context.c

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/*
 * SPU file system -- SPU context management
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
 *
 * Author: Arnd Bergmann <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/atomic.h>
#include <linux/sched.h>
#include <asm/spu.h>
#include <asm/spu_csa.h>
#include "spufs.h"
#include "sputrace.h"


atomic_t nr_spu_contexts = ATOMIC_INIT(0);

struct spu_context *alloc_spu_context(struct spu_gang *gang)
{
    struct spu_context *ctx;
    struct timespec ts;

    ctx = kzalloc(sizeof *ctx, GFP_KERNEL);
    if (!ctx)
        goto out;
    /* Binding to physical processor deferred
     * until spu_activate().
     */
    if (spu_init_csa(&ctx->csa))
        goto out_free;
    spin_lock_init(&ctx->mmio_lock);
    mutex_init(&ctx->mapping_lock);
    kref_init(&ctx->kref);
    mutex_init(&ctx->state_mutex);
    mutex_init(&ctx->run_mutex);
    init_waitqueue_head(&ctx->ibox_wq);
    init_waitqueue_head(&ctx->wbox_wq);
    init_waitqueue_head(&ctx->stop_wq);
    init_waitqueue_head(&ctx->mfc_wq);
    init_waitqueue_head(&ctx->run_wq);
    ctx->state = SPU_STATE_SAVED;
    ctx->ops = &spu_backing_ops;
    ctx->owner = get_task_mm(current);
    INIT_LIST_HEAD(&ctx->rq);
    INIT_LIST_HEAD(&ctx->aff_list);
    if (gang)
        spu_gang_add_ctx(gang, ctx);

    __spu_update_sched_info(ctx);
    spu_set_timeslice(ctx);
    ctx->stats.util_state = SPU_UTIL_IDLE_LOADED;
    ktime_get_ts(&ts);
    ctx->stats.tstamp = timespec_to_ns(&ts);

    atomic_inc(&nr_spu_contexts);
    goto out;
out_free:
    kfree(ctx);
    ctx = NULL;
out:
    return ctx;
}

void destroy_spu_context(struct kref *kref)
{
    struct spu_context *ctx;
    ctx = container_of(kref, struct spu_context, kref);
    spu_context_nospu_trace(destroy_spu_context__enter, ctx);
    mutex_lock(&ctx->state_mutex);
    spu_deactivate(ctx);
    mutex_unlock(&ctx->state_mutex);
    spu_fini_csa(&ctx->csa);
    if (ctx->gang)
        spu_gang_remove_ctx(ctx->gang, ctx);
    if (ctx->prof_priv_kref)
        kref_put(ctx->prof_priv_kref, ctx->prof_priv_release);
    BUG_ON(!list_empty(&ctx->rq));
    atomic_dec(&nr_spu_contexts);
    kfree(ctx->switch_log);
    kfree(ctx);
}

struct spu_context * get_spu_context(struct spu_context *ctx)
{
    kref_get(&ctx->kref);
    return ctx;
}

int put_spu_context(struct spu_context *ctx)
{
    return kref_put(&ctx->kref, &destroy_spu_context);
}

/* give up the mm reference when the context is about to be destroyed */
void spu_forget(struct spu_context *ctx)
{
    struct mm_struct *mm;

    /*
     * This is basically an open-coded spu_acquire_saved, except that
     * we don't acquire the state mutex interruptible, and we don't
     * want this context to be rescheduled on release.
     */
    mutex_lock(&ctx->state_mutex);
    if (ctx->state != SPU_STATE_SAVED)
        spu_deactivate(ctx);

    mm = ctx->owner;
    ctx->owner = NULL;
    mmput(mm);
    spu_release(ctx);
}

void spu_unmap_mappings(struct spu_context *ctx)
{
    mutex_lock(&ctx->mapping_lock);
    if (ctx->local_store)
        unmap_mapping_range(ctx->local_store, 0, LS_SIZE, 1);
    if (ctx->mfc)
        unmap_mapping_range(ctx->mfc, 0, SPUFS_MFC_MAP_SIZE, 1);
    if (ctx->cntl)
        unmap_mapping_range(ctx->cntl, 0, SPUFS_CNTL_MAP_SIZE, 1);
    if (ctx->signal1)
        unmap_mapping_range(ctx->signal1, 0, SPUFS_SIGNAL_MAP_SIZE, 1);
    if (ctx->signal2)
        unmap_mapping_range(ctx->signal2, 0, SPUFS_SIGNAL_MAP_SIZE, 1);
    if (ctx->mss)
        unmap_mapping_range(ctx->mss, 0, SPUFS_MSS_MAP_SIZE, 1);
    if (ctx->psmap)
        unmap_mapping_range(ctx->psmap, 0, SPUFS_PS_MAP_SIZE, 1);
    mutex_unlock(&ctx->mapping_lock);
}

int spu_acquire_saved(struct spu_context *ctx)
{
    int ret;

    spu_context_nospu_trace(spu_acquire_saved__enter, ctx);

    ret = spu_acquire(ctx);
    if (ret)
        return ret;

    if (ctx->state != SPU_STATE_SAVED) {
        set_bit(SPU_SCHED_WAS_ACTIVE, &ctx->sched_flags);
        spu_deactivate(ctx);
    }

    return 0;
}

void spu_release_saved(struct spu_context *ctx)
{
    BUG_ON(ctx->state != SPU_STATE_SAVED);

    if (test_and_clear_bit(SPU_SCHED_WAS_ACTIVE, &ctx->sched_flags) &&
            test_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags))
        spu_activate(ctx, 0);

    spu_release(ctx);
}