aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc/boot/main.c
blob: d872b758ef147ca1aea5d581f217266d34ec12a1 (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
/*
 * Copyright (C) Paul Mackerras 1997.
 *
 * Updates for PPC64 by Todd Inglett, Dave Engebretsen & Peter Bergner.
 *
 * 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; either version
 * 2 of the License, or (at your option) any later version.
 */
#include <stdarg.h>
#include <stddef.h>
#include "elf.h"
#include "page.h"
#include "string.h"
#include "stdio.h"
#include "ops.h"
#include "gunzip_util.h"
#include "flatdevtree.h"

extern char _start[];
extern char __bss_start[];
extern char _end[];
extern char _vmlinux_start[];
extern char _vmlinux_end[];
extern char _initrd_start[];
extern char _initrd_end[];
extern char _dtb_start[];
extern char _dtb_end[];

static struct gunzip_state gzstate;

struct addr_range {
	void *addr;
	unsigned long size;
};

struct elf_info {
	unsigned long loadsize;
	unsigned long memsize;
	unsigned long elfoffset;
};

typedef void (*kernel_entry_t)(unsigned long, unsigned long, void *);

#undef DEBUG

static int parse_elf64(void *hdr, struct elf_info *info)
{
	Elf64_Ehdr *elf64 = hdr;
	Elf64_Phdr *elf64ph;
	unsigned int i;

	if (!(elf64->e_ident[EI_MAG0]  == ELFMAG0	&&
	      elf64->e_ident[EI_MAG1]  == ELFMAG1	&&
	      elf64->e_ident[EI_MAG2]  == ELFMAG2	&&
	      elf64->e_ident[EI_MAG3]  == ELFMAG3	&&
	      elf64->e_ident[EI_CLASS] == ELFCLASS64	&&
	      elf64->e_ident[EI_DATA]  == ELFDATA2MSB	&&
	      elf64->e_type            == ET_EXEC	&&
	      elf64->e_machine         == EM_PPC64))
		return 0;

	elf64ph = (Elf64_Phdr *)((unsigned long)elf64 +
				 (unsigned long)elf64->e_phoff);
	for (i = 0; i < (unsigned int)elf64->e_phnum; i++, elf64ph++)
		if (elf64ph->p_type == PT_LOAD)
			break;
	if (i >= (unsigned int)elf64->e_phnum)
		return 0;

	info->loadsize = (unsigned long)elf64ph->p_filesz;
	info->memsize = (unsigned long)elf64ph->p_memsz;
	info->elfoffset = (unsigned long)elf64ph->p_offset;

	return 1;
}

static int parse_elf32(void *hdr, struct elf_info *info)
{
	Elf32_Ehdr *elf32 = hdr;
	Elf32_Phdr *elf32ph;
	unsigned int i;

	if (!(elf32->e_ident[EI_MAG0]  == ELFMAG0	&&
	      elf32->e_ident[EI_MAG1]  == ELFMAG1	&&
	      elf32->e_ident[EI_MAG2]  == ELFMAG2	&&
	      elf32->e_ident[EI_MAG3]  == ELFMAG3	&&
	      elf32->e_ident[EI_CLASS] == ELFCLASS32	&&
	      elf32->e_ident[EI_DATA]  == ELFDATA2MSB	&&
	      elf32->e_type            == ET_EXEC	&&
	      elf32->e_machine         == EM_PPC))
		return 0;

	elf32ph = (Elf32_Phdr *) ((unsigned long)elf32 + elf32->e_phoff);
	for (i = 0; i < elf32->e_phnum; i++, elf32ph++)
		if (elf32ph->p_type == PT_LOAD)
			break;
	if (i >= elf32->e_phnum)
		return 0;

	info->loadsize = elf32ph->p_filesz;
	info->memsize = elf32ph->p_memsz;
	info->elfoffset = elf32ph->p_offset;
	return 1;
}

static struct addr_range prep_kernel(void)
{
	char elfheader[256];
	void *vmlinuz_addr = _vmlinux_start;
	unsigned long vmlinuz_size = _vmlinux_end - _vmlinux_start;
	void *addr = 0;
	struct elf_info ei;
	int len;

	/* gunzip the ELF header of the kernel */
	gunzip_start(&gzstate, vmlinuz_addr, vmlinuz_size);
	gunzip_exactly(&gzstate, elfheader, sizeof(elfheader));

	if (!parse_elf64(elfheader, &ei) && !parse_elf32(elfheader, &ei)) {
		printf("Error: not a valid PPC32 or PPC64 ELF file!\n\r");
		exit();
	}
	if (platform_ops.image_hdr)
		platform_ops.image_hdr(elfheader);

	/* We need to alloc the memsize: gzip will expand the kernel
	 * text/data, then possible rubbish we don't care about. But
	 * the kernel bss must be claimed (it will be zero'd by the
	 * kernel itself)
	 */
	printf("Allocating 0x%lx bytes for kernel ...\n\r", ei.memsize);

	if (platform_ops.vmlinux_alloc) {
		addr = platform_ops.vmlinux_alloc(ei.memsize);
	} else {
		if ((unsigned long)_start < ei.memsize) {
			printf("Insufficient memory for kernel at address 0!"
			       " (_start=%lx)\n\r", _start);
			exit();
		}
	}

	/* Finally, gunzip the kernel */
	printf("gunzipping (0x%p <- 0x%p:0x%p)...", addr,
	       vmlinuz_addr, vmlinuz_addr+vmlinuz_size);
	/* discard up to the actual load data */
	gunzip_discard(&gzstate, ei.elfoffset - sizeof(elfheader));
	len = gunzip_finish(&gzstate, addr, ei.memsize);
	printf("done 0x%lx bytes\n\r", len);

	flush_cache(addr, ei.loadsize);

	return (struct addr_range){addr, ei.memsize};
}

static struct addr_range prep_initrd(struct addr_range vmlinux,
				     unsigned long initrd_addr,
				     unsigned long initrd_size)
{
	void *devp;
	u32 initrd_start, initrd_end;

	/* If we have an image attached to us, it overrides anything
	 * supplied by the loader. */
	if (_initrd_end > _initrd_start) {
		printf("Attached initrd image at 0x%p-0x%p\n\r",
		       _initrd_start, _initrd_end);
		initrd_addr = (unsigned long)_initrd_start;
		initrd_size = _initrd_end - _initrd_start;
	} else if (initrd_size > 0) {
		printf("Using loader supplied ramdisk at 0x%lx-0x%lx\n\r",
		       initrd_addr, initrd_addr + initrd_size);
	}

	/* If there's no initrd at all, we're done */
	if (! initrd_size)
		return (struct addr_range){0, 0};

	/*
	 * If the initrd is too low it will be clobbered when the
	 * kernel relocates to its final location.  In this case,
	 * allocate a safer place and move it.
	 */
	if (initrd_addr < vmlinux.size) {
		void *old_addr = (void *)initrd_addr;

		printf("Allocating 0x%lx bytes for initrd ...\n\r",
		       initrd_size);
		initrd_addr = (unsigned long)malloc(initrd_size);
		if (! initrd_addr) {
			printf("Can't allocate memory for initial "
			       "ramdisk !\n\r");
			exit();
		}
		printf("Relocating initrd 0x%p <- 0x%p (0x%lx bytes)\n\r",
		       initrd_addr, old_addr, initrd_size);
		memmove((void *)initrd_addr, old_addr, initrd_size);
	}

	printf("initrd head: 0x%lx\n\r", *((unsigned long *)initrd_addr));

	/* Tell the kernel initrd address via device tree */
	devp = finddevice("/chosen");
	if (! devp) {
		printf("Device tree has no chosen node!\n\r");
		exit();
	}

	initrd_start = (u32)initrd_addr;
	initrd_end = (u32)initrd_addr + initrd_size;

	setprop(devp, "linux,initrd-start", &initrd_start,
		sizeof(initrd_start));
	setprop(devp, "linux,initrd-end", &initrd_end, sizeof(initrd_end));

	return (struct addr_range){(void *)initrd_addr, initrd_size};
}

/* A buffer that may be edited by tools operating on a zImage binary so as to
 * edit the command line passed to vmlinux (by setting /chosen/bootargs).
 * The buffer is put in it's own section so that tools may locate it easier.
 */
static char builtin_cmdline[COMMAND_LINE_SIZE]
	__attribute__((__section__("__builtin_cmdline")));

static void get_cmdline(char *buf, int size)
{
	void *devp;
	int len = strlen(builtin_cmdline);

	buf[0] = '\0';

	if (len > 0) { /* builtin_cmdline overrides dt's /chosen/bootargs */
		len = min(len, size-1);
		strncpy(buf, builtin_cmdline, len);
		buf[len] = '\0';
	}
	else if ((devp = finddevice("/chosen")))
		getprop(devp, "bootargs", buf, size);
}

static void set_cmdline(char *buf)
{
	void *devp;

	if ((devp = finddevice("/chosen")))
		setprop(devp, "bootargs", buf, strlen(buf) + 1);
}

struct platform_ops platform_ops;
struct dt_ops dt_ops;
struct console_ops console_ops;
struct loader_info loader_info;

void start(void *sp)
{
	struct addr_range vmlinux, initrd;
	kernel_entry_t kentry;
	char cmdline[COMMAND_LINE_SIZE];
	unsigned long ft_addr = 0;

	if (console_ops.open && (console_ops.open() < 0))
		exit();
	if (platform_ops.fixups)
		platform_ops.fixups();

	printf("\n\rzImage starting: loaded at 0x%p (sp: 0x%p)\n\r",
	       _start, sp);

	vmlinux = prep_kernel();
	initrd = prep_initrd(vmlinux, loader_info.initrd_addr,
			     loader_info.initrd_size);

	/* If cmdline came from zimage wrapper or if we can edit the one
	 * in the dt, print it out and edit it, if possible.
	 */
	if ((strlen(builtin_cmdline) > 0) || console_ops.edit_cmdline) {
		get_cmdline(cmdline, COMMAND_LINE_SIZE);
		printf("\n\rLinux/PowerPC load: %s", cmdline);
		if (console_ops.edit_cmdline)
			console_ops.edit_cmdline(cmdline, COMMAND_LINE_SIZE);
		printf("\n\r");
		set_cmdline(cmdline);
	}

	printf("Finalizing device tree...");
	if (dt_ops.finalize)
		ft_addr = dt_ops.finalize();
	if (ft_addr)
		printf(" flat tree at 0x%lx\n\r", ft_addr);
	else
		printf(" using OF tree (promptr=%p)\n\r", loader_info.promptr);

	if (console_ops.close)
		console_ops.close();

	kentry = (kernel_entry_t) vmlinux.addr;
	if (ft_addr)
		kentry(ft_addr, 0, NULL);
	else
		kentry((unsigned long)initrd.addr, initrd.size,
		       loader_info.promptr);

	/* console closed so printf below may not work */
	printf("Error: Linux kernel returned to zImage boot wrapper!\n\r");
	exit();
}