Scott Wood <o...@buserror.net> writes: > On Wed, 2019-02-20 at 01:14 +1100, Michael Ellerman wrote: >> Christophe Leroy <christophe.le...@c-s.fr> writes: >> >> > On 02/08/2019 12:34 PM, Michael Ellerman wrote: >> > > In commit 7820856a4fcd ("powerpc/mm/book3e/64: Remove unsupported >> > > 64Kpage size from 64bit booke") we dropped the 64K page size support >> > > from the 64-bit nohash (Book3E) code. >> > > >> > > But we didn't update the dependencies of the PPC_64K_PAGES option, >> > > meaning a randconfig can still trigger this code and cause a build >> > > breakage, eg: >> > > arch/powerpc/include/asm/nohash/64/pgtable.h:14:2: error: #error >> > > "Page size not supported" >> > > arch/powerpc/include/asm/nohash/mmu-book3e.h:275:2: error: #error >> > > Unsupported page size >> > > >> > > So remove PPC_BOOK3E_64 from the dependencies. This also means we >> > > don't need to worry about PPC_FSL_BOOK3E, because that was just trying >> > > to prevent the PPC_BOOK3E_64=y && PPC_FSL_BOOK3E=y case. >> > >> > Does it means some cleanup could be done, for instance: >> > >> > arch/powerpc/include/asm/nohash/64/pgalloc.h:#ifndef CONFIG_PPC_64K_PAGES >> > arch/powerpc/include/asm/nohash/64/pgalloc.h:#endif /* >> > CONFIG_PPC_64K_PAGES */ >> > arch/powerpc/include/asm/nohash/64/pgtable.h:#ifdef CONFIG_PPC_64K_PAGES >> > arch/powerpc/include/asm/nohash/64/slice.h:#ifdef CONFIG_PPC_64K_PAGES >> > arch/powerpc/include/asm/nohash/64/slice.h:#else /* CONFIG_PPC_64K_PAGES >> > */ >> > arch/powerpc/include/asm/nohash/64/slice.h:#endif /* >> > !CONFIG_PPC_64K_PAGES */ >> > arch/powerpc/include/asm/nohash/pte-book3e.h:#ifdef CONFIG_PPC_64K_PAGES >> > >> > arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES >> > arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES >> > arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */ >> > arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES >> > arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES >> > arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES >> > arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */ >> > arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES >> > arch/powerpc/mm/tlb_low_64e.S:#endif /* CONFIG_PPC_64K_PAGES */ >> > arch/powerpc/mm/tlb_low_64e.S:#ifndef CONFIG_PPC_64K_PAGES >> > arch/powerpc/mm/tlb_low_64e.S:#ifdef CONFIG_PPC_64K_PAGES >> >> Probably. >> >> Some of the FSL chips do support 64K pages at least according to some >> datasheets. I don't know what would be required to get it working, or if >> it even works in practice. >> >> So it would be nice to get 64K working on those chips, but probably no >> one has time or motivation to do it. In which case yeah all that code >> should be removed. > > The primary TLB (TLB0) on these chips only supports 4K pages. TLB1 supports > many different sizes but is much smaller, hardware tablewalk only loads into > TLB0, etc.
Aha thanks. I wondered if there was some reason for it. So that makes it sound much less interesting, meaning all that 64K page code should go. cheers