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. */
14void 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
48int 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
56top:
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
81static 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
166out_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
171out:
172	return ret;
173}
174
175static 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
243static 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 */
272static 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
308static 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
352long 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
449out:
450	*event = ctx->event_return;
451out_unlock:
452	mutex_unlock(&ctx->run_mutex);
453	return ret;
454}
455