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ReturnInfinity / BareMetal-OS-legacy

BareMetal is a 64-bit OS for x86-64 based computers. The OS is written entirely in Assembly while applications can be written in Assembly, C/C++, and Rust.
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tried to add elf format support but failed to run any app #122

Open fcnn opened 7 years ago

fcnn commented 7 years ago

I tried to compile the kernel to elf64 format and the kernel start and run, but it failed to run any app. The testing app code:

mem_app: mov rax, 0x0000c300001234b8 ; machine code for: mov rax 0x1234 + ret mov rdi, 0x0000000000200000 stosq call 0x0000000000200000 ret

It is okay to call mem_app in the boot loader, but it hang up if I call mem_all right at the begin of kernel_start. any idea what's going wrong?

IanSeyler commented 7 years ago

I don't see any problems with the code you provided - I added it to the CLI testzone on my dev system and it worked correctly. I'll need more details on this (other code changes, compile methods, etc).

fcnn commented 7 years ago

I added some code in the pure64 boot loader to load elf kernel. the kernel is then compiled using:

nasm -felf64 -o kernel64.o kernel64.asm ld -T kernel.ld -o kernel64.sys kernel64.o strip kernel64.sys

of course also added entry point declaration and removed the ORG instruction.

now after some debugging, it seemed that mmu was not functioning properly. because the instruction,

call 0x200000

when in runtime, will actually becomes something like,

call 0x30af.... ; the address had automatically changed to 3M+

i saw that through qemu monitor window. i can't see any reason to cause such issue.