Questions tagged [kernel]
Code that is intended to run in an operating system kernel or kernel module
29 questions
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MemoryGraveyardDriver.sys - a kernel mode device driver managing a kilobyte of RAM for random reading/writing: Take II
(See the previous and initial iteration.)
This time I have incorporated some improvement points made by G. Sliepen:
driver.cpp:
...
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MemoryGraveyardDriver.sys - a kernel mode device driver managing a kilobyte of RAM for random reading/writing
(See the second and next iteration.)
Intro
I have this GitHub repository. Basically, it does not do anything fancy: it has a byte buffer of 1Kb size, and it intercepts ...
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LKM: Extract cpu model name from /proc/cpuinfo
I wrote a small LKM that opens the /proc/cpuinfo file, reads it line by line, and attempts to the cpu model name.
If the function fails to extract the cpu model ...
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Simple slab allocator in C
Here is the plan:
a slab takes up 1 page and it has PGSIZE / blocksize amount of blocks
the minimum blocksize is 8 bytes, otherwise the pointer to the next block ...
2
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Thread scheduler in C
I have made a simple round robin scheduler that switches between threads in ptable array. Currently it's only for 1 CPU, so there are no locks at the moment.
But ...
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364
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Virtual memory manager in C
Virtual Memory manager that has functions, mappage, unmappage, remappage
If the physical ...
3
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1
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370
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Bitmap page allocator in C
Bitmap page allocator that scans the bitmap linearly looking for size amount of pages. Everytime it founds a free page, it check if the next ...
3
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285
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UEFI bootloader
UEFI bootloader.
It reads the file kernel.elf on the disk image, reads through the program headers, copies the LOAD segments into memory, and finally calls ...
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Virtual memory manager, physical memory manager and buddy allocator
I'm writing memory manager for my toy operating system and I would like to get some feedback. There is physical memory manager, which uses bitmap, virtual memory manager which uses buddy algorithm for ...
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OSDEV Physical Memory Manager (PMM) in C
I ported the Physical Memory Manager from Vinix into C for a little OS I'm working on. I'd love to get some feedback.
Here's my code:
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Implement 2D and 1D std::array in opencl kernel
I am asked to implement the following part of code into kernel code. Actually, I have tried but not sure about the std::array.
This is the original code for the ...
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Makefile to compile an OS which also uses functions/macros
So I've started writing an OS to know how they work, and I came up with the following makefile to compile it.
The reason I used a makefile is because I wanted to see everything it was doing and have ...
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Posix signal implementation
My hobby is Unix-like operating systems.
Recently I began writing my own sel4-based Posix compliant OS. Here's the code for internal signal handling functions which presents a kind of backend to help ...
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Choose a kernel for next system boot
I have been testing a number of kernel builds and I decide to have a go at writing some Python code. The idea is to select which kernel to boot on the next reboot. I could have done it in Bash but ...
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Creating procfs entry on linux in Kernel Module
My Linux kernel version is
Linux version 5.0.0-29-generic
I'm currently learning how to write kernel modules for Linux and implemented this simple module which ...
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Getting an element from RCU-protected list in kernel
I wrote a function, read_fox_rcu() for getting an element from RCU-protected list in a linux device driver. read_fox_rcu() reads ...
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CUDA kernel to compare matrix entries, weighted with a pattern
I wonder if it's possible to optimize this code in CUDA. Could I get any hints how to? Equivalent algorithm runs faster in Matlab for me, but there I'm doing matrix operations.
Compution
I'm not ...
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Linux GPIO rotary encoder as volume control
I've written a kernel module (tested on Raspberry Pi) to use a rotary encoder as a volume control.
The Linux source tree already contains a driver for rotary encoders so I've just piggybacked off of ...
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ReadWriteSerializer
I am developing a C++ kernel, and I've got the need for manipulating huge data structures before the task-scheduler runs - it means in a non-preemptive environment.
For this, I have developed a read-...
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Generating bounded & unique random numbers in the Linux kernel
I recently needed to generate a series of unique random numbers (non-repeated) within a bounded range inside of the Linux kernel. The code I came up with is below. I'd appreciate any feedback -- again,...
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X86 Legacy boot loader error trapping
The boot loader that I'm designing is just simply going to setup (A) Stack, (B) Segment registers (C) Load remainder of track for specified device. Conventionally, this could have been up to 4 floppy ...
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Makefile for a custom operating system kernel
I'm now posting the second semi-complete part of my operating system makefile. The kernel itself is currently incomplete, so don't be surprised by the small size of the makefile. When the kernel ...
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Re-implementing memcpy
I have written an implementation of memcpy function and I want to know how good is it and if it gets the most out of the processor capabilities or not.
The reason ...
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Callback in Linux kernel driver in order to hide device's low-level protocol
I'm am writing a Linux kernel driver for HD44780 LCDs connected via I2C bus. In my last change I tried to decouple low-level code (which talks to the device via I2C) from device's logic (printing ...
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Kernel development
I'm trying to learn more about kernels, so naturally I started to program one. I'm using tutorials from here. Right now I have modified the printf() that was ...
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Homebrew std::string for use with kernel
I've ported some standard library facilities like vector, algorithm, etc. to my kernel so I can code in C++ instead of C. This is one of them. I'm looking for concerns regarding:
Performance
Safety
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Free a binary tree without using recursion or allocating memory
As the title says, the objective is to free a binary tree without using the stack or allocating memory.
This was required for a kernel module where resources were limited.
Result has a complexity of \...
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Simple Linux char driver
Since the resources I found to learn are generally out-of-date, I'm having to read a lot of documentation, which makes the learning process somewhat haphazard. The module makes a simple character ...
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