Can we run the linux kernel on specific cores in a Multi-core CPU?
I'm making a brainwave detection device. I'll be taking an Octa-Core ARM processor for the software processing.For the management of CPU cores, can I code Linux Kernel to strictly run on a specific set...
View ArticleRetrieve Callchain Using perf_event_open()
How can I use perf_event_open() to retrieve callchain? I do not want to use the callchains provided by oprofile and perf. I want to get them directly. It seems that I need to mmap() the file descriptor...
View ArticleWhich Linux kernel function creates the 'process 0'?
I'm trying to understand more about process 0, such as, whether it has a memory descriptor (non-NULLtask_struct->mm field) or not. It seems to me that a single 'process 0' is created on the boot...
View ArticleHow to use the stap -L option?
I am following the SystemTap tutorial and I am trying to do exercise 1 from section 2.3 - "Tracing. Exercises". The -L option seems to never work. I got this script:probe kernel.function("*nit*"){}I...
View ArticleLinux kernel driver makefile error: "No rule to make target 'hello.mod.o',...
I'm working through a hello world module example in O'Reilly's Linux Device Drivers. Below is the makefile I'm using, taken from the example in the book:# If KERNELRELEASE is defined, we've been...
View ArticleHow to create a device in /dev automatically upon loading of the kernel...
I am attempting to develop Linux device drivers and as my first attempt I am trying to develop a char device driver that has the following file options, struct file_operations fops{ .open=open_fun,...
View Articleebpf packet filter on payload matching
I am new in ebpf & xdp topic and want to do learn it. My question is how to use ebpf filter to filter the packet on specific payload matching? for example, if the data(payload) of the packet is...
View ArticleDoes atomic_inc_return() guarantees atomic return value?
Imagine the following use-case:static atomic_t ref_counter = ATOMIC_INIT(0);void incref(void) { if (atomic_inc_return(&ref_counter) == 1) { // init my stuff }}void decref(void) { if...
View ArticleDoes atomic_inc_return() guarantee atomic return value?
Imagine the following use-case:static atomic_t ref_counter = ATOMIC_INIT(0);void incref(void) { if (atomic_inc_return(&ref_counter) == 1) { // init my stuff }}void decref(void) { if...
View ArticleWhere Linux Kernel Setup GDT
I am reading through Linux Kernel code.I have some doubt regarding GDT(Global Descriptor Table) in Linux.My Questions are:Where Linux Kernel Setup Large GDT?I know that in pm.c...
View ArticleHow can I get my Linux kernel module to work across all processors?
I am writing a kernel module for an x86_64 Linux v3.19 machine that changes some control registers. I would like my changes to be uniform across the 4 processors I have, which as of now entails loading...
View ArticleAccessing 0xCxxxxxxx guest kernel pointers within qemu-system-mips
In my QEMU-based project (system emulation) I analyse various kernel structures of the guest Linux. To read the guest virtual memory I use cpu_memory_rw_debug() function.In particular, I search struct...
View ArticleLinux boot loop in 64-bit boot protocol
I'm trying to create a bootloader for Linux as a UEFI application. The problem is after jumping into the 64-bit kernel entry point QEMU will restart without any output. I really don't know what going...
View ArticleKernel sys_call_table address does not match address specified in system.map
I am trying to brush up on C so I have been playing around with the linux kernel's system call table (on 3.13.0-32-generic). I found a resource online that searches for the system call table with the...
View ArticleSoftware Security Testing of Existing Kernel Module - How To?
Let's say that i found the codebase for a specific Kernel module.I would like to perform software checks, i.e., from a security standpoint of said module.Q1:Should i compile the module from scratch and...
View ArticleIs Nginx's approach to CPUs scalability (per process epoll event queue) optimal?
Nginx's approach to CPUs scalability is based on the creation of the number of almost independent processes each owning an event queue and then using SO_REUSEPORT to spread incoming connections, IRQs,...
View ArticleHCR Bluetooth dongal not working in ubuntu 20.04 desktop
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I ran some command in linux mint and stuck on this screen
I fired some commands in my terminal in my linux mint but after rebooting I am unable to perform anything. No applet, no menubar, nothing. Please help me in solving this problem.
View ArticleWhat is the reason for the discrepancy between /proc/[pid]/status:RssAnon and...
I regularly notice discrepancies between the numbers given for RssAnon in /proc/[pid]/status and for Anonymous in /proc/[pid]/smaps_rollup. I also looked at RssShmem in /proc/[pid]/status, but that did...
View ArticleGenrate two different kernel image on a single compilation in yocto
Currently, I am working on the Yocto based project.On the board, we have two processors of the same series. However, we want to have a different kernel configuration and device tree for both...
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