xref: /linux/arch/powerpc/boot/main.c (revision f3539c12d8196ce0a1993364d30b3a18908470d1)
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 "reg.h"
20 
21 static struct gunzip_state gzstate;
22 
23 struct addr_range {
24 	void *addr;
25 	unsigned long size;
26 };
27 
28 #undef DEBUG
29 
30 static struct addr_range prep_kernel(void)
31 {
32 	char elfheader[256];
33 	void *vmlinuz_addr = _vmlinux_start;
34 	unsigned long vmlinuz_size = _vmlinux_end - _vmlinux_start;
35 	void *addr = 0;
36 	struct elf_info ei;
37 	int len;
38 
39 	/* gunzip the ELF header of the kernel */
40 	gunzip_start(&gzstate, vmlinuz_addr, vmlinuz_size);
41 	gunzip_exactly(&gzstate, elfheader, sizeof(elfheader));
42 
43 	if (!parse_elf64(elfheader, &ei) && !parse_elf32(elfheader, &ei))
44 		fatal("Error: not a valid PPC32 or PPC64 ELF file!\n\r");
45 
46 	if (platform_ops.image_hdr)
47 		platform_ops.image_hdr(elfheader);
48 
49 	/* We need to alloc the memsize: gzip will expand the kernel
50 	 * text/data, then possible rubbish we don't care about. But
51 	 * the kernel bss must be claimed (it will be zero'd by the
52 	 * kernel itself)
53 	 */
54 	printf("Allocating 0x%lx bytes for kernel ...\n\r", ei.memsize);
55 
56 	if (platform_ops.vmlinux_alloc) {
57 		addr = platform_ops.vmlinux_alloc(ei.memsize);
58 	} else {
59 		/*
60 		 * Check if the kernel image (without bss) would overwrite the
61 		 * bootwrapper. The device tree has been moved in fdt_init()
62 		 * to an area allocated with malloc() (somewhere past _end).
63 		 */
64 		if ((unsigned long)_start < ei.loadsize)
65 			fatal("Insufficient memory for kernel at address 0!"
66 			       " (_start=%p, uncompressed size=%08lx)\n\r",
67 			       _start, ei.loadsize);
68 
69 		if ((unsigned long)_end < ei.memsize)
70 			fatal("The final kernel image would overwrite the "
71 					"device tree\n\r");
72 	}
73 
74 	/* Finally, gunzip the kernel */
75 	printf("gunzipping (0x%p <- 0x%p:0x%p)...", addr,
76 	       vmlinuz_addr, vmlinuz_addr+vmlinuz_size);
77 	/* discard up to the actual load data */
78 	gunzip_discard(&gzstate, ei.elfoffset - sizeof(elfheader));
79 	len = gunzip_finish(&gzstate, addr, ei.loadsize);
80 	if (len != ei.loadsize)
81 		fatal("ran out of data!  only got 0x%x of 0x%lx bytes.\n\r",
82 				len, ei.loadsize);
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 
90 static 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  */
142 static char cmdline[BOOT_COMMAND_LINE_SIZE]
143 	__attribute__((__section__("__builtin_cmdline")));
144 
145 static void prep_cmdline(void *chosen)
146 {
147 	unsigned int getline_timeout = 5000;
148 	int v;
149 	int n;
150 
151 	/* Wait-for-input time */
152 	n = getprop(chosen, "linux,cmdline-timeout", &v, sizeof(v));
153 	if (n == sizeof(v))
154 		getline_timeout = v;
155 
156 	if (cmdline[0] == '\0')
157 		getprop(chosen, "bootargs", cmdline, BOOT_COMMAND_LINE_SIZE-1);
158 
159 	printf("\n\rLinux/PowerPC load: %s", cmdline);
160 
161 	/* If possible, edit the command line */
162 	if (console_ops.edit_cmdline && getline_timeout)
163 		console_ops.edit_cmdline(cmdline, BOOT_COMMAND_LINE_SIZE, getline_timeout);
164 
165 	printf("\n\r");
166 
167 	/* Put the command line back into the devtree for the kernel */
168 	setprop_str(chosen, "bootargs", cmdline);
169 }
170 
171 struct platform_ops platform_ops;
172 struct dt_ops dt_ops;
173 struct console_ops console_ops;
174 struct loader_info loader_info;
175 
176 void start(void)
177 {
178 	struct addr_range vmlinux, initrd;
179 	kernel_entry_t kentry;
180 	unsigned long ft_addr = 0;
181 	void *chosen;
182 
183 	/* Do this first, because malloc() could clobber the loader's
184 	 * command line.  Only use the loader command line if a
185 	 * built-in command line wasn't set by an external tool */
186 	if ((loader_info.cmdline_len > 0) && (cmdline[0] == '\0'))
187 		memmove(cmdline, loader_info.cmdline,
188 			min(loader_info.cmdline_len, BOOT_COMMAND_LINE_SIZE-1));
189 
190 	if (console_ops.open && (console_ops.open() < 0))
191 		exit();
192 	if (platform_ops.fixups)
193 		platform_ops.fixups();
194 
195 	printf("\n\rzImage starting: loaded at 0x%p (sp: 0x%p)\n\r",
196 	       _start, get_sp());
197 
198 	/* Ensure that the device tree has a /chosen node */
199 	chosen = finddevice("/chosen");
200 	if (!chosen)
201 		chosen = create_node(NULL, "chosen");
202 
203 	vmlinux = prep_kernel();
204 	initrd = prep_initrd(vmlinux, chosen,
205 			     loader_info.initrd_addr, loader_info.initrd_size);
206 	prep_cmdline(chosen);
207 
208 	printf("Finalizing device tree...");
209 	if (dt_ops.finalize)
210 		ft_addr = dt_ops.finalize();
211 	if (ft_addr)
212 		printf(" flat tree at 0x%lx\n\r", ft_addr);
213 	else
214 		printf(" using OF tree (promptr=%p)\n\r", loader_info.promptr);
215 
216 	if (console_ops.close)
217 		console_ops.close();
218 
219 	kentry = (kernel_entry_t) vmlinux.addr;
220 	if (ft_addr)
221 		kentry(ft_addr, 0, NULL);
222 	else
223 		kentry((unsigned long)initrd.addr, initrd.size,
224 		       loader_info.promptr);
225 
226 	/* console closed so printf in fatal below may not work */
227 	fatal("Error: Linux kernel returned to zImage boot wrapper!\n\r");
228 }
229