main.c revision 88e687313e683ee006152d611b95f40900e3bce0 
1/*
2 * Copyright (C) Paul Mackerras 1997.
3 *
4 * Updates for PPC64 by Todd Inglett, Dave Engebretsen & Peter Bergner.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11#include <stdarg.h>
12#include <stddef.h>
13#include "elf.h"
14#include "page.h"
15#include "string.h"
16#include "stdio.h"
17#include "ops.h"
18#include "gunzip_util.h"
19#include "flatdevtree.h"
20#include "reg.h"
21
22extern char _start[];
23extern char __bss_start[];
24extern char _end[];
25extern char _vmlinux_start[];
26extern char _vmlinux_end[];
27extern char _initrd_start[];
28extern char _initrd_end[];
29extern char _dtb_start[];
30extern char _dtb_end[];
31
32static struct gunzip_state gzstate;
33
34struct addr_range {
35	void *addr;
36	unsigned long size;
37};
38
39typedef void (*kernel_entry_t)(unsigned long, unsigned long, void *);
40
41#undef DEBUG
42
43static struct addr_range prep_kernel(void)
44{
45	char elfheader[256];
46	void *vmlinuz_addr = _vmlinux_start;
47	unsigned long vmlinuz_size = _vmlinux_end - _vmlinux_start;
48	void *addr = 0;
49	struct elf_info ei;
50	int len;
51
52	/* gunzip the ELF header of the kernel */
53	gunzip_start(&gzstate, vmlinuz_addr, vmlinuz_size);
54	gunzip_exactly(&gzstate, elfheader, sizeof(elfheader));
55
56	if (!parse_elf64(elfheader, &ei) && !parse_elf32(elfheader, &ei))
57		fatal("Error: not a valid PPC32 or PPC64 ELF file!\n\r");
58
59	if (platform_ops.image_hdr)
60		platform_ops.image_hdr(elfheader);
61
62	/* We need to alloc the memsize: gzip will expand the kernel
63	 * text/data, then possible rubbish we don't care about. But
64	 * the kernel bss must be claimed (it will be zero'd by the
65	 * kernel itself)
66	 */
67	printf("Allocating 0x%lx bytes for kernel ...\n\r", ei.memsize);
68
69	if (platform_ops.vmlinux_alloc) {
70		addr = platform_ops.vmlinux_alloc(ei.memsize);
71	} else {
72		if ((unsigned long)_start < ei.memsize)
73			fatal("Insufficient memory for kernel at address 0!"
74			       " (_start=%p)\n\r", _start);
75	}
76
77	/* Finally, gunzip the kernel */
78	printf("gunzipping (0x%p <- 0x%p:0x%p)...", addr,
79	       vmlinuz_addr, vmlinuz_addr+vmlinuz_size);
80	/* discard up to the actual load data */
81	gunzip_discard(&gzstate, ei.elfoffset - sizeof(elfheader));
82	len = gunzip_finish(&gzstate, addr, ei.memsize);
83	printf("done 0x%x bytes\n\r", len);
84
85	flush_cache(addr, ei.loadsize);
86
87	return (struct addr_range){addr, ei.memsize};
88}
89
90static struct addr_range prep_initrd(struct addr_range vmlinux, void *chosen,
91				     unsigned long initrd_addr,
92				     unsigned long initrd_size)
93{
94	/* If we have an image attached to us, it overrides anything
95	 * supplied by the loader. */
96	if (_initrd_end > _initrd_start) {
97		printf("Attached initrd image at 0x%p-0x%p\n\r",
98		       _initrd_start, _initrd_end);
99		initrd_addr = (unsigned long)_initrd_start;
100		initrd_size = _initrd_end - _initrd_start;
101	} else if (initrd_size > 0) {
102		printf("Using loader supplied ramdisk at 0x%lx-0x%lx\n\r",
103		       initrd_addr, initrd_addr + initrd_size);
104	}
105
106	/* If there's no initrd at all, we're done */
107	if (! initrd_size)
108		return (struct addr_range){0, 0};
109
110	/*
111	 * If the initrd is too low it will be clobbered when the
112	 * kernel relocates to its final location.  In this case,
113	 * allocate a safer place and move it.
114	 */
115	if (initrd_addr < vmlinux.size) {
116		void *old_addr = (void *)initrd_addr;
117
118		printf("Allocating 0x%lx bytes for initrd ...\n\r",
119		       initrd_size);
120		initrd_addr = (unsigned long)malloc(initrd_size);
121		if (! initrd_addr)
122			fatal("Can't allocate memory for initial "
123			       "ramdisk !\n\r");
124		printf("Relocating initrd 0x%lx <- 0x%p (0x%lx bytes)\n\r",
125		       initrd_addr, old_addr, initrd_size);
126		memmove((void *)initrd_addr, old_addr, initrd_size);
127	}
128
129	printf("initrd head: 0x%lx\n\r", *((unsigned long *)initrd_addr));
130
131	/* Tell the kernel initrd address via device tree */
132	setprop_val(chosen, "linux,initrd-start", (u32)(initrd_addr));
133	setprop_val(chosen, "linux,initrd-end", (u32)(initrd_addr+initrd_size));
134
135	return (struct addr_range){(void *)initrd_addr, initrd_size};
136}
137
138/* A buffer that may be edited by tools operating on a zImage binary so as to
139 * edit the command line passed to vmlinux (by setting /chosen/bootargs).
140 * The buffer is put in it's own section so that tools may locate it easier.
141 */
142static char cmdline[COMMAND_LINE_SIZE]
143	__attribute__((__section__("__builtin_cmdline")));
144
145static void prep_cmdline(void *chosen)
146{
147	if (cmdline[0] == '\0')
148		getprop(chosen, "bootargs", cmdline, COMMAND_LINE_SIZE-1);
149
150	printf("\n\rLinux/PowerPC load: %s", cmdline);
151	/* If possible, edit the command line */
152	if (console_ops.edit_cmdline)
153		console_ops.edit_cmdline(cmdline, COMMAND_LINE_SIZE);
154	printf("\n\r");
155
156	/* Put the command line back into the devtree for the kernel */
157	setprop_str(chosen, "bootargs", cmdline);
158}
159
160struct platform_ops platform_ops;
161struct dt_ops dt_ops;
162struct console_ops console_ops;
163struct loader_info loader_info;
164
165void start(void)
166{
167	struct addr_range vmlinux, initrd;
168	kernel_entry_t kentry;
169	unsigned long ft_addr = 0;
170	void *chosen;
171
172	/* Do this first, because malloc() could clobber the loader's
173	 * command line.  Only use the loader command line if a
174	 * built-in command line wasn't set by an external tool */
175	if ((loader_info.cmdline_len > 0) && (cmdline[0] == '\0'))
176		memmove(cmdline, loader_info.cmdline,
177			min(loader_info.cmdline_len, COMMAND_LINE_SIZE-1));
178
179	if (console_ops.open && (console_ops.open() < 0))
180		exit();
181	if (platform_ops.fixups)
182		platform_ops.fixups();
183
184	printf("\n\rzImage starting: loaded at 0x%p (sp: 0x%p)\n\r",
185	       _start, get_sp());
186
187	/* Ensure that the device tree has a /chosen node */
188	chosen = finddevice("/chosen");
189	if (!chosen)
190		chosen = create_node(NULL, "chosen");
191
192	vmlinux = prep_kernel();
193	initrd = prep_initrd(vmlinux, chosen,
194			     loader_info.initrd_addr, loader_info.initrd_size);
195	prep_cmdline(chosen);
196
197	printf("Finalizing device tree...");
198	if (dt_ops.finalize)
199		ft_addr = dt_ops.finalize();
200	if (ft_addr)
201		printf(" flat tree at 0x%lx\n\r", ft_addr);
202	else
203		printf(" using OF tree (promptr=%p)\n\r", loader_info.promptr);
204
205	if (console_ops.close)
206		console_ops.close();
207
208	kentry = (kernel_entry_t) vmlinux.addr;
209	if (ft_addr)
210		kentry(ft_addr, 0, NULL);
211	else
212		kentry((unsigned long)initrd.addr, initrd.size,
213		       loader_info.promptr);
214
215	/* console closed so printf in fatal below may not work */
216	fatal("Error: Linux kernel returned to zImage boot wrapper!\n\r");
217}
218