Stack Overflow
Stack Overflow

Questions tagged [userspace]

109 questions
3
votes
1 answer

Start / stop CAN boards from userspace using libsocketcan

I am trying to start / stop CAN boards or to update their baudrate using SocketCAN from userspace. My tests are performed on PeakSystem and IXXAT USB-to-CAN V1/V2 boards. My first attempt was to use visudo and to enable NOPASSWD to "ip link set…
Fylhan
  • 677
  • 6
  • 10
3
votes
0 answers

Access to sk_buff from user space

I'm working with a switch. Packets come into the kernel via a special gigabit port where each packet is preceded by a header that tells you what switch port the packet originally came in on. I'm working on a protocol that requires me to know the…
fanfoot
  • 31
  • 1
3
votes
1 answer

How to access a registered I2C device in the linux kernel from userspace

I want to be able to modify registers in a I2C slave device. The device has a driver in the kernel, and the driver registers an I2C client with the address of it. The driver is very basic and does output all the device functionality. I want to…
Arnon Charas
  • 108
  • 8
3
votes
1 answer

How to interrupt userspace application in Linux

I am developing a Linux DMA driver. The userspace application want the driver to perform asynchronous operation(Data transfer) and get informed only when the operation is completed. How does the userspace application get informed asynchronously? I…
lixunx
  • 53
  • 6
2
votes
0 answers

Camera Sensor Driver for ov9281

I am trying to write a bare-metal application to stream images on a VGA monitor using an ov9281 camera. This is my Hardware design. I have used the same design with the ov5640 camera (PCAM). Until now I am able to configure ov5640 and steam data…
Gowri Umesh
  • 21
  • 2
2
votes
0 answers

Compile kernel and userspace with two different toolchains in buildroot

Working with an old ARM board running a 2.6.35-custom kernel. Manufacturer provides two different cross-toolchains: * gcc version 4.3.3 (Sourcery G++ Lite 2009q1-203) --> kernel toolchain * gcc version 4.9.4 (crosstool-NG crosstool-ng-1.23.0) -->…
aicastell
  • 2,182
  • 2
  • 21
  • 33
2
votes
1 answer

Difference between copying user space memory and mapping userspace memory

What is the difference between copying from user space buffer to kernel space buffer and, mapping user space buffer to kernel space buffer and then copying kernel space buffer to another kernel data structure? What I meant to say is: The first…
blackdronzer
  • 39
  • 6
2
votes
2 answers

Measure overhead without pthread in C

I would like to share a test question I met recently and discuss about it: Write a C program that roughly measures the overhead of a context switch >between the kernel and userspace on a UNIX/Linux system (without using the >pthread API). Please…
Charles Julien
  • 365
  • 3
  • 16
2
votes
1 answer

Does QEMU emulate enough features for vfio to work in the guest?

I'm considering using vfio instead of uio to access a PCI device from userspace code within a QEMU guest. Can Linux running as a x86_64 QEMU guest use the vfio driver to make an emulated PCI device accessible to a userspace program running in the…
davidA
  • 12,528
  • 9
  • 64
  • 96
2
votes
3 answers

Is there a way I can use netlink for Inter-process communication (IPC) between two user space processes?

I am a newbie to Linux. I have two User space processes, A and B, and B has to receive messages from A, do some processing, and ack when done. So I was looking at a two-way messaging protocol and was seeing netlink being used for communication…
HackX123
  • 107
  • 1
  • 9
2
votes
0 answers

Is it possible to add platform data from userspace?

I am attempting to enable a platform device in Linux, but the device I am trying to use does not have any platform data. Is it possible to add this from userspace? Other thoughts I've had: Would I have to compile this platform data into the kernel…
Pengor
  • 27
  • 1
  • 7
2
votes
1 answer

Creating more privilege rings

As I understand it, there are two privilege rings in most operating systems: kernel mode and user mode. Could an operating system developer create additional privilege rings, like a middleware mode or a kernel module mode?
Melab
  • 2,594
  • 7
  • 30
  • 51
2
votes
0 answers

How to share memory between userspace and kernelspace

I need to share memory between userspace and kernelspace. The memory is allocated in userspace and in the kernel I want to build a memory descriptor list with physical addresses to initialize a DMA controller (that resides in FPGA). I'm using a Zynq…
Jurgen Vandermot
  • 29
  • 1
2
votes
0 answers

How to use get_user() to send data from user space to kernel space?

I have calculated the value of a parameter in user space and would like to pass the integer value to kernel space. I know that I have to use get_user(x, ptr), but I'm not sure how to provide the pointer to the kernel module. I have an integer…
Matt
  • 796
  • 12
  • 25
2
votes
2 answers

How does the Linux kernel "listen" to the C library?

I'm trying to build up a "big picture" of how things work in the Linux kernel and userspace, and I'm quite confused. I know that userspace make use of system calls to "talk" to the kernel, but I don't know how. I tried to read the C library and…
nowat
  • 120
  • 2
  • 9
1
2
3 4 5 6 7 8