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 = vzalloc(sizeof(struct spu_lscsa));
  40         if (!lscsa)
  41                 return -ENOMEM;
  42         csa->lscsa = lscsa;
  43
  44         /* Set LS pages reserved to allow for user-space mapping. */
  45         for (p = lscsa->ls; p < lscsa->ls + LS_SIZE; p += PAGE_SIZE)
  46                 SetPageReserved(vmalloc_to_page(p));
  47
  48         return 0;
  49 }
  50
  51 static void spu_free_lscsa_std(struct spu_state *csa)
  52 {
  53         /* Clear reserved bit before vfree. */
  54         unsigned char *p;
  55
  56         if (csa->lscsa == NULL)
  57                 return;
  58
  59         for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
  60                 ClearPageReserved(vmalloc_to_page(p));
  61
  62         vfree(csa->lscsa);
  63 }
  64
  65 #ifdef CONFIG_SPU_FS_64K_LS
  66
  67 #define SPU_64K_PAGE_SHIFT      16
  68 #define SPU_64K_PAGE_ORDER      (SPU_64K_PAGE_SHIFT - PAGE_SHIFT)
  69 #define SPU_64K_PAGE_COUNT      (1ul << SPU_64K_PAGE_ORDER)
  70
  71 int spu_alloc_lscsa(struct spu_state *csa)
  72 {
  73         struct page     **pgarray;
  74         unsigned char   *p;
  75         int             i, j, n_4k;
  76
  77         /* Check availability of 64K pages */
  78         if (!spu_64k_pages_available())
  79                 goto fail;
  80
  81         csa->use_big_pages = 1;
  82
  83         pr_debug("spu_alloc_lscsa(csa=0x%p), trying to allocate 64K pages\n",
  84                  csa);
  85
  86         /* First try to allocate our 64K pages. We need 5 of them
  87          * with the current implementation. In the future, we should try
  88          * to separate the lscsa with the actual local store image, thus
  89          * allowing us to require only 4 64K pages per context
  90          */
  91         for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++) {
  92                 /* XXX This is likely to fail, we should use a special pool
  93                  *     similar to what hugetlbfs does.
  94                  */
  95                 csa->lscsa_pages[i] = alloc_pages(GFP_KERNEL,
  96                                                   SPU_64K_PAGE_ORDER);
  97                 if (csa->lscsa_pages[i] == NULL)
  98                         goto fail;
  99         }
 100
 101         pr_debug(" success ! creating vmap...\n");
 102
 103         /* Now we need to create a vmalloc mapping of these for the kernel
 104          * and SPU context switch code to use. Currently, we stick to a
 105          * normal kernel vmalloc mapping, which in our case will be 4K
 106          */
 107         n_4k = SPU_64K_PAGE_COUNT * SPU_LSCSA_NUM_BIG_PAGES;
 108         pgarray = kmalloc(sizeof(struct page *) * n_4k, GFP_KERNEL);
 109         if (pgarray == NULL)
 110                 goto fail;
 111         for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++)
 112                 for (j = 0; j < SPU_64K_PAGE_COUNT; j++)
 113                         /* We assume all the struct page's are contiguous
 114                          * which should be hopefully the case for an order 4
 115                          * allocation..
 116                          */
 117                         pgarray[i * SPU_64K_PAGE_COUNT + j] =
 118                                 csa->lscsa_pages[i] + j;
 119         csa->lscsa = vmap(pgarray, n_4k, VM_USERMAP, PAGE_KERNEL);
 120         kfree(pgarray);
 121         if (csa->lscsa == NULL)
 122                 goto fail;
 123
 124         memset(csa->lscsa, 0, sizeof(struct spu_lscsa));
 125
 126         /* Set LS pages reserved to allow for user-space mapping.
 127          *
 128          * XXX isn't that a bit obsolete ? I think we should just
 129          * make sure the page count is high enough. Anyway, won't harm
 130          * for now
 131          */
 132         for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
 133                 SetPageReserved(vmalloc_to_page(p));
 134
 135         pr_debug(" all good !\n");
 136
 137         return 0;
 138 fail:
 139         pr_debug("spufs: failed to allocate lscsa 64K pages, falling back\n");
 140         spu_free_lscsa(csa);
 141         return spu_alloc_lscsa_std(csa);
 142 }
 143
 144 void spu_free_lscsa(struct spu_state *csa)
 145 {
 146         unsigned char *p;
 147         int i;
 148
 149         if (!csa->use_big_pages) {
 150                 spu_free_lscsa_std(csa);
 151                 return;
 152         }
 153         csa->use_big_pages = 0;
 154
 155         if (csa->lscsa == NULL)
 156                 goto free_pages;
 157
 158         for (p = csa->lscsa->ls; p < csa->lscsa->ls + LS_SIZE; p += PAGE_SIZE)
 159                 ClearPageReserved(vmalloc_to_page(p));
 160
 161         vunmap(csa->lscsa);
 162         csa->lscsa = NULL;
 163
 164  free_pages:
 165
 166         for (i = 0; i < SPU_LSCSA_NUM_BIG_PAGES; i++)
 167                 if (csa->lscsa_pages[i])
 168                         __free_pages(csa->lscsa_pages[i], SPU_64K_PAGE_ORDER);
 169 }
 170
 171 #else /* CONFIG_SPU_FS_64K_LS */
 172
 173 int spu_alloc_lscsa(struct spu_state *csa)
 174 {
 175         return spu_alloc_lscsa_std(csa);
 176 }
 177
 178 void spu_free_lscsa(struct spu_state *csa)
 179 {
 180         spu_free_lscsa_std(csa);
 181 }
 182
 183 #endif /* !defined(CONFIG_SPU_FS_64K_LS) */