Tagged Questions

1
vote
0answers
51 views
+250

Grub error 28: selected item cannot fit into memory when writing higher half kernel

I am trying to write a very basic kernel for i386 32-bit. I have been following JamesM's kernel tutorials. My kernel code itself currently does very little - where I am struggling is trying to get ...
1
vote
0answers
10 views

jffs2 scheduling while atomic error on kernel 2.6

Has anybody seen an error of "scheduling while atomic" with the jffs2 fs? It looks to be in the gcd kernel thread. What's the exact fix? It's on 2.6.39 kernel. If preemption is not configured, the ...
-3
votes
0answers
37 views

Kernel that runs python code [closed]

I want to make an os in python but from my research I know that it is hard because you need a kernel with the standard c libraries so I was wondering if i could find a kernel or make one that could ...
0
votes
0answers
49 views

Copying arguments from kernel space to userspace

I'm working with OS161 and I'm having some trouble with understanding copying program arguments from kernel space to userspace. Basically the kernel provides a starting pointer for the userspace that ...
2
votes
1answer
53 views

Sysfs to export device attributes

I've successfully added a device attribute to my device driver, but in all the examples that I found the attribute is used to inject data to the kernel, while my goal would be to export some data from ...
0
votes
1answer
56 views

How to preempt one process from another process/kernel thread?

I have a process P and a kernel thread KT. I want to synchronize execution of P with KT. KT is basically an event handler. But my requirement is that KT should not go ahead processing events if P is ...
2
votes
0answers
31 views

Development environment/process for systems (OS) programming? [closed]

What is a typical development environment/process used for operating systems programming. I am currently taking an OS course through my university where we are playing around in the MINIX OS (e.g. ...
1
vote
1answer
26 views

Kprobe on Linux Scheduler and finding linux scheduler

I have two question: 1 - In Fedora source code, where can I find scheduler code? 2 - Can I put Kprobe in Fedora Scheduler? (Or Can I use register_kprobe() in Fedora scheduler?) thanks.
1
vote
1answer
79 views

printk() doesn't print in /var/log/messages

My OS Ubuntu 12.04. I wrote this Kernel Module and i use insmod and rmmod command but there isn't anything in /var/log messages. how can i fix this problem? /* * hello-1.c - The simplest kernel ...
2
votes
2answers
58 views

x86 hardware Interrupt is not working on qemu

I'm writing a kernel (using qemu to simulate) for x86 as a school project and I ran into weird problem. Even though I have set the interrupt flag in the eflags register, I'm sill not getting any ...
0
votes
0answers
139 views

Proc file to enable or disable the dmesg or printk statements

I want to write a proc file by which i can enable or disable the printk msg printed on the console.Or there will be something like all the printk messages will be printed in my proc file.Then I will ...
1
vote
1answer
67 views

When are the contents of .exit.text section in an ARM vmlinux file discarded once it is loaded in memory?

I understand that the .exit.text section will be filled by the linker with functions defined with __exit macro. I can see the section on dissassembly of the vmlinux file. But I did not understand at ...
0
votes
1answer
67 views

Is it possible to wake a user Process from a kernel module

I have a user level process which is sleeping currently, by using sleep() function. I am trying to write a kernel module which can first extract the task_struct of the user process from its PID, and ...
1
vote
1answer
157 views

insmod: error when inserting kernel module

I am trying to implement a kernel module, which can access the task_struct of a user process, whose Process ID is already known to me. I am using find_get_pid and pid_task to get the task_struct of ...
1
vote
0answers
34 views

Query Related to Packet traversal in kernel

After reading the book "Understanding Linux Network internals". I came to know about some concepts of how we get the packet from the network:- > When working in interrupt driven model, the nic ...
1
vote
1answer
80 views

uprobe programming on ARM Target

I want place a uprobe on target ARMV7 Board, i have uprobe_example.ko which is build against kernel 2.6.39. insmod uprobe_example.ko vaddr=$vaddr pid=$! Uprobes handles interesting events in the ...
1
vote
0answers
40 views

How to display messages from kernel module without using dmesg?

In order to display the messages loaded into a kernel module, I can use the command dmesg Is there any alternatives for this command? How this function gets all these kernel messages?
1
vote
1answer
158 views

get fd from file pointer in kernel space

Given a struct file, is it possible to get the associated file descriptor in linux kernel space? I am trying to change permissions using either sys_chmod or sys_fchmod. One takes a file descriptor the ...
0
votes
0answers
132 views

ZwReadFile() oddly cannot read process modules from LoadImageNotifyRoutine()

I'm writing a windows kernel driver that is part of a set of tools meant to protect critical infrastructure and I've run into a very odd problem. My code catches executable loads using a ...
1
vote
1answer
169 views

Passing ioctl codes from Kernel module to Userspace program

ioctl codes in Kernel modules are usually defined as macros inside .c or .h file, i.e.: #define DRV_CTL_RESET _IO(DRV_MAGIC, 0x01) #define DRV_CTL_DSP_TO _IO(DRV_MAGIC, 0x02) and ...
2
votes
1answer
268 views

Unable to handle kernel paging request at X while intercepting the system call [duplicate]

Possible Duplicate: Linux Kernel: System call hooking example I have been trying to hook the system calls at the kernel level.I got the basic idea from this question.The system call I was ...
2
votes
2answers
120 views

How to access the Internet only via BIOS?

I'm writing a mini OS just for fun. I want to save some key information to one securiry server on the Internet and ever fetch it BEFORE booting my OS. So my problem is: How to access the Internet ...
0
votes
2answers
1k views

Compile error: Kernel module

I am a newbie at kernel programming & I wish to run this kernel module (posted below)... and i ran the makefile (posted below) for that, but I am getting the following errors: Can someone please ...
1
vote
0answers
42 views

KM Development/Testing Environment

I run Gentoo, and I compile an out-of-tree network kernel module on the host OS where I have a full dev environment. I then copy those kernel modules over to the KVM'd guest OS's where I load and test ...
0
votes
0answers
64 views

How can I install customized Android OS? [closed]

I want to install customized android OS in my samsung galaxy III. Can we do that or not ? If we can not do with Galaxy III, then Is there any other phone on which we can do the same ? Thanks In ...
1
vote
2answers
87 views

Dedicated memory allocation for mobile application

This question is for Android/any smart phone OS. I want to allocate small part of memory specially to my application to use. The purpose of doing that is another application running on my phone will ...
-2
votes
1answer
71 views

Android : Dedicated Memory Allocation For Application [closed]

[Asking the same question but not for iPhone but for Android platform] I want to allocate small part of memory specially to my application to use. The purpose of doing that is another application ...
-3
votes
1answer
165 views

linux kernel, how to loop through all cpus?

I need to loop through each cpu so I can get a per_cpu value from them, but there does not seem to be a for_each_cpu(i) macro. the linux kernal version is 2.6.26.5 I want to do something like: ...
0
votes
1answer
133 views

What is the best way to store information within the Linux kernel?

A kernel module I created is constantly generating information that I would like to store within the kernel and be readable from root. I was thinking of storing the information in some sort of log ...
0
votes
1answer
142 views

Having trouble finding the method __kernel_vsyscall within the Linux kernel

I am looking for the __kernel_vsyscall method within the linux kernel which is used to make system calls. I would like to observe its code to learn more about it, but my grep searches cannot seem to ...
0
votes
0answers
31 views

Kernel OpenCL weird behavior

So I was thinking the best way to go at this is just attach my code and explain what is going on. http://www.2shared.com/file/qJPty_V1/hello.html ...
1
vote
2answers
153 views

Understanding dequeue_rt_stack() for RT scheduling class linux

enqueue_task_rt function in ./kernel/sched/rt.c is responsible for queuing the task to the run queue. enqueue_task_rt contains call to enqueue_rt_entity which calls dequeue_rt_stack. Most part of the ...
0
votes
1answer
191 views

meaning of data members in sched_rt_entity

The following is the code for the entity class for RT policy in linux scheduling. struct sched_rt_entity { struct list_head run_list; unsigned long timeout; unsigned int time_slice; ...
1
vote
1answer
303 views

how list_head structure used for scheduling in kernel

I have read a few things from which I can make out that instead of scheduling a task with a scheduling policy it is better that we schedule an entity with a scheduling policy. The advantages being ...
0
votes
1answer
206 views

Linux UART driver - debugging time taken for __init call

I am a bit new to the Linux kernel and our team is trying to optimize the boot-up time for the device. It was observed that 8250 UART driver takes more than 1 second to complete the __init call. Using ...
-1
votes
1answer
230 views

Where is the “Zero divide” done in kernel for Arm Cortex A-9

I am looking into kernel source code (2.6.35 ) for Zero divide . I inserted Zero divide in user space program and all threads stopped. So I want to know Where is the "Zero divide" done in kernel for ...
6
votes
6answers
604 views

Kernel development and C++

From what I know, even though the common OS have parts written in other languages, the kernel is entirely written in C. I want to know if it's feasible to write a Kernel in C++ and if not, what would ...
0
votes
1answer
458 views

How can the linux bottom halfs execute in interrupt context?

While understanding the concepts of top halves and bottom halves, I came across with a question. Here is my understanding: Top half and Bottom half executes in interrupt context. The only ...
0
votes
3answers
310 views

CPU info in kernel module

I want to know the cpu info inside the kernel module like number of cpus,cores,etc. Are there ways to find it? Besides than opening file in kernel module like /proc/cpuinfo.
1
vote
0answers
69 views

sub tty console replication

i want to make a system that will output basic console i/o to a database and make a centralized history i can do actual searching on since 'history | grep' on many different boxes sucks. i looked into ...
2
votes
1answer
228 views

Weird output in PHP when reading hex data in serial

I'm having this weird output when I read hex characters in PHP, wherein PHP fetches its data from Arduino serial.. Here's the output.. ÿ ÿ^A ÿ^A I wrote a user space application which I use to ...
0
votes
1answer
435 views

Brans Kernel Development : Grub Multiboot header?

I am following Bran's kernel development tutorial. In his assembly code, he has the following block of code that he describes to be not so important but something that is do with GRUB. ; This part ...
-1
votes
2answers
77 views

Assembly OS outputting text unreliable

I've been trying to increase my baseline knowledge of Intel x86 Nasm by working on outputting a hardcoded text string in an OS/Kernel real mode environment using BIOS interrupts. Here's my code: ...
0
votes
1answer
144 views

Newly installed kernel runs only with initramfs> prompt

I just compiled Linux Kernel 2.6.27.62 and installed it in Ubuntu in VitualBox. Now, when I select the new kernel from the grub (legacy) menu, what comes out is the following: [ 13.084002] cpufreq: ...
0
votes
0answers
33 views

give variable number of int in /proc config file

I have a kernel extension that requires a few pid (process id) to work, but the number is variable.. can I have a proc file with a variable number of values, or should I just put a maximum value and ...
3
votes
1answer
327 views

Learning Linux Kernel [closed]

Ok I am wanting to learn how a OS kernel works and was wanting to read over the Linux kernel code. However, Ive never don't this kind of thing before and was wondering if there was specific way I ...
0
votes
0answers
1k views

Unable to handle kernel NULL pointer dereference at virtual address

I am working on an android-NDK project in which there is a continuous communication between android mobile and hardware through bluetooth. When the android mobile communicates with the hardware for ...
0
votes
1answer
396 views

pinning a pthread to a single core

I am trying to measure the performance of some library calls. My primary measurement tool is the rdtsc call. After doing some reading I realize that I need to disable preemption and interrupts in ...
1
vote
1answer
407 views

Clarifying who decides memory mappings and port IO mappings

I studied a bit about port mapped IO and memory mapped IO and I figured out how the first works (not the second yet), so if you have something well-explained about how memory mapped IO is performed (I ...
7
votes
1answer
667 views

How to map 1GB (or more) of physical memory

I have a setup with 2GB of memory and I would like to map 1GB (or more) of physical memory into user space virtual address. It is in theory possible since with 32bits setup, 3GB of virtual address is ...

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