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
34 const struct kexec_file_ops * const kexec_file_loaders[] = {
35 &kexec_elf64_ops,
36 NULL
37 };
38
arch_kexec_kernel_image_probe(struct kimage * image,void * buf,unsigned long buf_len)39 int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
40 unsigned long buf_len)
41 {
42 /* We don't support crash kernels yet. */
43 if (image->type == KEXEC_TYPE_CRASH)
44 return -EOPNOTSUPP;
45
46 return kexec_image_probe_default(image, buf, buf_len);
47 }
48
49 /**
50 * arch_kexec_walk_mem - call func(data) for each unreserved memory block
51 * @kbuf: Context info for the search. Also passed to @func.
52 * @func: Function to call for each memory block.
53 *
54 * This function is used by kexec_add_buffer and kexec_locate_mem_hole
55 * to find unreserved memory to load kexec segments into.
56 *
57 * Return: The memory walk will stop when func returns a non-zero value
58 * and that value will be returned. If all free regions are visited without
59 * func returning non-zero, then zero will be returned.
60 */
arch_kexec_walk_mem(struct kexec_buf * kbuf,int (* func)(struct resource *,void *))61 int arch_kexec_walk_mem(struct kexec_buf *kbuf,
62 int (*func)(struct resource *, void *))
63 {
64 int ret = 0;
65 u64 i;
66 phys_addr_t mstart, mend;
67 struct resource res = { };
68
69 if (kbuf->top_down) {
70 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, 0,
71 &mstart, &mend, NULL) {
72 /*
73 * In memblock, end points to the first byte after the
74 * range while in kexec, end points to the last byte
75 * in the range.
76 */
77 res.start = mstart;
78 res.end = mend - 1;
79 ret = func(&res, kbuf);
80 if (ret)
81 break;
82 }
83 } else {
84 for_each_free_mem_range(i, NUMA_NO_NODE, 0, &mstart, &mend,
85 NULL) {
86 /*
87 * In memblock, end points to the first byte after the
88 * range while in kexec, end points to the last byte
89 * in the range.
90 */
91 res.start = mstart;
92 res.end = mend - 1;
93 ret = func(&res, kbuf);
94 if (ret)
95 break;
96 }
97 }
98
99 return ret;
100 }
101
102 /**
103 * setup_purgatory - initialize the purgatory's global variables
104 * @image: kexec image.
105 * @slave_code: Slave code for the purgatory.
106 * @fdt: Flattened device tree for the next kernel.
107 * @kernel_load_addr: Address where the kernel is loaded.
108 * @fdt_load_addr: Address where the flattened device tree is loaded.
109 *
110 * Return: 0 on success, or negative errno on error.
111 */
setup_purgatory(struct kimage * image,const void * slave_code,const void * fdt,unsigned long kernel_load_addr,unsigned long fdt_load_addr)112 int setup_purgatory(struct kimage *image, const void *slave_code,
113 const void *fdt, unsigned long kernel_load_addr,
114 unsigned long fdt_load_addr)
115 {
116 unsigned int *slave_code_buf, master_entry;
117 int ret;
118
119 slave_code_buf = kmalloc(SLAVE_CODE_SIZE, GFP_KERNEL);
120 if (!slave_code_buf)
121 return -ENOMEM;
122
123 /* Get the slave code from the new kernel and put it in purgatory. */
124 ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
125 slave_code_buf, SLAVE_CODE_SIZE,
126 true);
127 if (ret) {
128 kfree(slave_code_buf);
129 return ret;
130 }
131
132 master_entry = slave_code_buf[0];
133 memcpy(slave_code_buf, slave_code, SLAVE_CODE_SIZE);
134 slave_code_buf[0] = master_entry;
135 ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
136 slave_code_buf, SLAVE_CODE_SIZE,
137 false);
138 kfree(slave_code_buf);
139
140 ret = kexec_purgatory_get_set_symbol(image, "kernel", &kernel_load_addr,
141 sizeof(kernel_load_addr), false);
142 if (ret)
143 return ret;
144 ret = kexec_purgatory_get_set_symbol(image, "dt_offset", &fdt_load_addr,
145 sizeof(fdt_load_addr), false);
146 if (ret)
147 return ret;
148
149 return 0;
150 }
151
152 /**
153 * delete_fdt_mem_rsv - delete memory reservation with given address and size
154 *
155 * Return: 0 on success, or negative errno on error.
156 */
delete_fdt_mem_rsv(void * fdt,unsigned long start,unsigned long size)157 int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
158 {
159 int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
160
161 for (i = 0; i < num_rsvs; i++) {
162 uint64_t rsv_start, rsv_size;
163
164 ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
165 if (ret) {
166 pr_err("Malformed device tree.\n");
167 return -EINVAL;
168 }
169
170 if (rsv_start == start && rsv_size == size) {
171 ret = fdt_del_mem_rsv(fdt, i);
172 if (ret) {
173 pr_err("Error deleting device tree reservation.\n");
174 return -EINVAL;
175 }
176
177 return 0;
178 }
179 }
180
181 return -ENOENT;
182 }
183
184 /*
185 * setup_new_fdt - modify /chosen and memory reservation for the next kernel
186 * @image: kexec image being loaded.
187 * @fdt: Flattened device tree for the next kernel.
188 * @initrd_load_addr: Address where the next initrd will be loaded.
189 * @initrd_len: Size of the next initrd, or 0 if there will be none.
190 * @cmdline: Command line for the next kernel, or NULL if there will
191 * be none.
192 *
193 * Return: 0 on success, or negative errno on error.
194 */
setup_new_fdt(const struct kimage * image,void * fdt,unsigned long initrd_load_addr,unsigned long initrd_len,const char * cmdline)195 int setup_new_fdt(const struct kimage *image, void *fdt,
196 unsigned long initrd_load_addr, unsigned long initrd_len,
197 const char *cmdline)
198 {
199 int ret, chosen_node;
200 const void *prop;
201
202 /* Remove memory reservation for the current device tree. */
203 ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params),
204 fdt_totalsize(initial_boot_params));
205 if (ret == 0)
206 pr_debug("Removed old device tree reservation.\n");
207 else if (ret != -ENOENT)
208 return ret;
209
210 chosen_node = fdt_path_offset(fdt, "/chosen");
211 if (chosen_node == -FDT_ERR_NOTFOUND) {
212 chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
213 "chosen");
214 if (chosen_node < 0) {
215 pr_err("Error creating /chosen.\n");
216 return -EINVAL;
217 }
218 } else if (chosen_node < 0) {
219 pr_err("Malformed device tree: error reading /chosen.\n");
220 return -EINVAL;
221 }
222
223 /* Did we boot using an initrd? */
224 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", NULL);
225 if (prop) {
226 uint64_t tmp_start, tmp_end, tmp_size;
227
228 tmp_start = fdt64_to_cpu(*((const fdt64_t *) prop));
229
230 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", NULL);
231 if (!prop) {
232 pr_err("Malformed device tree.\n");
233 return -EINVAL;
234 }
235 tmp_end = fdt64_to_cpu(*((const fdt64_t *) prop));
236
237 /*
238 * kexec reserves exact initrd size, while firmware may
239 * reserve a multiple of PAGE_SIZE, so check for both.
240 */
241 tmp_size = tmp_end - tmp_start;
242 ret = delete_fdt_mem_rsv(fdt, tmp_start, tmp_size);
243 if (ret == -ENOENT)
244 ret = delete_fdt_mem_rsv(fdt, tmp_start,
245 round_up(tmp_size, PAGE_SIZE));
246 if (ret == 0)
247 pr_debug("Removed old initrd reservation.\n");
248 else if (ret != -ENOENT)
249 return ret;
250
251 /* If there's no new initrd, delete the old initrd's info. */
252 if (initrd_len == 0) {
253 ret = fdt_delprop(fdt, chosen_node,
254 "linux,initrd-start");
255 if (ret) {
256 pr_err("Error deleting linux,initrd-start.\n");
257 return -EINVAL;
258 }
259
260 ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
261 if (ret) {
262 pr_err("Error deleting linux,initrd-end.\n");
263 return -EINVAL;
264 }
265 }
266 }
267
268 if (initrd_len) {
269 ret = fdt_setprop_u64(fdt, chosen_node,
270 "linux,initrd-start",
271 initrd_load_addr);
272 if (ret < 0)
273 goto err;
274
275 /* initrd-end is the first address after the initrd image. */
276 ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
277 initrd_load_addr + initrd_len);
278 if (ret < 0)
279 goto err;
280
281 ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
282 if (ret) {
283 pr_err("Error reserving initrd memory: %s\n",
284 fdt_strerror(ret));
285 return -EINVAL;
286 }
287 }
288
289 if (cmdline != NULL) {
290 ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
291 if (ret < 0)
292 goto err;
293 } else {
294 ret = fdt_delprop(fdt, chosen_node, "bootargs");
295 if (ret && ret != -FDT_ERR_NOTFOUND) {
296 pr_err("Error deleting bootargs.\n");
297 return -EINVAL;
298 }
299 }
300
301 ret = setup_ima_buffer(image, fdt, chosen_node);
302 if (ret) {
303 pr_err("Error setting up the new device tree.\n");
304 return ret;
305 }
306
307 ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
308 if (ret)
309 goto err;
310
311 return 0;
312
313 err:
314 pr_err("Error setting up the new device tree.\n");
315 return -EINVAL;
316 }
317
