Hi Yangyu, On 20/02/2024 20:01, Yangyu Chen wrote:
The BUILTIN_DTB kernel feature on RISC-V only works on K210 SoC only. This patch moved this configuration to entire riscv. Although BUILTIN_DTB is not a good choice for most platforms, it is likely to be a debug feature when some bootloader will always override something like the memory node in the device tree to adjust the memory size from SPD or configuration resistor, which makes it hard to do some debugging. As an example, some platforms with numa like sg2042 only support sv39 will fail to boot when there is no ZONE_HIGHMEM patch with 128G memory. If we want
Orthogonal to this patch, but if needs be, we can fix this issue with 128G on sv39 by changing the sv39 address space layout, we still have room to gain the 4G you miss, at that time I was pretty sure that amount of memory would come with sv48 :)
Thanks, Alex
a kernel without this patch to boot, we need to write the memory nodes in the DT manually. Also, changing DT on some platforms is not easy. For Milk-V Pioneer, the boot procedure is ZSBL -> OpenSBI -> LinuxBoot -> Linux. If DT gets changed, OpenSBI or LinuxBoot may refuse to boot. And there is some bug on LinuxBoot now which does not consume --dtb argument on kexec and always uses DT from memory. So I would like to do debugging on DT using BUILTIN_DTB, which makes it very simple, I can even install the kernel in the distro's way and provide a kernel package for other users to test. Yangyu Chen (1): riscv: dts: Allow BUILTIN_DTB for all socs arch/riscv/Kconfig | 16 ++++++++++++++- arch/riscv/Kconfig.socs | 32 ----------------------------- arch/riscv/boot/dts/Makefile | 2 +- arch/riscv/boot/dts/canaan/Makefile | 2 -- 4 files changed, 16 insertions(+), 36 deletions(-)
