cell/spufs/coredump.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * SPU core dump code
0004  *
0005  * (C) Copyright 2006 IBM Corp.
0006  *
0007  * Author: Dwayne Grant McConnell <decimal@us.ibm.com>
0008  */
0009
0010 #include <linux/elf.h>
0011 #include <linux/file.h>
0012 #include <linux/fdtable.h>
0013 #include <linux/fs.h>
0014 #include <linux/gfp.h>
0015 #include <linux/list.h>
0016 #include <linux/syscalls.h>
0017 #include <linux/coredump.h>
0018 #include <linux/binfmts.h>
0019
0020 #include <linux/uaccess.h>
0021
0022 #include "spufs.h"
0023
0024 static int spufs_ctx_note_size(struct spu_context *ctx, int dfd)
0025 {
0026     int i, sz, total = 0;
0027     char *name;
0028     char fullname[80];
0029
0030     for (i = 0; spufs_coredump_read[i].name != NULL; i++) {
0031         name = spufs_coredump_read[i].name;
0032         sz = spufs_coredump_read[i].size;
0033
0034         sprintf(fullname, "SPU/%d/%s", dfd, name);
0035
0036         total += sizeof(struct elf_note);
0037         total += roundup(strlen(fullname) + 1, 4);
0038         total += roundup(sz, 4);
0039     }
0040
0041     return total;
0042 }
0043
0044 static int match_context(const void *v, struct file *file, unsigned fd)
0045 {
0046     struct spu_context *ctx;
0047     if (file->f_op != &spufs_context_fops)
0048         return 0;
0049     ctx = SPUFS_I(file_inode(file))->i_ctx;
0050     if (ctx->flags & SPU_CREATE_NOSCHED)
0051         return 0;
0052     return fd + 1;
0053 }
0054
0055 /*
0056  * The additional architecture-specific notes for Cell are various
0057  * context files in the spu context.
0058  *
0059  * This function iterates over all open file descriptors and sees
0060  * if they are a directory in spufs.  In that case we use spufs
0061  * internal functionality to dump them without needing to actually
0062  * open the files.
0063  */
0064 /*
0065  * descriptor table is not shared, so files can't change or go away.
0066  */
0067 static struct spu_context *coredump_next_context(int *fd)
0068 {
0069     struct spu_context *ctx;
0070     struct file *file;
0071     int n = iterate_fd(current->files, *fd, match_context, NULL);
0072     if (!n)
0073         return NULL;
0074     *fd = n - 1;
0075
0076     rcu_read_lock();
0077     file = lookup_fd_rcu(*fd);
0078     ctx = SPUFS_I(file_inode(file))->i_ctx;
0079     get_spu_context(ctx);
0080     rcu_read_unlock();
0081
0082     return ctx;
0083 }
0084
0085 int spufs_coredump_extra_notes_size(void)
0086 {
0087     struct spu_context *ctx;
0088     int size = 0, rc, fd;
0089
0090     fd = 0;
0091     while ((ctx = coredump_next_context(&fd)) != NULL) {
0092         rc = spu_acquire_saved(ctx);
0093         if (rc) {
0094             put_spu_context(ctx);
0095             break;
0096         }
0097
0098         rc = spufs_ctx_note_size(ctx, fd);
0099         spu_release_saved(ctx);
0100         if (rc < 0) {
0101             put_spu_context(ctx);
0102             break;
0103         }
0104
0105         size += rc;
0106
0107         /* start searching the next fd next time */
0108         fd++;
0109         put_spu_context(ctx);
0110     }
0111
0112     return size;
0113 }
0114
0115 static int spufs_arch_write_note(struct spu_context *ctx, int i,
0116                   struct coredump_params *cprm, int dfd)
0117 {
0118     size_t sz = spufs_coredump_read[i].size;
0119     char fullname[80];
0120     struct elf_note en;
0121     int ret;
0122
0123     sprintf(fullname, "SPU/%d/%s", dfd, spufs_coredump_read[i].name);
0124     en.n_namesz = strlen(fullname) + 1;
0125     en.n_descsz = sz;
0126     en.n_type = NT_SPU;
0127
0128     if (!dump_emit(cprm, &en, sizeof(en)))
0129         return -EIO;
0130     if (!dump_emit(cprm, fullname, en.n_namesz))
0131         return -EIO;
0132     if (!dump_align(cprm, 4))
0133         return -EIO;
0134
0135     if (spufs_coredump_read[i].dump) {
0136         ret = spufs_coredump_read[i].dump(ctx, cprm);
0137         if (ret < 0)
0138             return ret;
0139     } else {
0140         char buf[32];
0141
0142         ret = snprintf(buf, sizeof(buf), "0x%.16llx",
0143                    spufs_coredump_read[i].get(ctx));
0144         if (ret >= sizeof(buf))
0145             return sizeof(buf);
0146
0147         /* count trailing the NULL: */
0148         if (!dump_emit(cprm, buf, ret + 1))
0149             return -EIO;
0150     }
0151
0152     dump_skip_to(cprm, roundup(cprm->pos - ret + sz, 4));
0153     return 0;
0154 }
0155
0156 int spufs_coredump_extra_notes_write(struct coredump_params *cprm)
0157 {
0158     struct spu_context *ctx;
0159     int fd, j, rc;
0160
0161     fd = 0;
0162     while ((ctx = coredump_next_context(&fd)) != NULL) {
0163         rc = spu_acquire_saved(ctx);
0164         if (rc)
0165             return rc;
0166
0167         for (j = 0; spufs_coredump_read[j].name != NULL; j++) {
0168             rc = spufs_arch_write_note(ctx, j, cprm, fd);
0169             if (rc) {
0170                 spu_release_saved(ctx);
0171                 return rc;
0172             }
0173         }
0174
0175         spu_release_saved(ctx);
0176
0177         /* start searching the next fd next time */
0178         fd++;
0179     }
0180
0181     return 0;
0182 }