linux/arch/powerpc/platforms/cell/spufs/run.c
<<
>>
Prefs
   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. */
  14void spufs_stop_callback(struct spu *spu, int irq)
  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                switch(irq) {
  28                case 0 :
  29                        ctx->csa.class_0_pending = spu->class_0_pending;
  30                        ctx->csa.class_0_dar = spu->class_0_dar;
  31                        break;
  32                case 1 :
  33                        ctx->csa.class_1_dsisr = spu->class_1_dsisr;
  34                        ctx->csa.class_1_dar = spu->class_1_dar;
  35                        break;
  36                case 2 :
  37                        break;
  38                }
  39
  40                /* ensure that the exception status has hit memory before a
  41                 * thread waiting on the context's stop queue is woken */
  42                smp_wmb();
  43
  44                wake_up_all(&ctx->stop_wq);
  45        }
  46}
  47
  48int spu_stopped(struct spu_context *ctx, u32 *stat)
  49{
  50        u64 dsisr;
  51        u32 stopped;
  52
  53        stopped = SPU_STATUS_INVALID_INSTR | SPU_STATUS_SINGLE_STEP |
  54                SPU_STATUS_STOPPED_BY_HALT | SPU_STATUS_STOPPED_BY_STOP;
  55
  56top:
  57        *stat = ctx->ops->status_read(ctx);
  58        if (*stat & stopped) {
  59                /*
  60                 * If the spu hasn't finished stopping, we need to
  61                 * re-read the register to get the stopped value.
  62                 */
  63                if (*stat & SPU_STATUS_RUNNING)
  64                        goto top;
  65                return 1;
  66        }
  67
  68        if (test_bit(SPU_SCHED_NOTIFY_ACTIVE, &ctx->sched_flags))
  69                return 1;
  70
  71        dsisr = ctx->csa.class_1_dsisr;
  72        if (dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED))
  73                return 1;
  74
  75        if (ctx->csa.class_0_pending)
  76                return 1;
  77
  78        return 0;
  79}
  80
  81static int spu_setup_isolated(struct spu_context *ctx)
  82{
  83        int ret;
  84        u64 __iomem *mfc_cntl;
  85        u64 sr1;
  86        u32 status;
  87        unsigned long timeout;
  88        const u32 status_loading = SPU_STATUS_RUNNING
  89                | SPU_STATUS_ISOLATED_STATE | SPU_STATUS_ISOLATED_LOAD_STATUS;
  90
  91        ret = -ENODEV;
  92        if (!isolated_loader)
  93                goto out;
  94
  95        /*
  96         * We need to exclude userspace access to the context.
  97         *
  98         * To protect against memory access we invalidate all ptes
  99         * and make sure the pagefault handlers block on the mutex.
 100         */
 101        spu_unmap_mappings(ctx);
 102
 103        mfc_cntl = &ctx->spu->priv2->mfc_control_RW;
 104
 105        /* purge the MFC DMA queue to ensure no spurious accesses before we
 106         * enter kernel mode */
 107        timeout = jiffies + HZ;
 108        out_be64(mfc_cntl, MFC_CNTL_PURGE_DMA_REQUEST);
 109        while ((in_be64(mfc_cntl) & MFC_CNTL_PURGE_DMA_STATUS_MASK)
 110                        != MFC_CNTL_PURGE_DMA_COMPLETE) {
 111                if (time_after(jiffies, timeout)) {
 112                        printk(KERN_ERR "%s: timeout flushing MFC DMA queue\n",
 113                                        __func__);
 114                        ret = -EIO;
 115                        goto out;
 116                }
 117                cond_resched();
 118        }
 119
 120        /* clear purge status */
 121        out_be64(mfc_cntl, 0);
 122
 123        /* put the SPE in kernel mode to allow access to the loader */
 124        sr1 = spu_mfc_sr1_get(ctx->spu);
 125        sr1 &= ~MFC_STATE1_PROBLEM_STATE_MASK;
 126        spu_mfc_sr1_set(ctx->spu, sr1);
 127
 128        /* start the loader */
 129        ctx->ops->signal1_write(ctx, (unsigned long)isolated_loader >> 32);
 130        ctx->ops->signal2_write(ctx,
 131                        (unsigned long)isolated_loader & 0xffffffff);
 132
 133        ctx->ops->runcntl_write(ctx,
 134                        SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
 135
 136        ret = 0;
 137        timeout = jiffies + HZ;
 138        while (((status = ctx->ops->status_read(ctx)) & status_loading) ==
 139                                status_loading) {
 140                if (time_after(jiffies, timeout)) {
 141                        printk(KERN_ERR "%s: timeout waiting for loader\n",
 142                                        __func__);
 143                        ret = -EIO;
 144                        goto out_drop_priv;
 145                }
 146                cond_resched();
 147        }
 148
 149        if (!(status & SPU_STATUS_RUNNING)) {
 150                /* If isolated LOAD has failed: run SPU, we will get a stop-and
 151                 * signal later. */
 152                pr_debug("%s: isolated LOAD failed\n", __func__);
 153                ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
 154                ret = -EACCES;
 155                goto out_drop_priv;
 156        }
 157
 158        if (!(status & SPU_STATUS_ISOLATED_STATE)) {
 159                /* This isn't allowed by the CBEA, but check anyway */
 160                pr_debug("%s: SPU fell out of isolated mode?\n", __func__);
 161                ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_STOP);
 162                ret = -EINVAL;
 163                goto out_drop_priv;
 164        }
 165
 166out_drop_priv:
 167        /* Finished accessing the loader. Drop kernel mode */
 168        sr1 |= MFC_STATE1_PROBLEM_STATE_MASK;
 169        spu_mfc_sr1_set(ctx->spu, sr1);
 170
 171out:
 172        return ret;
 173}
 174
 175static int spu_run_init(struct spu_context *ctx, u32 *npc)
 176{
 177        unsigned long runcntl = SPU_RUNCNTL_RUNNABLE;
 178        int ret;
 179
 180        spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
 181
 182        /*
 183         * NOSCHED is synchronous scheduling with respect to the caller.
 184         * The caller waits for the context to be loaded.
 185         */
 186        if (ctx->flags & SPU_CREATE_NOSCHED) {
 187                if (ctx->state == SPU_STATE_SAVED) {
 188                        ret = spu_activate(ctx, 0);
 189                        if (ret)
 190                                return ret;
 191                }
 192        }
 193
 194        /*
 195         * Apply special setup as required.
 196         */
 197        if (ctx->flags & SPU_CREATE_ISOLATE) {
 198                if (!(ctx->ops->status_read(ctx) & SPU_STATUS_ISOLATED_STATE)) {
 199                        ret = spu_setup_isolated(ctx);
 200                        if (ret)
 201                                return ret;
 202                }
 203
 204                /*
 205                 * If userspace has set the runcntrl register (eg, to
 206                 * issue an isolated exit), we need to re-set it here
 207                 */
 208                runcntl = ctx->ops->runcntl_read(ctx) &
 209                        (SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
 210                if (runcntl == 0)
 211                        runcntl = SPU_RUNCNTL_RUNNABLE;
 212        } else {
 213                unsigned long privcntl;
 214
 215                if (test_thread_flag(TIF_SINGLESTEP))
 216                        privcntl = SPU_PRIVCNTL_MODE_SINGLE_STEP;
 217                else
 218                        privcntl = SPU_PRIVCNTL_MODE_NORMAL;
 219
 220                ctx->ops->privcntl_write(ctx, privcntl);
 221                ctx->ops->npc_write(ctx, *npc);
 222        }
 223
 224        ctx->ops->runcntl_write(ctx, runcntl);
 225
 226        if (ctx->flags & SPU_CREATE_NOSCHED) {
 227                spuctx_switch_state(ctx, SPU_UTIL_USER);
 228        } else {
 229
 230                if (ctx->state == SPU_STATE_SAVED) {
 231                        ret = spu_activate(ctx, 0);
 232                        if (ret)
 233                                return ret;
 234                } else {
 235                        spuctx_switch_state(ctx, SPU_UTIL_USER);
 236                }
 237        }
 238
 239        set_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
 240        return 0;
 241}
 242
 243static int spu_run_fini(struct spu_context *ctx, u32 *npc,
 244                               u32 *status)
 245{
 246        int ret = 0;
 247
 248        spu_del_from_rq(ctx);
 249
 250        *status = ctx->ops->status_read(ctx);
 251        *npc = ctx->ops->npc_read(ctx);
 252
 253        spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
 254        clear_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
 255        spu_switch_log_notify(NULL, ctx, SWITCH_LOG_EXIT, *status);
 256        spu_release(ctx);
 257
 258        if (signal_pending(current))
 259                ret = -ERESTARTSYS;
 260
 261        return ret;
 262}
 263
 264/*
 265 * SPU syscall restarting is tricky because we violate the basic
 266 * assumption that the signal handler is running on the interrupted
 267 * thread. Here instead, the handler runs on PowerPC user space code,
 268 * while the syscall was called from the SPU.
 269 * This means we can only do a very rough approximation of POSIX
 270 * signal semantics.
 271 */
 272static int spu_handle_restartsys(struct spu_context *ctx, long *spu_ret,
 273                          unsigned int *npc)
 274{
 275        int ret;
 276
 277        switch (*spu_ret) {
 278        case -ERESTARTSYS:
 279        case -ERESTARTNOINTR:
 280                /*
 281                 * Enter the regular syscall restarting for
 282                 * sys_spu_run, then restart the SPU syscall
 283                 * callback.
 284                 */
 285                *npc -= 8;
 286                ret = -ERESTARTSYS;
 287                break;
 288        case -ERESTARTNOHAND:
 289        case -ERESTART_RESTARTBLOCK:
 290                /*
 291                 * Restart block is too hard for now, just return -EINTR
 292                 * to the SPU.
 293                 * ERESTARTNOHAND comes from sys_pause, we also return
 294                 * -EINTR from there.
 295                 * Assume that we need to be restarted ourselves though.
 296                 */
 297                *spu_ret = -EINTR;
 298                ret = -ERESTARTSYS;
 299                break;
 300        default:
 301                printk(KERN_WARNING "%s: unexpected return code %ld\n",
 302                        __func__, *spu_ret);
 303                ret = 0;
 304        }
 305        return ret;
 306}
 307
 308static int spu_process_callback(struct spu_context *ctx)
 309{
 310        struct spu_syscall_block s;
 311        u32 ls_pointer, npc;
 312        void __iomem *ls;
 313        long spu_ret;
 314        int ret;
 315
 316        /* get syscall block from local store */
 317        npc = ctx->ops->npc_read(ctx) & ~3;
 318        ls = (void __iomem *)ctx->ops->get_ls(ctx);
 319        ls_pointer = in_be32(ls + npc);
 320        if (ls_pointer > (LS_SIZE - sizeof(s)))
 321                return -EFAULT;
 322        memcpy_fromio(&s, ls + ls_pointer, sizeof(s));
 323
 324        /* do actual syscall without pinning the spu */
 325        ret = 0;
 326        spu_ret = -ENOSYS;
 327        npc += 4;
 328
 329        if (s.nr_ret < __NR_syscalls) {
 330                spu_release(ctx);
 331                /* do actual system call from here */
 332                spu_ret = spu_sys_callback(&s);
 333                if (spu_ret <= -ERESTARTSYS) {
 334                        ret = spu_handle_restartsys(ctx, &spu_ret, &npc);
 335                }
 336                mutex_lock(&ctx->state_mutex);
 337                if (ret == -ERESTARTSYS)
 338                        return ret;
 339        }
 340
 341        /* need to re-get the ls, as it may have changed when we released the
 342         * spu */
 343        ls = (void __iomem *)ctx->ops->get_ls(ctx);
 344
 345        /* write result, jump over indirect pointer */
 346        memcpy_toio(ls + ls_pointer, &spu_ret, sizeof(spu_ret));
 347        ctx->ops->npc_write(ctx, npc);
 348        ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
 349        return ret;
 350}
 351
 352long spufs_run_spu(struct spu_context *ctx, u32 *npc, u32 *event)
 353{
 354        int ret;
 355        struct spu *spu;
 356        u32 status;
 357
 358        if (mutex_lock_interruptible(&ctx->run_mutex))
 359                return -ERESTARTSYS;
 360
 361        ctx->event_return = 0;
 362
 363        ret = spu_acquire(ctx);
 364        if (ret)
 365                goto out_unlock;
 366
 367        spu_enable_spu(ctx);
 368
 369        spu_update_sched_info(ctx);
 370
 371        ret = spu_run_init(ctx, npc);
 372        if (ret) {
 373                spu_release(ctx);
 374                goto out;
 375        }
 376
 377        do {
 378                ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, &status));
 379                if (unlikely(ret)) {
 380                        /*
 381                         * This is nasty: we need the state_mutex for all the
 382                         * bookkeeping even if the syscall was interrupted by
 383                         * a signal. ewww.
 384                         */
 385                        mutex_lock(&ctx->state_mutex);
 386                        break;
 387                }
 388                spu = ctx->spu;
 389                if (unlikely(test_and_clear_bit(SPU_SCHED_NOTIFY_ACTIVE,
 390                                                &ctx->sched_flags))) {
 391                        if (!(status & SPU_STATUS_STOPPED_BY_STOP)) {
 392                                spu_switch_notify(spu, ctx);
 393                                continue;
 394                        }
 395                }
 396
 397                spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
 398
 399                if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
 400                    (status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
 401                        ret = spu_process_callback(ctx);
 402                        if (ret)
 403                                break;
 404                        status &= ~SPU_STATUS_STOPPED_BY_STOP;
 405                }
 406                ret = spufs_handle_class1(ctx);
 407                if (ret)
 408                        break;
 409
 410                ret = spufs_handle_class0(ctx);
 411                if (ret)
 412                        break;
 413
 414                if (signal_pending(current))
 415                        ret = -ERESTARTSYS;
 416        } while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
 417                                      SPU_STATUS_STOPPED_BY_HALT |
 418                                       SPU_STATUS_SINGLE_STEP)));
 419
 420        spu_disable_spu(ctx);
 421        ret = spu_run_fini(ctx, npc, &status);
 422        spu_yield(ctx);
 423
 424        if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
 425            (((status >> SPU_STOP_STATUS_SHIFT) & 0x3f00) == 0x2100))
 426                ctx->stats.libassist++;
 427
 428        if ((ret == 0) ||
 429            ((ret == -ERESTARTSYS) &&
 430             ((status & SPU_STATUS_STOPPED_BY_HALT) ||
 431              (status & SPU_STATUS_SINGLE_STEP) ||
 432              ((status & SPU_STATUS_STOPPED_BY_STOP) &&
 433               (status >> SPU_STOP_STATUS_SHIFT != 0x2104)))))
 434                ret = status;
 435
 436        /* Note: we don't need to force_sig SIGTRAP on single-step
 437         * since we have TIF_SINGLESTEP set, thus the kernel will do
 438         * it upon return from the syscall anyawy
 439         */
 440        if (unlikely(status & SPU_STATUS_SINGLE_STEP))
 441                ret = -ERESTARTSYS;
 442
 443        else if (unlikely((status & SPU_STATUS_STOPPED_BY_STOP)
 444            && (status >> SPU_STOP_STATUS_SHIFT) == 0x3fff)) {
 445                force_sig(SIGTRAP, current);
 446                ret = -ERESTARTSYS;
 447        }
 448
 449out:
 450        *event = ctx->event_return;
 451out_unlock:
 452        mutex_unlock(&ctx->run_mutex);
 453        return ret;
 454}
 455