summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/machine_kexec_file.c
blob: f413f57f8d2097383a230d940c0deb3dd753ece5 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * s390 code for kexec_file_load system call
 *
 * Copyright IBM Corp. 2018
 *
 * Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com>
 */

#include <linux/elf.h>
#include <linux/kexec.h>
#include <asm/setup.h>

const struct kexec_file_ops * const kexec_file_loaders[] = {
	&s390_kexec_elf_ops,
	&s390_kexec_image_ops,
	NULL,
};

int *kexec_file_update_kernel(struct kimage *image,
			      struct s390_load_data *data)
{
	unsigned long *loc;

	if (image->cmdline_buf_len >= ARCH_COMMAND_LINE_SIZE)
		return ERR_PTR(-EINVAL);

	if (image->cmdline_buf_len)
		memcpy(data->kernel_buf + COMMAND_LINE_OFFSET,
		       image->cmdline_buf, image->cmdline_buf_len);

	if (image->type == KEXEC_TYPE_CRASH) {
		loc = (unsigned long *)(data->kernel_buf + OLDMEM_BASE_OFFSET);
		*loc = crashk_res.start;

		loc = (unsigned long *)(data->kernel_buf + OLDMEM_SIZE_OFFSET);
		*loc = crashk_res.end - crashk_res.start + 1;
	}

	if (image->initrd_buf) {
		loc = (unsigned long *)(data->kernel_buf + INITRD_START_OFFSET);
		*loc = data->initrd_load_addr;

		loc = (unsigned long *)(data->kernel_buf + INITRD_SIZE_OFFSET);
		*loc = image->initrd_buf_len;
	}

	return NULL;
}

static int kexec_file_update_purgatory(struct kimage *image)
{
	u64 entry, type;
	int ret;

	if (image->type == KEXEC_TYPE_CRASH) {
		entry = STARTUP_KDUMP_OFFSET;
		type = KEXEC_TYPE_CRASH;
	} else {
		entry = STARTUP_NORMAL_OFFSET;
		type = KEXEC_TYPE_DEFAULT;
	}

	ret = kexec_purgatory_get_set_symbol(image, "kernel_entry", &entry,
					     sizeof(entry), false);
	if (ret)
		return ret;

	ret = kexec_purgatory_get_set_symbol(image, "kernel_type", &type,
					     sizeof(type), false);
	if (ret)
		return ret;

	if (image->type == KEXEC_TYPE_CRASH) {
		u64 crash_size;

		ret = kexec_purgatory_get_set_symbol(image, "crash_start",
						     &crashk_res.start,
						     sizeof(crashk_res.start),
						     false);
		if (ret)
			return ret;

		crash_size = crashk_res.end - crashk_res.start + 1;
		ret = kexec_purgatory_get_set_symbol(image, "crash_size",
						     &crash_size,
						     sizeof(crash_size),
						     false);
	}
	return ret;
}

int kexec_file_add_purgatory(struct kimage *image, struct s390_load_data *data)
{
	struct kexec_buf buf;
	int ret;

	buf.image = image;

	data->memsz = ALIGN(data->memsz, PAGE_SIZE);
	buf.mem = data->memsz;
	if (image->type == KEXEC_TYPE_CRASH)
		buf.mem += crashk_res.start;

	ret = kexec_load_purgatory(image, &buf);
	if (ret)
		return ret;

	ret = kexec_file_update_purgatory(image);
	return ret;
}

int kexec_file_add_initrd(struct kimage *image, struct s390_load_data *data,
			  char *initrd, unsigned long initrd_len)
{
	struct kexec_buf buf;
	int ret;

	buf.image = image;

	buf.buffer = initrd;
	buf.bufsz = initrd_len;

	data->memsz = ALIGN(data->memsz, PAGE_SIZE);
	buf.mem = data->memsz;
	if (image->type == KEXEC_TYPE_CRASH)
		buf.mem += crashk_res.start;
	buf.memsz = buf.bufsz;

	data->initrd_load_addr = buf.mem;
	data->memsz += buf.memsz;

	ret = kexec_add_buffer(&buf);
	return ret;
}

/*
 * The kernel is loaded to a fixed location. Turn off kexec_locate_mem_hole
 * and provide kbuf->mem by hand.
 */
int arch_kexec_walk_mem(struct kexec_buf *kbuf,
			int (*func)(struct resource *, void *))
{
	return 1;
}

int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
				     Elf_Shdr *section,
				     const Elf_Shdr *relsec,
				     const Elf_Shdr *symtab)
{
	Elf_Rela *relas;
	int i;

	relas = (void *)pi->ehdr + relsec->sh_offset;

	for (i = 0; i < relsec->sh_size / sizeof(*relas); i++) {
		const Elf_Sym *sym;	/* symbol to relocate */
		unsigned long addr;	/* final location after relocation */
		unsigned long val;	/* relocated symbol value */
		void *loc;		/* tmp location to modify */

		sym = (void *)pi->ehdr + symtab->sh_offset;
		sym += ELF64_R_SYM(relas[i].r_info);

		if (sym->st_shndx == SHN_UNDEF)
			return -ENOEXEC;

		if (sym->st_shndx == SHN_COMMON)
			return -ENOEXEC;

		if (sym->st_shndx >= pi->ehdr->e_shnum &&
		    sym->st_shndx != SHN_ABS)
			return -ENOEXEC;

		loc = pi->purgatory_buf;
		loc += section->sh_offset;
		loc += relas[i].r_offset;

		val = sym->st_value;
		if (sym->st_shndx != SHN_ABS)
			val += pi->sechdrs[sym->st_shndx].sh_addr;
		val += relas[i].r_addend;

		addr = section->sh_addr + relas[i].r_offset;

		switch (ELF64_R_TYPE(relas[i].r_info)) {
		case R_390_8:		/* Direct 8 bit.   */
			*(u8 *)loc = val;
			break;
		case R_390_12:		/* Direct 12 bit.  */
			*(u16 *)loc &= 0xf000;
			*(u16 *)loc |= val & 0xfff;
			break;
		case R_390_16:		/* Direct 16 bit.  */
			*(u16 *)loc = val;
			break;
		case R_390_20:		/* Direct 20 bit.  */
			*(u32 *)loc &= 0xf00000ff;
			*(u32 *)loc |= (val & 0xfff) << 16;	/* DL */
			*(u32 *)loc |= (val & 0xff000) >> 4;	/* DH */
			break;
		case R_390_32:		/* Direct 32 bit.  */
			*(u32 *)loc = val;
			break;
		case R_390_64:		/* Direct 64 bit.  */
			*(u64 *)loc = val;
			break;
		case R_390_PC16:	/* PC relative 16 bit.	*/
			*(u16 *)loc = (val - addr);
			break;
		case R_390_PC16DBL:	/* PC relative 16 bit shifted by 1.  */
			*(u16 *)loc = (val - addr) >> 1;
			break;
		case R_390_PC32DBL:	/* PC relative 32 bit shifted by 1.  */
			*(u32 *)loc = (val - addr) >> 1;
			break;
		case R_390_PC32:	/* PC relative 32 bit.	*/
			*(u32 *)loc = (val - addr);
			break;
		case R_390_PC64:	/* PC relative 64 bit.	*/
			*(u64 *)loc = (val - addr);
			break;
		default:
			break;
		}
	}
	return 0;
}

int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
				  unsigned long buf_len)
{
	/* A kernel must be at least large enough to contain head.S. During
	 * load memory in head.S will be accessed, e.g. to register the next
	 * command line. If the next kernel were smaller the current kernel
	 * will panic at load.
	 *
	 * 0x11000 = sizeof(head.S)
	 */
	if (buf_len < 0x11000)
		return -ENOEXEC;

	return kexec_image_probe_default(image, buf, buf_len);
}