Hi, Arnd, On Tue, Jul 6, 2021 at 6:12 PM Arnd Bergmann <arnd@xxxxxxxxxx> wrote: > > Tue, Jul 6, 2021 at 6:18 AM Huacai Chen <chenhuacai@xxxxxxxxxxx> wrote: > > > --- /dev/null > > +++ b/arch/loongarch/Kbuild > > @@ -0,0 +1,21 @@ > > +# Fail on warnings - also for files referenced in subdirs > > +# -Werror can be disabled for specific files using: > > +# CFLAGS_<file.o> := -Wno-error > > +ifeq ($(W),) > > +subdir-ccflags-y := -Werror > > +endif > > This tends to break building with 'make W=12' or similar, I would recommend not > adding -Werror. It is a good idea though to have your CI systems build > with -Werror > enabled on the command line though. If we use W=???, corresponding flags will be used; if we don't use W=???, -Werrer flag is used here. So it seems not break the building. > > > +# platform specific definitions > > +include arch/loongarch/Kbuild.platforms > > +obj-y := $(platform-y) > > + > > I would recommend not planning on having platform specific files. The way > we do it on modern platforms (arm64, rv64) is to have all the device drivers > in the driver subsystems instead. > > > + select GENERIC_IOMAP > > GENERIC_IOMAP is one of those you probably don't want here. If PCI I/O > space is mapped into MMIO registers, just do what arm64 has and make > ioport_map() return a pointer, then make ioread32() an alias for readl(). OK, I will try. > > > + select HAVE_CBPF_JIT if !64BIT > > + select HAVE_EBPF_JIT if 64BIT > > These look like you incorrectly copied them from MIPS. I don't see any EBPF_JIT > implemementation (I may have missed that, as I'm still starting), but > you probably > don't want the CBPF version for 32-bit anyway. OK, they should be removed at this time. > > > + select HAVE_IDE > > drivers/ide/ was just removed,so this line can go as well. > > > + select VIRT_TO_BUS > > Remove this: if you still require a driver that fails to use the dma-mapping > API, fix the driver instead so it can work with IOMMUs. OK, they will be removed in the next version. > > > +menu "Machine selection" > > + > > +choice > > + prompt "System type" > > + default MACH_LOONGSON64 > > + > > +config MACH_LOONGSON64 > > + bool "Loongson 64-bit family of machines" > > There should generally not be a 'choice' menu to select between > different machine types, but instead the kernel should be able > to run on all platforms that have the same instruction set. > > Maybe just make this a silent option and use 'select > MACH_LOONGSON64' so you can pick up the device drivers > that mips uses. OK, thanks. > > > + select ARCH_MIGHT_HAVE_PC_PARPORT > > + select ARCH_MIGHT_HAVE_PC_SERIO > > + select GENERIC_ISA_DMA > > + select ISA > > Do you actually have ISA-style add-on cards? If not, then > remove the ISA options. If you do, which drivers are they? Yes, there is an LPC controller in LS7A, and superio is connected on it for laptops. > > > +config CPU_LOONGSON64 > > + bool "Loongson 64-bit CPU" > > + depends on SYS_HAS_CPU_LOONGSON64 > > + select CPU_SUPPORTS_64BIT_KERNEL > > + select GPIOLIB > > + select SWIOTLB > > + select ARCH_SUPPORTS_ATOMIC_RMW > > + help > > + The Loongson 64-bit processor implements the LoongArch64 (the 64-bit > > + version of LoongArch) instruction set. > > + > > +endchoice > > + > > +config SYS_HAS_CPU_LOONGSON64 > > + bool > > + > > +endmenu > > + > > +config SYS_SUPPORTS_32BIT_KERNEL > > + bool > > +config SYS_SUPPORTS_64BIT_KERNEL > > + bool > > +config CPU_SUPPORTS_32BIT_KERNEL > > + bool > > +config CPU_SUPPORTS_64BIT_KERNEL > > + bool > > Same for the CPUs: I would suggest you keep this simple until you get > to the point of actually having multiple CPUs that you need to distinguish. > > Different 64-bit CPUs are hopefully going to be compatible with one > another, so they should not be listed as mutually exclusive in a > 'choice' statement. The complexity with two levels of 32/64 support > is probably not going to be helpful here either. > > The 'select' statements that you have under CPU_LOONGSON64 > ook like they should just be in the top level. > > GPIOLIB and SWIOTLB could just be left user selectable, if turning > them off results only in run-time loss of functionality but not a > build failure. > > > +menu "Kernel type" > > + > > +choice > > + prompt "Kernel code model" > > + help > > + You should only select this option if you have a workload that > > + actually benefits from 64-bit processing or if your machine has > > + large memory. You will only be presented a single option in this > > + menu if your system does not support both 32-bit and 64-bit kernels. > > + > > +config 32BIT > > + bool "32-bit kernel" > > + depends on CPU_SUPPORTS_32BIT_KERNEL && SYS_SUPPORTS_32BIT_KERNEL > > + help > > + Select this option if you want to build a 32-bit kernel. > > + > > +config 64BIT > > + bool "64-bit kernel" > > + depends on CPU_SUPPORTS_64BIT_KERNEL && SYS_SUPPORTS_64BIT_KERNEL > > + help > > + Select this option if you want to build a 64-bit kernel. > > + > > +endchoice > > Since you don't support any 32-bit target at the moment, just make CONFIG_64BIT > a default-on statement, and make it user-selectable only when you add a 32-bit > target. OK. Huacai > > > +choice > > + prompt "Kernel page size" > > + default PAGE_SIZE_16KB > > + > > +config PAGE_SIZE_4KB > > + bool "4kB" > > + help > > + This option select the standard 4kB Linux page size. > > + > > +config PAGE_SIZE_16KB > > + bool "16kB" > > + help > > + This option select the standard 16kB Linux page size. > > + > > +config PAGE_SIZE_64KB > > + bool "64kB" > > + help > > + This option select the standard 64kB Linux page size. > > + > > +endchoice > > + > > +choice > > + prompt "Virtual memory address space bits" > > + default VA_BITS_40 > > + help > > + Allows choosing one of multiple possible virtual memory > > + address space bits for applications. The level of page > > + translation table is determined by a combination of page > > + size and virtual memory address space bits. > > + > > +config VA_BITS_40 > > + bool "40-bits" > > + depends on 64BIT > > + help > > + Support a maximum at least 40 bits of application virtual memory. > > + > > +config VA_BITS_48 > > + bool "48-bits" > > + depends on 64BIT > > + help > > + Support a maximum at least 48 bits of application virtual memory. > > + > > +endchoice > > Isn't the size of the address space tied to the page size? > > Arnd
