Hi Julien, > On Aug 21, 2023, at 17:18, Julien Grall <jul...@xen.org> wrote: > > Hi Henry, > > On 14/08/2023 05:25, Henry Wang wrote: >> The MMU specific code in head.S will not be used on MPU systems. >> Instead of introducing more #ifdefs which will bring complexity >> to the code, move MMU related code to mmu/head.S and keep common >> code in head.S. Two notes while moving: >> - As "fail" in original head.S is very simple and this name is too >> easy to be conflicted, duplicate it in mmu/head.S instead of >> exporting it. >> - Use ENTRY() for enable_secondary_cpu_mm, enable_boot_cpu_mm and >> setup_fixmap to please the compiler after the code movement. > > I am not sure I understand why you are saying "to please the compiler" here. > Isn't it necessary for the linker (not the compiler) to find the function? > And therefore there is no pleasing (as in this is not a bug in the toolchain).
Yes it meant to be linker, sorry for the confusion. What I want to express is without the ENTRY(), for example if we remove the ENTRY() around the setup_fixmap(), we will have: ``` aarch64-none-linux-gnu-ld: prelink.o: in function `primary_switched': /home/xinwan02/repos_for_development/xen_playground/xen/xen/arch/arm/arm64/head.S:278: undefined reference to `setup_fixmap' /home/xinwan02/repos_for_development/xen_playground/xen/xen/arch/arm/arm64/head.S:278:(.text.header+0x1a0): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `setup_fixmap' make[2]: *** [arch/arm/Makefile:95: xen-syms] Error 1 make[1]: *** [build.mk:90: xen] Error 2 make: *** [Makefile:598: xen] Error 2 ``` I will use the word “linker” in v6 if you agree. > > Other than that, the split looks good to me. May I please take this as a Reviewed-by tag? I will add the tag if you are happy with that. Kind regards, Henry > > Cheers, > > -- > Julien Grall
