arch/powerpc/platforms/cell/spufs/run.c

   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 void spufs_dma_callback(struct spu *spu, int type)
  22 {
  23         struct spu_context *ctx = spu->ctx;
  24
  25         if (ctx->flags & SPU_CREATE_EVENTS_ENABLED) {
  26                 ctx->event_return |= type;
  27                 wake_up_all(&ctx->stop_wq);
  28         } else {
  29                 switch (type) {
  30                 case SPE_EVENT_DMA_ALIGNMENT:
  31                 case SPE_EVENT_SPE_DATA_STORAGE:
  32                 case SPE_EVENT_INVALID_DMA:
  33                         force_sig(SIGBUS, /* info, */ current);
  34                         break;
  35                 case SPE_EVENT_SPE_ERROR:
  36                         force_sig(SIGILL, /* info */ current);
  37                         break;
  38                 }
  39         }
  40 }
  41
  42 static inline int spu_stopped(struct spu_context *ctx, u32 * stat)
  43 {
  44         struct spu *spu;
  45         u64 pte_fault;
  46
  47         *stat = ctx->ops->status_read(ctx);
  48         if (ctx->state != SPU_STATE_RUNNABLE)
  49                 return 1;
  50         spu = ctx->spu;
  51         pte_fault = spu->dsisr &
  52             (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED);
  53         return (!(*stat & 0x1) || pte_fault || spu->class_0_pending) ? 1 : 0;
  54 }
  55
  56 static int spu_setup_isolated(struct spu_context *ctx)
  57 {
  58         int ret;
  59         u64 __iomem *mfc_cntl;
  60         u64 sr1;
  61         u32 status;
  62         unsigned long timeout;
  63         const u32 status_loading = SPU_STATUS_RUNNING
  64                 | SPU_STATUS_ISOLATED_STATE | SPU_STATUS_ISOLATED_LOAD_STATUS;
  65
  66         if (!isolated_loader)
  67                 return -ENODEV;
  68
  69         ret = spu_acquire_exclusive(ctx);
  70         if (ret)
  71                 goto out;
  72
  73         mfc_cntl = &ctx->spu->priv2->mfc_control_RW;
  74
  75         /* purge the MFC DMA queue to ensure no spurious accesses before we
  76          * enter kernel mode */
  77         timeout = jiffies + HZ;
  78         out_be64(mfc_cntl, MFC_CNTL_PURGE_DMA_REQUEST);
  79         while ((in_be64(mfc_cntl) & MFC_CNTL_PURGE_DMA_STATUS_MASK)
  80                         != MFC_CNTL_PURGE_DMA_COMPLETE) {
  81                 if (time_after(jiffies, timeout)) {
  82                         printk(KERN_ERR "%s: timeout flushing MFC DMA queue\n",
  83                                         __FUNCTION__);
  84                         ret = -EIO;
  85                         goto out_unlock;
  86                 }
  87                 cond_resched();
  88         }
  89
  90         /* put the SPE in kernel mode to allow access to the loader */
  91         sr1 = spu_mfc_sr1_get(ctx->spu);
  92         sr1 &= ~MFC_STATE1_PROBLEM_STATE_MASK;
  93         spu_mfc_sr1_set(ctx->spu, sr1);
  94
  95         /* start the loader */
  96         ctx->ops->signal1_write(ctx, (unsigned long)isolated_loader >> 32);
  97         ctx->ops->signal2_write(ctx,
  98                         (unsigned long)isolated_loader & 0xffffffff);
  99
 100         ctx->ops->runcntl_write(ctx,
 101                         SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
 102
 103         ret = 0;
 104         timeout = jiffies + HZ;
 105         while (((status = ctx->ops->status_read(ctx)) & status_loading) ==
 106                                 status_loading) {
 107                 if (time_after(jiffies, timeout)) {
 108                         printk(KERN_ERR "%s: timeout waiting for loader\n",
 109                                         __FUNCTION__);
 110                         ret = -EIO;
 111                         goto out_drop_priv;
 112                 }
 113                 cond_resched();
 114         }
 115
 116         if (!(status & SPU_STATUS_RUNNING)) {
 117                 /* If isolated LOAD has failed: run SPU, we will get a stop-and
 118                  * signal later. */
 119                 pr_debug("%s: isolated LOAD failed\n", __FUNCTION__);
 120                 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
 121                 ret = -EACCES;
 122
 123         } else if (!(status & SPU_STATUS_ISOLATED_STATE)) {
 124                 /* This isn't allowed by the CBEA, but check anyway */
 125                 pr_debug("%s: SPU fell out of isolated mode?\n", __FUNCTION__);
 126                 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_STOP);
 127                 ret = -EINVAL;
 128         }
 129
 130 out_drop_priv:
 131         /* Finished accessing the loader. Drop kernel mode */
 132         sr1 |= MFC_STATE1_PROBLEM_STATE_MASK;
 133         spu_mfc_sr1_set(ctx->spu, sr1);
 134
 135 out_unlock:
 136         spu_release(ctx);
 137 out:
 138         return ret;
 139 }
 140
 141 static inline int spu_run_init(struct spu_context *ctx, u32 * npc)
 142 {
 143         int ret;
 144         unsigned long runcntl = SPU_RUNCNTL_RUNNABLE;
 145
 146         ret = spu_acquire_runnable(ctx);
 147         if (ret)
 148                 return ret;
 149
 150         if (ctx->flags & SPU_CREATE_ISOLATE) {
 151                 if (!(ctx->ops->status_read(ctx) & SPU_STATUS_ISOLATED_STATE)) {
 152                         /* Need to release ctx, because spu_setup_isolated will
 153                          * acquire it exclusively.
 154                          */
 155                         spu_release(ctx);
 156                         ret = spu_setup_isolated(ctx);
 157                         if (!ret)
 158                                 ret = spu_acquire_runnable(ctx);
 159                 }
 160
 161                 /* if userspace has set the runcntrl register (eg, to issue an
 162                  * isolated exit), we need to re-set it here */
 163                 runcntl = ctx->ops->runcntl_read(ctx) &
 164                         (SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
 165                 if (runcntl == 0)
 166                         runcntl = SPU_RUNCNTL_RUNNABLE;
 167         } else
 168                 ctx->ops->npc_write(ctx, *npc);
 169
 170         ctx->ops->runcntl_write(ctx, runcntl);
 171         return ret;
 172 }
 173
 174 static inline int spu_run_fini(struct spu_context *ctx, u32 * npc,
 175                                u32 * status)
 176 {
 177         int ret = 0;
 178
 179         *status = ctx->ops->status_read(ctx);
 180         *npc = ctx->ops->npc_read(ctx);
 181         spu_release(ctx);
 182
 183         if (signal_pending(current))
 184                 ret = -ERESTARTSYS;
 185
 186         return ret;
 187 }
 188
 189 static inline int spu_reacquire_runnable(struct spu_context *ctx, u32 *npc,
 190                                          u32 *status)
 191 {
 192         int ret;
 193
 194         if ((ret = spu_run_fini(ctx, npc, status)) != 0)
 195                 return ret;
 196         if (*status & (SPU_STATUS_STOPPED_BY_STOP |
 197                        SPU_STATUS_STOPPED_BY_HALT)) {
 198                 return *status;
 199         }
 200         if ((ret = spu_run_init(ctx, npc)) != 0)
 201                 return ret;
 202         return 0;
 203 }
 204
 205 /*
 206  * SPU syscall restarting is tricky because we violate the basic
 207  * assumption that the signal handler is running on the interrupted
 208  * thread. Here instead, the handler runs on PowerPC user space code,
 209  * while the syscall was called from the SPU.
 210  * This means we can only do a very rough approximation of POSIX
 211  * signal semantics.
 212  */
 213 int spu_handle_restartsys(struct spu_context *ctx, long *spu_ret,
 214                           unsigned int *npc)
 215 {
 216         int ret;
 217
 218         switch (*spu_ret) {
 219         case -ERESTARTSYS:
 220         case -ERESTARTNOINTR:
 221                 /*
 222                  * Enter the regular syscall restarting for
 223                  * sys_spu_run, then restart the SPU syscall
 224                  * callback.
 225                  */
 226                 *npc -= 8;
 227                 ret = -ERESTARTSYS;
 228                 break;
 229         case -ERESTARTNOHAND:
 230         case -ERESTART_RESTARTBLOCK:
 231                 /*
 232                  * Restart block is too hard for now, just return -EINTR
 233                  * to the SPU.
 234                  * ERESTARTNOHAND comes from sys_pause, we also return
 235                  * -EINTR from there.
 236                  * Assume that we need to be restarted ourselves though.
 237                  */
 238                 *spu_ret = -EINTR;
 239                 ret = -ERESTARTSYS;
 240                 break;
 241         default:
 242                 printk(KERN_WARNING "%s: unexpected return code %ld\n",
 243                         __FUNCTION__, *spu_ret);
 244                 ret = 0;
 245         }
 246         return ret;
 247 }
 248
 249 int spu_process_callback(struct spu_context *ctx)
 250 {
 251         struct spu_syscall_block s;
 252         u32 ls_pointer, npc;
 253         char *ls;
 254         long spu_ret;
 255         int ret;
 256
 257         /* get syscall block from local store */
 258         npc = ctx->ops->npc_read(ctx);
 259         ls = ctx->ops->get_ls(ctx);
 260         ls_pointer = *(u32*)(ls + npc);
 261         if (ls_pointer > (LS_SIZE - sizeof(s)))
 262                 return -EFAULT;
 263         memcpy(&s, ls + ls_pointer, sizeof (s));
 264
 265         /* do actual syscall without pinning the spu */
 266         ret = 0;
 267         spu_ret = -ENOSYS;
 268         npc += 4;
 269
 270         if (s.nr_ret < __NR_syscalls) {
 271                 spu_release(ctx);
 272                 /* do actual system call from here */
 273                 spu_ret = spu_sys_callback(&s);
 274                 if (spu_ret <= -ERESTARTSYS) {
 275                         ret = spu_handle_restartsys(ctx, &spu_ret, &npc);
 276                 }
 277                 spu_acquire(ctx);
 278                 if (ret == -ERESTARTSYS)
 279                         return ret;
 280         }
 281
 282         /* write result, jump over indirect pointer */
 283         memcpy(ls + ls_pointer, &spu_ret, sizeof (spu_ret));
 284         ctx->ops->npc_write(ctx, npc);
 285         ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
 286         return ret;
 287 }
 288
 289 static inline int spu_process_events(struct spu_context *ctx)
 290 {
 291         struct spu *spu = ctx->spu;
 292         u64 pte_fault = MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED;
 293         int ret = 0;
 294
 295         if (spu->dsisr & pte_fault)
 296                 ret = spu_irq_class_1_bottom(spu);
 297         if (spu->class_0_pending)
 298                 ret = spu_irq_class_0_bottom(spu);
 299         if (!ret && signal_pending(current))
 300                 ret = -ERESTARTSYS;
 301         return ret;
 302 }
 303
 304 long spufs_run_spu(struct file *file, struct spu_context *ctx,
 305                    u32 *npc, u32 *event)
 306 {
 307         int ret;
 308         u32 status;
 309
 310         if (down_interruptible(&ctx->run_sema))
 311                 return -ERESTARTSYS;
 312
 313         ctx->ops->master_start(ctx);
 314         ctx->event_return = 0;
 315         ret = spu_run_init(ctx, npc);
 316         if (ret)
 317                 goto out;
 318
 319         do {
 320                 ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, &status));
 321                 if (unlikely(ret))
 322                         break;
 323                 if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
 324                     (status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
 325                         ret = spu_process_callback(ctx);
 326                         if (ret)
 327                                 break;
 328                         status &= ~SPU_STATUS_STOPPED_BY_STOP;
 329                 }
 330                 if (unlikely(ctx->state != SPU_STATE_RUNNABLE)) {
 331                         ret = spu_reacquire_runnable(ctx, npc, &status);
 332                         if (ret)
 333                                 goto out2;
 334                         continue;
 335                 }
 336                 ret = spu_process_events(ctx);
 337
 338         } while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
 339                                       SPU_STATUS_STOPPED_BY_HALT)));
 340
 341         ctx->ops->master_stop(ctx);
 342         ret = spu_run_fini(ctx, npc, &status);
 343         spu_yield(ctx);
 344
 345 out2:
 346         if ((ret == 0) ||
 347             ((ret == -ERESTARTSYS) &&
 348              ((status & SPU_STATUS_STOPPED_BY_HALT) ||
 349               ((status & SPU_STATUS_STOPPED_BY_STOP) &&
 350                (status >> SPU_STOP_STATUS_SHIFT != 0x2104)))))
 351                 ret = status;
 352
 353         if ((status & SPU_STATUS_STOPPED_BY_STOP)
 354             && (status >> SPU_STOP_STATUS_SHIFT) == 0x3fff) {
 355                 force_sig(SIGTRAP, current);
 356                 ret = -ERESTARTSYS;
 357         }
 358
 359 out:
 360         *event = ctx->event_return;
 361         up(&ctx->run_sema);
 362         return ret;
 363 }