On Monday 10 November 2014 18:08:03 Ard Biesheuvel wrote: > On 10 November 2014 17:57, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Monday 10 November 2014 17:51:45 Ard Biesheuvel wrote: > >> Create a new /sys entry '/sys/firmware/fdt' to export the FDT blob > >> that was passed to the kernel by the bootloader. This allows userland > >> applications such as kexec to access the raw binary. > >> > >> The fact that this node does not reside under /sys/firmware/device-tree > >> is deliberate: FDT is also used on arm64 UEFI/ACPI systems to > >> communicate just the UEFI and ACPI entry points, but the FDT is never > >> unflattened and used to configure the system. > >> > >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> > > > > Can you elaborate on the motivation? Initially the fdt format was > > introduced to make it easy to pass the information from /proc/device-tree > > to the next kernel for kexec. Are you interested in cases where this does > > not work? > > > > /sys/firmware/device-tree only gets populated if you are really > booting in DT mode, i.e., when the device tree is unflattened. > However, in ACPI mode we still need to access the data that was > communicated between UEFI and the kernel in the /chosen node if we > want to support kexec under UEFI. Ah, now I get it. Arnd -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
