On Fri, Feb 23, 2024 at 3:23 AM Will Deacon <will@xxxxxxxxxx> wrote: > > On Thu, Feb 22, 2024 at 05:03:17PM -0700, Rob Herring wrote: > > On Fri, Feb 16, 2024 at 05:05:54PM -0800, Stephen Boyd wrote: > > > Call this function unconditionally so that we can populate an empty DTB > > > on platforms that don't boot with a firmware provided or builtin DTB. > > > When ACPI is in use, unflatten_device_tree() ignores the > > > 'initial_boot_params' pointer so the live DT on those systems won't be > > > whatever that's pointing to. Similarly, when kexec copies the DT data > > > the previous kernel to the new one on ACPI systems, > > > of_kexec_alloc_and_setup_fdt() will ignore the live DT (the empty root > > > one) and copy the 'initial_boot_params' data. > > > > > > Cc: Rob Herring <robh+dt@xxxxxxxxxx> > > > Cc: Frank Rowand <frowand.list@xxxxxxxxx> > > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > > > Cc: Will Deacon <will@xxxxxxxxxx> > > > Cc: Mark Rutland <mark.rutland@xxxxxxx> > > > Cc: <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx> > > > Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxx> > > > --- > > > arch/arm64/kernel/setup.c | 3 +-- > > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > Catalin, Will, Can I get an ack on this so I can take the series via the > > DT tree. > > Mark had strong pretty strong objections to this in version one: Yes, I had concerns with it as well. > https://lore.kernel.org/all/ZaZtbU9hre3YhZam@FVFF77S0Q05N/ > > and this patch looks the same now as it did then. Did something else > change? Yes, that version unflattened the bootloader passed DT. Now within unflatten_devicetree(), the bootloader DT is ignored if ACPI is enabled and we unflatten an empty tree. That will prevent the kernel getting 2 h/w descriptions if/when a platform does such a thing. Also, kexec still uses the bootloader provided DT as before. Rob
