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

   1 /*
   2  * SPU local store allocation routines
   3  *
   4  * Copyright 2007 Benjamin Herrenschmidt, IBM Corp.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2, or (at your option)
   9  * any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #undef DEBUG
  22
  23 #include <linux/kernel.h>
  24 #include <linux/mm.h>
  25 #include <linux/slab.h>
  26 #include <linux/vmalloc.h>
  27
  28 #include <asm/spu.h>
  29 #include <asm/spu_csa.h>
  30 #include <asm/mmu.h>
  31
  32 #include "spufs.h"
  33
  34 static int spu_alloc_lscsa_std(struct spu_state *csa)
  35 {
  36         struct spu_lscsa *lscsa;
  37         unsigned char *p;
  38
  39         lscsa = vmalloc(sizeof(struct spu_lscsa));
  40         if (!lscsa)
  41                 return -ENOMEM;
  42         memset(lscsa, 0, sizeof(struct spu_lscsa));
  43         csa->lscsa = lscsa;
  44
  45         /* Set LS pages reserved to allow for user-space mapping. */
  46         for (p = lscsa->ls; p < lscsa->ls + LS_SIZE; p += PAGE_SIZE)
  47                 SetPageReserved(vmalloc_to_page(p));
  48
  49         return 0;
  50 }
  51
  52 static void spu_free_lscsa_std(struct spu_state *csa)
  53 {
  54         /* Clear reserved bit before vfree. */
  55         unsigned char *p;
  56
  57         if (csa->lscsa == NULL)
  58                 return;
  59
  60         for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
  61                 ClearPageReserved(vmalloc_to_page(p));
  62
  63         vfree(csa->lscsa);
  64 }
  65
  66 #ifdef CONFIG_SPU_FS_64K_LS
  67
  68 #define SPU_64K_PAGE_SHIFT      16
  69 #define SPU_64K_PAGE_ORDER      (SPU_64K_PAGE_SHIFT - PAGE_SHIFT)
  70 #define SPU_64K_PAGE_COUNT      (1ul << SPU_64K_PAGE_ORDER)
  71
  72 int spu_alloc_lscsa(struct spu_state *csa)
  73 {
  74         struct page     **pgarray;
  75         unsigned char   *p;
  76         int             i, j, n_4k;
  77
  78         /* Check availability of 64K pages */
  79         if (!spu_64k_pages_available())
  80                 goto fail;
  81
  82         csa->use_big_pages = 1;
  83
  84         pr_debug("spu_alloc_lscsa(csa=0x%p), trying to allocate 64K pages\n",
  85                  csa);
  86
  87         /* First try to allocate our 64K pages. We need 5 of them
  88          * with the current implementation. In the future, we should try
  89          * to separate the lscsa with the actual local store image, thus
  90          * allowing us to require only 4 64K pages per context
  91          */
  92         for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++) {
  93                 /* XXX This is likely to fail, we should use a special pool
  94                  *     similiar to what hugetlbfs does.
  95                  */
  96                 csa->lscsa_pages[i] = alloc_pages(GFP_KERNEL,
  97                                                   SPU_64K_PAGE_ORDER);
  98                 if (csa->lscsa_pages[i] == NULL)
  99                         goto fail;
 100         }
 101
 102         pr_debug(" success ! creating vmap...\n");
 103
 104         /* Now we need to create a vmalloc mapping of these for the kernel
 105          * and SPU context switch code to use. Currently, we stick to a
 106          * normal kernel vmalloc mapping, which in our case will be 4K
 107          */
 108         n_4k = SPU_64K_PAGE_COUNT * SPU_LSCSA_NUM_BIG_PAGES;
 109         pgarray = kmalloc(sizeof(struct page *) * n_4k, GFP_KERNEL);
 110         if (pgarray == NULL)
 111                 goto fail;
 112         for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++)
 113                 for (j = 0; j < SPU_64K_PAGE_COUNT; j++)
 114                         /* We assume all the struct page's are contiguous
 115                          * which should be hopefully the case for an order 4
 116                          * allocation..
 117                          */
 118                         pgarray[i * SPU_64K_PAGE_COUNT + j] =
 119                                 csa->lscsa_pages[i] + j;
 120         csa->lscsa = vmap(pgarray, n_4k, VM_USERMAP, PAGE_KERNEL);
 121         kfree(pgarray);
 122         if (csa->lscsa == NULL)
 123                 goto fail;
 124
 125         memset(csa->lscsa, 0, sizeof(struct spu_lscsa));
 126
 127         /* Set LS pages reserved to allow for user-space mapping.
 128          *
 129          * XXX isn't that a bit obsolete ? I think we should just
 130          * make sure the page count is high enough. Anyway, won't harm
 131          * for now
 132          */
 133         for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
 134                 SetPageReserved(vmalloc_to_page(p));
 135
 136         pr_debug(" all good !\n");
 137
 138         return 0;
 139 fail:
 140         pr_debug("spufs: failed to allocate lscsa 64K pages, falling back\n");
 141         spu_free_lscsa(csa);
 142         return spu_alloc_lscsa_std(csa);
 143 }
 144
 145 void spu_free_lscsa(struct spu_state *csa)
 146 {
 147         unsigned char *p;
 148         int i;
 149
 150         if (!csa->use_big_pages) {
 151                 spu_free_lscsa_std(csa);
 152                 return;
 153         }
 154         csa->use_big_pages = 0;
 155
 156         if (csa->lscsa == NULL)
 157                 goto free_pages;
 158
 159         for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
 160                 ClearPageReserved(vmalloc_to_page(p));
 161
 162         vunmap(csa->lscsa);
 163         csa->lscsa = NULL;
 164
 165  free_pages:
 166
 167         for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++)
 168                 if (csa->lscsa_pages[i])
 169                         __free_pages(csa->lscsa_pages[i], SPU_64K_PAGE_ORDER);
 170 }
 171
 172 #else /* CONFIG_SPU_FS_64K_LS */
 173
 174 int spu_alloc_lscsa(struct spu_state *csa)
 175 {
 176         return spu_alloc_lscsa_std(csa);
 177 }
 178
 179 void spu_free_lscsa(struct spu_state *csa)
 180 {
 181         spu_free_lscsa_std(csa);
 182 }
 183
 184 #endif /* !defined(CONFIG_SPU_FS_64K_LS) */