diff options
Diffstat (limited to 'Documentation/lguest')
| -rw-r--r-- | Documentation/lguest/lguest.c | 47 |
1 files changed, 22 insertions, 25 deletions
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 3949620..5bdc37f 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -52,7 +52,7 @@ typedef uint8_t u8; #include "linux/virtio_blk.h" #include "linux/virtio_console.h" #include "linux/virtio_ring.h" -#include "asm-x86/e820.h" +#include "asm-x86/bootparam.h" /*:*/ #define PAGE_PRESENT 0x7 /* Present, RW, Execute */ @@ -335,7 +335,7 @@ static unsigned long map_elf(int elf_fd, const Elf32_Ehdr *ehdr) * the funky header so we know where in the file to load, and away we go! */ static unsigned long load_bzimage(int fd) { - u8 hdr[1024]; + struct boot_params boot; int r; /* Modern bzImages get loaded at 1M. */ void *p = from_guest_phys(0x100000); @@ -343,22 +343,21 @@ static unsigned long load_bzimage(int fd) /* Go back to the start of the file and read the header. It should be * a Linux boot header (see Documentation/i386/boot.txt) */ lseek(fd, 0, SEEK_SET); - read(fd, hdr, sizeof(hdr)); + read(fd, &boot, sizeof(boot)); - /* At offset 0x202, we expect the magic "HdrS" */ - if (memcmp(hdr + 0x202, "HdrS", 4) != 0) + /* Inside the setup_hdr, we expect the magic "HdrS" */ + if (memcmp(&boot.hdr.header, "HdrS", 4) != 0) errx(1, "This doesn't look like a bzImage to me"); - /* The byte at 0x1F1 tells us how many extra sectors of - * header: skip over them all. */ - lseek(fd, (unsigned long)(hdr[0x1F1]+1) * 512, SEEK_SET); + /* Skip over the extra sectors of the header. */ + lseek(fd, (boot.hdr.setup_sects+1) * 512, SEEK_SET); /* Now read everything into memory. in nice big chunks. */ while ((r = read(fd, p, 65536)) > 0) p += r; - /* Finally, 0x214 tells us where to start the kernel. */ - return *(unsigned long *)&hdr[0x214]; + /* Finally, code32_start tells us where to enter the kernel. */ + return boot.hdr.code32_start; } /*L:140 Loading the kernel is easy when it's a "vmlinux", but most kernels @@ -1531,7 +1530,7 @@ int main(int argc, char *argv[]) /* A temporary and the /dev/lguest file descriptor. */ int i, c, lguest_fd; /* The boot information for the Guest. */ - void *boot; + struct boot_params *boot; /* If they specify an initrd file to load. */ const char *initrd_name = NULL; @@ -1607,10 +1606,10 @@ int main(int argc, char *argv[]) initrd_size = load_initrd(initrd_name, mem); /* These are the location in the Linux boot header where the * start and size of the initrd are expected to be found. */ - *(unsigned long *)(boot+0x218) = mem - initrd_size; - *(unsigned long *)(boot+0x21c) = initrd_size; + boot->hdr.ramdisk_image = mem - initrd_size; + boot->hdr.ramdisk_size = initrd_size; /* The bootloader type 0xFF means "unknown"; that's OK. */ - *(unsigned char *)(boot+0x210) = 0xFF; + boot->hdr.type_of_loader = 0xFF; } /* Set up the initial linear pagetables, starting below the initrd. */ @@ -1618,23 +1617,21 @@ int main(int argc, char *argv[]) /* The Linux boot header contains an "E820" memory map: ours is a * simple, single region. */ - *(char*)(boot+E820NR) = 1; - *((struct e820entry *)(boot+E820MAP)) - = ((struct e820entry) { 0, mem, E820_RAM }); + boot->e820_entries = 1; + boot->e820_map[0] = ((struct e820entry) { 0, mem, E820_RAM }); /* The boot header contains a command line pointer: we put the command - * line after the boot header (at address 4096) */ - *(u32 *)(boot + 0x228) = 4096; - concat(boot + 4096, argv+optind+2); + * line after the boot header. */ + boot->hdr.cmd_line_ptr = to_guest_phys(boot + 1); + concat((char *)(boot + 1), argv+optind+2); /* Boot protocol version: 2.07 supports the fields for lguest. */ - *(u16 *)(boot + 0x206) = 0x207; + boot->hdr.version = 0x207; /* The hardware_subarch value of "1" tells the Guest it's an lguest. */ - *(u32 *)(boot + 0x23c) = 1; + boot->hdr.hardware_subarch = 1; - /* Set bit 6 of the loadflags (aka. KEEP_SEGMENTS) so the entry path - * does not try to reload segment registers. */ - *(u8 *)(boot + 0x211) |= (1 << 6); + /* Tell the entry path not to try to reload segment registers. */ + boot->hdr.loadflags |= KEEP_SEGMENTS; /* We tell the kernel to initialize the Guest: this returns the open * /dev/lguest file descriptor. */ |
