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
24static 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
44static 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 */
67static 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
88int 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
118static 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
159int 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