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ipxe/src/arch/i386/core/multiboot_loader.c

144 lines
4.0 KiB
C

/* Multiboot support
*
* 2003-07-02 mmap fix and header probe by SONE Takeshi
*/
struct multiboot_mods {
unsigned mod_start;
unsigned mod_end;
unsigned char *string;
unsigned reserved;
};
struct multiboot_mmap {
unsigned int size;
unsigned int base_addr_low;
unsigned int base_addr_high;
unsigned int length_low;
unsigned int length_high;
unsigned int type;
};
/* The structure of a Multiboot 0.6 parameter block. */
struct multiboot_info {
unsigned int flags;
#define MULTIBOOT_MEM_VALID 0x01
#define MULTIBOOT_BOOT_DEV_VALID 0x02
#define MULTIBOOT_CMDLINE_VALID 0x04
#define MULTIBOOT_MODS_VALID 0x08
#define MULTIBOOT_AOUT_SYMS_VALID 0x10
#define MULTIBOOT_ELF_SYMS_VALID 0x20
#define MULTIBOOT_MMAP_VALID 0x40
unsigned int memlower;
unsigned int memupper;
unsigned int bootdev;
unsigned int cmdline; /* physical address of the command line */
unsigned mods_count;
struct multiboot_mods *mods_addr;
unsigned syms_num;
unsigned syms_size;
unsigned syms_addr;
unsigned syms_shndx;
unsigned mmap_length;
unsigned mmap_addr;
/* The structure actually ends here, so I might as well put
* the ugly e820 parameters here...
*/
struct multiboot_mmap mmap[E820MAX];
};
/* Multiboot image header (minimal part) */
struct multiboot_header {
unsigned int magic;
#define MULTIBOOT_HEADER_MAGIC 0x1BADB002
unsigned int flags;
unsigned int checksum;
};
static struct multiboot_header *mbheader;
static struct multiboot_info mbinfo;
static void multiboot_probe(unsigned char *data, int len)
{
int offset;
struct multiboot_header *h;
/* Multiboot spec requires the header to be in first 8KB of the image */
if (len > 8192)
len = 8192;
for (offset = 0; offset < len; offset += 4) {
h = (struct multiboot_header *) (data + offset);
if (h->magic == MULTIBOOT_HEADER_MAGIC
&& h->magic + h->flags + h->checksum == 0) {
printf("/Multiboot");
mbheader = h;
return;
}
}
mbheader = 0;
}
static inline void multiboot_boot(unsigned long entry)
{
unsigned char cmdline[512], *c;
int i;
if (!mbheader)
return;
/* Etherboot limits the command line to the kernel name,
* default parameters and user prompted parameters. All of
* them are shorter than 256 bytes. As the kernel name and
* the default parameters come from the same BOOTP/DHCP entry
* (or if they don't, the parameters are empty), only two
* strings of the maximum size are possible. Note this buffer
* can overrun if a stupid file name is chosen. Oh well. */
c = cmdline;
for (i = 0; KERNEL_BUF[i] != 0; i++) {
switch (KERNEL_BUF[i]) {
case ' ':
case '\\':
case '"':
*c++ = '\\';
break;
default:
break;
}
*c++ = KERNEL_BUF[i];
}
(void)sprintf(c, " -retaddr %#lX", virt_to_phys(xend32));
mbinfo.flags = MULTIBOOT_MMAP_VALID | MULTIBOOT_MEM_VALID |MULTIBOOT_CMDLINE_VALID;
mbinfo.memlower = meminfo.basememsize;
mbinfo.memupper = meminfo.memsize;
mbinfo.bootdev = 0; /* not booted from disk */
mbinfo.cmdline = virt_to_phys(cmdline);
for (i = 0; i < (int) meminfo.map_count; i++) {
mbinfo.mmap[i].size = sizeof(struct multiboot_mmap)
- sizeof(unsigned int);
mbinfo.mmap[i].base_addr_low =
(unsigned int) meminfo.map[i].addr;
mbinfo.mmap[i].base_addr_high =
(unsigned int) (meminfo.map[i].addr >> 32);
mbinfo.mmap[i].length_low =
(unsigned int) meminfo.map[i].size;
mbinfo.mmap[i].length_high =
(unsigned int) (meminfo.map[i].size >> 32);
mbinfo.mmap[i].type = meminfo.map[i].type;
}
mbinfo.mmap_length = meminfo.map_count * sizeof(struct multiboot_mmap);
mbinfo.mmap_addr = virt_to_phys(mbinfo.mmap);
/* The Multiboot 0.6 spec requires all segment registers to be
* loaded with an unrestricted, writeable segment.
* xstart32 does this for us.
*/
/* Start the kernel, passing the Multiboot information record
* and the magic number. */
os_regs.eax = 0x2BADB002;
os_regs.ebx = virt_to_phys(&mbinfo);
xstart32(entry);
longjmp(restart_etherboot, -2);
}