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1/*
2 * ppc64 code to implement the kexec_file_load syscall
3 *
4 * Copyright (C) 2004 Adam Litke (agl@us.ibm.com)
5 * Copyright (C) 2004 IBM Corp.
6 * Copyright (C) 2004,2005 Milton D Miller II, IBM Corporation
7 * Copyright (C) 2005 R Sharada (sharada@in.ibm.com)
8 * Copyright (C) 2006 Mohan Kumar M (mohan@in.ibm.com)
9 * Copyright (C) 2016 IBM Corporation
10 *
11 * Based on kexec-tools' kexec-elf-ppc64.c, fs2dt.c.
12 * Heavily modified for the kernel by
13 * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
14 *
15 * This program is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation (version 2 of the License).
18 *
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
23 */
24
25#include <linux/slab.h>
26#include <linux/kexec.h>
27#include <linux/memblock.h>
28#include <linux/of_fdt.h>
29#include <linux/libfdt.h>
30#include <asm/ima.h>
31
32#define SLAVE_CODE_SIZE 256
33
34static struct kexec_file_ops *kexec_file_loaders[] = {
35 &kexec_elf64_ops,
36};
37
38int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
39 unsigned long buf_len)
40{
41 int i, ret = -ENOEXEC;
42 struct kexec_file_ops *fops;
43
44 /* We don't support crash kernels yet. */
45 if (image->type == KEXEC_TYPE_CRASH)
46 return -ENOTSUPP;
47
48 for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) {
49 fops = kexec_file_loaders[i];
50 if (!fops || !fops->probe)
51 continue;
52
53 ret = fops->probe(buf, buf_len);
54 if (!ret) {
55 image->fops = fops;
56 return ret;
57 }
58 }
59
60 return ret;
61}
62
63void *arch_kexec_kernel_image_load(struct kimage *image)
64{
65 if (!image->fops || !image->fops->load)
66 return ERR_PTR(-ENOEXEC);
67
68 return image->fops->load(image, image->kernel_buf,
69 image->kernel_buf_len, image->initrd_buf,
70 image->initrd_buf_len, image->cmdline_buf,
71 image->cmdline_buf_len);
72}
73
74int arch_kimage_file_post_load_cleanup(struct kimage *image)
75{
76 if (!image->fops || !image->fops->cleanup)
77 return 0;
78
79 return image->fops->cleanup(image->image_loader_data);
80}
81
82/**
83 * arch_kexec_walk_mem - call func(data) for each unreserved memory block
84 * @kbuf: Context info for the search. Also passed to @func.
85 * @func: Function to call for each memory block.
86 *
87 * This function is used by kexec_add_buffer and kexec_locate_mem_hole
88 * to find unreserved memory to load kexec segments into.
89 *
90 * Return: The memory walk will stop when func returns a non-zero value
91 * and that value will be returned. If all free regions are visited without
92 * func returning non-zero, then zero will be returned.
93 */
94int arch_kexec_walk_mem(struct kexec_buf *kbuf, int (*func)(u64, u64, void *))
95{
96 int ret = 0;
97 u64 i;
98 phys_addr_t mstart, mend;
99
100 if (kbuf->top_down) {
101 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, 0,
102 &mstart, &mend, NULL) {
103 /*
104 * In memblock, end points to the first byte after the
105 * range while in kexec, end points to the last byte
106 * in the range.
107 */
108 ret = func(mstart, mend - 1, kbuf);
109 if (ret)
110 break;
111 }
112 } else {
113 for_each_free_mem_range(i, NUMA_NO_NODE, 0, &mstart, &mend,
114 NULL) {
115 /*
116 * In memblock, end points to the first byte after the
117 * range while in kexec, end points to the last byte
118 * in the range.
119 */
120 ret = func(mstart, mend - 1, kbuf);
121 if (ret)
122 break;
123 }
124 }
125
126 return ret;
127}
128
129/**
130 * setup_purgatory - initialize the purgatory's global variables
131 * @image: kexec image.
132 * @slave_code: Slave code for the purgatory.
133 * @fdt: Flattened device tree for the next kernel.
134 * @kernel_load_addr: Address where the kernel is loaded.
135 * @fdt_load_addr: Address where the flattened device tree is loaded.
136 *
137 * Return: 0 on success, or negative errno on error.
138 */
139int setup_purgatory(struct kimage *image, const void *slave_code,
140 const void *fdt, unsigned long kernel_load_addr,
141 unsigned long fdt_load_addr)
142{
143 unsigned int *slave_code_buf, master_entry;
144 int ret;
145
146 slave_code_buf = kmalloc(SLAVE_CODE_SIZE, GFP_KERNEL);
147 if (!slave_code_buf)
148 return -ENOMEM;
149
150 /* Get the slave code from the new kernel and put it in purgatory. */
151 ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
152 slave_code_buf, SLAVE_CODE_SIZE,
153 true);
154 if (ret) {
155 kfree(slave_code_buf);
156 return ret;
157 }
158
159 master_entry = slave_code_buf[0];
160 memcpy(slave_code_buf, slave_code, SLAVE_CODE_SIZE);
161 slave_code_buf[0] = master_entry;
162 ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
163 slave_code_buf, SLAVE_CODE_SIZE,
164 false);
165 kfree(slave_code_buf);
166
167 ret = kexec_purgatory_get_set_symbol(image, "kernel", &kernel_load_addr,
168 sizeof(kernel_load_addr), false);
169 if (ret)
170 return ret;
171 ret = kexec_purgatory_get_set_symbol(image, "dt_offset", &fdt_load_addr,
172 sizeof(fdt_load_addr), false);
173 if (ret)
174 return ret;
175
176 return 0;
177}
178
179/**
180 * delete_fdt_mem_rsv - delete memory reservation with given address and size
181 *
182 * Return: 0 on success, or negative errno on error.
183 */
184int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
185{
186 int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
187
188 for (i = 0; i < num_rsvs; i++) {
189 uint64_t rsv_start, rsv_size;
190
191 ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
192 if (ret) {
193 pr_err("Malformed device tree.\n");
194 return -EINVAL;
195 }
196
197 if (rsv_start == start && rsv_size == size) {
198 ret = fdt_del_mem_rsv(fdt, i);
199 if (ret) {
200 pr_err("Error deleting device tree reservation.\n");
201 return -EINVAL;
202 }
203
204 return 0;
205 }
206 }
207
208 return -ENOENT;
209}
210
211/*
212 * setup_new_fdt - modify /chosen and memory reservation for the next kernel
213 * @image: kexec image being loaded.
214 * @fdt: Flattened device tree for the next kernel.
215 * @initrd_load_addr: Address where the next initrd will be loaded.
216 * @initrd_len: Size of the next initrd, or 0 if there will be none.
217 * @cmdline: Command line for the next kernel, or NULL if there will
218 * be none.
219 *
220 * Return: 0 on success, or negative errno on error.
221 */
222int setup_new_fdt(const struct kimage *image, void *fdt,
223 unsigned long initrd_load_addr, unsigned long initrd_len,
224 const char *cmdline)
225{
226 int ret, chosen_node;
227 const void *prop;
228
229 /* Remove memory reservation for the current device tree. */
230 ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params),
231 fdt_totalsize(initial_boot_params));
232 if (ret == 0)
233 pr_debug("Removed old device tree reservation.\n");
234 else if (ret != -ENOENT)
235 return ret;
236
237 chosen_node = fdt_path_offset(fdt, "/chosen");
238 if (chosen_node == -FDT_ERR_NOTFOUND) {
239 chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
240 "chosen");
241 if (chosen_node < 0) {
242 pr_err("Error creating /chosen.\n");
243 return -EINVAL;
244 }
245 } else if (chosen_node < 0) {
246 pr_err("Malformed device tree: error reading /chosen.\n");
247 return -EINVAL;
248 }
249
250 /* Did we boot using an initrd? */
251 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", NULL);
252 if (prop) {
253 uint64_t tmp_start, tmp_end, tmp_size;
254
255 tmp_start = fdt64_to_cpu(*((const fdt64_t *) prop));
256
257 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", NULL);
258 if (!prop) {
259 pr_err("Malformed device tree.\n");
260 return -EINVAL;
261 }
262 tmp_end = fdt64_to_cpu(*((const fdt64_t *) prop));
263
264 /*
265 * kexec reserves exact initrd size, while firmware may
266 * reserve a multiple of PAGE_SIZE, so check for both.
267 */
268 tmp_size = tmp_end - tmp_start;
269 ret = delete_fdt_mem_rsv(fdt, tmp_start, tmp_size);
270 if (ret == -ENOENT)
271 ret = delete_fdt_mem_rsv(fdt, tmp_start,
272 round_up(tmp_size, PAGE_SIZE));
273 if (ret == 0)
274 pr_debug("Removed old initrd reservation.\n");
275 else if (ret != -ENOENT)
276 return ret;
277
278 /* If there's no new initrd, delete the old initrd's info. */
279 if (initrd_len == 0) {
280 ret = fdt_delprop(fdt, chosen_node,
281 "linux,initrd-start");
282 if (ret) {
283 pr_err("Error deleting linux,initrd-start.\n");
284 return -EINVAL;
285 }
286
287 ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
288 if (ret) {
289 pr_err("Error deleting linux,initrd-end.\n");
290 return -EINVAL;
291 }
292 }
293 }
294
295 if (initrd_len) {
296 ret = fdt_setprop_u64(fdt, chosen_node,
297 "linux,initrd-start",
298 initrd_load_addr);
299 if (ret < 0) {
300 pr_err("Error setting up the new device tree.\n");
301 return -EINVAL;
302 }
303
304 /* initrd-end is the first address after the initrd image. */
305 ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
306 initrd_load_addr + initrd_len);
307 if (ret < 0) {
308 pr_err("Error setting up the new device tree.\n");
309 return -EINVAL;
310 }
311
312 ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
313 if (ret) {
314 pr_err("Error reserving initrd memory: %s\n",
315 fdt_strerror(ret));
316 return -EINVAL;
317 }
318 }
319
320 if (cmdline != NULL) {
321 ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
322 if (ret < 0) {
323 pr_err("Error setting up the new device tree.\n");
324 return -EINVAL;
325 }
326 } else {
327 ret = fdt_delprop(fdt, chosen_node, "bootargs");
328 if (ret && ret != -FDT_ERR_NOTFOUND) {
329 pr_err("Error deleting bootargs.\n");
330 return -EINVAL;
331 }
332 }
333
334 ret = setup_ima_buffer(image, fdt, chosen_node);
335 if (ret) {
336 pr_err("Error setting up the new device tree.\n");
337 return ret;
338 }
339
340 ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
341 if (ret) {
342 pr_err("Error setting up the new device tree.\n");
343 return -EINVAL;
344 }
345
346 return 0;
347}