passing bootargs to Linux on NIOS
Hi,
I'm currently implementing the bootm command for the NIOS processor from Altera. I'd like to pass boot arguments to the kernel. I tried to figure
out how it works in other architectures, but I'm still clueless.
I call the function theKernel(...) with some arguments like I have seen it in other implementations. Now my question is, how do I access these arguments in the kernel?. I know the NIOS processor is passing the first 4 arguments in registers when calling a function as a subroutine. But in the linux kernel in main.c is another call in the function start_kernel() for a kernel specific setup [setup_arch()] which will move the window-pointer and so change the registerfile. Therefore I cannot access the registers directly.
Or should I just define a piece of memory to put the arguments in? It will be hard coded in the kernel then.
Any hints? Every answer will be appreciated.
Thomas
Quoted 4 lines · In message <[email protected]> you wrote:
I'm currently implementing the bootm command for the NIOS processor from Altera. I'd like to pass boot arguments to the kernel. I tried to figure
out how it works in other architectures, but I'm still clueless.
What exactly don't you understand?
Quoted 3 lines
I call the function theKernel(...) with some arguments like I have seen it in other implementations. Now my question is, how do I access these arguments in the kernel?. I know the NIOS processor is passing the first
Well, how does the NIOS version of the kernel access it's boot arguments?
Quoted 2 lines
4 arguments in registers when calling a function as a subroutine. But in the linux kernel in
main.cis another call in the function
main.c is not the right place to look. You want to check the kernel's entry point, i. e. "_start" (there is probably some "head.S" file n your source tree?).
Quoted 2 lines
Or should I just define a piece of memory to put the arguments in? It will be hard coded in the kernel then.
You design it...
Best regards,
Wolfgang Denk
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Software Engineering: Embedded and Realtime Systems, Embedded Linux
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