diff options
| -rw-r--r-- | fw_cfg.c | 45 | ||||
| -rw-r--r-- | include/bios.h | 2 | ||||
| -rw-r--r-- | linuxboot.c | 146 | ||||
| -rw-r--r-- | main.c | 2 |
4 files changed, 160 insertions, 35 deletions
@@ -1,7 +1,9 @@ #include "bios.h" +#include "stdio.h" #include "ioport.h" #include "string.h" #include "fw_cfg.h" +#include "linuxboot.h" struct fw_cfg_file { uint32_t size; @@ -48,3 +50,46 @@ void fw_cfg_file_select(int id) { fw_cfg_select(files[id].select); } + +void boot_from_fwcfg(void) +{ + struct linuxboot_args args; + uint32_t kernel_size; + + fw_cfg_select(FW_CFG_CMDLINE_SIZE); + args.cmdline_size = fw_cfg_readl_le(); + fw_cfg_select(FW_CFG_INITRD_SIZE); + args.initrd_size = fw_cfg_readl_le(); + + /* QEMU has already split the real mode and protected mode + * parts. Recombine them in args.vmlinuz_size. + */ + fw_cfg_select(FW_CFG_KERNEL_SIZE); + kernel_size = fw_cfg_readl_le(); + fw_cfg_select(FW_CFG_SETUP_SIZE); + args.vmlinuz_size = kernel_size + fw_cfg_readl_le(); + + fw_cfg_select(FW_CFG_SETUP_DATA); + fw_cfg_read(args.header, sizeof(args.header)); + + if (!parse_bzimage(&args)) + return; + + /* SETUP_DATA already selected */ + if (args.setup_size > sizeof(args.header)) + fw_cfg_read(args.setup_addr + sizeof(args.header), + args.setup_size - sizeof(args.header)); + + fw_cfg_select(FW_CFG_KERNEL_DATA); + fw_cfg_read(args.kernel_addr, kernel_size); + + fw_cfg_select(FW_CFG_CMDLINE_DATA); + fw_cfg_read(args.cmdline_addr, args.cmdline_size); + + if (args.initrd_size) { + fw_cfg_select(FW_CFG_INITRD_DATA); + fw_cfg_read(args.initrd_addr, args.initrd_size); + } + + boot_bzimage(&args); +} diff --git a/include/bios.h b/include/bios.h index dfc20af..93c4c96 100644 --- a/include/bios.h +++ b/include/bios.h @@ -36,7 +36,7 @@ extern void bios_irq(void); extern void bios_int10(void); extern void bios_int15(void); -extern void boot_linux(void); +extern void boot_from_fwcfg(void); extern struct e820map e820; diff --git a/linuxboot.c b/linuxboot.c index 51bfba3..fc8b7fa 100644 --- a/linuxboot.c +++ b/linuxboot.c @@ -1,19 +1,119 @@ #include "bios.h" -#include "ioport.h" -#include "fw_cfg.h" +#include "linuxboot.h" +#include "string.h" +#include "stdio.h" -static void *_fw_cfg_read_blob(int faddr, int fsize, int fdata) +static inline uint16_t lduw_p(void *p) { - void *addr; - int length; - - fw_cfg_select(faddr); - addr = (void *)fw_cfg_readl_le(); - fw_cfg_select(fsize); - length = fw_cfg_readl_le(); - fw_cfg_select(fdata); - fw_cfg_read(addr, length); - return addr; + uint16_t val; + memcpy(&val, p, 2); + return val; +} + +static inline uint32_t ldl_p(void *p) +{ + uint32_t val; + memcpy(&val, p, 4); + return val; +} + +static inline void stw_p(void *p, uint16_t val) +{ + memcpy(p, &val, 2); +} + +static inline void stl_p(void *p, uint32_t val) +{ + memcpy(p, &val, 4); +} + +bool parse_bzimage(struct linuxboot_args *args) +{ + uint8_t *header = args->header; + + uint32_t real_addr, cmdline_addr, prot_addr, initrd_addr; + uint32_t setup_size; + uint32_t initrd_max; + uint16_t protocol; + + if (ldl_p(header+0x202) == 0x53726448) + protocol = lduw_p(header+0x206); + else { + // if (parse_multiboot(&args)) return; + protocol = 0; + } + + if (protocol < 0x200 || !(header[0x211] & 0x01)) { + /* Low kernel */ + real_addr = 0x90000; + cmdline_addr = (0x9a000 - args->cmdline_size) & ~15; + prot_addr = 0x10000; + } else if (protocol < 0x202) { + /* High but ancient kernel */ + real_addr = 0x90000; + cmdline_addr = (0x9a000 - args->cmdline_size) & ~15; + prot_addr = 0x100000; + } else { + /* High and recent kernel */ + real_addr = 0x10000; + cmdline_addr = 0x20000; + prot_addr = 0x100000; + } + + if (protocol >= 0x203) + initrd_max = ldl_p(header+0x22c); + else + initrd_max = 0x37ffffff; + + if (protocol >= 0x202) + stl_p(header+0x228, cmdline_addr); + else { + stw_p(header+0x20, 0xA33F); + stw_p(header+0x22, cmdline_addr-real_addr); + } + + /* 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); + } + + if (args->initrd_size) + initrd_addr = (initrd_max - args->initrd_size) & ~4095; + else + initrd_addr = 0; + stl_p(header+0x218, initrd_addr); + stl_p(header+0x21c, args->initrd_size); + + /* load kernel and setup */ + setup_size = header[0x1f1]; + if (setup_size == 0) + setup_size = 4; + + args->setup_size = (setup_size+1)*512; + args->kernel_size = args->vmlinuz_size - setup_size; + args->initrd_addr = (void *)initrd_addr; + args->setup_addr = (void *)real_addr; + args->kernel_addr = (void *)prot_addr; + args->cmdline_addr = (void *)cmdline_addr; + return true; +} + +void boot_bzimage(struct linuxboot_args *args) +{ + memcpy(args->setup_addr, args->header, sizeof(args->header)); + asm volatile( + "ljmp $0x18, $pm16_boot_linux - 0xf0000" + : : + "b" (((uintptr_t) args->setup_addr) >> 4), + "d" (args->cmdline_addr - args->setup_addr - 16)); + panic(); } /* BX = address of data block @@ -35,23 +135,3 @@ asm("pm16_boot_linux:" "xor %ebp, %ebp;" "lret;" ".code32"); - -void boot_linux(void) -{ - void *setup_addr, *cmdline_addr; - -#define fw_cfg_read_blob(f) \ - _fw_cfg_read_blob(f##_ADDR, f##_SIZE, f##_DATA) - - setup_addr = fw_cfg_read_blob(FW_CFG_SETUP); - cmdline_addr = fw_cfg_read_blob(FW_CFG_CMDLINE); - fw_cfg_read_blob(FW_CFG_INITRD); - fw_cfg_read_blob(FW_CFG_KERNEL); - - asm volatile( - "ljmp $0x18, $pm16_boot_linux - 0xf0000" - : : - "b" (((uintptr_t) setup_addr) >> 4), - "d" (cmdline_addr - setup_addr - 16)); - panic(); -} @@ -104,6 +104,6 @@ int main(void) // extract_smbios(); // extract_kernel(); // make_bios_readonly(); - boot_linux(); + boot_from_fwcfg(); panic(); } |