summaryrefslogtreecommitdiff
path: root/arch/powerpc/kernel/machine_kexec_file_64.c
blob: 992c0d258e5d564c3b57526e968b26e78bb9292d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
/*
 * ppc64 code to implement the kexec_file_load syscall
 *
 * Copyright (C) 2004  Adam Litke (agl@us.ibm.com)
 * Copyright (C) 2004  IBM Corp.
 * Copyright (C) 2004,2005  Milton D Miller II, IBM Corporation
 * Copyright (C) 2005  R Sharada (sharada@in.ibm.com)
 * Copyright (C) 2006  Mohan Kumar M (mohan@in.ibm.com)
 * Copyright (C) 2016  IBM Corporation
 *
 * Based on kexec-tools' kexec-elf-ppc64.c, fs2dt.c.
 * Heavily modified for the kernel by
 * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation (version 2 of the License).
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/slab.h>
#include <linux/kexec.h>
#include <linux/memblock.h>
#include <linux/of_fdt.h>
#include <linux/libfdt.h>
#include <asm/ima.h>

#define SLAVE_CODE_SIZE		256

static struct kexec_file_ops *kexec_file_loaders[] = {
	&kexec_elf64_ops,
};

int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
				  unsigned long buf_len)
{
	int i, ret = -ENOEXEC;
	struct kexec_file_ops *fops;

	/* We don't support crash kernels yet. */
	if (image->type == KEXEC_TYPE_CRASH)
		return -ENOTSUPP;

	for (i = 0; i < ARRAY_SIZE(kexec_file_loaders); i++) {
		fops = kexec_file_loaders[i];
		if (!fops || !fops->probe)
			continue;

		ret = fops->probe(buf, buf_len);
		if (!ret) {
			image->fops = fops;
			return ret;
		}
	}

	return ret;
}

void *arch_kexec_kernel_image_load(struct kimage *image)
{
	if (!image->fops || !image->fops->load)
		return ERR_PTR(-ENOEXEC);

	return image->fops->load(image, image->kernel_buf,
				 image->kernel_buf_len, image->initrd_buf,
				 image->initrd_buf_len, image->cmdline_buf,
				 image->cmdline_buf_len);
}

int arch_kimage_file_post_load_cleanup(struct kimage *image)
{
	if (!image->fops || !image->fops->cleanup)
		return 0;

	return image->fops->cleanup(image->image_loader_data);
}

/**
 * arch_kexec_walk_mem - call func(data) for each unreserved memory block
 * @kbuf:	Context info for the search. Also passed to @func.
 * @func:	Function to call for each memory block.
 *
 * This function is used by kexec_add_buffer and kexec_locate_mem_hole
 * to find unreserved memory to load kexec segments into.
 *
 * Return: The memory walk will stop when func returns a non-zero value
 * and that value will be returned. If all free regions are visited without
 * func returning non-zero, then zero will be returned.
 */
int arch_kexec_walk_mem(struct kexec_buf *kbuf, int (*func)(u64, u64, void *))
{
	int ret = 0;
	u64 i;
	phys_addr_t mstart, mend;

	if (kbuf->top_down) {
		for_each_free_mem_range_reverse(i, NUMA_NO_NODE, 0,
						&mstart, &mend, NULL) {
			/*
			 * In memblock, end points to the first byte after the
			 * range while in kexec, end points to the last byte
			 * in the range.
			 */
			ret = func(mstart, mend - 1, kbuf);
			if (ret)
				break;
		}
	} else {
		for_each_free_mem_range(i, NUMA_NO_NODE, 0, &mstart, &mend,
					NULL) {
			/*
			 * In memblock, end points to the first byte after the
			 * range while in kexec, end points to the last byte
			 * in the range.
			 */
			ret = func(mstart, mend - 1, kbuf);
			if (ret)
				break;
		}
	}

	return ret;
}

/**
 * setup_purgatory - initialize the purgatory's global variables
 * @image:		kexec image.
 * @slave_code:		Slave code for the purgatory.
 * @fdt:		Flattened device tree for the next kernel.
 * @kernel_load_addr:	Address where the kernel is loaded.
 * @fdt_load_addr:	Address where the flattened device tree is loaded.
 *
 * Return: 0 on success, or negative errno on error.
 */
int setup_purgatory(struct kimage *image, const void *slave_code,
		    const void *fdt, unsigned long kernel_load_addr,
		    unsigned long fdt_load_addr)
{
	unsigned int *slave_code_buf, master_entry;
	int ret;

	slave_code_buf = kmalloc(SLAVE_CODE_SIZE, GFP_KERNEL);
	if (!slave_code_buf)
		return -ENOMEM;

	/* Get the slave code from the new kernel and put it in purgatory. */
	ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
					     slave_code_buf, SLAVE_CODE_SIZE,
					     true);
	if (ret) {
		kfree(slave_code_buf);
		return ret;
	}

	master_entry = slave_code_buf[0];
	memcpy(slave_code_buf, slave_code, SLAVE_CODE_SIZE);
	slave_code_buf[0] = master_entry;
	ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
					     slave_code_buf, SLAVE_CODE_SIZE,
					     false);
	kfree(slave_code_buf);

	ret = kexec_purgatory_get_set_symbol(image, "kernel", &kernel_load_addr,
					     sizeof(kernel_load_addr), false);
	if (ret)
		return ret;
	ret = kexec_purgatory_get_set_symbol(image, "dt_offset", &fdt_load_addr,
					     sizeof(fdt_load_addr), false);
	if (ret)
		return ret;

	return 0;
}

/**
 * delete_fdt_mem_rsv - delete memory reservation with given address and size
 *
 * Return: 0 on success, or negative errno on error.
 */
int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
{
	int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);

	for (i = 0; i < num_rsvs; i++) {
		uint64_t rsv_start, rsv_size;

		ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
		if (ret) {
			pr_err("Malformed device tree.\n");
			return -EINVAL;
		}

		if (rsv_start == start && rsv_size == size) {
			ret = fdt_del_mem_rsv(fdt, i);
			if (ret) {
				pr_err("Error deleting device tree reservation.\n");
				return -EINVAL;
			}

			return 0;
		}
	}

	return -ENOENT;
}

/*
 * setup_new_fdt - modify /chosen and memory reservation for the next kernel
 * @image:		kexec image being loaded.
 * @fdt:		Flattened device tree for the next kernel.
 * @initrd_load_addr:	Address where the next initrd will be loaded.
 * @initrd_len:		Size of the next initrd, or 0 if there will be none.
 * @cmdline:		Command line for the next kernel, or NULL if there will
 *			be none.
 *
 * Return: 0 on success, or negative errno on error.
 */
int setup_new_fdt(const struct kimage *image, void *fdt,
		  unsigned long initrd_load_addr, unsigned long initrd_len,
		  const char *cmdline)
{
	int ret, chosen_node;
	const void *prop;

	/* Remove memory reservation for the current device tree. */
	ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params),
				 fdt_totalsize(initial_boot_params));
	if (ret == 0)
		pr_debug("Removed old device tree reservation.\n");
	else if (ret != -ENOENT)
		return ret;

	chosen_node = fdt_path_offset(fdt, "/chosen");
	if (chosen_node == -FDT_ERR_NOTFOUND) {
		chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
					      "chosen");
		if (chosen_node < 0) {
			pr_err("Error creating /chosen.\n");
			return -EINVAL;
		}
	} else if (chosen_node < 0) {
		pr_err("Malformed device tree: error reading /chosen.\n");
		return -EINVAL;
	}

	/* Did we boot using an initrd? */
	prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", NULL);
	if (prop) {
		uint64_t tmp_start, tmp_end, tmp_size;

		tmp_start = fdt64_to_cpu(*((const fdt64_t *) prop));

		prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", NULL);
		if (!prop) {
			pr_err("Malformed device tree.\n");
			return -EINVAL;
		}
		tmp_end = fdt64_to_cpu(*((const fdt64_t *) prop));

		/*
		 * kexec reserves exact initrd size, while firmware may
		 * reserve a multiple of PAGE_SIZE, so check for both.
		 */
		tmp_size = tmp_end - tmp_start;
		ret = delete_fdt_mem_rsv(fdt, tmp_start, tmp_size);
		if (ret == -ENOENT)
			ret = delete_fdt_mem_rsv(fdt, tmp_start,
						 round_up(tmp_size, PAGE_SIZE));
		if (ret == 0)
			pr_debug("Removed old initrd reservation.\n");
		else if (ret != -ENOENT)
			return ret;

		/* If there's no new initrd, delete the old initrd's info. */
		if (initrd_len == 0) {
			ret = fdt_delprop(fdt, chosen_node,
					  "linux,initrd-start");
			if (ret) {
				pr_err("Error deleting linux,initrd-start.\n");
				return -EINVAL;
			}

			ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
			if (ret) {
				pr_err("Error deleting linux,initrd-end.\n");
				return -EINVAL;
			}
		}
	}

	if (initrd_len) {
		ret = fdt_setprop_u64(fdt, chosen_node,
				      "linux,initrd-start",
				      initrd_load_addr);
		if (ret < 0) {
			pr_err("Error setting up the new device tree.\n");
			return -EINVAL;
		}

		/* initrd-end is the first address after the initrd image. */
		ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
				      initrd_load_addr + initrd_len);
		if (ret < 0) {
			pr_err("Error setting up the new device tree.\n");
			return -EINVAL;
		}

		ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
		if (ret) {
			pr_err("Error reserving initrd memory: %s\n",
			       fdt_strerror(ret));
			return -EINVAL;
		}
	}

	if (cmdline != NULL) {
		ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
		if (ret < 0) {
			pr_err("Error setting up the new device tree.\n");
			return -EINVAL;
		}
	} else {
		ret = fdt_delprop(fdt, chosen_node, "bootargs");
		if (ret && ret != -FDT_ERR_NOTFOUND) {
			pr_err("Error deleting bootargs.\n");
			return -EINVAL;
		}
	}

	ret = setup_ima_buffer(image, fdt, chosen_node);
	if (ret) {
		pr_err("Error setting up the new device tree.\n");
		return ret;
	}

	ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
	if (ret) {
		pr_err("Error setting up the new device tree.\n");
		return -EINVAL;
	}

	return 0;
}