctx->ops->status_read(ctx);
251 *npc = ctx->ops->npc_read(ctx);
252
253 spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
254 clear_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
255 spu_switch_log_notify(NULL, ctx, SWITCH_LOG_EXIT, *status);
256 spu_release(ctx);
257
258 if (signal_pending(current))
259 ret = -ERESTARTSYS;
260
261 return ret;
262 }
263
264 /*
265 * SPU syscall restarting is tricky because we violate the basic
266 * assumption that the signal handler is running on the interrupted
267 * thread. Here instead, the handler runs on PowerPC user space code,
268 * while the syscall was called from the SPU.
269 * This means we can only do a very rough approximation of POSIX
270 * signal semantics.
271 */
spu_handle_restartsys(struct spu_context * ctx,long * spu_ret,unsigned int * npc)272 static int spu_handle_restartsys(struct spu_context *ctx, long *spu_ret,
273 unsigned int *npc)
274 {
275 int ret;
276
277 switch (*spu_ret) {
278 case -ERESTARTSYS:
279 case -ERESTARTNOINTR:
280 /*
281 * Enter the regular syscall restarting for
282 * sys_spu_run, then restart the SPU syscall
283 * callback.
284 */
285 *npc -= 8;
286 ret = -ERESTARTSYS;
287 break;
288 case -ERESTARTNOHAND:
289 case -ERESTART_RESTARTBLOCK:
290 /*
291 * Restart block is too hard for now, just return -EINTR
292 * to the SPU.
293 * ERESTARTNOHAND comes from sys_pause, we also return
294 * -EINTR from there.
295 * Assume that we need to be restarted ourselves though.
296 */
297 *spu_ret = -EINTR;
298 ret = -ERESTARTSYS;
299 break;
300 default:
301 printk(KERN_WARNING "%s: unexpected return code %ld\n",
302 __func__, *spu_ret);
303 ret = 0;
304 }
305 return ret;
306 }
307
spu_process_callback(struct spu_context * ctx)308 static int spu_process_callback(struct spu_context *ctx)
309 {
310 struct spu_syscall_block s;
311 u32 ls_pointer, npc;
312 void __iomem *ls;
313 long spu_ret;
314 int ret;
315
316 /* get syscall block from local store */
317 npc = ctx->ops->npc_read(ctx) & ~3;
318 ls = (void __iomem *)ctx->ops->get_ls(ctx);
319 ls_pointer = in_be32(ls + npc);
320 if (ls_pointer > (LS_SIZE - sizeof(s)))
321 return -EFAULT;
322 memcpy_fromio(&s, ls + ls_pointer, sizeof(s));
323
324 /* do actual syscall without pinning the spu */
325 ret = 0;
326 spu_ret = -ENOSYS;
327 npc += 4;
328
329 if (s.nr_ret < __NR_syscalls) {
330 spu_release(ctx);
331 /* do actual system call from here */
332 spu_ret = spu_sys_callback(&s);
333 if (spu_ret <= -ERESTARTSYS) {
334 ret = spu_handle_restartsys(ctx, &spu_ret, &npc);
335 }
336 mutex_lock(&ctx->state_mutex);
337 if (ret == -ERESTARTSYS)
338 return ret;
339 }
340
341 /* need to re-get the ls, as it may have changed when we released the
342 * spu */
343 ls = (void __iomem *)ctx->ops->get_ls(ctx);
344
345 /* write result, jump over indirect pointer */
346 memcpy_toio(ls + ls_pointer, &spu_ret, sizeof(spu_ret));
347 ctx->ops->npc_write(ctx, npc);
348 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
349 return ret;
350 }
351
spufs_run_spu(struct spu_context * ctx,u32 * npc,u32 * event)352 long spufs_run_spu(struct spu_context *ctx, u32 *npc, u32 *event)
353 {
354 int ret;
355 struct spu *spu;
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 spu = ctx->spu;
389 if (unlikely(test_and_clear_bit(SPU_SCHED_NOTIFY_ACTIVE,
390 &ctx->sched_flags))) {
391 if (!(status & SPU_STATUS_STOPPED_BY_STOP)) {
392 spu_switch_notify(spu, ctx);
393 continue;
394 }
395 }
396
397 spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
398
399 if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
400 (status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
401 ret = spu_process_callback(ctx);
402 if (ret)
403 break;
404 status &= ~SPU_STATUS_STOPPED_BY_STOP;
405 }
406 ret = spufs_handle_class1(ctx);
407 if (ret)
408 break;
409
410 ret = spufs_handle_class0(ctx);
411 if (ret)
412 break;
413
414 if (signal_pending(current))
415 ret = -ERESTARTSYS;
416 } while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
417 SPU_STATUS_STOPPED_BY_HALT |
418 SPU_STATUS_SINGLE_STEP)));
419
420 spu_disable_spu(ctx);
421 ret = spu_run_fini(ctx, npc, &status);
422 spu_yield(ctx);
423
424 if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
425 (((status >> SPU_STOP_STATUS_SHIFT) & 0x3f00) == 0x2100))
426 ctx->stats.libassist++;
427
428 if ((ret == 0) ||
429 ((ret == -ERESTARTSYS) &&
430 ((status & SPU_STATUS_STOPPED_BY_HALT) ||
431 (status & SPU_STATUS_SINGLE_STEP) ||
432 ((status & SPU_STATUS_STOPPED_BY_STOP) &&
433 (status >> SPU_STOP_STATUS_SHIFT != 0x2104)))))
434 ret = status;
435
436 /* Note: we don't need to force_sig SIGTRAP on single-step
437 * since we have TIF_SINGLESTEP set, thus the kernel will do
438 * it upon return from the syscall anyawy
439 */
440 if (unlikely(status & SPU_STATUS_SINGLE_STEP))
441 ret = -ERESTARTSYS;
442
443 else if (unlikely((status & SPU_STATUS_STOPPED_BY_STOP)
444 && (status >> SPU_STOP_STATUS_SHIFT) == 0x3fff)) {
445 force_sig(SIGTRAP, current);
446 ret = -ERESTARTSYS;
447 }
448
449 out:
450 *event = ctx->event_return;
451 out_unlock:
452 mutex_unlock(&ctx->run_mutex);
453 return ret;
454 }
455