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

   1 /*
   2  * SPU core dump code
   3  *
   4  * (C) Copyright 2006 IBM Corp.
   5  *
   6  * Author: Dwayne Grant McConnell <decimal@us.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/elf.h>
  24 #include <linux/file.h>
  25 #include <linux/fdtable.h>
  26 #include <linux/fs.h>
  27 #include <linux/gfp.h>
  28 #include <linux/list.h>
  29 #include <linux/syscalls.h>
  30
  31 #include <asm/uaccess.h>
  32
  33 #include "spufs.h"
  34
  35 static ssize_t do_coredump_read(int num, struct spu_context *ctx, void *buffer,
  36                                 size_t size, loff_t *off)
  37 {
  38         u64 data;
  39         int ret;
  40
  41         if (spufs_coredump_read[num].read)
  42                 return spufs_coredump_read[num].read(ctx, buffer, size, off);
  43
  44         data = spufs_coredump_read[num].get(ctx);
  45         ret = snprintf(buffer, size, "0x%.16llx", data);
  46         if (ret >= size)
  47                 return size;
  48         return ++ret; /* count trailing NULL */
  49 }
  50
  51 /*
  52  * These are the only things you should do on a core-file: use only these
  53  * functions to write out all the necessary info.
  54  */
  55 static int spufs_dump_write(struct file *file, const void *addr, int nr, loff_t *foffset)
  56 {
  57         unsigned long limit = rlimit(RLIMIT_CORE);
  58         ssize_t written;
  59
  60         if (*foffset + nr > limit)
  61                 return -EIO;
  62
  63         written = file->f_op->write(file, addr, nr, &file->f_pos);
  64         *foffset += written;
  65
  66         if (written != nr)
  67                 return -EIO;
  68
  69         return 0;
  70 }
  71
  72 static int spufs_dump_align(struct file *file, char *buf, loff_t new_off,
  73                             loff_t *foffset)
  74 {
  75         int rc, size;
  76
  77         size = min((loff_t)PAGE_SIZE, new_off - *foffset);
  78         memset(buf, 0, size);
  79
  80         rc = 0;
  81         while (rc == 0 && new_off > *foffset) {
  82                 size = min((loff_t)PAGE_SIZE, new_off - *foffset);
  83                 rc = spufs_dump_write(file, buf, size, foffset);
  84         }
  85
  86         return rc;
  87 }
  88
  89 static int spufs_ctx_note_size(struct spu_context *ctx, int dfd)
  90 {
  91         int i, sz, total = 0;
  92         char *name;
  93         char fullname[80];
  94
  95         for (i = 0; spufs_coredump_read[i].name != NULL; i++) {
  96                 name = spufs_coredump_read[i].name;
  97                 sz = spufs_coredump_read[i].size;
  98
  99                 sprintf(fullname, "SPU/%d/%s", dfd, name);
 100
 101                 total += sizeof(struct elf_note);
 102                 total += roundup(strlen(fullname) + 1, 4);
 103                 total += roundup(sz, 4);
 104         }
 105
 106         return total;
 107 }
 108
 109 /*
 110  * The additional architecture-specific notes for Cell are various
 111  * context files in the spu context.
 112  *
 113  * This function iterates over all open file descriptors and sees
 114  * if they are a directory in spufs.  In that case we use spufs
 115  * internal functionality to dump them without needing to actually
 116  * open the files.
 117  */
 118 static struct spu_context *coredump_next_context(int *fd)
 119 {
 120         struct fdtable *fdt = files_fdtable(current->files);
 121         struct file *file;
 122         struct spu_context *ctx = NULL;
 123
 124         for (; *fd < fdt->max_fds; (*fd)++) {
 125                 if (!FD_ISSET(*fd, fdt->open_fds))
 126                         continue;
 127
 128                 file = fcheck(*fd);
 129
 130                 if (!file || file->f_op != &spufs_context_fops)
 131                         continue;
 132
 133                 ctx = SPUFS_I(file->f_dentry->d_inode)->i_ctx;
 134                 if (ctx->flags & SPU_CREATE_NOSCHED)
 135                         continue;
 136
 137                 break;
 138         }
 139
 140         return ctx;
 141 }
 142
 143 int spufs_coredump_extra_notes_size(void)
 144 {
 145         struct spu_context *ctx;
 146         int size = 0, rc, fd;
 147
 148         fd = 0;
 149         while ((ctx = coredump_next_context(&fd)) != NULL) {
 150                 rc = spu_acquire_saved(ctx);
 151                 if (rc)
 152                         break;
 153                 rc = spufs_ctx_note_size(ctx, fd);
 154                 spu_release_saved(ctx);
 155                 if (rc < 0)
 156                         break;
 157
 158                 size += rc;
 159
 160                 /* start searching the next fd next time */
 161                 fd++;
 162         }
 163
 164         return size;
 165 }
 166
 167 static int spufs_arch_write_note(struct spu_context *ctx, int i,
 168                                   struct file *file, int dfd, loff_t *foffset)
 169 {
 170         loff_t pos = 0;
 171         int sz, rc, nread, total = 0;
 172         const int bufsz = PAGE_SIZE;
 173         char *name;
 174         char fullname[80], *buf;
 175         struct elf_note en;
 176
 177         buf = (void *)get_zeroed_page(GFP_KERNEL);
 178         if (!buf)
 179                 return -ENOMEM;
 180
 181         name = spufs_coredump_read[i].name;
 182         sz = spufs_coredump_read[i].size;
 183
 184         sprintf(fullname, "SPU/%d/%s", dfd, name);
 185         en.n_namesz = strlen(fullname) + 1;
 186         en.n_descsz = sz;
 187         en.n_type = NT_SPU;
 188
 189         rc = spufs_dump_write(file, &en, sizeof(en), foffset);
 190         if (rc)
 191                 goto out;
 192
 193         rc = spufs_dump_write(file, fullname, en.n_namesz, foffset);
 194         if (rc)
 195                 goto out;
 196
 197         rc = spufs_dump_align(file, buf, roundup(*foffset, 4), foffset);
 198         if (rc)
 199                 goto out;
 200
 201         do {
 202                 nread = do_coredump_read(i, ctx, buf, bufsz, &pos);
 203                 if (nread > 0) {
 204                         rc = spufs_dump_write(file, buf, nread, foffset);
 205                         if (rc)
 206                                 goto out;
 207                         total += nread;
 208                 }
 209         } while (nread == bufsz && total < sz);
 210
 211         if (nread < 0) {
 212                 rc = nread;
 213                 goto out;
 214         }
 215
 216         rc = spufs_dump_align(file, buf, roundup(*foffset - total + sz, 4),
 217                               foffset);
 218
 219 out:
 220         free_page((unsigned long)buf);
 221         return rc;
 222 }
 223
 224 int spufs_coredump_extra_notes_write(struct file *file, loff_t *foffset)
 225 {
 226         struct spu_context *ctx;
 227         int fd, j, rc;
 228
 229         fd = 0;
 230         while ((ctx = coredump_next_context(&fd)) != NULL) {
 231                 rc = spu_acquire_saved(ctx);
 232                 if (rc)
 233                         return rc;
 234
 235                 for (j = 0; spufs_coredump_read[j].name != NULL; j++) {
 236                         rc = spufs_arch_write_note(ctx, j, file, fd, foffset);
 237                         if (rc) {
 238                                 spu_release_saved(ctx);
 239                                 return rc;
 240                         }
 241                 }
 242
 243                 spu_release_saved(ctx);
 244
 245                 /* start searching the next fd next time */
 246                 fd++;
 247         }
 248
 249         return 0;
 250 }