20230826 使用qemu boot gdb

// The entry point is in its own section ".text.boot".
.section ".text.boot"

// The symbol "_start" is the kernel's entry point, make it global.
.global _start

// Entry point for the main core.
_start:
  b .

/* Entry point defined in file "boot.S". */
ENTRY(_start)
 
SECTIONS {
  /* Our kernel image will be placed at address 0x80000. */
  . = 0x80000;
  /* It starts with the ".text" segment. */
  .text : {
    /* The ".text" segment itself starts with the code from "boot.S". */
    /* The "_start" symbol (at the beginning of "boot.S") is at 0x80000. */
    *(.text.boot)
  }
}

BINROOT=/Applications/ArmGNUToolchain/12.3.rel1/aarch64-none-elf/bin/aarch64-none-elf-
.PHONY: all
all: kernel8.img

boot.o: boot.S
	${BINROOT}as -c $< -o $@

kernel8.elf: kernel8.ld boot.o
	${BINROOT}ld -T $< -o $@ $(filter-out $<,$^)

kernel8.img: kernel8.elf
	${BINROOT}objcopy -O binary $< $@

.PHONY: clean
clean:
	@rm -f boot.o
	@rm -f kernel8.elf
	@rm -f kernel8.img

.PHONY: run-gdb
run-gdb: kernel8.img
        @echo "[QEMU]    running with $<"
        @echo "(Press Ctrl-A X to exit QEMU.)"
        ${Q}qemu-system-aarch64 -s -S -M cubieboard -nographic -kernel $<

.PHONY: gdb
gdb: kernel8.elf
        @echo "[GDB]     running with $<"
        ${Q}${BINROOT}gdb -ex "target remote :1234" $<