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This is only a fragment of code; do you have a link to all of your code right from when the boot manager hands over control, and your limine config file? (Presumably you are using the limine boot manager?)
As you are running in qemu I would use gdb to single step your code from the entry point. You can then determine exactly where it is faulting and what the machine state is at that point (including the faulting address if it’s a page fault). You might like to first use objdump to produce a disassembly listing to make sure the code is what you think it is.
/* Tell the linker that we want an x86_64 ELF64 output file */
OUTPUT_FORMAT(elf64-x86-64)
OUTPUT_ARCH(i386:x86-64)
/* We want the symbol _start to be our entry point */
ENTRY(_start)
/* Define the program headers we want so the bootloader gives us the right */
/* MMU permissions */
PHDRS
{
text PT_LOAD FLAGS((1 << 0) | (1 << 2)) ; /* Execute + Read */
rodata PT_LOAD FLAGS((1 << 2)) ; /* Read only */
data PT_LOAD FLAGS((1 << 1) | (1 << 2)) ; /* Write + Read */
vm_data PT_LOAD FLAGS((1 << 1) | (1 << 2)) ; /* Write + Read */
}
SECTIONS
{
/* We wanna be placed in the topmost 2GiB of the address space, for optimisations */
/* and because that is what the Limine spec mandates. */
/* Any address in this region will do, but often 0xffffffff80000000 is chosen as */
/* that is the beginning of the region. */
. = 0xffffffff80000000;
.text : {
*(.text .text.*)
} :text
/* Move to the next memory page for .rodata */
. += CONSTANT(MAXPAGESIZE);
.rodata : {
*(.rodata .rodata.*)
} :rodata
/* Move to the next memory page for .data */
. += CONSTANT(MAXPAGESIZE);
.data : {
*(.data .data.*)
} :data
/* NOTE: .bss needs to be the last thing mapped to :data, otherwise lots of */
/* unnecessary zeros will be written to the binary. */
/* If you need, for example, .init_array and .fini_array, those should be placed */
/* above this. */
.bss : {
*(COMMON)
*(.bss .bss.*)
} :data
.vm_data (NOLOAD) : {
*(.vm_data)
}
vm_data_start = .;
vm_data_end = . + SIZEOF(.vm_data);
/* Discard .note.* and .eh_frame since they may cause issues on some hosts. */
/DISCARD/ : {
*(.eh_frame)
*(.note .note.*)
}
}
If you look at the reference example for limine you will see that it defines a .limine_requests section and markers for the start and end of this section. As far as I can see, you don’t define these. Which probably explains your problem.
TBH, I’d just do all this in C, following the template - it’s so much easier.
