release/src-rt-6.x/linux/linux-2.6/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 & 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 }