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. */
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 
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 
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 
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 
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  */
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 
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 
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