I edit the function netif_rx in the dev.c at the /net/core just to make a printk when a packet arrives.
I called "make" at the kernel's root directory but i don't know witch module was compiled. I need to update the old-module ir order to turn on the changes that i made.
If i want to see my changes i need to:
1-make at the kernel's root directory;
2- make modules;
3-make bzImage;
4- insert the new bzImage on the grub file;
5-Reboot;
I want to to access directly to the modulean update withou do all that things.
Could you help me.
Best regards,
Ricardo Ribeiro
If I get your goal correctly, the simplest you can do is to implement your own kernel module where you register a protocol handler for ETH_P_ALL with dev_add_pack(). This way you will receive all incoming packets for a particular device (if you also specify pt->dev) or all devices (if pt->dev is NULL).
Related
I am pretty new to linux kernel.I am trying to generate PWM through linux. The API man talks about a sysfs interface. I want to implement a userspace program in C. But using PWM forces me to use a command line. Furthermore, using read, write is a problem in C as when I am using cd, it is changing path directory.
Thus the path is variable. Is there any way I can pass values to pwm_config() without using sysfs? Perhaps through ioctl? If yes, then what would be the procedure?
Application C code:
void main(){
int export = open("/sys/class/pwm/pmwchip0/export",O_WRONLY);
int period,duty_cycle,enable;
if(export == -1)
{
perror("Export:");
}
and so on for other files like period and duty cycle.
When I try to run my application I get the following error.
Export:: No such file or directory
Export_write: Bad file descriptor
Period_write:: Bad file descriptor
Duty_cycle_write:: Bad file descriptor
Enable_write:: Bad file descriptor
As far as I know, the sysfs is the only standard userspace interface to PWM. But anything you can do from the command line can be done in C (the shell is written in C, after all).
The problem you are having with cd is not actually a problem. Inside sysfs the directories in /sys/class/pwd/* are actually symbolic links to the proper devices. In your case /sys/class/pwm/pwmchip0 is a symlink to /sys/devices/soc0/amba/f8001000.timer/pwm/pwmchip0.
The funny thing is that some shells, when you cd a symbolic link will resolve to the real directory, but other shells will actually keep the symlink name as the current directory.
But that issue with the directory symlinks should not be an issue for you. A C program willing to manage PWM devices should not change the working directory. Instead open the files with the full path:
open("/sys/class/pwm/pwmchip0/npwm", O_RDONLY);
and so on.
OK, so I have this embedded kernel whose network card used to work fine with the LLTEMAC option. The new one with LL_TEMAC doesn't. I still see the code with LLTEMAC in the source, but not in the available option in the .config file:
$ ack-grep LLTEMAC
drivers/net/ethernet/xilinx/xilinx_lltemac/Makefile:10:obj-$(CONFIG_XILINX_LLTEMAC) := xilinx_temac.o
drivers/net/ethernet/xilinx/xilinx_lltemac/xlltemac_main.c:2: * Xilinx Ethernet: Linux driver for the XPS_LLTEMAC core.
drivers/net/ethernet/xilinx/xilinx_lltemac/xlltemac_main.c:452:#ifdef CONFIG_XILINX_LLTEMAC_MARVELL_88E1111_RGMII
...
include/linux/xilinx_devices.h:83:/* LLTEMAC platform data */
Is there a way to compile the kernel with this removed option ?
Simply adding CONFIG_XILINX_LLTEMAC=y CONFIG_XILINX_LLTEMAC_MARVELL_88E1111_GMII=y to the .config file does not do anything as the dislaimer states: # Automatically generated file; DO NOT EDIT.
Thanks.
Why not just update this individual driver to understand the new configuration option?
I am using a command in the proc file system which is the following
echo 0 > /proc/sys/net/ipv4/ip_forward
Note: I don't want to know the basic of the command written above, I want what all happens when it goes inside the kernel. As, I want to implement one of the /proc file.
Now if I want to trace the code right from when the 0 is echoed in the file-system then how to go about it. I mean if I want to trace what happens when I do this.
I want to see where in the kernel code this 0 is accepted and in which value does it get stored inorder to make the changes. Please, can somebody tell what all happens when you call this command. I want in detail explain. I don't want the description of the command.
Any related article on how it changes the kernel parameters is also fine.
I have read this but, not explained there. http://www.linuxjournal.com/article/8381
Thanks
search through linux tree (especially network stack) for create_proc_entry function. Figure out what file creates ip_forward (it must be in ip4v drivers) from name passed to create_proc_entry.
When you find the file, look at where proc_dir_entry structure is created and what functions are assigned to its read_proc, write_proc members.
I'm developing a device driver for embedded linux(ARM).
How can I compile the KO file generated as a part of the kernel,
in a way that the module will be loaded in boot ?
this is the first time I need to compile the driver into the kernel and not as a loadable module. so I'm not sure how to do it.
Thanks,
Ramon.
For your first question, I assume that you want to build your driver statically into the kernel image(not as a module). First, you select a directory in drivers directory where you want to put your driver files. Assume you want to put your files in drivers/char/. Copy your files into this directory. There will be a Kconfig file in the drivers/char/ directory, open it and add an entry like this in the before the endmenu.
config MYDRIVER
bool "This is a driver for something"
default n
help
This is a test driver.
Save the file and open Makefile in the same directory. Goto end of the file and add the following entry.
obj-$(CONFIG_MYDRIVER) += mydriver.o
That's it you have added the file to the kernel tree. Now, as usual, do make menuconfig and select MYDRIVER.
See this Kernel Compilation article for more info.
You need to build your device driver as a built-in. You can either edit your kernel .config file manually and change "=m" to "=y" for the CONFIG option that belongs to your module, or use make menuconfig to change <M> to <*> for your device driver.
before -> <M> Your Device Driver Name Here
after -> <*> Your Device Driver Name Here
hi all:
recently i'm working on make checkpoint on linux process and encountered a problem,it looks like that when i munmap memory map of the executable to current process,the symlink /proc/self/exe is dead.what i want is to make this symlink pointing to a other executable(the one for my resumed processs),is that possible?i tried delete it and recreate, permission denied. english is not my native language, i hope i've made my point,thanx
prctl(PR_SET_MM_EXE_FILE, ...)
Supersede the /proc/pid/exe symbolic link with a new one pointing to a new executable file identified by the file descriptor provided in arg3 argument. The file descriptor should be obtained with a regular open(2) call.
No. /proc is completely managed by the kernel and does not allow changes like that.
But you may be able to start a new process (with fork() perhaps) and map your memory snapshot into that.