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 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 & SPU_STATUS_RUNNING) || pte_fault || spu->class_0_pending) ?
  33                 1 : 0;
  34 }
  35
  36 static int spu_setup_isolated(struct spu_context *ctx)
  37 {
  38         int ret;
  39         u64 __iomem *mfc_cntl;
  40         u64 sr1;
  41         u32 status;
  42         unsigned long timeout;
  43         const u32 status_loading = SPU_STATUS_RUNNING
  44                 | SPU_STATUS_ISOLATED_STATE | SPU_STATUS_ISOLATED_LOAD_STATUS;
  45
  46         ret = -ENODEV;
  47         if (!isolated_loader)
  48                 goto out;
  49
  50         /*
  51          * We need to exclude userspace access to the context.
  52          *
  53          * To protect against memory access we invalidate all ptes
  54          * and make sure the pagefault handlers block on the mutex.
  55          */
  56         spu_unmap_mappings(ctx);
  57
  58         mfc_cntl = &ctx->spu->priv2->mfc_control_RW;
  59
  60         /* purge the MFC DMA queue to ensure no spurious accesses before we
  61          * enter kernel mode */
  62         timeout = jiffies + HZ;
  63         out_be64(mfc_cntl, MFC_CNTL_PURGE_DMA_REQUEST);
  64         while ((in_be64(mfc_cntl) & MFC_CNTL_PURGE_DMA_STATUS_MASK)
  65                         != MFC_CNTL_PURGE_DMA_COMPLETE) {
  66                 if (time_after(jiffies, timeout)) {
  67                         printk(KERN_ERR "%s: timeout flushing MFC DMA queue\n",
  68                                         __FUNCTION__);
  69                         ret = -EIO;
  70                         goto out;
  71                 }
  72                 cond_resched();
  73         }
  74
  75         /* put the SPE in kernel mode to allow access to the loader */
  76         sr1 = spu_mfc_sr1_get(ctx->spu);
  77         sr1 &= ~MFC_STATE1_PROBLEM_STATE_MASK;
  78         spu_mfc_sr1_set(ctx->spu, sr1);
  79
  80         /* start the loader */
  81         ctx->ops->signal1_write(ctx, (unsigned long)isolated_loader >> 32);
  82         ctx->ops->signal2_write(ctx,
  83                         (unsigned long)isolated_loader & 0xffffffff);
  84
  85         ctx->ops->runcntl_write(ctx,
  86                         SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
  87
  88         ret = 0;
  89         timeout = jiffies + HZ;
  90         while (((status = ctx->ops->status_read(ctx)) & status_loading) ==
  91                                 status_loading) {
  92                 if (time_after(jiffies, timeout)) {
  93                         printk(KERN_ERR "%s: timeout waiting for loader\n",
  94                                         __FUNCTION__);
  95                         ret = -EIO;
  96                         goto out_drop_priv;
  97                 }
  98                 cond_resched();
  99         }
 100
 101         if (!(status & SPU_STATUS_RUNNING)) {
 102                 /* If isolated LOAD has failed: run SPU, we will get a stop-and
 103                  * signal later. */
 104                 pr_debug("%s: isolated LOAD failed\n", __FUNCTION__);
 105                 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
 106                 ret = -EACCES;
 107                 goto out_drop_priv;
 108         }
 109
 110         if (!(status & SPU_STATUS_ISOLATED_STATE)) {
 111                 /* This isn't allowed by the CBEA, but check anyway */
 112                 pr_debug("%s: SPU fell out of isolated mode?\n", __FUNCTION__);
 113                 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_STOP);
 114                 ret = -EINVAL;
 115                 goto out_drop_priv;
 116         }
 117
 118 out_drop_priv:
 119         /* Finished accessing the loader. Drop kernel mode */
 120         sr1 |= MFC_STATE1_PROBLEM_STATE_MASK;
 121         spu_mfc_sr1_set(ctx->spu, sr1);
 122
 123 out:
 124         return ret;
 125 }
 126
 127 static int spu_run_init(struct spu_context *ctx, u32 * npc)
 128 {
 129         if (ctx->flags & SPU_CREATE_ISOLATE) {
 130                 unsigned long runcntl;
 131
 132                 if (!(ctx->ops->status_read(ctx) & SPU_STATUS_ISOLATED_STATE)) {
 133                         int ret = spu_setup_isolated(ctx);
 134                         if (ret)
 135                                 return ret;
 136                 }
 137
 138                 /* if userspace has set the runcntrl register (eg, to issue an
 139                  * isolated exit), we need to re-set it here */
 140                 runcntl = ctx->ops->runcntl_read(ctx) &
 141                         (SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
 142                 if (runcntl == 0)
 143                         runcntl = SPU_RUNCNTL_RUNNABLE;
 144                 ctx->ops->runcntl_write(ctx, runcntl);
 145         } else {
 146                 unsigned long mode = SPU_PRIVCNTL_MODE_NORMAL;
 147                 ctx->ops->npc_write(ctx, *npc);
 148                 if (test_thread_flag(TIF_SINGLESTEP))
 149                         mode = SPU_PRIVCNTL_MODE_SINGLE_STEP;
 150                 out_be64(&ctx->spu->priv2->spu_privcntl_RW, mode);
 151                 ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
 152         }
 153
 154         return 0;
 155 }
 156
 157 static int spu_run_fini(struct spu_context *ctx, u32 * npc,
 158                                u32 * status)
 159 {
 160         int ret = 0;
 161
 162         *status = ctx->ops->status_read(ctx);
 163         *npc = ctx->ops->npc_read(ctx);
 164         spu_release(ctx);
 165
 166         if (signal_pending(current))
 167                 ret = -ERESTARTSYS;
 168
 169         return ret;
 170 }
 171
 172 static int spu_reacquire_runnable(struct spu_context *ctx, u32 *npc,
 173                                          u32 *status)
 174 {
 175         int ret;
 176
 177         ret = spu_run_fini(ctx, npc, status);
 178         if (ret)
 179                 return ret;
 180
 181         if (*status & (SPU_STATUS_STOPPED_BY_STOP | SPU_STATUS_STOPPED_BY_HALT))
 182                 return *status;
 183
 184         ret = spu_acquire_runnable(ctx, 0);
 185         if (ret)
 186                 return ret;
 187
 188         ret = spu_run_init(ctx, npc);
 189         if (ret) {
 190                 spu_release(ctx);
 191                 return ret;
 192         }
 193         return 0;
 194 }
 195
 196 /*
 197  * SPU syscall restarting is tricky because we violate the basic
 198  * assumption that the signal handler is running on the interrupted
 199  * thread. Here instead, the handler runs on PowerPC user space code,
 200  * while the syscall was called from the SPU.
 201  * This means we can only do a very rough approximation of POSIX
 202  * signal semantics.
 203  */
 204 int spu_handle_restartsys(struct spu_context *ctx, long *spu_ret,
 205                           unsigned int *npc)
 206 {
 207         int ret;
 208
 209         switch (*spu_ret) {
 210         case -ERESTARTSYS:
 211         case -ERESTARTNOINTR:
 212                 /*
 213                  * Enter the regular syscall restarting for
 214                  * sys_spu_run, then restart the SPU syscall
 215                  * callback.
 216                  */
 217                 *npc -= 8;
 218                 ret = -ERESTARTSYS;
 219                 break;
 220         case -ERESTARTNOHAND:
 221         case -ERESTART_RESTARTBLOCK:
 222                 /*
 223                  * Restart block is too hard for now, just return -EINTR
 224                  * to the SPU.
 225                  * ERESTARTNOHAND comes from sys_pause, we also return
 226                  * -EINTR from there.
 227                  * Assume that we need to be restarted ourselves though.
 228                  */
 229                 *spu_ret = -EINTR;
 230                 ret = -ERESTARTSYS;
 231                 break;
 232         default:
 233                 printk(KERN_WARNING "%s: unexpected return code %ld\n",
 234                         __FUNCTION__, *spu_ret);
 235                 ret = 0;
 236         }
 237         return ret;
 238 }
 239
 240 int spu_process_callback(struct spu_context *ctx)
 241 {
 242         struct spu_syscall_block s;
 243         u32 ls_pointer, npc;
 244         void __iomem *ls;
 245         long spu_ret;
 246         int ret;
 247
 248         /* get syscall block from local store */
 249         npc = ctx->ops->npc_read(ctx) & ~3;
 250         ls = (void __iomem *)ctx->ops->get_ls(ctx);
 251         ls_pointer = in_be32(ls + npc);
 252         if (ls_pointer > (LS_SIZE - sizeof(s)))
 253                 return -EFAULT;
 254         memcpy_fromio(&s, ls + ls_pointer, sizeof(s));
 255
 256         /* do actual syscall without pinning the spu */
 257         ret = 0;
 258         spu_ret = -ENOSYS;
 259         npc += 4;
 260
 261         if (s.nr_ret < __NR_syscalls) {
 262                 spu_release(ctx);
 263                 /* do actual system call from here */
 264                 spu_ret = spu_sys_callback(&s);
 265                 if (spu_ret <= -ERESTARTSYS) {
 266                         ret = spu_handle_restartsys(ctx, &spu_ret, &npc);
 267                 }
 268                 spu_acquire(ctx);
 269                 if (ret == -ERESTARTSYS)
 270                         return ret;
 271         }
 272
 273         /* write result, jump over indirect pointer */
 274         memcpy_toio(ls + ls_pointer, &spu_ret, sizeof(spu_ret));
 275         ctx->ops->npc_write(ctx, npc);
 276         ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
 277         return ret;
 278 }
 279
 280 static inline int spu_process_events(struct spu_context *ctx)
 281 {
 282         struct spu *spu = ctx->spu;
 283         int ret = 0;
 284
 285         if (spu->class_0_pending)
 286                 ret = spu_irq_class_0_bottom(spu);
 287         if (!ret && signal_pending(current))
 288                 ret = -ERESTARTSYS;
 289         return ret;
 290 }
 291
 292 long spufs_run_spu(struct file *file, struct spu_context *ctx,
 293                    u32 *npc, u32 *event)
 294 {
 295         int ret;
 296         u32 status;
 297
 298         if (mutex_lock_interruptible(&ctx->run_mutex))
 299                 return -ERESTARTSYS;
 300
 301         ctx->ops->master_start(ctx);
 302         ctx->event_return = 0;
 303
 304         spu_acquire(ctx);
 305         if (ctx->state == SPU_STATE_SAVED) {
 306                 __spu_update_sched_info(ctx);
 307
 308                 ret = spu_activate(ctx, 0);
 309                 if (ret) {
 310                         spu_release(ctx);
 311                         goto out;
 312                 }
 313         } else {
 314                 /*
 315                  * We have to update the scheduling priority under active_mutex
 316                  * to protect against find_victim().
 317                  */
 318                 spu_update_sched_info(ctx);
 319         }
 320
 321         ret = spu_run_init(ctx, npc);
 322         if (ret) {
 323                 spu_release(ctx);
 324                 goto out;
 325         }
 326
 327         do {
 328                 ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, &status));
 329                 if (unlikely(ret))
 330                         break;
 331                 if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
 332                     (status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
 333                         ret = spu_process_callback(ctx);
 334                         if (ret)
 335                                 break;
 336                         status &= ~SPU_STATUS_STOPPED_BY_STOP;
 337                 }
 338                 ret = spufs_handle_class1(ctx);
 339                 if (ret)
 340                         break;
 341
 342                 if (unlikely(ctx->state != SPU_STATE_RUNNABLE)) {
 343                         ret = spu_reacquire_runnable(ctx, npc, &status);
 344                         if (ret)
 345                                 goto out2;
 346                         continue;
 347                 }
 348                 ret = spu_process_events(ctx);
 349
 350         } while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
 351                                       SPU_STATUS_STOPPED_BY_HALT |
 352                                        SPU_STATUS_SINGLE_STEP)));
 353
 354         ctx->ops->master_stop(ctx);
 355         ret = spu_run_fini(ctx, npc, &status);
 356         spu_yield(ctx);
 357
 358 out2:
 359         if ((ret == 0) ||
 360             ((ret == -ERESTARTSYS) &&
 361              ((status & SPU_STATUS_STOPPED_BY_HALT) ||
 362               (status & SPU_STATUS_SINGLE_STEP) ||
 363               ((status & SPU_STATUS_STOPPED_BY_STOP) &&
 364                (status >> SPU_STOP_STATUS_SHIFT != 0x2104)))))
 365                 ret = status;
 366
 367         /* Note: we don't need to force_sig SIGTRAP on single-step
 368          * since we have TIF_SINGLESTEP set, thus the kernel will do
 369          * it upon return from the syscall anyawy
 370          */
 371         if ((status & SPU_STATUS_STOPPED_BY_STOP)
 372             && (status >> SPU_STOP_STATUS_SHIFT) == 0x3fff) {
 373                 force_sig(SIGTRAP, current);
 374                 ret = -ERESTARTSYS;
 375         }
 376
 377 out:
 378         *event = ctx->event_return;
 379         mutex_unlock(&ctx->run_mutex);
 380         return ret;
 381 }