mirror of
https://github.com/xemu-project/xemu.git
synced 2024-11-27 05:20:50 +00:00
Linux loader rewrite, by H. Peter Anvin.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2835 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
ths
parent
57fa1fb31c
commit
642a4f967f
304
hw/pc.c
304
hw/pc.c
@ -31,10 +31,6 @@
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#define VGABIOS_CIRRUS_FILENAME "vgabios-cirrus.bin"
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#define LINUX_BOOT_FILENAME "linux_boot.bin"
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#define KERNEL_LOAD_ADDR 0x00100000
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#define MAX_INITRD_LOAD_ADDR 0x38000000
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#define KERNEL_PARAMS_ADDR 0x00090000
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#define KERNEL_CMDLINE_ADDR 0x00099000
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/* Leave a chunk of memory at the top of RAM for the BIOS ACPI tables. */
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#define ACPI_DATA_SIZE 0x10000
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@ -350,6 +346,61 @@ void bochs_bios_init(void)
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register_ioport_write(0x503, 1, 1, bochs_bios_write, NULL);
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}
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/* Generate an initial boot sector which sets state and jump to
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a specified vector */
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static int generate_bootsect(uint32_t gpr[8], uint16_t segs[6], uint16_t ip)
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{
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uint8_t bootsect[512], *p;
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int i;
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if (bs_table[0] == NULL) {
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fprintf(stderr, "A disk image must be given for 'hda' when booting "
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"a Linux kernel\n");
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exit(1);
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}
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memset(bootsect, 0, sizeof(bootsect));
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/* Copy the MSDOS partition table if possible */
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bdrv_read(bs_table[0], 0, bootsect, 1);
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/* Make sure we have a partition signature */
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bootsect[510] = 0x55;
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bootsect[511] = 0xaa;
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/* Actual code */
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p = bootsect;
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*p++ = 0xfa; /* CLI */
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*p++ = 0xfc; /* CLD */
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for (i = 0; i < 6; i++) {
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if (i == 1) /* Skip CS */
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continue;
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*p++ = 0xb8; /* MOV AX,imm16 */
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*p++ = segs[i];
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*p++ = segs[i] >> 8;
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*p++ = 0x8e; /* MOV <seg>,AX */
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*p++ = 0xc0 + (i << 3);
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}
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for (i = 0; i < 8; i++) {
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*p++ = 0x66; /* 32-bit operand size */
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*p++ = 0xb8 + i; /* MOV <reg>,imm32 */
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*p++ = gpr[i];
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*p++ = gpr[i] >> 8;
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*p++ = gpr[i] >> 16;
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*p++ = gpr[i] >> 24;
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}
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*p++ = 0xea; /* JMP FAR */
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*p++ = ip; /* IP */
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*p++ = ip >> 8;
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*p++ = segs[1]; /* CS */
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*p++ = segs[1] >> 8;
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bdrv_set_boot_sector(bs_table[0], bootsect, sizeof(bootsect));
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}
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int load_kernel(const char *filename, uint8_t *addr,
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uint8_t *real_addr)
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@ -370,7 +421,7 @@ int load_kernel(const char *filename, uint8_t *addr,
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if (read(fd, real_addr + 512, setup_sects * 512) !=
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setup_sects * 512)
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goto fail;
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/* load 32 bit code */
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size = read(fd, addr, 16 * 1024 * 1024);
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if (size < 0)
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@ -382,6 +433,169 @@ int load_kernel(const char *filename, uint8_t *addr,
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return -1;
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}
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static long get_file_size(FILE *f)
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{
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long where, size;
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/* XXX: on Unix systems, using fstat() probably makes more sense */
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where = ftell(f);
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fseek(f, 0, SEEK_END);
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size = ftell(f);
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fseek(f, where, SEEK_SET);
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return size;
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}
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static void load_linux(const char *kernel_filename,
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const char *initrd_filename,
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const char *kernel_cmdline)
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{
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uint16_t protocol;
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uint32_t gpr[8];
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uint16_t seg[6];
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uint16_t real_seg;
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int setup_size, kernel_size, initrd_size, cmdline_size;
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uint32_t initrd_max;
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uint8_t header[1024];
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uint8_t *real_addr, *prot_addr, *cmdline_addr, *initrd_addr;
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FILE *f, *fi;
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/* Align to 16 bytes as a paranoia measure */
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cmdline_size = (strlen(kernel_cmdline)+16) & ~15;
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/* load the kernel header */
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f = fopen(kernel_filename, "rb");
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if (!f || !(kernel_size = get_file_size(f)) ||
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fread(header, 1, 1024, f) != 1024) {
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fprintf(stderr, "qemu: could not load kernel '%s'\n",
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kernel_filename);
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exit(1);
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}
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/* kernel protocol version */
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fprintf(stderr, "header magic: %#x\n", ldl_p(header+0x202));
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if (ldl_p(header+0x202) == 0x53726448)
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protocol = lduw_p(header+0x206);
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else
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protocol = 0;
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if (protocol < 0x200 || !(header[0x211] & 0x01)) {
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/* Low kernel */
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real_addr = phys_ram_base + 0x90000;
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cmdline_addr = phys_ram_base + 0x9a000 - cmdline_size;
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prot_addr = phys_ram_base + 0x10000;
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} else if (protocol < 0x202) {
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/* High but ancient kernel */
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real_addr = phys_ram_base + 0x90000;
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cmdline_addr = phys_ram_base + 0x9a000 - cmdline_size;
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prot_addr = phys_ram_base + 0x100000;
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} else {
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/* High and recent kernel */
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real_addr = phys_ram_base + 0x10000;
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cmdline_addr = phys_ram_base + 0x20000;
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prot_addr = phys_ram_base + 0x100000;
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}
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fprintf(stderr,
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"qemu: real_addr = %#zx\n"
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"qemu: cmdline_addr = %#zx\n"
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"qemu: prot_addr = %#zx\n",
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real_addr-phys_ram_base,
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cmdline_addr-phys_ram_base,
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prot_addr-phys_ram_base);
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/* highest address for loading the initrd */
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if (protocol >= 0x203)
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initrd_max = ldl_p(header+0x22c);
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else
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initrd_max = 0x37ffffff;
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if (initrd_max >= ram_size-ACPI_DATA_SIZE)
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initrd_max = ram_size-ACPI_DATA_SIZE-1;
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/* kernel command line */
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pstrcpy(cmdline_addr, 4096, kernel_cmdline);
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if (protocol >= 0x202) {
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stl_p(header+0x228, cmdline_addr-phys_ram_base);
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} else {
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stw_p(header+0x20, 0xA33F);
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stw_p(header+0x22, cmdline_addr-real_addr);
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}
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/* loader type */
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/* High nybble = B reserved for Qemu; low nybble is revision number.
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If this code is substantially changed, you may want to consider
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incrementing the revision. */
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if (protocol >= 0x200)
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header[0x210] = 0xB0;
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/* heap */
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if (protocol >= 0x201) {
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header[0x211] |= 0x80; /* CAN_USE_HEAP */
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stw_p(header+0x224, cmdline_addr-real_addr-0x200);
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}
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/* load initrd */
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if (initrd_filename) {
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if (protocol < 0x200) {
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fprintf(stderr, "qemu: linux kernel too old to load a ram disk\n");
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exit(1);
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}
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fi = fopen(initrd_filename, "rb");
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if (!fi) {
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fprintf(stderr, "qemu: could not load initial ram disk '%s'\n",
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initrd_filename);
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exit(1);
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}
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initrd_size = get_file_size(fi);
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initrd_addr = phys_ram_base + ((initrd_max-initrd_size) & ~4095);
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fprintf(stderr, "qemu: loading initrd (%#x bytes) at %#zx\n",
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initrd_size, initrd_addr-phys_ram_base);
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if (fread(initrd_addr, 1, initrd_size, fi) != initrd_size) {
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fprintf(stderr, "qemu: read error on initial ram disk '%s'\n",
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initrd_filename);
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exit(1);
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}
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fclose(fi);
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stl_p(header+0x218, initrd_addr-phys_ram_base);
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stl_p(header+0x21c, initrd_size);
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}
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/* store the finalized header and load the rest of the kernel */
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memcpy(real_addr, header, 1024);
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setup_size = header[0x1f1];
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if (setup_size == 0)
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setup_size = 4;
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setup_size = (setup_size+1)*512;
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kernel_size -= setup_size; /* Size of protected-mode code */
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if (fread(real_addr+1024, 1, setup_size-1024, f) != setup_size-1024 ||
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fread(prot_addr, 1, kernel_size, f) != kernel_size) {
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fprintf(stderr, "qemu: read error on kernel '%s'\n",
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kernel_filename);
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exit(1);
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}
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fclose(f);
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/* generate bootsector to set up the initial register state */
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real_seg = (real_addr-phys_ram_base) >> 4;
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seg[0] = seg[2] = seg[3] = seg[4] = seg[4] = real_seg;
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seg[1] = real_seg+0x20; /* CS */
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memset(gpr, 0, sizeof gpr);
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gpr[4] = cmdline_addr-real_addr-16; /* SP (-16 is paranoia) */
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generate_bootsect(gpr, seg, 0);
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}
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static void main_cpu_reset(void *opaque)
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{
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CPUState *env = opaque;
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@ -453,9 +667,8 @@ static void pc_init1(int ram_size, int vga_ram_size, int boot_device,
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int pci_enabled)
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{
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char buf[1024];
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int ret, linux_boot, initrd_size, i;
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int ret, linux_boot, i;
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ram_addr_t ram_addr, vga_ram_addr, bios_offset, vga_bios_offset;
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ram_addr_t initrd_offset;
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int bios_size, isa_bios_size, vga_bios_size;
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PCIBus *pci_bus;
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int piix3_devfn = -1;
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@ -570,81 +783,8 @@ static void pc_init1(int ram_size, int vga_ram_size, int boot_device,
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bochs_bios_init();
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if (linux_boot) {
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uint8_t bootsect[512];
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uint8_t old_bootsect[512];
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if (bs_table[0] == NULL) {
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fprintf(stderr, "A disk image must be given for 'hda' when booting a Linux kernel\n");
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exit(1);
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}
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snprintf(buf, sizeof(buf), "%s/%s", bios_dir, LINUX_BOOT_FILENAME);
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ret = load_image(buf, bootsect);
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if (ret != sizeof(bootsect)) {
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fprintf(stderr, "qemu: could not load linux boot sector '%s'\n",
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buf);
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exit(1);
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}
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if (bdrv_read(bs_table[0], 0, old_bootsect, 1) >= 0) {
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/* copy the MSDOS partition table */
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memcpy(bootsect + 0x1be, old_bootsect + 0x1be, 0x40);
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}
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bdrv_set_boot_sector(bs_table[0], bootsect, sizeof(bootsect));
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/* now we can load the kernel */
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ret = load_kernel(kernel_filename,
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phys_ram_base + KERNEL_LOAD_ADDR,
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phys_ram_base + KERNEL_PARAMS_ADDR);
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if (ret < 0) {
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fprintf(stderr, "qemu: could not load kernel '%s'\n",
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kernel_filename);
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exit(1);
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}
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/* load initrd */
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initrd_size = 0;
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initrd_offset = 0;
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if (initrd_filename) {
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initrd_size = get_image_size (initrd_filename);
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if (initrd_size > 0) {
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initrd_offset = (ram_size - initrd_size) & TARGET_PAGE_MASK;
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/* Leave space for BIOS ACPI tables. */
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initrd_offset -= ACPI_DATA_SIZE;
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/* Avoid the last 64k to avoid 2.2.x kernel bugs. */
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initrd_offset -= 0x10000;
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if (initrd_offset > MAX_INITRD_LOAD_ADDR)
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initrd_offset = MAX_INITRD_LOAD_ADDR;
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if (initrd_size > ram_size
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|| initrd_offset < KERNEL_LOAD_ADDR + ret) {
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fprintf(stderr,
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"qemu: memory too small for initial ram disk '%s'\n",
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initrd_filename);
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exit(1);
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}
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initrd_size = load_image(initrd_filename,
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phys_ram_base + initrd_offset);
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}
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if (initrd_size < 0) {
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fprintf(stderr, "qemu: could not load initial ram disk '%s'\n",
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initrd_filename);
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exit(1);
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}
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}
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if (initrd_size > 0) {
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stl_raw(phys_ram_base + KERNEL_PARAMS_ADDR + 0x218, initrd_offset);
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stl_raw(phys_ram_base + KERNEL_PARAMS_ADDR + 0x21c, initrd_size);
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}
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pstrcpy(phys_ram_base + KERNEL_CMDLINE_ADDR, 4096,
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kernel_cmdline);
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stw_raw(phys_ram_base + KERNEL_PARAMS_ADDR + 0x20, 0xA33F);
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stw_raw(phys_ram_base + KERNEL_PARAMS_ADDR + 0x22,
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KERNEL_CMDLINE_ADDR - KERNEL_PARAMS_ADDR);
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/* loader type */
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stw_raw(phys_ram_base + KERNEL_PARAMS_ADDR + 0x210, 0x01);
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}
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if (linux_boot)
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load_linux(kernel_filename, initrd_filename, kernel_cmdline);
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cpu_irq = qemu_allocate_irqs(pic_irq_request, first_cpu, 1);
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i8259 = i8259_init(cpu_irq[0]);
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@ -6,16 +6,9 @@ include ../config-host.mak
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DEFINES=
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TARGETS=
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ifeq ($(ARCH),i386)
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TARGETS+=linux_boot.bin
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endif
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all: $(TARGETS)
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linux_boot.bin: linux_boot.o
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ld --oformat binary -Ttext 0 -o $@ $<
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chmod a-x $@
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%.o: %.S
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$(CC) $(DEFINES) -c -o $@ $<
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