Messages in this thread | | | Subject | Re: [PATCH v2 1/4] mm: define MAX_PTRS_PER_{PTE,PMD,PUD} | From | Christophe Leroy <> | Date | Tue, 10 Dec 2019 07:35:15 +0100 |
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Le 10/12/2019 à 05:47, Daniel Axtens a écrit : > powerpc has boot-time configurable PTRS_PER_PTE, PMD and PUD. The > values are selected based on the MMU under which the kernel is > booted. This is much like how 4 vs 5-level paging on x86_64 leads to > boot-time configurable PTRS_PER_P4D. > > So far, this hasn't leaked out of arch/powerpc. But with KASAN, we > have static arrays based on PTRS_PER_*, so for powerpc support must > provide constant upper bounds for generic code. > > Define MAX_PTRS_PER_{PTE,PMD,PUD} for this purpose. > > I have configured these constants: > - in asm-generic headers > - on arches that implement KASAN: x86, s390, arm64, xtensa and powerpc
I think we shoud avoid spreading default values all over the place when all arches but one uses the default.
I would drop this patch 1, squash the powerpc part of it in the last patch, and define defaults in patch 2, see my comments there.
> > I haven't wired up any other arches just yet - there is no user of > the constants outside of the KASAN code I add in the next patch, so > missing the constants on arches that don't support KASAN shouldn't > break anything. > > Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr> > Signed-off-by: Daniel Axtens <dja@axtens.net> > --- > arch/arm64/include/asm/pgtable-hwdef.h | 3 +++ > arch/powerpc/include/asm/book3s/64/hash.h | 4 ++++ > arch/powerpc/include/asm/book3s/64/pgtable.h | 7 +++++++ > arch/powerpc/include/asm/book3s/64/radix.h | 5 +++++ > arch/s390/include/asm/pgtable.h | 3 +++ > arch/x86/include/asm/pgtable_types.h | 5 +++++ > arch/xtensa/include/asm/pgtable.h | 1 + > include/asm-generic/pgtable-nop4d-hack.h | 9 +++++---- > include/asm-generic/pgtable-nopmd.h | 9 +++++---- > include/asm-generic/pgtable-nopud.h | 9 +++++---- > 10 files changed, 43 insertions(+), 12 deletions(-) >
Christophe
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