Hi Roy, On 01/04/2019 20:09, Roy Pledge wrote: > I'm trying to understand if memory reserved in the device tree via the > "reserved-memory" facility is preserved during a kexec system call, > i.e., is the memory at the same location with the contents undisturbed > when the new kernel starts?
If the reservation is a static-allocation (so the address appears in the DT) then the new kernel should know this is reserved too, and not touch it. If its a dynamic-allocation, the address isn't in the DT, so the new kernel can't know. It will dynamically allocate a new reservation, which may be in a different place. If the data didn't matter at the first-boot, it probably doesn't matter over subsequent kexec either. As an outlier: the gic has some funny requirements around this. It needs to dynamically allocate a page during first-boot that is preserved over kexec. It does this using efi_mem_reserve_persistent(). Thanks, James
