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