On 4/14/21 10:52 AM, Christophe Leroy wrote: > > > Le 14/04/2021 à 04:54, Anshuman Khandual a écrit : >> Currently most platforms define FIRST_USER_ADDRESS as 0UL duplicating the >> same code all over. Instead define a new option ARCH_HAS_FIRST_USER_ADDRESS >> for those platforms which would override generic default FIRST_USER_ADDRESS >> value 0UL. This makes it much cleaner with reduced code. >> >> Cc: linux-alpha@xxxxxxxxxxxxxxx >> Cc: linux-snps-arc@xxxxxxxxxxxxxxxxxxx >> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx >> Cc: linux-csky@xxxxxxxxxxxxxxx >> Cc: linux-hexagon@xxxxxxxxxxxxxxx >> Cc: linux-ia64@xxxxxxxxxxxxxxx >> Cc: linux-m68k@xxxxxxxxxxxxxxxxxxxx >> Cc: linux-mips@xxxxxxxxxxxxxxx >> Cc: openrisc@xxxxxxxxxxxxxxxxxxxx >> Cc: linux-parisc@xxxxxxxxxxxxxxx >> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx >> Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx >> Cc: linux-s390@xxxxxxxxxxxxxxx >> Cc: linux-sh@xxxxxxxxxxxxxxx >> Cc: sparclinux@xxxxxxxxxxxxxxx >> Cc: linux-um@xxxxxxxxxxxxxxxxxxx >> Cc: linux-xtensa@xxxxxxxxxxxxxxxx >> Cc: x86@xxxxxxxxxx >> Cc: linux-mm@xxxxxxxxx >> Cc: linux-kernel@xxxxxxxxxxxxxxx >> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> >> --- >> arch/alpha/include/asm/pgtable.h | 1 - >> arch/arc/include/asm/pgtable.h | 6 ------ >> arch/arm/Kconfig | 1 + >> arch/arm64/include/asm/pgtable.h | 2 -- >> arch/csky/include/asm/pgtable.h | 1 - >> arch/hexagon/include/asm/pgtable.h | 3 --- >> arch/ia64/include/asm/pgtable.h | 1 - >> arch/m68k/include/asm/pgtable_mm.h | 1 - >> arch/microblaze/include/asm/pgtable.h | 2 -- >> arch/mips/include/asm/pgtable-32.h | 1 - >> arch/mips/include/asm/pgtable-64.h | 1 - >> arch/nds32/Kconfig | 1 + >> arch/nios2/include/asm/pgtable.h | 2 -- >> arch/openrisc/include/asm/pgtable.h | 1 - >> arch/parisc/include/asm/pgtable.h | 2 -- >> arch/powerpc/include/asm/book3s/pgtable.h | 1 - >> arch/powerpc/include/asm/nohash/32/pgtable.h | 1 - >> arch/powerpc/include/asm/nohash/64/pgtable.h | 2 -- >> arch/riscv/include/asm/pgtable.h | 2 -- >> arch/s390/include/asm/pgtable.h | 2 -- >> arch/sh/include/asm/pgtable.h | 2 -- >> arch/sparc/include/asm/pgtable_32.h | 1 - >> arch/sparc/include/asm/pgtable_64.h | 3 --- >> arch/um/include/asm/pgtable-2level.h | 1 - >> arch/um/include/asm/pgtable-3level.h | 1 - >> arch/x86/include/asm/pgtable_types.h | 2 -- >> arch/xtensa/include/asm/pgtable.h | 1 - >> include/linux/mm.h | 4 ++++ >> mm/Kconfig | 4 ++++ >> 29 files changed, 10 insertions(+), 43 deletions(-) >> >> diff --git a/include/linux/mm.h b/include/linux/mm.h >> index 8ba434287387..47098ccd715e 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -46,6 +46,10 @@ extern int sysctl_page_lock_unfairness; >> void init_mm_internals(void); >> +#ifndef ARCH_HAS_FIRST_USER_ADDRESS > > I guess you didn't test it ..... :) In fact I did :) Though just booted it on arm64 and cross compiled on multiple others platforms. > > should be #ifndef CONFIG_ARCH_HAS_FIRST_USER_ADDRESS Right, meant that instead. > >> +#define FIRST_USER_ADDRESS 0UL >> +#endif > > But why do we need a config option at all for that ? > > Why not just: > > #ifndef FIRST_USER_ADDRESS > #define FIRST_USER_ADDRESS 0UL > #endif This sounds simpler. But just wondering, would not there be any possibility of build problems due to compilation sequence between arch and generic code ?
