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         /*
  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                 ctx->csa.class_0_pending = spu->class_0_pending;
  28                 ctx->csa.dsisr = spu->dsisr;
  29                 ctx->csa.dar = spu->dar;
  30
  31                 /* ensure that the exception status has hit memory before a
  32                  * thread waiting on the context's stop queue is woken */
  33                 smp_wmb();
  34
  35                 wake_up_all(&ctx->stop_wq);
  36         }
  37
  38         /* Clear callback arguments from spu structure */
  39         spu->class_0_pending = 0;
  40         spu->dsisr = 0;
  41         spu->dar = 0;
  42 }
  43
  44 int spu_stopped(struct spu_context *ctx, u32 *stat)
  45 {
  46         u64 dsisr;
  47         u32 stopped;
  48
  49         *stat = ctx->ops->status_read(ctx);
  50
  51         if (test_bit(SPU_SCHED_NOTIFY_ACTIVE, &ctx->sched_flags))
  52                 return 1;
  53
  54         stopped = SPU_STATUS_INVALID_INSTR | SPU_STATUS_SINGLE_STEP |
  55                 SPU_STATUS_STOPPED_BY_HALT | SPU_STATUS_STOPPED_BY_STOP;
  56         if (!(*stat & SPU_STATUS_RUNNING) && (*stat & stopped))
  57                 return 1;
  58
  59         dsisr = ctx->csa.dsisr;
  60         if (dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED))
  61                 return 1;
  62
  63         if (ctx->csa.class_0_pending)
  64                 return 1;
  65
  66         return 0;
  67 }
  68
  69 static int spu_setup_isolated(struct spu_context *ctx)
  70 {
  71         int ret;
  72         u64 __iomem *mfc_cntl;
  73         u64 sr1;
  74         u32 status;
  75         unsigned long timeout;
  76         const u32 status_loading = SPU_STATUS_RUNNING
  77                 | SPU_STATUS_ISOLATED_STATE | SPU_STATUS_ISOLATED_LOAD_STATUS;
  78
  79         ret = -ENODEV;
  80         if (!isolated_loader)
  81                 goto out;
  82
  83         /*
  84          * We need to exclude userspace access to the context.
  85          *
  86          * To protect against memory access we invalidate all ptes
  87          * and make sure the pagefault handlers block on the mutex.
  88          */
  89         spu_unmap_mappings(ctx);
  90
  91         mfc_cntl = &ctx->spu->priv2->mfc_control_RW;
  92
  93         /* purge the MFC DMA queue to ensure no spurious accesses before we
  94          * enter kernel mode */
  95         timeout = jiffies + HZ;
  96         out_be64(mfc_cntl, MFC_CNTL_PURGE_DMA_REQUEST);
  97         while ((in_be64(mfc_cntl) & MFC_CNTL_PURGE_DMA_STATUS_MASK)
  98                         != MFC_CNTL_PURGE_DMA_COMPLETE) {
  99                 if (time_after(jiffies, timeout)) {
 100                         printk(KERN_ERR "%s: timeout flushing MFC DMA queue\n",
 101                                         __FUNCTION__);
 102                         ret = -EIO;
 103                         goto out;
 104                 }
 105                 cond_resched();
 106         }
 107
 108         /* put the SPE in kernel mode to allow access to the loader */
 109         sr1 = spu_mfc_sr1_get(ctx->spu);
 110         sr1 &= ~MFC_STATE1_PROBLEM_STATE_MASK;
 111         spu_mfc_sr1_set(ctx->spu, sr1);
 112
 113         /* start the loader */
 114         ctx->ops->signal1_write(ctx, (unsigned long)isolated_loader >> 32);
 115         ctx->ops->signal2_write(ctx,
 116                         (unsigned long)isolated_loader & 0xffffffff);
 117
 118         ctx->ops->runcntl_write(ctx,
 119                         SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
 120
 121         ret = 0;
 122         timeout = jiffies + HZ;
 123         while (((status = ctx->ops->status_read(ctx)) & status_loading) ==
 124                                 status_loading) {
 125                 if (time_after(jiffies, timeout)) {
 126                         printk(KERN_ERR "%s: timeout waiting for loader\n",
 127                                         __FUNCTION__);
 128                         ret = -EIO;
 129                         goto out_drop_priv;
 130                 }
 131                 cond_resched();
 132         }
 133
 134         if (!(status & SPU_STATUS_RUNNING)) {
 135                 /* If isolated LOAD has failed: run SPU, we will get a stop-and
 136                  * signal later. */
 137                 pr_debug("%s: isolated LOAD failed\n", __FUNCTION__);
 138                 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
 139                 ret = -EACCES;
 140                 goto out_drop_priv;
 141         }
 142
 143         if (!(status & SPU_STATUS_ISOLATED_STATE)) {
 144                 /* This isn't allowed by the CBEA, but check anyway */
 145                 pr_debug("%s: SPU fell out of isolated mode?\n", __FUNCTION__);
 146                 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_STOP);
 147                 ret = -EINVAL;
 148                 goto out_drop_priv;
 149         }
 150
 151 out_drop_priv:
 152         /* Finished accessing the loader. Drop kernel mode */
 153         sr1 |= MFC_STATE1_PROBLEM_STATE_MASK;
 154         spu_mfc_sr1_set(ctx->spu, sr1);
 155
 156 out:
 157         return ret;
 158 }
 159
 160 static int spu_run_init(struct spu_context *ctx, u32 *npc)
 161 {
 162         unsigned long runcntl = SPU_RUNCNTL_RUNNABLE;
 163         int ret;
 164
 165         spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
 166
 167         /*
 168          * NOSCHED is synchronous scheduling with respect to the caller.
 169          * The caller waits for the context to be loaded.
 170          */
 171         if (ctx->flags & SPU_CREATE_NOSCHED) {
 172                 if (ctx->state == SPU_STATE_SAVED) {
 173                         ret = spu_activate(ctx, 0);
 174                         if (ret)
 175                                 return ret;
 176                 }
 177         }
 178
 179         /*
 180          * Apply special setup as required.
 181          */
 182         if (ctx->flags & SPU_CREATE_ISOLATE) {
 183                 if (!(ctx->ops->status_read(ctx) & SPU_STATUS_ISOLATED_STATE)) {
 184                         ret = spu_setup_isolated(ctx);
 185                         if (ret)
 186                                 return ret;
 187                 }
 188
 189                 /*
 190                  * If userspace has set the runcntrl register (eg, to
 191                  * issue an isolated exit), we need to re-set it here
 192                  */
 193                 runcntl = ctx->ops->runcntl_read(ctx) &
 194                         (SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
 195                 if (runcntl == 0)
 196                         runcntl = SPU_RUNCNTL_RUNNABLE;
 197         }
 198
 199         if (ctx->flags & SPU_CREATE_NOSCHED) {
 200                 spuctx_switch_state(ctx, SPU_UTIL_USER);
 201                 ctx->ops->runcntl_write(ctx, runcntl);
 202         } else {
 203                 unsigned long privcntl;
 204
 205                 if (test_thread_flag(TIF_SINGLESTEP))
 206                         privcntl = SPU_PRIVCNTL_MODE_SINGLE_STEP;
 207                 else
 208                         privcntl = SPU_PRIVCNTL_MODE_NORMAL;
 209
 210                 ctx->ops->npc_write(ctx, *npc);
 211                 ctx->ops->privcntl_write(ctx, privcntl);
 212                 ctx->ops->runcntl_write(ctx, runcntl);
 213
 214                 if (ctx->state == SPU_STATE_SAVED) {
 215                         ret = spu_activate(ctx, 0);
 216                         if (ret)
 217                                 return ret;
 218                 } else {
 219                         spuctx_switch_state(ctx, SPU_UTIL_USER);
 220                 }
 221         }
 222
 223 <<<<<<< HEAD:arch/powerpc/platforms/cell/spufs/run.c
 224 =======
 225         set_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
 226 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/powerpc/platforms/cell/spufs/run.c
 227         return 0;
 228 }
 229
 230 static int spu_run_fini(struct spu_context *ctx, u32 *npc,
 231                                u32 *status)
 232 {
 233         int ret = 0;
 234
 235         spu_del_from_rq(ctx);
 236
 237         *status = ctx->ops->status_read(ctx);
 238         *npc = ctx->ops->npc_read(ctx);
 239
 240         spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
 241 <<<<<<< HEAD:arch/powerpc/platforms/cell/spufs/run.c
 242 =======
 243         clear_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
 244 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/powerpc/platforms/cell/spufs/run.c
 245         spu_release(ctx);
 246
 247         if (signal_pending(current))
 248                 ret = -ERESTARTSYS;
 249
 250         return ret;
 251 }
 252
 253 /*
 254  * SPU syscall restarting is tricky because we violate the basic
 255  * assumption that the signal handler is running on the interrupted
 256  * thread. Here instead, the handler runs on PowerPC user space code,
 257  * while the syscall was called from the SPU.
 258  * This means we can only do a very rough approximation of POSIX
 259  * signal semantics.
 260  */
 261 static int spu_handle_restartsys(struct spu_context *ctx, long *spu_ret,
 262                           unsigned int *npc)
 263 {
 264         int ret;
 265
 266         switch (*spu_ret) {
 267         case -ERESTARTSYS:
 268         case -ERESTARTNOINTR:
 269                 /*
 270                  * Enter the regular syscall restarting for
 271                  * sys_spu_run, then restart the SPU syscall
 272                  * callback.
 273                  */
 274                 *npc -= 8;
 275                 ret = -ERESTARTSYS;
 276                 break;
 277         case -ERESTARTNOHAND:
 278         case -ERESTART_RESTARTBLOCK:
 279                 /*
 280                  * Restart block is too hard for now, just return -EINTR
 281                  * to the SPU.
 282                  * ERESTARTNOHAND comes from sys_pause, we also return
 283                  * -EINTR from there.
 284                  * Assume that we need to be restarted ourselves though.
 285                  */
 286                 *spu_ret = -EINTR;
 287                 ret = -ERESTARTSYS;
 288                 break;
 289         default:
 290                 printk(KERN_WARNING "%s: unexpected return code %ld\n",
 291                         __FUNCTION__, *spu_ret);
 292                 ret = 0;
 293         }
 294         return ret;
 295 }
 296
 297 static int spu_process_callback(struct spu_context *ctx)
 298 {
 299         struct spu_syscall_block s;
 300         u32 ls_pointer, npc;
 301         void __iomem *ls;
 302         long spu_ret;
 303         int ret, ret2;
 304
 305         /* get syscall block from local store */
 306         npc = ctx->ops->npc_read(ctx) & ~3;
 307         ls = (void __iomem *)ctx->ops->get_ls(ctx);
 308         ls_pointer = in_be32(ls + npc);
 309         if (ls_pointer > (LS_SIZE - sizeof(s)))
 310                 return -EFAULT;
 311         memcpy_fromio(&s, ls + ls_pointer, sizeof(s));
 312
 313         /* do actual syscall without pinning the spu */
 314         ret = 0;
 315         spu_ret = -ENOSYS;
 316         npc += 4;
 317
 318         if (s.nr_ret < __NR_syscalls) {
 319                 spu_release(ctx);
 320                 /* do actual system call from here */
 321                 spu_ret = spu_sys_callback(&s);
 322                 if (spu_ret <= -ERESTARTSYS) {
 323                         ret = spu_handle_restartsys(ctx, &spu_ret, &npc);
 324                 }
 325                 ret2 = spu_acquire(ctx);
 326                 if (ret == -ERESTARTSYS)
 327                         return ret;
 328                 if (ret2)
 329                         return -EINTR;
 330         }
 331
 332         /* write result, jump over indirect pointer */
 333         memcpy_toio(ls + ls_pointer, &spu_ret, sizeof(spu_ret));
 334         ctx->ops->npc_write(ctx, npc);
 335         ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
 336         return ret;
 337 }
 338
 339 long spufs_run_spu(struct spu_context *ctx, u32 *npc, u32 *event)
 340 {
 341         int ret;
 342         struct spu *spu;
 343         u32 status;
 344
 345         if (mutex_lock_interruptible(&ctx->run_mutex))
 346                 return -ERESTARTSYS;
 347
 348         spu_enable_spu(ctx);
 349         ctx->event_return = 0;
 350
 351         ret = spu_acquire(ctx);
 352         if (ret)
 353                 goto out_unlock;
 354
 355         spu_update_sched_info(ctx);
 356
 357         ret = spu_run_init(ctx, npc);
 358         if (ret) {
 359                 spu_release(ctx);
 360                 goto out;
 361         }
 362
 363         do {
 364                 ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, &status));
 365                 if (unlikely(ret)) {
 366                         /*
 367                          * This is nasty: we need the state_mutex for all the
 368                          * bookkeeping even if the syscall was interrupted by
 369                          * a signal. ewww.
 370                          */
 371                         mutex_lock(&ctx->state_mutex);
 372                         break;
 373                 }
 374                 spu = ctx->spu;
 375                 if (unlikely(test_and_clear_bit(SPU_SCHED_NOTIFY_ACTIVE,
 376                                                 &ctx->sched_flags))) {
 377                         if (!(status & SPU_STATUS_STOPPED_BY_STOP)) {
 378                                 spu_switch_notify(spu, ctx);
 379                                 continue;
 380                         }
 381                 }
 382
 383                 spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
 384
 385                 if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
 386                     (status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
 387                         ret = spu_process_callback(ctx);
 388                         if (ret)
 389                                 break;
 390                         status &= ~SPU_STATUS_STOPPED_BY_STOP;
 391                 }
 392                 ret = spufs_handle_class1(ctx);
 393                 if (ret)
 394                         break;
 395
 396                 ret = spufs_handle_class0(ctx);
 397                 if (ret)
 398                         break;
 399
 400                 if (signal_pending(current))
 401                         ret = -ERESTARTSYS;
 402         } while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
 403                                       SPU_STATUS_STOPPED_BY_HALT |
 404                                        SPU_STATUS_SINGLE_STEP)));
 405
 406         spu_disable_spu(ctx);
 407         ret = spu_run_fini(ctx, npc, &status);
 408         spu_yield(ctx);
 409
 410         if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
 411             (((status >> SPU_STOP_STATUS_SHIFT) & 0x3f00) == 0x2100))
 412                 ctx->stats.libassist++;
 413
 414         if ((ret == 0) ||
 415             ((ret == -ERESTARTSYS) &&
 416              ((status & SPU_STATUS_STOPPED_BY_HALT) ||
 417               (status & SPU_STATUS_SINGLE_STEP) ||
 418               ((status & SPU_STATUS_STOPPED_BY_STOP) &&
 419                (status >> SPU_STOP_STATUS_SHIFT != 0x2104)))))
 420                 ret = status;
 421
 422         /* Note: we don't need to force_sig SIGTRAP on single-step
 423          * since we have TIF_SINGLESTEP set, thus the kernel will do
 424          * it upon return from the syscall anyawy
 425          */
 426         if (unlikely(status & SPU_STATUS_SINGLE_STEP))
 427                 ret = -ERESTARTSYS;
 428
 429         else if (unlikely((status & SPU_STATUS_STOPPED_BY_STOP)
 430             && (status >> SPU_STOP_STATUS_SHIFT) == 0x3fff)) {
 431                 force_sig(SIGTRAP, current);
 432                 ret = -ERESTARTSYS;
 433         }
 434
 435 out:
 436         *event = ctx->event_return;
 437 out_unlock:
 438         mutex_unlock(&ctx->run_mutex);
 439         return ret;
 440 }