Hi Akashi, On 15/05/18 05:35, AKASHI Takahiro wrote: > On Mon, May 07, 2018 at 02:59:07PM +0900, AKASHI Takahiro wrote: >> On Tue, May 01, 2018 at 06:46:09PM +0100, James Morse wrote: >>> On 25/04/18 07:26, AKASHI Takahiro wrote: >>>> We need to prevent firmware-reserved memory regions, particularly EFI >>>> memory map as well as ACPI tables, from being corrupted by loading >>>> kernel/initrd (or other kexec buffers). We also want to support memory >>>> allocation in top-down manner in addition to default bottom-up. >>>> So let's have arm64 specific arch_kexec_walk_mem() which will search >>>> for available memory ranges in usable memblock list, >>>> i.e. !NOMAP & !reserved, >>> >>>> instead of system resource tree. >>> >>> Didn't we try to fix the system-resource-tree in order to fix regular-kexec to >>> be safe in the EFI-memory-map/ACPI-tables case? >>> >>> It would be good to avoid having two ways of doing this, and I would like to >>> avoid having extra arch code... >> >> I know what you mean. >> /proc/iomem or system resource is, in my opinion, not the best place to >> describe memory usage of kernel but rather to describe *physical* hardware >> layout. As we are still discussing about "reserved" memory, I don't want >> to depend on it. I agree. We have funny stuff that isn't hardware-layout, but is important for the next boot. The kernel doesn't have an ABI to support when it queries the list itself. >> Along with memblock list, we will have more accurate control over memory >> usage. >>> If the argument is walking memblock gives a better answer than the stringy >>> walk_system_ram_res() thing, is there any mileage in moving this code into >>> kexec_file.c, and using it if !IS_ENABLED(CONFIG_ARCH_DISCARD_MEMBLOCK)? >>> >>> This would save arm64/powerpc having near-identical implementations. >>> 32bit arm keeps memblock if it has kexec, so it may be useful there too if >>> kexec_file_load() support is added. > If you don't have further objection, I will take memblock approach > (with factoring out powerpc's arch_kexec_walk_mem()). If we're agreed that the memblock walking is generic, then it would be quicker to make the arm64 version as close as possible and merge them as a later series. (saves a cross arch dependency) With that, Reviewed-by: James Morse <james.morse@xxxxxxx> Thanks, James _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
