提交 642a4f96 编写于 作者: T ths

Linux loader rewrite, by H. Peter Anvin.


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2835 c046a42c-6fe2-441c-8c8c-71466251a162
上级 57fa1fb3
...@@ -31,10 +31,6 @@ ...@@ -31,10 +31,6 @@
#define VGABIOS_CIRRUS_FILENAME "vgabios-cirrus.bin" #define VGABIOS_CIRRUS_FILENAME "vgabios-cirrus.bin"
#define LINUX_BOOT_FILENAME "linux_boot.bin" #define LINUX_BOOT_FILENAME "linux_boot.bin"
#define KERNEL_LOAD_ADDR 0x00100000
#define MAX_INITRD_LOAD_ADDR 0x38000000
#define KERNEL_PARAMS_ADDR 0x00090000
#define KERNEL_CMDLINE_ADDR 0x00099000
/* Leave a chunk of memory at the top of RAM for the BIOS ACPI tables. */ /* Leave a chunk of memory at the top of RAM for the BIOS ACPI tables. */
#define ACPI_DATA_SIZE 0x10000 #define ACPI_DATA_SIZE 0x10000
...@@ -350,6 +346,61 @@ void bochs_bios_init(void) ...@@ -350,6 +346,61 @@ void bochs_bios_init(void)
register_ioport_write(0x503, 1, 1, bochs_bios_write, NULL); register_ioport_write(0x503, 1, 1, bochs_bios_write, NULL);
} }
/* Generate an initial boot sector which sets state and jump to
a specified vector */
static int generate_bootsect(uint32_t gpr[8], uint16_t segs[6], uint16_t ip)
{
uint8_t bootsect[512], *p;
int i;
if (bs_table[0] == NULL) {
fprintf(stderr, "A disk image must be given for 'hda' when booting "
"a Linux kernel\n");
exit(1);
}
memset(bootsect, 0, sizeof(bootsect));
/* Copy the MSDOS partition table if possible */
bdrv_read(bs_table[0], 0, bootsect, 1);
/* Make sure we have a partition signature */
bootsect[510] = 0x55;
bootsect[511] = 0xaa;
/* Actual code */
p = bootsect;
*p++ = 0xfa; /* CLI */
*p++ = 0xfc; /* CLD */
for (i = 0; i < 6; i++) {
if (i == 1) /* Skip CS */
continue;
*p++ = 0xb8; /* MOV AX,imm16 */
*p++ = segs[i];
*p++ = segs[i] >> 8;
*p++ = 0x8e; /* MOV <seg>,AX */
*p++ = 0xc0 + (i << 3);
}
for (i = 0; i < 8; i++) {
*p++ = 0x66; /* 32-bit operand size */
*p++ = 0xb8 + i; /* MOV <reg>,imm32 */
*p++ = gpr[i];
*p++ = gpr[i] >> 8;
*p++ = gpr[i] >> 16;
*p++ = gpr[i] >> 24;
}
*p++ = 0xea; /* JMP FAR */
*p++ = ip; /* IP */
*p++ = ip >> 8;
*p++ = segs[1]; /* CS */
*p++ = segs[1] >> 8;
bdrv_set_boot_sector(bs_table[0], bootsect, sizeof(bootsect));
}
int load_kernel(const char *filename, uint8_t *addr, int load_kernel(const char *filename, uint8_t *addr,
uint8_t *real_addr) uint8_t *real_addr)
...@@ -370,7 +421,7 @@ int load_kernel(const char *filename, uint8_t *addr, ...@@ -370,7 +421,7 @@ int load_kernel(const char *filename, uint8_t *addr,
if (read(fd, real_addr + 512, setup_sects * 512) != if (read(fd, real_addr + 512, setup_sects * 512) !=
setup_sects * 512) setup_sects * 512)
goto fail; goto fail;
/* load 32 bit code */ /* load 32 bit code */
size = read(fd, addr, 16 * 1024 * 1024); size = read(fd, addr, 16 * 1024 * 1024);
if (size < 0) if (size < 0)
...@@ -382,6 +433,169 @@ int load_kernel(const char *filename, uint8_t *addr, ...@@ -382,6 +433,169 @@ int load_kernel(const char *filename, uint8_t *addr,
return -1; return -1;
} }
static long get_file_size(FILE *f)
{
long where, size;
/* XXX: on Unix systems, using fstat() probably makes more sense */
where = ftell(f);
fseek(f, 0, SEEK_END);
size = ftell(f);
fseek(f, where, SEEK_SET);
return size;
}
static void load_linux(const char *kernel_filename,
const char *initrd_filename,
const char *kernel_cmdline)
{
uint16_t protocol;
uint32_t gpr[8];
uint16_t seg[6];
uint16_t real_seg;
int setup_size, kernel_size, initrd_size, cmdline_size;
uint32_t initrd_max;
uint8_t header[1024];
uint8_t *real_addr, *prot_addr, *cmdline_addr, *initrd_addr;
FILE *f, *fi;
/* Align to 16 bytes as a paranoia measure */
cmdline_size = (strlen(kernel_cmdline)+16) & ~15;
/* load the kernel header */
f = fopen(kernel_filename, "rb");
if (!f || !(kernel_size = get_file_size(f)) ||
fread(header, 1, 1024, f) != 1024) {
fprintf(stderr, "qemu: could not load kernel '%s'\n",
kernel_filename);
exit(1);
}
/* kernel protocol version */
fprintf(stderr, "header magic: %#x\n", ldl_p(header+0x202));
if (ldl_p(header+0x202) == 0x53726448)
protocol = lduw_p(header+0x206);
else
protocol = 0;
if (protocol < 0x200 || !(header[0x211] & 0x01)) {
/* Low kernel */
real_addr = phys_ram_base + 0x90000;
cmdline_addr = phys_ram_base + 0x9a000 - cmdline_size;
prot_addr = phys_ram_base + 0x10000;
} else if (protocol < 0x202) {
/* High but ancient kernel */
real_addr = phys_ram_base + 0x90000;
cmdline_addr = phys_ram_base + 0x9a000 - cmdline_size;
prot_addr = phys_ram_base + 0x100000;
} else {
/* High and recent kernel */
real_addr = phys_ram_base + 0x10000;
cmdline_addr = phys_ram_base + 0x20000;
prot_addr = phys_ram_base + 0x100000;
}
fprintf(stderr,
"qemu: real_addr = %#zx\n"
"qemu: cmdline_addr = %#zx\n"
"qemu: prot_addr = %#zx\n",
real_addr-phys_ram_base,
cmdline_addr-phys_ram_base,
prot_addr-phys_ram_base);
/* highest address for loading the initrd */
if (protocol >= 0x203)
initrd_max = ldl_p(header+0x22c);
else
initrd_max = 0x37ffffff;
if (initrd_max >= ram_size-ACPI_DATA_SIZE)
initrd_max = ram_size-ACPI_DATA_SIZE-1;
/* kernel command line */
pstrcpy(cmdline_addr, 4096, kernel_cmdline);
if (protocol >= 0x202) {
stl_p(header+0x228, cmdline_addr-phys_ram_base);
} else {
stw_p(header+0x20, 0xA33F);
stw_p(header+0x22, cmdline_addr-real_addr);
}
/* loader type */
/* High nybble = B reserved for Qemu; low nybble is revision number.
If this code is substantially changed, you may want to consider
incrementing the revision. */
if (protocol >= 0x200)
header[0x210] = 0xB0;
/* heap */
if (protocol >= 0x201) {
header[0x211] |= 0x80; /* CAN_USE_HEAP */
stw_p(header+0x224, cmdline_addr-real_addr-0x200);
}
/* load initrd */
if (initrd_filename) {
if (protocol < 0x200) {
fprintf(stderr, "qemu: linux kernel too old to load a ram disk\n");
exit(1);
}
fi = fopen(initrd_filename, "rb");
if (!fi) {
fprintf(stderr, "qemu: could not load initial ram disk '%s'\n",
initrd_filename);
exit(1);
}
initrd_size = get_file_size(fi);
initrd_addr = phys_ram_base + ((initrd_max-initrd_size) & ~4095);
fprintf(stderr, "qemu: loading initrd (%#x bytes) at %#zx\n",
initrd_size, initrd_addr-phys_ram_base);
if (fread(initrd_addr, 1, initrd_size, fi) != initrd_size) {
fprintf(stderr, "qemu: read error on initial ram disk '%s'\n",
initrd_filename);
exit(1);
}
fclose(fi);
stl_p(header+0x218, initrd_addr-phys_ram_base);
stl_p(header+0x21c, initrd_size);
}
/* store the finalized header and load the rest of the kernel */
memcpy(real_addr, header, 1024);
setup_size = header[0x1f1];
if (setup_size == 0)
setup_size = 4;
setup_size = (setup_size+1)*512;
kernel_size -= setup_size; /* Size of protected-mode code */
if (fread(real_addr+1024, 1, setup_size-1024, f) != setup_size-1024 ||
fread(prot_addr, 1, kernel_size, f) != kernel_size) {
fprintf(stderr, "qemu: read error on kernel '%s'\n",
kernel_filename);
exit(1);
}
fclose(f);
/* generate bootsector to set up the initial register state */
real_seg = (real_addr-phys_ram_base) >> 4;
seg[0] = seg[2] = seg[3] = seg[4] = seg[4] = real_seg;
seg[1] = real_seg+0x20; /* CS */
memset(gpr, 0, sizeof gpr);
gpr[4] = cmdline_addr-real_addr-16; /* SP (-16 is paranoia) */
generate_bootsect(gpr, seg, 0);
}
static void main_cpu_reset(void *opaque) static void main_cpu_reset(void *opaque)
{ {
CPUState *env = opaque; CPUState *env = opaque;
...@@ -453,9 +667,8 @@ static void pc_init1(int ram_size, int vga_ram_size, int boot_device, ...@@ -453,9 +667,8 @@ static void pc_init1(int ram_size, int vga_ram_size, int boot_device,
int pci_enabled) int pci_enabled)
{ {
char buf[1024]; char buf[1024];
int ret, linux_boot, initrd_size, i; int ret, linux_boot, i;
ram_addr_t ram_addr, vga_ram_addr, bios_offset, vga_bios_offset; ram_addr_t ram_addr, vga_ram_addr, bios_offset, vga_bios_offset;
ram_addr_t initrd_offset;
int bios_size, isa_bios_size, vga_bios_size; int bios_size, isa_bios_size, vga_bios_size;
PCIBus *pci_bus; PCIBus *pci_bus;
int piix3_devfn = -1; int piix3_devfn = -1;
...@@ -570,81 +783,8 @@ static void pc_init1(int ram_size, int vga_ram_size, int boot_device, ...@@ -570,81 +783,8 @@ static void pc_init1(int ram_size, int vga_ram_size, int boot_device,
bochs_bios_init(); bochs_bios_init();
if (linux_boot) { if (linux_boot)
uint8_t bootsect[512]; load_linux(kernel_filename, initrd_filename, kernel_cmdline);
uint8_t old_bootsect[512];
if (bs_table[0] == NULL) {
fprintf(stderr, "A disk image must be given for 'hda' when booting a Linux kernel\n");
exit(1);
}
snprintf(buf, sizeof(buf), "%s/%s", bios_dir, LINUX_BOOT_FILENAME);
ret = load_image(buf, bootsect);
if (ret != sizeof(bootsect)) {
fprintf(stderr, "qemu: could not load linux boot sector '%s'\n",
buf);
exit(1);
}
if (bdrv_read(bs_table[0], 0, old_bootsect, 1) >= 0) {
/* copy the MSDOS partition table */
memcpy(bootsect + 0x1be, old_bootsect + 0x1be, 0x40);
}
bdrv_set_boot_sector(bs_table[0], bootsect, sizeof(bootsect));
/* now we can load the kernel */
ret = load_kernel(kernel_filename,
phys_ram_base + KERNEL_LOAD_ADDR,
phys_ram_base + KERNEL_PARAMS_ADDR);
if (ret < 0) {
fprintf(stderr, "qemu: could not load kernel '%s'\n",
kernel_filename);
exit(1);
}
/* load initrd */
initrd_size = 0;
initrd_offset = 0;
if (initrd_filename) {
initrd_size = get_image_size (initrd_filename);
if (initrd_size > 0) {
initrd_offset = (ram_size - initrd_size) & TARGET_PAGE_MASK;
/* Leave space for BIOS ACPI tables. */
initrd_offset -= ACPI_DATA_SIZE;
/* Avoid the last 64k to avoid 2.2.x kernel bugs. */
initrd_offset -= 0x10000;
if (initrd_offset > MAX_INITRD_LOAD_ADDR)
initrd_offset = MAX_INITRD_LOAD_ADDR;
if (initrd_size > ram_size
|| initrd_offset < KERNEL_LOAD_ADDR + ret) {
fprintf(stderr,
"qemu: memory too small for initial ram disk '%s'\n",
initrd_filename);
exit(1);
}
initrd_size = load_image(initrd_filename,
phys_ram_base + initrd_offset);
}
if (initrd_size < 0) {
fprintf(stderr, "qemu: could not load initial ram disk '%s'\n",
initrd_filename);
exit(1);
}
}
if (initrd_size > 0) {
stl_raw(phys_ram_base + KERNEL_PARAMS_ADDR + 0x218, initrd_offset);
stl_raw(phys_ram_base + KERNEL_PARAMS_ADDR + 0x21c, initrd_size);
}
pstrcpy(phys_ram_base + KERNEL_CMDLINE_ADDR, 4096,
kernel_cmdline);
stw_raw(phys_ram_base + KERNEL_PARAMS_ADDR + 0x20, 0xA33F);
stw_raw(phys_ram_base + KERNEL_PARAMS_ADDR + 0x22,
KERNEL_CMDLINE_ADDR - KERNEL_PARAMS_ADDR);
/* loader type */
stw_raw(phys_ram_base + KERNEL_PARAMS_ADDR + 0x210, 0x01);
}
cpu_irq = qemu_allocate_irqs(pic_irq_request, first_cpu, 1); cpu_irq = qemu_allocate_irqs(pic_irq_request, first_cpu, 1);
i8259 = i8259_init(cpu_irq[0]); i8259 = i8259_init(cpu_irq[0]);
......
...@@ -6,16 +6,9 @@ include ../config-host.mak ...@@ -6,16 +6,9 @@ include ../config-host.mak
DEFINES= DEFINES=
TARGETS= TARGETS=
ifeq ($(ARCH),i386)
TARGETS+=linux_boot.bin
endif
all: $(TARGETS) all: $(TARGETS)
linux_boot.bin: linux_boot.o
ld --oformat binary -Ttext 0 -o $@ $<
chmod a-x $@
%.o: %.S %.o: %.S
$(CC) $(DEFINES) -c -o $@ $< $(CC) $(DEFINES) -c -o $@ $<
......
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