release/src-rt-6.x/linux/linux-2.6/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/vmalloc.h>
  26
  27 #include <asm/spu.h>
  28 #include <asm/spu_csa.h>
  29 #include <asm/mmu.h>
  30
  31 static int spu_alloc_lscsa_std(struct spu_state *csa)
  32 {
  33         struct spu_lscsa *lscsa;
  34         unsigned char *p;
  35
  36         lscsa = vmalloc(sizeof(struct spu_lscsa));
  37         if (!lscsa)
  38                 return -ENOMEM;
  39         memset(lscsa, 0, sizeof(struct spu_lscsa));
  40         csa->lscsa = lscsa;
  41
  42         /* Set LS pages reserved to allow for user-space mapping. */
  43         for (p = lscsa->ls; p < lscsa->ls + LS_SIZE; p += PAGE_SIZE)
  44                 SetPageReserved(vmalloc_to_page(p));
  45
  46         return 0;
  47 }
  48
  49 static void spu_free_lscsa_std(struct spu_state *csa)
  50 {
  51         /* Clear reserved bit before vfree. */
  52         unsigned char *p;
  53
  54         if (csa->lscsa == NULL)
  55                 return;
  56
  57         for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
  58                 ClearPageReserved(vmalloc_to_page(p));
  59
  60         vfree(csa->lscsa);
  61 }
  62
  63 #ifdef CONFIG_SPU_FS_64K_LS
  64
  65 #define SPU_64K_PAGE_SHIFT      16
  66 #define SPU_64K_PAGE_ORDER      (SPU_64K_PAGE_SHIFT - PAGE_SHIFT)
  67 #define SPU_64K_PAGE_COUNT      (1ul << SPU_64K_PAGE_ORDER)
  68
  69 int spu_alloc_lscsa(struct spu_state *csa)
  70 {
  71         struct page     **pgarray;
  72         unsigned char   *p;
  73         int             i, j, n_4k;
  74
  75         /* Check availability of 64K pages */
  76         if (mmu_psize_defs[MMU_PAGE_64K].shift == 0)
  77                 goto fail;
  78
  79         csa->use_big_pages = 1;
  80
  81         pr_debug("spu_alloc_lscsa(csa=0x%p), trying to allocate 64K pages\n",
  82                  csa);
  83
  84         /* First try to allocate our 64K pages. We need 5 of them
  85          * with the current implementation. In the future, we should try
  86          * to separate the lscsa with the actual local store image, thus
  87          * allowing us to require only 4 64K pages per context
  88          */
  89         for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++) {
  90                 /* XXX This is likely to fail, we should use a special pool
  91                  *     similiar to what hugetlbfs does.
  92                  */
  93                 csa->lscsa_pages[i] = alloc_pages(GFP_KERNEL,
  94                                                   SPU_64K_PAGE_ORDER);
  95                 if (csa->lscsa_pages[i] == NULL)
  96                         goto fail;
  97         }
  98
  99         pr_debug(" success ! creating vmap...\n");
 100
 101         /* Now we need to create a vmalloc mapping of these for the kernel
 102          * and SPU context switch code to use. Currently, we stick to a
 103          * normal kernel vmalloc mapping, which in our case will be 4K
 104          */
 105         n_4k = SPU_64K_PAGE_COUNT * SPU_LSCSA_NUM_BIG_PAGES;
 106         pgarray = kmalloc(sizeof(struct page *) * n_4k, GFP_KERNEL);
 107         if (pgarray == NULL)
 108                 goto fail;
 109         for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++)
 110                 for (j = 0; j < SPU_64K_PAGE_COUNT; j++)
 111                         /* We assume all the struct page's are contiguous
 112                          * which should be hopefully the case for an order 4
 113                          * allocation..
 114                          */
 115                         pgarray[i * SPU_64K_PAGE_COUNT + j] =
 116                                 csa->lscsa_pages[i] + j;
 117         csa->lscsa = vmap(pgarray, n_4k, VM_USERMAP, PAGE_KERNEL);
 118         kfree(pgarray);
 119         if (csa->lscsa == NULL)
 120                 goto fail;
 121
 122         memset(csa->lscsa, 0, sizeof(struct spu_lscsa));
 123
 124         /* Set LS pages reserved to allow for user-space mapping.
 125          *
 126          * XXX isn't that a bit obsolete ? I think we should just
 127          * make sure the page count is high enough. Anyway, won't harm
 128          * for now
 129          */
 130         for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
 131                 SetPageReserved(vmalloc_to_page(p));
 132
 133         pr_debug(" all good !\n");
 134
 135         return 0;
 136 fail:
 137         pr_debug("spufs: failed to allocate lscsa 64K pages, falling back\n");
 138         spu_free_lscsa(csa);
 139         return spu_alloc_lscsa_std(csa);
 140 }
 141
 142 void spu_free_lscsa(struct spu_state *csa)
 143 {
 144         unsigned char *p;
 145         int i;
 146
 147         if (!csa->use_big_pages) {
 148                 spu_free_lscsa_std(csa);
 149                 return;
 150         }
 151         csa->use_big_pages = 0;
 152
 153         if (csa->lscsa == NULL)
 154                 goto free_pages;
 155
 156         for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
 157                 ClearPageReserved(vmalloc_to_page(p));
 158
 159         vunmap(csa->lscsa);
 160         csa->lscsa = NULL;
 161
 162  free_pages:
 163
 164         for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++)
 165                 if (csa->lscsa_pages[i])
 166                         __free_pages(csa->lscsa_pages[i], SPU_64K_PAGE_ORDER);
 167 }
 168
 169 #else /* CONFIG_SPU_FS_64K_LS */
 170
 171 int spu_alloc_lscsa(struct spu_state *csa)
 172 {
 173         return spu_alloc_lscsa_std(csa);
 174 }
 175
 176 void spu_free_lscsa(struct spu_state *csa)
 177 {
 178         spu_free_lscsa_std(csa);
 179 }
 180
 181 #endif /* !defined(CONFIG_SPU_FS_64K_LS) */