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 = NULL;
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_fdget_rcu(*fd);
78 rcu_read_unlock();
79 if (file) {
80 ctx = SPUFS_I(file_inode(file))->i_ctx;
81 get_spu_context(ctx);
82 fput(file);
83 }
84
85 return ctx;
86 }
87
spufs_coredump_extra_notes_size(void)88 int spufs_coredump_extra_notes_size(void)
89 {
90 struct spu_context *ctx;
91 int size = 0, rc, fd;
92
93 fd = 0;
94 while ((ctx = coredump_next_context(&fd)) != NULL) {
95 rc = spu_acquire_saved(ctx);
96 if (rc) {
97 put_spu_context(ctx);
98 break;
99 }
100
101 rc = spufs_ctx_note_size(ctx, fd);
102 spu_release_saved(ctx);
103 if (rc < 0) {
104 put_spu_context(ctx);
105 break;
106 }
107
108 size += rc;
109
110 /* start searching the next fd next time */
111 fd++;
112 put_spu_context(ctx);
113 }
114
115 return size;
116 }
117
spufs_arch_write_note(struct spu_context * ctx,int i,struct coredump_params * cprm,int dfd)118 static int spufs_arch_write_note(struct spu_context *ctx, int i,
119 struct coredump_params *cprm, int dfd)
120 {
121 size_t sz = spufs_coredump_read[i].size;
122 char fullname[80];
123 struct elf_note en;
124 int ret;
125
126 sprintf(fullname, "SPU/%d/%s", dfd, spufs_coredump_read[i].name);
127 en.n_namesz = strlen(fullname) + 1;
128 en.n_descsz = sz;
129 en.n_type = NT_SPU;
130
131 if (!dump_emit(cprm, &en, sizeof(en)))
132 return -EIO;
133 if (!dump_emit(cprm, fullname, en.n_namesz))
134 return -EIO;
135 if (!dump_align(cprm, 4))
136 return -EIO;
137
138 if (spufs_coredump_read[i].dump) {
139 ret = spufs_coredump_read[i].dump(ctx, cprm);
140 if (ret < 0)
141 return ret;
142 } else {
143 char buf[32];
144
145 ret = snprintf(buf, sizeof(buf), "0x%.16llx",
146 spufs_coredump_read[i].get(ctx));
147 if (ret >= sizeof(buf))
148 return sizeof(buf);
149
150 /* count trailing the NULL: */
151 if (!dump_emit(cprm, buf, ret + 1))
152 return -EIO;
153 }
154
155 dump_skip_to(cprm, roundup(cprm->pos - ret + sz, 4));
156 return 0;
157 }
158
spufs_coredump_extra_notes_write(struct coredump_params * cprm)159 int spufs_coredump_extra_notes_write(struct coredump_params *cprm)
160 {
161 struct spu_context *ctx;
162 int fd, j, rc;
163
164 fd = 0;
165 while ((ctx = coredump_next_context(&fd)) != NULL) {
166 rc = spu_acquire_saved(ctx);
167 if (rc)
168 return rc;
169
170 for (j = 0; spufs_coredump_read[j].name != NULL; j++) {
171 rc = spufs_arch_write_note(ctx, j, cprm, fd);
172 if (rc) {
173 spu_release_saved(ctx);
174 return rc;
175 }
176 }
177
178 spu_release_saved(ctx);
179
180 /* start searching the next fd next time */
181 fd++;
182 }
183
184 return 0;
185 }
186