arch/powerpc/platforms/cell/spufs/context.c

   1 /*
   2  * SPU file system -- SPU context management
   3  *
   4  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
   5  *
   6  * Author: Arnd Bergmann <arndb@de.ibm.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2, or (at your option)
  11  * any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22
  23 #include <linux/fs.h>
  24 #include <linux/mm.h>
  25 #include <linux/slab.h>
  26 #include <asm/spu.h>
  27 #include <asm/spu_csa.h>
  28 #include "spufs.h"
  29
  30 struct spu_context *alloc_spu_context(struct spu_gang *gang)
  31 {
  32         struct spu_context *ctx;
  33         ctx = kzalloc(sizeof *ctx, GFP_KERNEL);
  34         if (!ctx)
  35                 goto out;
  36         /* Binding to physical processor deferred
  37          * until spu_activate().
  38          */
  39         spu_init_csa(&ctx->csa);
  40         if (!ctx->csa.lscsa) {
  41                 goto out_free;
  42         }
  43         spin_lock_init(&ctx->mmio_lock);
  44         spin_lock_init(&ctx->mapping_lock);
  45         kref_init(&ctx->kref);
  46         mutex_init(&ctx->state_mutex);
  47         init_MUTEX(&ctx->run_sema);
  48         init_waitqueue_head(&ctx->ibox_wq);
  49         init_waitqueue_head(&ctx->wbox_wq);
  50         init_waitqueue_head(&ctx->stop_wq);
  51         init_waitqueue_head(&ctx->mfc_wq);
  52         ctx->state = SPU_STATE_SAVED;
  53         ctx->ops = &spu_backing_ops;
  54         ctx->owner = get_task_mm(current);
  55         if (gang)
  56                 spu_gang_add_ctx(gang, ctx);
  57         ctx->rt_priority = current->rt_priority;
  58         ctx->policy = current->policy;
  59         ctx->prio = current->prio;
  60         INIT_DELAYED_WORK(&ctx->sched_work, spu_sched_tick);
  61         goto out;
  62 out_free:
  63         kfree(ctx);
  64         ctx = NULL;
  65 out:
  66         return ctx;
  67 }
  68
  69 void destroy_spu_context(struct kref *kref)
  70 {
  71         struct spu_context *ctx;
  72         ctx = container_of(kref, struct spu_context, kref);
  73         mutex_lock(&ctx->state_mutex);
  74         spu_deactivate(ctx);
  75         mutex_unlock(&ctx->state_mutex);
  76         spu_fini_csa(&ctx->csa);
  77         if (ctx->gang)
  78                 spu_gang_remove_ctx(ctx->gang, ctx);
  79         kfree(ctx);
  80 }
  81
  82 struct spu_context * get_spu_context(struct spu_context *ctx)
  83 {
  84         kref_get(&ctx->kref);
  85         return ctx;
  86 }
  87
  88 int put_spu_context(struct spu_context *ctx)
  89 {
  90         return kref_put(&ctx->kref, &destroy_spu_context);
  91 }
  92
  93 /* give up the mm reference when the context is about to be destroyed */
  94 void spu_forget(struct spu_context *ctx)
  95 {
  96         struct mm_struct *mm;
  97         spu_acquire_saved(ctx);
  98         mm = ctx->owner;
  99         ctx->owner = NULL;
 100         mmput(mm);
 101         spu_release(ctx);
 102 }
 103
 104 void spu_unmap_mappings(struct spu_context *ctx)
 105 {
 106         if (ctx->local_store)
 107                 unmap_mapping_range(ctx->local_store, 0, LS_SIZE, 1);
 108         if (ctx->mfc)
 109                 unmap_mapping_range(ctx->mfc, 0, 0x1000, 1);
 110         if (ctx->cntl)
 111                 unmap_mapping_range(ctx->cntl, 0, 0x1000, 1);
 112         if (ctx->signal1)
 113                 unmap_mapping_range(ctx->signal1, 0, PAGE_SIZE, 1);
 114         if (ctx->signal2)
 115                 unmap_mapping_range(ctx->signal2, 0, PAGE_SIZE, 1);
 116         if (ctx->mss)
 117                 unmap_mapping_range(ctx->mss, 0, 0x1000, 1);
 118         if (ctx->psmap)
 119                 unmap_mapping_range(ctx->psmap, 0, 0x20000, 1);
 120 }
 121
 122 /**
 123  * spu_acquire_exclusive - lock spu contex and protect against userspace access
 124  * @ctx:        spu contex to lock
 125  *
 126  * Note:
 127  *      Returns 0 and with the context locked on success
 128  *      Returns negative error and with the context _unlocked_ on failure.
 129  */
 130 int spu_acquire_exclusive(struct spu_context *ctx)
 131 {
 132         int ret = -EINVAL;
 133
 134         spu_acquire(ctx);
 135         /*
 136          * Context is about to be freed, so we can't acquire it anymore.
 137          */
 138         if (!ctx->owner)
 139                 goto out_unlock;
 140
 141         if (ctx->state == SPU_STATE_SAVED) {
 142                 ret = spu_activate(ctx, 0);
 143                 if (ret)
 144                         goto out_unlock;
 145         } else {
 146                 /*
 147                  * We need to exclude userspace access to the context.
 148                  *
 149                  * To protect against memory access we invalidate all ptes
 150                  * and make sure the pagefault handlers block on the mutex.
 151                  */
 152                 spu_unmap_mappings(ctx);
 153         }
 154
 155         return 0;
 156
 157  out_unlock:
 158         spu_release(ctx);
 159         return ret;
 160 }
 161
 162 /**
 163  * spu_acquire_runnable - lock spu contex and make sure it is in runnable state
 164  * @ctx:        spu contex to lock
 165  *
 166  * Note:
 167  *      Returns 0 and with the context locked on success
 168  *      Returns negative error and with the context _unlocked_ on failure.
 169  */
 170 int spu_acquire_runnable(struct spu_context *ctx, unsigned long flags)
 171 {
 172         int ret = -EINVAL;
 173
 174         spu_acquire(ctx);
 175         if (ctx->state == SPU_STATE_SAVED) {
 176                 /*
 177                  * Context is about to be freed, so we can't acquire it anymore.
 178                  */
 179                 if (!ctx->owner)
 180                         goto out_unlock;
 181                 ret = spu_activate(ctx, flags);
 182                 if (ret)
 183                         goto out_unlock;
 184         }
 185
 186         return 0;
 187
 188  out_unlock:
 189         spu_release(ctx);
 190         return ret;
 191 }
 192
 193 /**
 194  * spu_acquire_saved - lock spu contex and make sure it is in saved state
 195  * @ctx:        spu contex to lock
 196  */
 197 void spu_acquire_saved(struct spu_context *ctx)
 198 {
 199         spu_acquire(ctx);
 200         if (ctx->state != SPU_STATE_SAVED)
 201                 spu_deactivate(ctx);
 202 }