Rob Herring <r...@kernel.org> writes: > On Tue, Jun 15, 2021 at 10:13 AM nramas <nra...@linux.microsoft.com> wrote: >> >> On Tue, 2021-06-15 at 08:01 -0600, Rob Herring wrote: >> > On Tue, Jun 15, 2021 at 6:18 AM Geert Uytterhoeven < >> > ge...@linux-m68k.org> wrote: >> > > >> > > > +void *of_kexec_alloc_and_setup_fdt(const struct kimage *image, >> > > > + unsigned long >> > > > initrd_load_addr, >> > > > + unsigned long initrd_len, >> > > > + const char *cmdline, size_t >> > > > extra_fdt_size) >> > > > +{ >> > > > + /* Did we boot using an initrd? */ >> > > > + prop = fdt_getprop(fdt, chosen_node, "linux,initrd- >> > > > start", NULL); >> > > > + if (prop) { >> > > > + u64 tmp_start, tmp_end, tmp_size; >> > > > + >> > > > + tmp_start = fdt64_to_cpu(*((const fdt64_t *) >> > > > prop)); >> > > > + >> > > > + prop = fdt_getprop(fdt, chosen_node, >> > > > "linux,initrd-end", NULL); >> > > > + if (!prop) { >> > > > + ret = -EINVAL; >> > > > + goto out; >> > > > + } >> > > > + >> > > > + tmp_end = fdt64_to_cpu(*((const fdt64_t *) >> > > > prop)); >> > > >> > > Some kernel code assumes "linux,initrd-{start,end}" are 64-bit, >> > > other code assumes 32-bit. >> > >> > It can be either. The above code was a merge of arm64 and powerpc >> > both >> > of which use 64-bit and still only runs on those arches. It looks >> > like >> > some powerpc platforms may use 32-bit, but this would have been >> > broken >> > before.
>> of_kexec_alloc_and_setup_fdt() is called from elf_64.c (in >> arch/powerpc/kexec) which is for 64-bit powerpc platform only. > > 64-bit PPC could be writing 32-bit property values. The architecture > size doesn't necessarily matter. And if the values came from the > bootloader, who knows what size it used. > > This code is 32-bit powerpc only?: > > arch/powerpc/boot/main.c- /* Tell the kernel initrd address via device > tree */ > arch/powerpc/boot/main.c: setprop_val(chosen, "linux,initrd-start", > (u32)(initrd_addr)); > arch/powerpc/boot/main.c- setprop_val(chosen, "linux,initrd-end", > (u32)(initrd_addr+initrd_size)); Historically that code was always built 32-bit, even when used with a 64-bit kernel. These days it is also built 64-bit (for ppc64le). It looks like the drivers/of/fdt.c code can handle either 64 or 32-bit, so I guess that's why it seems to be working. Although I'm not sure how much testing the 64-bit case gets, because the distros tend to just use the vmlinux. cheers