On Wed, Jul 14, 2021 at 02:50:12PM +0200, Geert Uytterhoeven wrote: > Add two global variables (cap_mem_addr and cap_mem_size) for storing a > base address and size, describing a limited region in which memory may > be considered available for use by the kernel. If enabled, memory > outside of this range is not available for use. > > These variables can by filled by firmware-specific code, and used in > calls to memblock_cap_memory_range() by architecture-specific code. > An example user is the parser of the "linux,usable-memory-range" > property in the DT "/chosen" node. > > Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > --- > This is similar to how the initial ramdisk (phys_initrd_{start,size}) > and ELF core headers (elfcorehdr_{addr,size})) are handled. > > Does there exist a suitable place in the common memblock code to call > "memblock_cap_memory_range(cap_mem_addr, cap_mem_size)", or does this > have to be done in architecture-specific code? Can't you just call it from early_init_dt_scan_usablemem? If the property is present, you want to call it. If the property is not present, nothing happens. Rob