1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * SPU core dump code
4 *
5 * (C) Copyright 2006 IBM Corp.
6 *
7 * Author: Dwayne Grant McConnell <decimal@us.ibm.com>
8 */
9
10 #include <linux/elf.h>
11 #include <linux/file.h>
12 #include <linux/fdtable.h>
13 #include <linux/fs.h>
14 #include <linux/gfp.h>
15 #include <linux/list.h>
16 #include <linux/syscalls.h>
17 #include <linux/coredump.h>
18 #include <linux/binfmts.h>
19
20 #include <linux/uaccess.h>
21
22 #include "spufs.h"
23
spufs_ctx_note_size(struct spu_context * ctx,int dfd)24 static int spufs_ctx_note_size(struct spu_context *ctx, int dfd)
25 {
26 int i, sz, total = 0;
27 char *name;
28 char fullname[80];
29
30 for (i = 0; spufs_coredump_read[i].name != NULL; i++) {
31 name = spufs_coredump_read[i].name;
32 sz = spufs_coredump_read[i].size;
33
34 sprintf(fullname, "SPU/%d/%s", dfd, name);
35
36 total += sizeof(struct elf_note);
37 total += roundup(strlen(fullname) + 1, 4);
38 total += roundup(sz, 4);
39 }
40
41 return total;
42 }
43
match_context(const void * v,struct file * file,unsigned fd)44 static int match_context(const void *v, struct file *file, unsigned fd)
45 {
46 struct spu_context *ctx;
47 if (file->f_op != &spufs_context_fops)
48 return 0;
49 ctx = SPUFS_I(file_inode(file))->i_ctx;
50 if (ctx->flags & SPU_CREATE_NOSCHED)
51 return 0;
52 return fd + 1;
53 }
54
55 /*
56 * The additional architecture-specific notes for Cell are various
57 * context files in the spu context.
58 *
59 * This function iterates over all open file descriptors and sees
60 * if they are a directory in spufs. In that case we use spufs
61 * internal functionality to dump them without needing to actually
62 * open the files.
63 */
64 /*
65 * descriptor table is not shared, so files can't change or go away.
66 */
coredump_next_context(int * fd)67 static struct spu_context *coredump_next_context(int *fd)
68 {
69 struct spu_context *ctx;
70 struct file *file;
71 int n = iterate_fd(current->files, *fd, match_context, NULL);
72 if (!n)
73 return NULL;
74 *fd = n - 1;
75
76 rcu_read_lock();
77 file = lookup_fd_rcu(*fd);
78 ctx = SPUFS_I(file_inode(file))->i_ctx;
79 get_spu_context(ctx);
80 rcu_read_unlock();
81
82 return ctx;
83 }
84
spufs_coredump_extra_notes_size(void)85 int spufs_coredump_extra_notes_size(void)
86 {
87 struct spu_context *ctx;
88 int size = 0, rc, fd;
89
90 fd = 0;
91 while ((ctx = coredump_next_context(&fd)) != NULL) {
92 rc = spu_acquire_saved(ctx);
93 if (rc) {
94 put_spu_context(ctx);
95 break;
96 }
97
98 rc = spufs_ctx_note_size(ctx, fd);
99 spu_release_saved(ctx);
100 if (rc < 0) {
101 put_spu_context(ctx);
102 break;
103 }
104
105 size += rc;
106
107 /* start searching the next fd next time */
108 fd++;
109 put_spu_context(ctx);
110 }
111
112 return size;
113 }
114
spufs_arch_write_note(struct spu_context * ctx,int i,struct coredump_params * cprm,int dfd)115 static int spufs_arch_write_note(struct spu_context *ctx, int i,
116 struct coredump_params *cprm, int dfd)
117 {
118 size_t sz = spufs_coredump_read[i].size;
119 char fullname[80];
120 struct elf_note en;
121 int ret;
122
123 sprintf(fullname, "SPU/%d/%s", dfd, spufs_coredump_read[i].name);
124 en.n_namesz = strlen(fullname) + 1;
125 en.n_descsz = sz;
126 en.n_type = NT_SPU;
127
128 if (!dump_emit(cprm, &en, sizeof(en)))
129 return -EIO;
130 if (!dump_emit(cprm, fullname, en.n_namesz))
131 return -EIO;
132 if (!dump_align(cprm, 4))
133 return -EIO;
134
135 if (spufs_coredump_read[i].dump) {
136 ret = spufs_coredump_read[i].dump(ctx, cprm);
137 if (ret < 0)
138 return ret;
139 } else {
140 char buf[32];
141
142 ret = snprintf(buf, sizeof(buf), "0x%.16llx",
143 spufs_coredump_read[i].get(ctx));
144 if (ret >= sizeof(buf))
145 return sizeof(buf);
146
147 /* count trailing the NULL: */
148 if (!dump_emit(cprm, buf, ret + 1))
149 return -EIO;
150 }
151
152 dump_skip_to(cprm, roundup(cprm->pos - ret + sz, 4));
153 return 0;
154 }
155
spufs_coredump_extra_notes_write(struct coredump_params * cprm)156 int spufs_coredump_extra_notes_write(struct coredump_params *cprm)
157 {
158 struct spu_context *ctx;
159 int fd, j, rc;
160
161 fd = 0;
162 while ((ctx = coredump_next_context(&fd)) != NULL) {
163 rc = spu_acquire_saved(ctx);
164 if (rc)
165 return rc;
166
167 for (j = 0; spufs_coredump_read[j].name != NULL; j++) {
168 rc = spufs_arch_write_note(ctx, j, cprm, fd);
169 if (rc) {
170 spu_release_saved(ctx);
171 return rc;
172 }
173 }
174
175 spu_release_saved(ctx);
176
177 /* start searching the next fd next time */
178 fd++;
179 }
180
181 return 0;
182 }
183