2 * Copyright (c) 2011 The Chromium OS Authors.
4 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
6 * See file CREDITS for list of people who contributed to this
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation; either version 2 of
12 * the License, or (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
26 * Linux x86 zImage and bzImage loading
28 * based on the procdure described in
29 * linux/Documentation/i386/boot.txt
34 #include <asm/ptrace.h>
35 #include <asm/zimage.h>
36 #include <asm/realmode.h>
37 #include <asm/byteorder.h>
38 #include <asm/bootparam.h>
43 * relative to setup_base (which is 0x90000 currently)
45 * 0x0000-0x7FFF Real mode kernel
46 * 0x8000-0x8FFF Stack and heap
47 * 0x9000-0x90FF Kernel command line
49 #define DEFAULT_SETUP_BASE 0x90000
50 #define COMMAND_LINE_OFFSET 0x9000
51 #define HEAP_END_OFFSET 0x8e00
53 #define COMMAND_LINE_SIZE 2048
55 static void build_command_line(char *command_line, int auto_boot)
57 char *env_command_line;
59 command_line[0] = '\0';
61 env_command_line = getenv("bootargs");
63 /* set console= argument if we use a serial console */
64 if (!strstr(env_command_line, "console=")) {
65 if (!strcmp(getenv("stdout"), "serial")) {
67 /* We seem to use serial console */
68 sprintf(command_line, "console=ttyS0,%s ",
74 strcat(command_line, "auto ");
77 strcat(command_line, env_command_line);
79 printf("Kernel command line: \"%s\"\n", command_line);
82 void *load_zimage(char *image, unsigned long kernel_size,
83 unsigned long initrd_addr, unsigned long initrd_size,
86 struct boot_params *setup_base;
92 struct boot_params *params = (struct boot_params *)image;
93 struct setup_header *hdr = ¶ms->hdr;
95 /* base address for real-mode segment */
96 setup_base = (struct boot_params *)DEFAULT_SETUP_BASE;
98 if (KERNEL_MAGIC != hdr->boot_flag) {
99 printf("Error: Invalid Boot Flag "
100 "(found 0x%04x, expected 0x%04x)\n",
101 hdr->boot_flag, KERNEL_MAGIC);
104 printf("Valid Boot Flag\n");
107 /* determine boot protocol version */
108 if (KERNEL_V2_MAGIC == hdr->header) {
109 printf("Magic signature found\n");
111 bootproto = hdr->version;
113 /* Very old kernel */
114 printf("Magic signature not found\n");
118 /* determine size of setup */
119 if (0 == hdr->setup_sects) {
120 printf("Setup Sectors = 0 (defaulting to 4)\n");
121 setup_size = 5 * 512;
123 setup_size = (hdr->setup_sects + 1) * 512;
126 printf("Setup Size = 0x%8.8lx\n", (ulong)setup_size);
128 if (setup_size > SETUP_MAX_SIZE)
129 printf("Error: Setup is too large (%d bytes)\n", setup_size);
131 /* Determine image type */
132 big_image = (bootproto >= 0x0200) &&
133 (hdr->loadflags & BIG_KERNEL_FLAG);
135 /* Determine load address */
137 load_address = (void *)BZIMAGE_LOAD_ADDR;
139 load_address = (void *)ZIMAGE_LOAD_ADDR;
142 printf("Moving Real-Mode Code to 0x%8.8lx (%d bytes)\n",
143 (ulong)setup_base, setup_size);
144 memmove(setup_base, image, setup_size);
146 printf("Using boot protocol version %x.%02x\n",
147 (bootproto & 0xff00) >> 8, bootproto & 0xff);
149 if (bootproto == 0x0100) {
150 setup_base->screen_info.cl_magic = COMMAND_LINE_MAGIC;
151 setup_base->screen_info.cl_offset = COMMAND_LINE_OFFSET;
154 * A very old kernel MUST have its real-mode code
157 if ((u32)setup_base != 0x90000) {
158 /* Copy the real-mode kernel */
159 memmove((void *)0x90000, setup_base, setup_size);
161 /* Copy the command line */
162 memmove((void *)0x99000,
163 (u8 *)setup_base + COMMAND_LINE_OFFSET,
167 setup_base = (struct boot_params *)0x90000;
170 /* It is recommended to clear memory up to the 32K mark */
171 memset((u8 *)0x90000 + setup_size, 0,
172 SETUP_MAX_SIZE - setup_size);
175 /* We are now setting up the real-mode version of the header */
176 hdr = &setup_base->hdr;
178 if (bootproto >= 0x0200) {
179 hdr->type_of_loader = 8;
181 if (hdr->setup_sects >= 15) {
182 printf("Linux kernel version %s\n",
184 hdr->kernel_version + 0x200);
186 printf("Setup Sectors < 15 - "
187 "Cannot print kernel version.\n");
191 printf("Initial RAM disk at linear address "
192 "0x%08lx, size %ld bytes\n",
193 initrd_addr, initrd_size);
195 hdr->ramdisk_image = initrd_addr;
196 hdr->ramdisk_size = initrd_size;
200 if (bootproto >= 0x0201) {
201 hdr->heap_end_ptr = HEAP_END_OFFSET;
202 hdr->loadflags |= HEAP_FLAG;
205 if (bootproto >= 0x0202) {
207 (uintptr_t)setup_base + COMMAND_LINE_OFFSET;
208 } else if (bootproto >= 0x0200) {
209 setup_base->screen_info.cl_magic = COMMAND_LINE_MAGIC;
210 setup_base->screen_info.cl_offset = COMMAND_LINE_OFFSET;
212 hdr->setup_move_size = 0x9100;
215 if (bootproto >= 0x0204)
216 kernel_size = hdr->syssize * 16;
218 kernel_size -= setup_size;
222 if ((kernel_size) > BZIMAGE_MAX_SIZE) {
223 printf("Error: bzImage kernel too big! "
224 "(size: %ld, max: %d)\n",
225 kernel_size, BZIMAGE_MAX_SIZE);
228 } else if ((kernel_size) > ZIMAGE_MAX_SIZE) {
229 printf("Error: zImage kernel too big! (size: %ld, max: %d)\n",
230 kernel_size, ZIMAGE_MAX_SIZE);
234 /* build command line at COMMAND_LINE_OFFSET */
235 build_command_line((char *)setup_base + COMMAND_LINE_OFFSET, auto_boot);
237 printf("Loading %czImage at address 0x%08x (%ld bytes)\n",
238 big_image ? 'b' : ' ', (u32)load_address, kernel_size);
241 memmove(load_address, image + setup_size, kernel_size);
243 /* ready for booting */
247 void boot_zimage(void *setup_base)
251 memset(®s, 0, sizeof(struct pt_regs));
252 regs.xds = (u32)setup_base >> 4;
257 enter_realmode(((u32)setup_base + SETUP_START_OFFSET) >> 4, 0,
261 int do_zboot(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
264 void *bzImage_addr = NULL;
266 ulong bzImage_size = 0;
268 disable_interrupts();
270 /* Setup board for maximum PC/AT Compatibility */
271 setup_pcat_compatibility();
274 /* argv[1] holds the address of the bzImage */
277 s = getenv("fileaddr");
281 bzImage_addr = (void *)simple_strtoul(s, NULL, 16);
284 /* argv[2] holds the size of the bzImage */
285 bzImage_size = simple_strtoul(argv[2], NULL, 16);
288 base_ptr = load_zimage(bzImage_addr, bzImage_size, 0, 0, 0);
291 printf("## Kernel loading failed ...\n");
293 printf("## Transferring control to Linux "
294 "(at address %08x) ...\n",
297 /* we assume that the kernel is in place */
298 printf("\nStarting kernel ...\n\n");
300 boot_zimage(base_ptr);
301 /* does not return */
308 zboot, 2, 0, do_zboot,