On Sat, Apr 30, 2016 at 1:50 PM, Russell King - ARM Linux <linux at arm.linux.org.uk> wrote: > On Sat, Apr 30, 2016 at 08:57:34AM +0530, Pratyush Anand wrote: >> On Fri, Apr 29, 2016 at 11:30 PM, Russell King - ARM Linux >> <linux at arm.linux.org.uk> wrote: >> > On Fri, Apr 29, 2016 at 08:26:00PM +0530, Pratyush Anand wrote: >> >> Hi Russell, >> >> >> >> On Thu, Apr 28, 2016 at 2:58 PM, Russell King >> >> <rmk+kernel at arm.linux.org.uk> wrote: >> >> > Advertise the location of bootable RAM to kexec-tools. kexec needs to >> >> > know where it can place the kernel in RAM, and so be executable when >> >> > the system needs to jump into it. >> >> > >> >> > Advertise these areas in /proc/iomem with a "System RAM (boot alias)" >> >> > tag. >> >> > >> >> > Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk> >> >> >> >> Can you please also share git tree path of corresponding kexec-tools changes? >> >> >> >> Could it be a better idea (if things in user space become simpler) >> >> that in stead of patch 5 and 6, we pass arch_phys_to_idmap_offset to >> >> user space, and then user space manipulates existing "Crash kernel" >> >> and "System RAM" resources. >> > >> > Given that it's only _one_ platform right now, I don't think that >> > additional complexity is worth it. It means that we have to invent >> >> Probably, I could not communicate it well. I was not trying to have >> *additional* complexity. Wanted to see if things could be simpler >> rather. So this is what my understanding was: >> -- We create one patch to pass arch_phys_to_idmap_offset to user space >> (say in /sys/kernel/bootmem_idmap_offset) >> -- We do not use patch 5,6,11 and 12 of this series. Probably few more >> content of the series will go away. > > Patches 11 and 12 don't go away with what you're suggesting. Patches > 11 and 12 are necessary to allow the boot-view addresses to be passed > into the kernel through kexec, and to allow kexec to find appropriate > memory resources. But once we would have manipulated "start" and "end" of "Crash Kernel" and "System RAM" resources in user space using /sys/kernel/bootmem_idmap_offset , then kernel through kexec system call would have already receive boot-view addresses, no? ~Pratyush
