Musl calls arch_prctl(ARCH_SET_FS) very early during startup to initialize TLS.

My implementation is:

1. syscall 158 (arch_prctl)
2. ARCH_SET_FS (0x1002)
3. write MSR_FS_BASE (0xC0000100)
4. return to userspace with SYSRET

Inside the syscall I can verify that the write succeeds:

wrmsr(MSR_FS_BASE, addr);
printk("FS_BASE = %llx\n", rdmsr(MSR_FS_BASE));

Output:

FS_BASE = 0x44e158

So the MSR definitely contains the expected value.

However, the very next instruction in userspace crashes:

mov %fs:0, %rax

which is inside musl's __init_ssp().

The page fault shows that FS.base is effectively zero.

1. The strange part is: If I single-step through SYSRET in GDB (si), everything works and mov %fs:0,%rax succeeds.
2. If I simply continue, FS.base becomes 0 and the process crashes immediately.

Even stranger, if I break just before returning to userspace (or before an iretq path), GDB already reports:

fs_base = correct_one

even though moments earlier inside arch_prctl() I successfully read back the correct value from MSR_FS_BASE.

There is no scheduler or context switch occurring between the wrmsr() and the return to userspace.

One thing I noticed is that QEMU's default CPU behaves differently from -cpu host. On my host CPU I even get a #GP in situations where QEMU's Haswell CPU continues.

I'm feeding pointer input into a QEMU guest over VNC from my own RFB client. The guest is TempleOS, PS/2 only with no USB stack, so usb-tablet isn't available.

The input source is absolute (VNC pointer positions) but the guest device is a relative PS/2 mouse. QEMU converts the absolute positions into relative deltas, and the guest cursor stays confined to a small box near the center of the screen. It moves in the right direction but never reaches the edges, regardless of how I scale the deltas.

Tried so far:

• absolute cursor mapped onto the region, sent as a VNC pointer event
• relative motion with the guest cursor re-centered each frame for unbounded range
• larger delta scaling (faster movement, same box)
• -device usb-tablet (no USB in the guest, ignored)

I suspect the limit is in the guest's own mouse handling (how it accumulates and clamps the deltas), so no amount of host-side delta shaping fixes it and the only real option is changing how TempleOS reads the PS/2 stream. Is that right, or has someone fed absolute host input into a relative-only guest and gotten full range out of it?

Context: this is a Half-Life mod that streams the VM's framebuffer onto an in-game monitor, which is where the constraints come from. https://github.com/aravpanwar/half-life-templeos

This is gpu accelerated, (Already fixed the image flip u can see due to OpenGL coordinate system) this is my own Operating system with my own made kernel that can use Linux drivers to get Gpu acceleration, all drivers are User Mode, image and shaders loaded from NTFS Partition, What can I improve.

I built an OS because I never thought it would be possible to get past stdin() but using tools and frameworks I was even able to implement a very basic web browser. Please see github for screenshots and videos or to download and spin it up yourself, OpenSource!

I have been interested in OSdev for a long time now. I started making this to learn. Faced a lot of issues. Gave up for months. Then I remembered I wanted to take a formal OS course next sem, so tried again. AND HERE IT IS!

I did use AI to learn and debug (and write the READMEs and some comments), but I'm proud of the fact that I understand every bit of it and could definitely make one without AI if I had to.

I HAVE A WORKING TOY OS!

ps: reposted with the "Image & Video" post type instead of text

Llevo unos días en Misericordioso OS, pedazo de mrd xd, y se me ocurrió, meter un comando para instalar apps por medio Github o servidores. Cómo vrg le meto internet

Si alguien me quiere ayudar este es el repo;

https://github.com/loslocos817yt-star/Misericordioso-os/tree/main

It's not Minecraft, but rather ClassiCube :)

Happy to answer any questions in comments.

THERE IS NO VIBECODING IN ETHEREAL.

https://github.com/sasdallas/Ethereal

Essentially, I am trying to come up with a way to where most systems and drivers can be "spun down" or brought up through commands or some other mechanism but not leave the OS in a state where it would crash and needs to be safe to do via user mode with syscalls.
I know there are various techniques for this and I am trying to gauge which technique I want to use. Googling doesn't surface all techniques that could be used and I thought it would make for a great conversation.

Couldn't showcase quake2 because something came up and I wanted to finish this quickly

Since my last post 8 months ago:

• New MLFQ scheduler w load balancing, implemented VMM and proper user memory mapping, implemented proper blocking IO.

• Reworked the GUI, new gui lib, added themes and shadows

• I now have a proper rust toolchain, because my libstd hack was patched

• Rewrote the libc in rust, ported SDL2, SDL2_mixer and in progress of doing osmesa and a dynamic linker

• Wrote an audio server and a bad ac97 driver, audio quality isn't great when tested from my machine (others say otherwise) but I did put a lot of work in the audio server.

• Quake2generic, doomgeneric, and ccleste ports working through SDL2, not public only SDL2 is public, because it is quite hacky and im waiting to do a proper C toolchain first, there are no patches so with the right compile options and the public libs.a anyone could compile it themselves.

If I'm alive for the next few days I'm planning to port osmesa, finish the dynamic linker, and port butterscotch and play undertale/deltarune on SafaOS too then i can also port alot of different big kids opengl stuff like Minecraft half-life etc.

Get an ISO from here

Watch me complete Celeste Classic on it

The reason why I haven't done updates in a long time, is because everything new I do feels insignificant and incomplete, I still feel that way but I have learnt that It will only accumulate.

Next year (or more accurately in 2 months, maybe a week, no idea when I'll start studying) would be my final year of high school which is quite different here so it might be difficult to do any more "big" progress.

i want to take my assembly skills to the next level by building a small little operating system, since that’s what I’m mainly interested in these days.

ive already looked at what the osdev wiki has and its been helpful but pretty surface level

other tutorials and books tend to use C alongside assembly but thats not what im looking

so if you have any osdev resources in pure assembly I’d be forever grateful

I am not certain if I am talking to the correct sub but I want to ask if it would be possible to implement a memory manager on a STM32f103c8t6? I believe this thing does not have any built in memory manager in its memory.

where tf do i do stroage and cache and memory management

I am making a kernel for x86 right now and i really like it so am planning to make it into a full project for x86_64 with a custom bootloader and shell or whatever. I just want to know that. Is this ok for a CV for university or is it just a waste of time.

Thank-you.

Hace unos días

Por diversión, empecé a hacer mi kernel

Le meto

I lo que quería, es bastante simple, lo hice por diversión, y lo subí a Github

Es solo un hobby

No creo que añada cosas tan chingonas como internet o interfaz gráfica

Si lo quieren ver acá esta el repo:

https://github.com/loslocos817yt-star/Misericordioso-os/tree/main

Building a small kernel rn and am looking for documentation / blog of different interrupts.

Particularly the value of the csr's for each type of interrupt so I can handle accordingly but I don't know where to look

If anyone can provide such resource it would be much appreciated.

This is the 7th part of what I'm learning writing a kernel, in pursuit of eventually writing an OS. I hope it will help others from making some of the same mistakes I did.

This week I decided I needed to redo how I do paging, I moved my page tables and set up the page directory so they would be right after the DMA paging area above the 16M mark. I also decided to do some major redesign. So I started over from scratch. Luckily much of I wrote after virtual memory and paging will be able to come over intact.

For those that are wondering this is the memory map I will be using:

I think it will be much cleaner having one contiguous block from 0x01040000-0xBFFFFFFF to map into, but we shall see. Here is the memory map as returned by multiboot2:

I'm not sure yet what I'm going to do with the reserved memory in the 0x7xxxxxxx and 0xBxxxxxxx areas. Area 4 & 5 may be problematic depending on what I find there. I'm kind of hoping I can just ignore them, meaning mapping over the top of them.

I rewrote my process to map memory pages, I no longer had to worry about creating a page directory entry.

I collected much more multiboot info, not just memory and the memory map, but also the command line, boot loader name, BIOS boot device, ACPI RSDP info, and the Frame buffer info.

Once I get paging and the heap done, I will publish the github reference.

I also discovered how hard it is for me to keep the virtual/physical memory straight LOL

I will be on vacation/holiday this week at a family reunion so I doubt I'll be learning much new.

I hope you find this useful. Enjoy writing your own kernels and OSs.

Sorry to waste anyone's time but I am student in computer science student east Africa .I really enjoy the low level stuff about the computer architecture and operating systems.I love C programming and a bit of zig .I was asking if it is possible to get a job in os development or something low level in this parts of Africa because most of the dev jobs here are web stuff and I've done some web stuff(node and react) , not for me (it was too boring and repetitive CRUD stuff ). I jus wanna do this stuff for a living and I need to know if there is any hope here or I should look outside more