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)
15 {
16 	struct spu_context *ctx = spu->ctx;
17 
18 	wake_up_all(&ctx->stop_wq);
19 }
20 
21 static inline int spu_stopped(struct spu_context *ctx, u32 * stat)
22 {
23 	struct spu *spu;
24 	u64 pte_fault;
25 
26 	*stat = ctx->ops->status_read(ctx);
27 	if (ctx->state != SPU_STATE_RUNNABLE)
28 		return 1;
29 	spu = ctx->spu;
30 	pte_fault = spu->dsisr &
31 	    (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED);
32 	return (!(*stat & 0x1) || pte_fault || spu->class_0_pending) ? 1 : 0;
33 }
34 
35 static int spu_setup_isolated(struct spu_context *ctx)
36 {
37 	int ret;
38 	u64 __iomem *mfc_cntl;
39 	u64 sr1;
40 	u32 status;
41 	unsigned long timeout;
42 	const u32 status_loading = SPU_STATUS_RUNNING
43 		| SPU_STATUS_ISOLATED_STATE | SPU_STATUS_ISOLATED_LOAD_STATUS;
44 
45 	ret = -ENODEV;
46 	if (!isolated_loader)
47 		goto out;
48 
49 	/*
50 	 * We need to exclude userspace access to the context.
51 	 *
52 	 * To protect against memory access we invalidate all ptes
53 	 * and make sure the pagefault handlers block on the mutex.
54 	 */
55 	spu_unmap_mappings(ctx);
56 
57 	mfc_cntl = &ctx->spu->priv2->mfc_control_RW;
58 
59 	/* purge the MFC DMA queue to ensure no spurious accesses before we
60 	 * enter kernel mode */
61 	timeout = jiffies + HZ;
62 	out_be64(mfc_cntl, MFC_CNTL_PURGE_DMA_REQUEST);
63 	while ((in_be64(mfc_cntl) & MFC_CNTL_PURGE_DMA_STATUS_MASK)
64 			!= MFC_CNTL_PURGE_DMA_COMPLETE) {
65 		if (time_after(jiffies, timeout)) {
66 			printk(KERN_ERR "%s: timeout flushing MFC DMA queue\n",
67 					__FUNCTION__);
68 			ret = -EIO;
69 			goto out;
70 		}
71 		cond_resched();
72 	}
73 
74 	/* put the SPE in kernel mode to allow access to the loader */
75 	sr1 = spu_mfc_sr1_get(ctx->spu);
76 	sr1 &= ~MFC_STATE1_PROBLEM_STATE_MASK;
77 	spu_mfc_sr1_set(ctx->spu, sr1);
78 
79 	/* start the loader */
80 	ctx->ops->signal1_write(ctx, (unsigned long)isolated_loader >> 32);
81 	ctx->ops->signal2_write(ctx,
82 			(unsigned long)isolated_loader & 0xffffffff);
83 
84 	ctx->ops->runcntl_write(ctx,
85 			SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
86 
87 	ret = 0;
88 	timeout = jiffies + HZ;
89 	while (((status = ctx->ops->status_read(ctx)) & status_loading) ==
90 				status_loading) {
91 		if (time_after(jiffies, timeout)) {
92 			printk(KERN_ERR "%s: timeout waiting for loader\n",
93 					__FUNCTION__);
94 			ret = -EIO;
95 			goto out_drop_priv;
96 		}
97 		cond_resched();
98 	}
99 
100 	if (!(status & SPU_STATUS_RUNNING)) {
101 		/* If isolated LOAD has failed: run SPU, we will get a stop-and
102 		 * signal later. */
103 		pr_debug("%s: isolated LOAD failed\n", __FUNCTION__);
104 		ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
105 		ret = -EACCES;
106 		goto out_drop_priv;
107 	}
108 
109 	if (!(status & SPU_STATUS_ISOLATED_STATE)) {
110 		/* This isn't allowed by the CBEA, but check anyway */
111 		pr_debug("%s: SPU fell out of isolated mode?\n", __FUNCTION__);
112 		ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_STOP);
113 		ret = -EINVAL;
114 		goto out_drop_priv;
115 	}
116 
117 out_drop_priv:
118 	/* Finished accessing the loader. Drop kernel mode */
119 	sr1 |= MFC_STATE1_PROBLEM_STATE_MASK;
120 	spu_mfc_sr1_set(ctx->spu, sr1);
121 
122 out:
123 	return ret;
124 }
125 
126 static int spu_run_init(struct spu_context *ctx, u32 * npc)
127 {
128 	if (ctx->flags & SPU_CREATE_ISOLATE) {
129 		unsigned long runcntl;
130 
131 		if (!(ctx->ops->status_read(ctx) & SPU_STATUS_ISOLATED_STATE)) {
132 			int ret = spu_setup_isolated(ctx);
133 			if (ret)
134 				return ret;
135 		}
136 
137 		/* if userspace has set the runcntrl register (eg, to issue an
138 		 * isolated exit), we need to re-set it here */
139 		runcntl = ctx->ops->runcntl_read(ctx) &
140 			(SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
141 		if (runcntl == 0)
142 			runcntl = SPU_RUNCNTL_RUNNABLE;
143 		ctx->ops->runcntl_write(ctx, runcntl);
144 	} else {
145 		spu_start_tick(ctx);
146 		ctx->ops->npc_write(ctx, *npc);
147 		ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
148 	}
149 
150 	return 0;
151 }
152 
153 static int spu_run_fini(struct spu_context *ctx, u32 * npc,
154 			       u32 * status)
155 {
156 	int ret = 0;
157 
158 	spu_stop_tick(ctx);
159 	*status = ctx->ops->status_read(ctx);
160 	*npc = ctx->ops->npc_read(ctx);
161 	spu_release(ctx);
162 
163 	if (signal_pending(current))
164 		ret = -ERESTARTSYS;
165 
166 	return ret;
167 }
168 
169 static int spu_reacquire_runnable(struct spu_context *ctx, u32 *npc,
170 				         u32 *status)
171 {
172 	int ret;
173 
174 	ret = spu_run_fini(ctx, npc, status);
175 	if (ret)
176 		return ret;
177 
178 	if (*status & (SPU_STATUS_STOPPED_BY_STOP | SPU_STATUS_STOPPED_BY_HALT))
179 		return *status;
180 
181 	ret = spu_acquire_runnable(ctx, 0);
182 	if (ret)
183 		return ret;
184 
185 	ret = spu_run_init(ctx, npc);
186 	if (ret) {
187 		spu_release(ctx);
188 		return ret;
189 	}
190 	return 0;
191 }
192 
193 /*
194  * SPU syscall restarting is tricky because we violate the basic
195  * assumption that the signal handler is running on the interrupted
196  * thread. Here instead, the handler runs on PowerPC user space code,
197  * while the syscall was called from the SPU.
198  * This means we can only do a very rough approximation of POSIX
199  * signal semantics.
200  */
201 int spu_handle_restartsys(struct spu_context *ctx, long *spu_ret,
202 			  unsigned int *npc)
203 {
204 	int ret;
205 
206 	switch (*spu_ret) {
207 	case -ERESTARTSYS:
208 	case -ERESTARTNOINTR:
209 		/*
210 		 * Enter the regular syscall restarting for
211 		 * sys_spu_run, then restart the SPU syscall
212 		 * callback.
213 		 */
214 		*npc -= 8;
215 		ret = -ERESTARTSYS;
216 		break;
217 	case -ERESTARTNOHAND:
218 	case -ERESTART_RESTARTBLOCK:
219 		/*
220 		 * Restart block is too hard for now, just return -EINTR
221 		 * to the SPU.
222 		 * ERESTARTNOHAND comes from sys_pause, we also return
223 		 * -EINTR from there.
224 		 * Assume that we need to be restarted ourselves though.
225 		 */
226 		*spu_ret = -EINTR;
227 		ret = -ERESTARTSYS;
228 		break;
229 	default:
230 		printk(KERN_WARNING "%s: unexpected return code %ld\n",
231 			__FUNCTION__, *spu_ret);
232 		ret = 0;
233 	}
234 	return ret;
235 }
236 
237 int spu_process_callback(struct spu_context *ctx)
238 {
239 	struct spu_syscall_block s;
240 	u32 ls_pointer, npc;
241 	void __iomem *ls;
242 	long spu_ret;
243 	int ret;
244 
245 	/* get syscall block from local store */
246 	npc = ctx->ops->npc_read(ctx) & ~3;
247 	ls = (void __iomem *)ctx->ops->get_ls(ctx);
248 	ls_pointer = in_be32(ls + npc);
249 	if (ls_pointer > (LS_SIZE - sizeof(s)))
250 		return -EFAULT;
251 	memcpy_fromio(&s, ls + ls_pointer, sizeof(s));
252 
253 	/* do actual syscall without pinning the spu */
254 	ret = 0;
255 	spu_ret = -ENOSYS;
256 	npc += 4;
257 
258 	if (s.nr_ret < __NR_syscalls) {
259 		spu_release(ctx);
260 		/* do actual system call from here */
261 		spu_ret = spu_sys_callback(&s);
262 		if (spu_ret <= -ERESTARTSYS) {
263 			ret = spu_handle_restartsys(ctx, &spu_ret, &npc);
264 		}
265 		spu_acquire(ctx);
266 		if (ret == -ERESTARTSYS)
267 			return ret;
268 	}
269 
270 	/* write result, jump over indirect pointer */
271 	memcpy_toio(ls + ls_pointer, &spu_ret, sizeof(spu_ret));
272 	ctx->ops->npc_write(ctx, npc);
273 	ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
274 	return ret;
275 }
276 
277 static inline int spu_process_events(struct spu_context *ctx)
278 {
279 	struct spu *spu = ctx->spu;
280 	int ret = 0;
281 
282 	if (spu->class_0_pending)
283 		ret = spu_irq_class_0_bottom(spu);
284 	if (!ret && signal_pending(current))
285 		ret = -ERESTARTSYS;
286 	return ret;
287 }
288 
289 long spufs_run_spu(struct file *file, struct spu_context *ctx,
290 		   u32 *npc, u32 *event)
291 {
292 	int ret;
293 	u32 status;
294 
295 	if (mutex_lock_interruptible(&ctx->run_mutex))
296 		return -ERESTARTSYS;
297 
298 	ctx->ops->master_start(ctx);
299 	ctx->event_return = 0;
300 
301 	ret = spu_acquire_runnable(ctx, 0);
302 	if (ret)
303 		return ret;
304 
305 	ret = spu_run_init(ctx, npc);
306 	if (ret) {
307 		spu_release(ctx);
308 		goto out;
309 	}
310 
311 	do {
312 		ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, &status));
313 		if (unlikely(ret))
314 			break;
315 		if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
316 		    (status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
317 			ret = spu_process_callback(ctx);
318 			if (ret)
319 				break;
320 			status &= ~SPU_STATUS_STOPPED_BY_STOP;
321 		}
322 		ret = spufs_handle_class1(ctx);
323 		if (ret)
324 			break;
325 
326 		if (unlikely(ctx->state != SPU_STATE_RUNNABLE)) {
327 			ret = spu_reacquire_runnable(ctx, npc, &status);
328 			if (ret) {
329 				spu_stop_tick(ctx);
330 				goto out2;
331 			}
332 			continue;
333 		}
334 		ret = spu_process_events(ctx);
335 
336 	} while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
337 				      SPU_STATUS_STOPPED_BY_HALT)));
338 
339 	ctx->ops->master_stop(ctx);
340 	ret = spu_run_fini(ctx, npc, &status);
341 	spu_yield(ctx);
342 
343 out2:
344 	if ((ret == 0) ||
345 	    ((ret == -ERESTARTSYS) &&
346 	     ((status & SPU_STATUS_STOPPED_BY_HALT) ||
347 	      ((status & SPU_STATUS_STOPPED_BY_STOP) &&
348 	       (status >> SPU_STOP_STATUS_SHIFT != 0x2104)))))
349 		ret = status;
350 
351 	if ((status & SPU_STATUS_STOPPED_BY_STOP)
352 	    && (status >> SPU_STOP_STATUS_SHIFT) == 0x3fff) {
353 		force_sig(SIGTRAP, current);
354 		ret = -ERESTARTSYS;
355 	}
356 
357 out:
358 	*event = ctx->event_return;
359 	mutex_unlock(&ctx->run_mutex);
360 	return ret;
361 }
362