Hi Julien, > On Aug 21, 2023, at 16:33, Julien Grall <jul...@xen.org> wrote: > > Hi Henry, > > On 14/08/2023 05:25, Henry Wang wrote: >> From: Wei Chen <wei.c...@arm.com> >> At the moment, on MMU system, enable_mmu() will return to an >> address in the 1:1 mapping, then each path is responsible to >> switch to virtual runtime mapping. Then remove_identity_mapping() >> is called on the boot CPU to remove all 1:1 mapping. >> Since remove_identity_mapping() is not necessary on Non-MMU system, >> and we also avoid creating empty function for Non-MMU system, trying >> to keep only one codeflow in arm64/head.S, we move path switch and >> remove_identity_mapping() in enable_mmu() on MMU system. >> As the remove_identity_mapping should only be called for the boot >> CPU only, so we introduce enable_boot_cpu_mm() for boot CPU and >> enable_secondary_cpu_mm() for secondary CPUs in this patch. >> Signed-off-by: Wei Chen <wei.c...@arm.com> >> Signed-off-by: Penny Zheng <penny.zh...@arm.com> > Signed-off-by: Henry Wang >> <henry.w...@arm.com> > > One remark below. With or without it addressed: > > Reviewed-by: Julien Grall <jgr...@amazon.com>
Thanks, I will take this tag with ... > > [...] > >> +/* >> + * Enable mm (turn on the data cache and the MMU) for secondary CPUs. >> + * The function will return to the virtual address provided in LR (e.g. the >> + * runtime mapping). >> + * >> + * Inputs: >> + * lr : Virtual address to return to. >> + * >> + * Clobbers x0 - x5 >> + */ >> +enable_secondary_cpu_mm: >> + mov x5, lr >> + >> + load_paddr x0, init_ttbr >> + ldr x0, [x0] >> + >> + bl enable_mmu >> + mov lr, x5 >> + >> + /* Return to the virtual address requested by the caller. */ >> + ret >> +ENDPROC(enable_secondary_cpu_mm) > > NIT: enable_mmu() could directly return to the virtual address. This would > reduce the function to: > > load_paddr x0, init_ttbr > ldr x0, [x0] > > /* Return to the virtual address requested by the caller. > b enable_mmu …this fixed in v6 since I think there is likely to be a v6, and I think I also need to address the commit message nit pointed out by Jan in the last patch. Kind regards, Henry
