> 2023年5月30日 12:07，Maciej W. Rozycki <macro@xxxxxxxxxxx> 写道： > > On Tue, 30 May 2023, Jiaxun Yang wrote: > >>>> M5150 and P5600 are two MIPS32R5 kernels, however as MIPS32R5 is >>>> backward compatible with MIPS32R2 there is no reason to forbid >>>> M5150 and P5600 on MIPS32R2 kernel. >>> >>> What problem are you trying to solve? The CONFIG_SYS_HAS_CPU_* settings >>> denote overall platform's support for the given CPU and have nothing to do >>> with what architecture level a given kernel has been configured for. You >>> do need to get the settings right for your platform, just as you do in >>> 2/2, but this 1/2 part looks wrong to me. >> >> Well the universal target is to allow R2 generic kernel to run on R5 CPUs. >> As R5 is backward compatible we can just have one universal kernel binary. > > Sure, but this change is not needed for it. You just need to declare > which ISA revisions your platform supports and leave `__get_cpu_type' > alone. It has worked like that for a decade now. I’m afraid it won’t work as you expected. Actually I ran into a problem that `case CPU_P5600` in c-r4k.c is optimised out by compiler, because the codepath is marked as unreachable. Thanks - Jiaxun > > Back in the day I used to run R1 kernels on R2 hardware myself. And > maybe MIPS IV on R1 even, as we had MIPS Malta CPU modules with both MIPS > IV devices (QED RM5261/RM7061) and MIPS64r1 devices (MIPS 5Kc/20Kc/25Kf) > and switching the kernel when swapping modules was a nuisance. The Malta > config still supports these devices although some may not exist anymore. > > Maciej
