1 /* ----------------------------------------------------------------------- *
3 * Copyright 2007-2009 H. Peter Anvin - All Rights Reserved
4 * Copyright 2009-2011 Intel Corporation; author: H. Peter Anvin
6 * Permission is hereby granted, free of charge, to any person
7 * obtaining a copy of this software and associated documentation
8 * files (the "Software"), to deal in the Software without
9 * restriction, including without limitation the rights to use,
10 * copy, modify, merge, publish, distribute, sublicense, and/or
11 * sell copies of the Software, and to permit persons to whom
12 * the Software is furnished to do so, subject to the following
15 * The above copyright notice and this permission notice shall
16 * be included in all copies or substantial portions of the Software.
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
20 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
22 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
23 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
24 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
25 * OTHER DEALINGS IN THE SOFTWARE.
27 * ----------------------------------------------------------------------- */
32 * Load a Linux kernel (Image/zImage/bzImage).
41 #include <suffix_number.h>
42 #include <syslinux/align.h>
43 #include <syslinux/linux.h>
44 #include <syslinux/bootrm.h>
45 #include <syslinux/movebits.h>
49 uint8_t boot_sector_1[0x0020];
50 uint16_t old_cmd_line_magic;
51 uint16_t old_cmd_line_offset;
52 uint8_t boot_sector_2[0x01f1 - 0x0024];
63 uint32_t realmode_swtch;
65 uint16_t kernel_version;
66 uint8_t type_of_loader;
68 uint16_t setup_move_size;
69 uint32_t code32_start;
70 uint32_t ramdisk_image;
71 uint32_t ramdisk_size;
72 uint32_t bootsect_kludge;
73 uint16_t heap_end_ptr;
75 uint32_t cmd_line_ptr;
76 uint32_t initrd_addr_max;
77 uint32_t kernel_alignment;
78 uint8_t relocatable_kernel;
80 uint32_t cmdline_max_len;
81 uint32_t hardware_subarch;
82 uint64_t hardware_subarch_data;
83 uint32_t payload_offset;
84 uint32_t payload_length;
86 uint64_t pref_address;
90 #define BOOT_MAGIC 0xAA55
91 #define LINUX_MAGIC ('H' + ('d' << 8) + ('r' << 16) + ('S' << 24))
92 #define OLD_CMDLINE_MAGIC 0xA33F
95 #define LOAD_HIGH 0x01
96 #define CAN_USE_HEAP 0x80
99 * Find the last instance of a particular command line argument
100 * (which should include the final =; do not use for boolean arguments)
101 * Note: the resulting string is typically not null-terminated.
103 static const char *find_argument(const char *cmdline, const char *argument)
105 const char *found = NULL;
106 const char *p = cmdline;
107 bool was_space = true;
108 size_t la = strlen(argument);
113 } else if (was_space) {
114 if (!memcmp(p, argument, la))
124 /* Truncate to 32 bits, with saturate */
125 static inline uint32_t saturate32(unsigned long long v)
127 return (v > 0xffffffff) ? 0xffffffff : (uint32_t) v;
130 /* Get the combined size of the initramfs */
131 static addr_t initramfs_size(struct initramfs *initramfs)
133 struct initramfs *ip;
139 for (ip = initramfs->next; ip->len; ip = ip->next) {
140 size = (size + ip->align - 1) & ~(ip->align - 1); /* Alignment */
147 /* Create the appropriate mappings for the initramfs */
148 static int map_initramfs(struct syslinux_movelist **fraglist,
149 struct syslinux_memmap **mmap,
150 struct initramfs *initramfs, addr_t addr)
152 struct initramfs *ip;
153 addr_t next_addr, len, pad;
155 for (ip = initramfs->next; ip->len; ip = ip->next) {
157 next_addr = addr + len;
159 /* If this isn't the last entry, extend the zero-pad region
160 to enforce the alignment of the next chunk. */
162 pad = -next_addr & (ip->next->align - 1);
168 if (syslinux_add_movelist(fraglist, addr, (addr_t) ip->data, len))
171 if (len > ip->data_len) {
172 if (syslinux_add_memmap(mmap, addr + ip->data_len,
173 len - ip->data_len, SMT_ZERO))
182 int syslinux_boot_linux(void *kernel_buf, size_t kernel_size,
183 struct initramfs *initramfs, char *cmdline)
185 struct linux_header hdr, *whdr;
186 size_t real_mode_size, prot_mode_size;
187 addr_t real_mode_base, prot_mode_base;
189 size_t cmdline_size, cmdline_offset;
190 struct syslinux_rm_regs regs;
191 struct syslinux_movelist *fraglist = NULL;
192 struct syslinux_memmap *mmap = NULL;
193 struct syslinux_memmap *amap = NULL;
195 uint32_t memlimit = 0;
196 uint16_t video_mode = 0;
199 cmdline_size = strlen(cmdline) + 1;
201 if (kernel_size < 2 * 512)
204 /* Look for specific command-line arguments we care about */
205 if ((arg = find_argument(cmdline, "mem=")))
206 memlimit = saturate32(suffix_number(arg));
208 if ((arg = find_argument(cmdline, "vga="))) {
209 switch (arg[0] | 0x20) {
210 case 'a': /* "ask" */
213 case 'e': /* "ext" */
216 case 'n': /* "normal" */
219 case 'c': /* "current" */
223 video_mode = strtoul(arg, NULL, 0);
228 /* Copy the header into private storage */
229 /* Use whdr to modify the actual kernel header */
230 memcpy(&hdr, kernel_buf, sizeof hdr);
231 whdr = (struct linux_header *)kernel_buf;
233 if (hdr.boot_flag != BOOT_MAGIC)
236 if (hdr.header != LINUX_MAGIC) {
237 hdr.version = 0x0100; /* Very old kernel */
241 whdr->vid_mode = video_mode;
243 if (!hdr.setup_sects)
246 if (hdr.version < 0x0203)
247 hdr.initrd_addr_max = 0x37ffffff;
249 if (!memlimit && memlimit - 1 > hdr.initrd_addr_max)
250 memlimit = hdr.initrd_addr_max + 1; /* Zero for no limit */
252 if (hdr.version < 0x0205 || !(hdr.loadflags & LOAD_HIGH))
253 hdr.relocatable_kernel = 0;
255 if (hdr.version < 0x0206)
256 hdr.cmdline_max_len = 256;
258 if (cmdline_size > hdr.cmdline_max_len) {
259 cmdline_size = hdr.cmdline_max_len;
260 cmdline[cmdline_size - 1] = '\0';
263 if (hdr.version < 0x0202 || !(hdr.loadflags & 0x01))
264 cmdline_offset = (0x9ff0 - cmdline_size) & ~15;
266 cmdline_offset = 0x10000;
268 real_mode_size = (hdr.setup_sects + 1) << 9;
269 real_mode_base = (hdr.loadflags & LOAD_HIGH) ? 0x10000 : 0x90000;
270 prot_mode_base = (hdr.loadflags & LOAD_HIGH) ? 0x100000 : 0x10000;
271 prot_mode_size = kernel_size - real_mode_size;
273 if (hdr.version < 0x020a) {
275 * The 3* here is a total fudge factor... it's supposed to
276 * account for the fact that the kernel needs to be
277 * decompressed, and then followed by the BSS and BRK regions.
278 * This doesn't, however, account for the fact that the kernel
279 * is decompressed into a whole other place, either.
281 hdr.init_size = 3 * prot_mode_size;
284 if (!(hdr.loadflags & LOAD_HIGH) && prot_mode_size > 512 * 1024)
285 goto bail; /* Kernel cannot be loaded low */
287 if (initramfs && hdr.version < 0x0200)
288 goto bail; /* initrd/initramfs not supported */
290 if (hdr.version >= 0x0200) {
291 whdr->type_of_loader = 0x30; /* SYSLINUX unknown module */
292 if (hdr.version >= 0x0201) {
293 whdr->heap_end_ptr = cmdline_offset - 0x0200;
294 whdr->loadflags |= CAN_USE_HEAP;
296 if (hdr.version >= 0x0202) {
297 whdr->cmd_line_ptr = real_mode_base + cmdline_offset;
299 whdr->old_cmd_line_magic = OLD_CMDLINE_MAGIC;
300 whdr->old_cmd_line_offset = cmdline_offset;
301 /* Be paranoid and round up to a multiple of 16 */
302 whdr->setup_move_size = (cmdline_offset + cmdline_size + 15) & ~15;
306 /* Get the memory map */
307 mmap = syslinux_memory_map(); /* Memory map for shuffle_boot */
308 amap = syslinux_dup_memmap(mmap); /* Keep track of available memory */
312 dprintf("Initial memory map:\n");
313 syslinux_dump_memmap(mmap);
315 /* If the user has specified a memory limit, mark that as unavailable.
316 Question: should we mark this off-limit in the mmap as well (meaning
317 it's unavailable to the boot loader, which probably has already touched
318 some of it), or just in the amap? */
320 if (syslinux_add_memmap(&amap, memlimit, -memlimit, SMT_RESERVED))
323 /* Place the kernel in memory */
325 /* First, find a suitable place for the protected-mode code */
326 if (syslinux_memmap_type(amap, prot_mode_base, prot_mode_size)
328 const struct syslinux_memmap *mp;
329 if (!hdr.relocatable_kernel)
330 goto bail; /* Can't relocate - no hope */
333 for (mp = amap; mp; mp = mp->next) {
336 end = mp->next->start;
338 if (mp->type != SMT_FREE)
341 if (end <= prot_mode_base)
342 continue; /* Only relocate upwards */
344 if (start <= prot_mode_base)
345 start = prot_mode_base;
347 start = ALIGN_UP(start, hdr.kernel_alignment);
351 if (end - start >= hdr.init_size) {
352 whdr->code32_start += start - prot_mode_base;
353 prot_mode_base = start;
364 if (syslinux_memmap_type(amap, real_mode_base,
365 cmdline_offset + cmdline_size) != SMT_FREE) {
366 const struct syslinux_memmap *mp;
369 for (mp = amap; mp; mp = mp->next) {
372 end = mp->next->start;
374 if (mp->type != SMT_FREE)
377 if (start < real_mode_base)
378 start = real_mode_base; /* Lowest address we'll use */
379 if (end > 640 * 1024)
382 start = ALIGN_UP(start, 16);
383 if (start > 0x90000 || start >= end)
386 if (end - start >= cmdline_offset + cmdline_size) {
387 real_mode_base = start;
394 if (syslinux_add_movelist(&fraglist, real_mode_base, (addr_t) kernel_buf,
397 if (syslinux_add_memmap
398 (&amap, real_mode_base, cmdline_offset + cmdline_size, SMT_ALLOC))
401 /* Zero region between real mode code and cmdline */
402 if (syslinux_add_memmap(&mmap, real_mode_base + real_mode_size,
403 cmdline_offset - real_mode_size, SMT_ZERO))
407 if (syslinux_add_movelist(&fraglist, real_mode_base + cmdline_offset,
408 (addr_t) cmdline, cmdline_size))
411 /* Protected-mode code */
412 if (syslinux_add_movelist(&fraglist, prot_mode_base,
413 (addr_t) kernel_buf + real_mode_size,
416 if (syslinux_add_memmap(&amap, prot_mode_base, prot_mode_size, SMT_ALLOC))
419 /* Figure out the size of the initramfs, and where to put it.
420 We should put it at the highest possible address which is
421 <= hdr.initrd_addr_max, which fits the entire initramfs. */
423 irf_size = initramfs_size(initramfs); /* Handles initramfs == NULL */
426 addr_t best_addr = 0;
427 struct syslinux_memmap *ml;
428 const addr_t align_mask = INITRAMFS_MAX_ALIGN - 1;
431 for (ml = amap; ml->type != SMT_END; ml = ml->next) {
432 addr_t adj_start = (ml->start + align_mask) & ~align_mask;
433 addr_t adj_end = ml->next->start & ~align_mask;
434 if (ml->type == SMT_FREE && adj_end - adj_start >= irf_size)
435 best_addr = (adj_end - irf_size) & ~align_mask;
439 goto bail; /* Insufficient memory for initramfs */
441 whdr->ramdisk_image = best_addr;
442 whdr->ramdisk_size = irf_size;
444 if (syslinux_add_memmap(&amap, best_addr, irf_size, SMT_ALLOC))
447 if (map_initramfs(&fraglist, &mmap, initramfs, best_addr))
452 /* Set up the registers on entry */
453 memset(®s, 0, sizeof regs);
454 regs.es = regs.ds = regs.ss = regs.fs = regs.gs = real_mode_base >> 4;
455 regs.cs = (real_mode_base >> 4) + 0x20;
457 /* Linux is OK with sp = 0 = 64K, but perhaps other things aren't... */
458 regs.esp.w[0] = min(cmdline_offset, (size_t) 0xfff0);
460 dprintf("Final memory map:\n");
461 syslinux_dump_memmap(mmap);
463 dprintf("Final available map:\n");
464 syslinux_dump_memmap(amap);
466 dprintf("Initial movelist:\n");
467 syslinux_dump_movelist(fraglist);
469 syslinux_shuffle_boot_rm(fraglist, mmap, 0, ®s);
472 syslinux_free_movelist(fraglist);
473 syslinux_free_memmap(mmap);
474 syslinux_free_memmap(amap);