aboutsummaryrefslogtreecommitdiffstats
path: root/arch/powerpc/boot/main.c
blob: 416dc3857bfe8dcc468c8f6c3d0953970a31de40 (plain) (blame)
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
/*
 * 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"
#include "reg.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;
};

#undef DEBUG

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))
		fatal("Error: not a valid PPC32 or PPC64 ELF file!\n\r");

	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)
			fatal("Insufficient memory for kernel at address 0!"
			       " (_start=%p)\n\r", _start);
	}

	/* 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.loadsize);
	if (len != ei.loadsize)
		fatal("ran out of data!  only got 0x%x of 0x%lx bytes.\n\r",
				len, ei.loadsize);
	printf("done 0x%x 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, void *chosen,
				     unsigned long initrd_addr,
				     unsigned long initrd_size)
{
	/* 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)
			fatal("Can't allocate memory for initial "
			       "ramdisk !\n\r");
		printf("Relocating initrd 0x%lx <- 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 */
	setprop_val(chosen, "linux,initrd-start", (u32)(initrd_addr));
	setprop_val(chosen, "linux,initrd-end", (u32)(initrd_addr+initrd_size));

	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 cmdline[COMMAND_LINE_SIZE]
	__attribute__((__section__("__builtin_cmdline")));

static void prep_cmdline(void *chosen)
{
	if (cmdline[0] == '\0')
		getprop(chosen, "bootargs", cmdline, COMMAND_LINE_SIZE-1);

	printf("\n\rLinux/PowerPC load: %s", cmdline);
	/* If possible, edit the command line */
	if (console_ops.edit_cmdline)
		console_ops.edit_cmdline(cmdline, COMMAND_LINE_SIZE);
	printf("\n\r");

	/* Put the command line back into the devtree for the kernel */
	setprop_str(chosen, "bootargs", cmdline);
}

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

void start(void)
{
	struct addr_range vmlinux, initrd;
	kernel_entry_t kentry;
	unsigned long ft_addr = 0;
	void *chosen;

	/* Do this first, because malloc() could clobber the loader's
	 * command line.  Only use the loader command line if a
	 * built-in command line wasn't set by an external tool */
	if ((loader_info.cmdline_len > 0) && (cmdline[0] == '\0'))
		memmove(cmdline, loader_info.cmdline,
			min(loader_info.cmdline_len, COMMAND_LINE_SIZE-1));

	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, get_sp());

	/* Ensure that the device tree has a /chosen node */
	chosen = finddevice("/chosen");
	if (!chosen)
		chosen = create_node(NULL, "chosen");

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

	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 in fatal below may not work */
	fatal("Error: Linux kernel returned to zImage boot wrapper!\n\r");
}