Chris Lalancette wrote:
Hello all,
I have been trying to implement some sort of save/restore kernel memory image for the linux kernel (x86 only right now), without much success. Let me explain the situation:
I have a hardware device that I can generate interrupts with. I also have a machine with 512M of memory, and I am passing the kernel the command line mem=256M. My idea is to generate an interrupt with the hardware device, and then inside of the interrupt handler make a copy of the entire contents of RAM into the unused upper 256M of memory; later on, with another interrupt, I would like to restore that previously saved memory image. This way we can go "back in time", similar to what software suspend is doing, but without as many constraints (i.e. we have a hardware interrupt to work with, we reserved the same amount of physical memory to use, etc.). Before I went much further, I figured I would ask if anyone on the list has tried this, and if there are any reasons why this is not possible.
You're assuming that the state of the memory is the *state* of the entire system.
This fails because there is a lot of state information in hardware registers, external peripheral devices, etc., etc.