xref: /openbmc/linux/arch/powerpc/boot/main.c (revision fa7f32422ea1ac276b45b96a540ed5981caaa61f)
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 "reg.h"
19 
20 struct addr_range {
21 	void *addr;
22 	unsigned long size;
23 };
24 
25 #undef DEBUG
26 
27 static struct addr_range prep_kernel(void)
28 {
29 	char elfheader[256];
30 	unsigned char *vmlinuz_addr = (unsigned char *)_vmlinux_start;
31 	unsigned long vmlinuz_size = _vmlinux_end - _vmlinux_start;
32 	void *addr = 0;
33 	struct elf_info ei;
34 	long len;
35 
36 	partial_decompress(vmlinuz_addr, vmlinuz_size,
37 		elfheader, sizeof(elfheader), 0);
38 
39 	if (!parse_elf64(elfheader, &ei) && !parse_elf32(elfheader, &ei))
40 		fatal("Error: not a valid PPC32 or PPC64 ELF file!\n\r");
41 
42 	if (platform_ops.image_hdr)
43 		platform_ops.image_hdr(elfheader);
44 
45 	/* We need to alloc the memsize: gzip will expand the kernel
46 	 * text/data, then possible rubbish we don't care about. But
47 	 * the kernel bss must be claimed (it will be zero'd by the
48 	 * kernel itself)
49 	 */
50 	printf("Allocating 0x%lx bytes for kernel...\n\r", ei.memsize);
51 
52 	if (platform_ops.vmlinux_alloc) {
53 		addr = platform_ops.vmlinux_alloc(ei.memsize);
54 	} else {
55 		/*
56 		 * Check if the kernel image (without bss) would overwrite the
57 		 * bootwrapper. The device tree has been moved in fdt_init()
58 		 * to an area allocated with malloc() (somewhere past _end).
59 		 */
60 		if ((unsigned long)_start < ei.loadsize)
61 			fatal("Insufficient memory for kernel at address 0!"
62 			       " (_start=%p, uncompressed size=%08lx)\n\r",
63 			       _start, ei.loadsize);
64 
65 		if ((unsigned long)_end < ei.memsize)
66 			fatal("The final kernel image would overwrite the "
67 					"device tree\n\r");
68 	}
69 
70 	/* Finally, decompress the kernel */
71 	printf("Decompressing (0x%p <- 0x%p:0x%p)...\n\r", addr,
72 	       vmlinuz_addr, vmlinuz_addr+vmlinuz_size);
73 
74 	len = partial_decompress(vmlinuz_addr, vmlinuz_size,
75 		addr, ei.loadsize, ei.elfoffset);
76 
77 	if (len < 0)
78 		fatal("Decompression failed with error code %ld\n\r", len);
79 
80 	if (len != ei.loadsize)
81 		 fatal("Decompression error: got 0x%lx bytes, expected 0x%lx.\n\r",
82 			 len, ei.loadsize);
83 
84 	printf("Done! Decompressed 0x%lx bytes\n\r", len);
85 
86 	flush_cache(addr, ei.loadsize);
87 
88 	return (struct addr_range){addr, ei.memsize};
89 }
90 
91 static struct addr_range prep_initrd(struct addr_range vmlinux, void *chosen,
92 				     unsigned long initrd_addr,
93 				     unsigned long initrd_size)
94 {
95 	/* If we have an image attached to us, it overrides anything
96 	 * supplied by the loader. */
97 	if (_initrd_end > _initrd_start) {
98 		printf("Attached initrd image at 0x%p-0x%p\n\r",
99 		       _initrd_start, _initrd_end);
100 		initrd_addr = (unsigned long)_initrd_start;
101 		initrd_size = _initrd_end - _initrd_start;
102 	} else if (initrd_size > 0) {
103 		printf("Using loader supplied ramdisk at 0x%lx-0x%lx\n\r",
104 		       initrd_addr, initrd_addr + initrd_size);
105 	}
106 
107 	/* If there's no initrd at all, we're done */
108 	if (! initrd_size)
109 		return (struct addr_range){0, 0};
110 
111 	/*
112 	 * If the initrd is too low it will be clobbered when the
113 	 * kernel relocates to its final location.  In this case,
114 	 * allocate a safer place and move it.
115 	 */
116 	if (initrd_addr < vmlinux.size) {
117 		void *old_addr = (void *)initrd_addr;
118 
119 		printf("Allocating 0x%lx bytes for initrd ...\n\r",
120 		       initrd_size);
121 		initrd_addr = (unsigned long)malloc(initrd_size);
122 		if (! initrd_addr)
123 			fatal("Can't allocate memory for initial "
124 			       "ramdisk !\n\r");
125 		printf("Relocating initrd 0x%lx <- 0x%p (0x%lx bytes)\n\r",
126 		       initrd_addr, old_addr, initrd_size);
127 		memmove((void *)initrd_addr, old_addr, initrd_size);
128 	}
129 
130 	printf("initrd head: 0x%lx\n\r", *((unsigned long *)initrd_addr));
131 
132 	/* Tell the kernel initrd address via device tree */
133 	setprop_val(chosen, "linux,initrd-start", (u32)(initrd_addr));
134 	setprop_val(chosen, "linux,initrd-end", (u32)(initrd_addr+initrd_size));
135 
136 	return (struct addr_range){(void *)initrd_addr, initrd_size};
137 }
138 
139 /* A buffer that may be edited by tools operating on a zImage binary so as to
140  * edit the command line passed to vmlinux (by setting /chosen/bootargs).
141  * The buffer is put in it's own section so that tools may locate it easier.
142  */
143 static char cmdline[BOOT_COMMAND_LINE_SIZE]
144 	__attribute__((__section__("__builtin_cmdline")));
145 
146 static void prep_cmdline(void *chosen)
147 {
148 	unsigned int getline_timeout = 5000;
149 	int v;
150 	int n;
151 
152 	/* Wait-for-input time */
153 	n = getprop(chosen, "linux,cmdline-timeout", &v, sizeof(v));
154 	if (n == sizeof(v))
155 		getline_timeout = v;
156 
157 	if (cmdline[0] == '\0')
158 		getprop(chosen, "bootargs", cmdline, BOOT_COMMAND_LINE_SIZE-1);
159 
160 	printf("\n\rLinux/PowerPC load: %s", cmdline);
161 
162 	/* If possible, edit the command line */
163 	if (console_ops.edit_cmdline && getline_timeout)
164 		console_ops.edit_cmdline(cmdline, BOOT_COMMAND_LINE_SIZE, getline_timeout);
165 
166 	printf("\n\r");
167 
168 	/* Put the command line back into the devtree for the kernel */
169 	setprop_str(chosen, "bootargs", cmdline);
170 }
171 
172 struct platform_ops platform_ops;
173 struct dt_ops dt_ops;
174 struct console_ops console_ops;
175 struct loader_info loader_info;
176 
177 void start(void)
178 {
179 	struct addr_range vmlinux, initrd;
180 	kernel_entry_t kentry;
181 	unsigned long ft_addr = 0;
182 	void *chosen;
183 
184 	/* Do this first, because malloc() could clobber the loader's
185 	 * command line.  Only use the loader command line if a
186 	 * built-in command line wasn't set by an external tool */
187 	if ((loader_info.cmdline_len > 0) && (cmdline[0] == '\0'))
188 		memmove(cmdline, loader_info.cmdline,
189 			min(loader_info.cmdline_len, BOOT_COMMAND_LINE_SIZE-1));
190 
191 	if (console_ops.open && (console_ops.open() < 0))
192 		exit();
193 	if (platform_ops.fixups)
194 		platform_ops.fixups();
195 
196 	printf("\n\rzImage starting: loaded at 0x%p (sp: 0x%p)\n\r",
197 	       _start, get_sp());
198 
199 	/* Ensure that the device tree has a /chosen node */
200 	chosen = finddevice("/chosen");
201 	if (!chosen)
202 		chosen = create_node(NULL, "chosen");
203 
204 	vmlinux = prep_kernel();
205 	initrd = prep_initrd(vmlinux, chosen,
206 			     loader_info.initrd_addr, loader_info.initrd_size);
207 	prep_cmdline(chosen);
208 
209 	printf("Finalizing device tree...");
210 	if (dt_ops.finalize)
211 		ft_addr = dt_ops.finalize();
212 	if (ft_addr)
213 		printf(" flat tree at 0x%lx\n\r", ft_addr);
214 	else
215 		printf(" using OF tree (promptr=%p)\n\r", loader_info.promptr);
216 
217 	if (console_ops.close)
218 		console_ops.close();
219 
220 	kentry = (kernel_entry_t) vmlinux.addr;
221 	if (ft_addr)
222 		kentry(ft_addr, 0, NULL);
223 	else
224 		kentry((unsigned long)initrd.addr, initrd.size,
225 		       loader_info.promptr);
226 
227 	/* console closed so printf in fatal below may not work */
228 	fatal("Error: Linux kernel returned to zImage boot wrapper!\n\r");
229 }
230