[LITMUS^RT] Interrupt Context

[Björn Brandenburg]

> On 25. Jul 2017, at 08:26, Neil Patrao <illusion.webs at ymail.com> wrote:
> 
> >
> > This depends on whether you are running in kernel mode or in user mode. 
> 
> My program is running in the kernel mode.

Just to clarify, do you mean that you are creating a kernel thread via a custom loadable kernel module? I don't know how else you would get a custom program to run in kernel mode in Linux. 

> This is the hardware: https://www.aim-online.com/products/hardware/mil-std-1553/ape1553-x.aspx
> It has a board support package which includes the driver and a library to access the hardware.
> All calls are made using the library. To access the device (under /dev/) via the library, the application
> either needs to run as root or the permissions to the device has to be changed.

This actually sounds like your code is *not* running in kernel mode, because otherwise there would be no need to use device files. 

> 
> Below is an excerpt from the BSP manual:
> 
> 
> Also, the programming manual suggests to use 2 separate functions to read/write from hardware.
> 1. In case of accessing from interrupt handler function

Which interrupt handler?

> 2. In case of accessing normally from the program

You mean from regular process context in user mode?

> This is what got me thinking if the interrupt runs in the process context or not.

Which method are you using?

- Björn 
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