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https://gitlab.com/qemu-project/qboot.git
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8ca302e86d
QEMU places setup_data at a particular location, which cannot be relocated due to it containing self references in absolute address terms. For this reason, it supplies the intended location in FW_CFG_SETUP_ADDR. That is what is used in the option ROMs provided by QEMU, use this too in qboot. This also has the effect of removing the 8k limit on the copied size, since the header is copied to the right location from the beginning. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Message-Id: <20220916133603.693135-1-Jason@zx2c4.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
129 lines
3.2 KiB
C
129 lines
3.2 KiB
C
#include "bios.h"
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#include "linuxboot.h"
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#include "memaccess.h"
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#include "ioport.h"
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#include "start_info.h"
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#include "string.h"
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#include "stdio.h"
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#include "benchmark.h"
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struct hvm_start_info start_info = {0};
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bool parse_bzimage(struct linuxboot_args *args)
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{
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uint8_t *header = args->setup_addr;
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uint32_t real_addr, cmdline_addr, prot_addr, initrd_addr;
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uint32_t setup_size;
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uint32_t initrd_max;
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uint16_t protocol;
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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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/* assume multiboot. TODO: scan for header */
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return false;
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// protocol = 0;
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}
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if (protocol < 0x200 || !(header[0x211] & 0x01)) {
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/* Low kernel */
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real_addr = 0x90000;
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cmdline_addr = (0x9a000 - args->cmdline_size) & ~15;
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prot_addr = 0x10000;
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} else if (protocol < 0x202) {
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/* High but ancient kernel */
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real_addr = 0x90000;
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cmdline_addr = (0x9a000 - args->cmdline_size) & ~15;
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prot_addr = 0x100000;
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} else {
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/* High and recent kernel */
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real_addr = 0x10000;
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cmdline_addr = 0x20000;
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prot_addr = 0x100000;
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}
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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 > lowmem - 1)
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initrd_max = lowmem - 1;
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if (protocol >= 0x202)
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stl_p(header+0x228, cmdline_addr);
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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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/* 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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if (args->initrd_size)
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initrd_addr = (initrd_max - args->initrd_size) & ~4095;
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else
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initrd_addr = 0;
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stl_p(header+0x218, initrd_addr);
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stl_p(header+0x21c, args->initrd_size);
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/* load kernel and setup */
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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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args->setup_size = (setup_size+1)*512;
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args->kernel_size = args->vmlinuz_size - setup_size;
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args->initrd_addr = (void *)initrd_addr;
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args->kernel_addr = (void *)prot_addr;
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args->cmdline_addr = (void *)cmdline_addr;
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return true;
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}
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void boot_bzimage(struct linuxboot_args *args)
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{
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#ifdef BENCHMARK_HACK
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/* Exit just before getting to vmlinuz, so that it is easy
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* to time/profile the firmware.
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*/
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outb(LINUX_EXIT_PORT, LINUX_START_BOOT);
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#endif
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asm volatile(
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"ljmp $0x18, $pm16_boot_linux - 0xf0000"
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: :
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"b" (((uintptr_t) args->setup_addr) >> 4),
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"d" (args->cmdline_addr - args->setup_addr - 16));
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panic();
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}
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/* BX = address of data block
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* DX = cmdline_addr-setup_addr-16
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*/
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asm("pm16_boot_linux:"
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".code16;"
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"mov $0x20, %ax; mov %ax, %ds; mov %ax, %es;"
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"mov %ax, %fs; mov %ax, %gs; mov %ax, %ss;"
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"xor %eax, %eax; mov %eax, %cr0;"
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"ljmpl $0xf000, $(1f - 0xf0000); 1:"
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"mov %bx, %ds; mov %bx, %es;"
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"mov %bx, %fs; mov %bx, %gs; mov %bx, %ss;"
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"mov %dx, %sp;"
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"add $0x20, %bx; pushw %bx;" // push CS
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"pushw %ax;" // push IP
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"xor %ebx, %ebx;"
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"xor %ecx, %ecx;"
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"xor %edx, %edx;"
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"xor %edi, %edi;"
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"xor %ebp, %ebp;"
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"lret;"
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".code32");
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