Re: [PATCH v8 00/14] Convert powerpc to default topdown mmap layout (v8)

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Hi Michael, hi Andrew

Le 09/03/2022 à 18:44, Christophe Leroy a écrit :
> Rebased on top of powerpc/next branch
> 
> This series converts powerpc to default topdown mmap layout.
> 
> powerpc requires its own arch_get_unmapped_area() only when
> slices are needed, which is only for book3s/64. First part of
> the series moves slices into book3s/64 specific directories
> and cleans up other subarchitectures.
> 
> Last part converts to default topdown mmap layout.
> 
> A small modification is done to core mm to allow
> powerpc to still provide its own arch_randomize_brk()
> 
> Another modification is done to core mm to allow powerpc
> to use generic versions of get_unmapped_area functions for Radix
> while still providing its own implementation for Hash, the
> selection between Radix and Hash being doing at runtime.
> 
> Last modification to core mm is to give len and flags to
> arch_get_mmap_end().
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

What's the way forward for this series ?

Patches 1 has been merged in PCI tree.

Patches 2 to 5 are core mm, patch 5 being a fix.

Then patches 6 to 14 are powerpc.

What will be the merge strategy ? I guess it's a bit late to get it 
through powerpc tree, so I was just wondering whether we could get 
patches 2 to 5 in mm this cycle, and the powerpc ones next cycle ?

Thanks
Christophe

> 
> Changes in v8:
> - Moved patch "sizes.h: Add SZ_1T macro" up from which is already in linux-next but not in Linus tree yet.
> - Rebased on today's powerpc/next
> 
> Changes in v7:
> - Taken into account comments from Catalin (patches 3 and 4)
> 
> Changes in v6:
> - New patch (patch 4) to take arch_get_mmap_base() and arch_get_mmap_end() into account in generic hugetlb_get_unmapped_area()
> - Get back arch_randomize_brk() simplification as it relies on default topdown mmap layout.
> - Fixed precedence between || and && in powerpc's arch_get_mmap_end() (patch 9)
> 
> Changes in v5:
> - Added patch 3
> - Added arch_get_mmap_base() and arch_get_mmap_end() to patch 7 to better match original powerpc behaviour
> - Switched patched 10 and 11 and performed full randomisation in patch 10 just before switching to default implementation, as suggested by Nic.
> 
> Changes in v4:
> - Move arch_randomize_brk() simplification out of this series
> - Add a change to core mm to enable using generic implementation
> while providing arch specific one at the same time.
> - Reworked radix get_unmapped_area to use generic implementation
> - Rebase on top of Nic's series v6
> 
> Changes in v3:
> - Fixed missing <linux/elf-randomize.h> in last patch
> - Added a patch to move SZ_1T out of drivers/pci/controller/pci-xgene.c
> 
> Changes in v2:
> - Moved patch 4 before patch 2
> - Make generic arch_randomize_brk() __weak
> - Added patch 9
> 
> Christophe Leroy (14):
>    sizes.h: Add SZ_1T macro
>    mm: Allow arch specific arch_randomize_brk() with
>      CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
>    mm, hugetlbfs: Allow an arch to always use generic versions of
>      get_unmapped_area functions
>    mm: Add len and flags parameters to arch_get_mmap_end()
>    mm, hugetlbfs: Allow for "high" userspace addresses
>    powerpc/mm: Move vma_mmu_pagesize()
>    powerpc/mm: Make slice specific to book3s/64
>    powerpc/mm: Remove CONFIG_PPC_MM_SLICES
>    powerpc/mm: Use generic_get_unmapped_area() and call it from
>      arch_get_unmapped_area()
>    powerpc/mm: Use generic_hugetlb_get_unmapped_area()
>    powerpc/mm: Move get_unmapped_area functions to slice.c
>    powerpc/mm: Enable full randomisation of memory mappings
>    powerpc/mm: Convert to default topdown mmap layout
>    powerpc: Simplify and move arch_randomize_brk()
> 
>   arch/arm64/include/asm/processor.h            |   4 +-
>   arch/powerpc/Kconfig                          |   2 +-
>   arch/powerpc/include/asm/book3s/64/hugetlb.h  |   4 -
>   arch/powerpc/include/asm/book3s/64/mmu-hash.h |   1 +
>   arch/powerpc/include/asm/book3s/64/mmu.h      |   6 -
>   arch/powerpc/include/asm/book3s/64/slice.h    |  24 ++
>   arch/powerpc/include/asm/hugetlb.h            |   2 +-
>   arch/powerpc/include/asm/paca.h               |   7 -
>   arch/powerpc/include/asm/page.h               |   1 -
>   arch/powerpc/include/asm/processor.h          |   2 -
>   arch/powerpc/include/asm/slice.h              |  46 ----
>   arch/powerpc/include/asm/task_size_64.h       |   8 +
>   arch/powerpc/kernel/paca.c                    |   5 -
>   arch/powerpc/kernel/process.c                 |  41 ---
>   arch/powerpc/mm/Makefile                      |   3 +-
>   arch/powerpc/mm/book3s64/Makefile             |   2 +-
>   arch/powerpc/mm/book3s64/hash_utils.c         |  33 ++-
>   arch/powerpc/mm/book3s64/radix_hugetlbpage.c  |  55 ----
>   arch/powerpc/mm/{ => book3s64}/slice.c        |  71 ++++-
>   arch/powerpc/mm/hugetlbpage.c                 |  34 ---
>   arch/powerpc/mm/mmap.c                        | 256 ------------------
>   arch/powerpc/mm/nohash/mmu_context.c          |   9 -
>   arch/powerpc/mm/nohash/tlb.c                  |   4 -
>   arch/powerpc/platforms/Kconfig.cputype        |   4 -
>   drivers/pci/controller/pci-xgene.c            |   1 -
>   fs/hugetlbfs/inode.c                          |  26 +-
>   include/linux/hugetlb.h                       |   5 +
>   include/linux/sched/mm.h                      |  17 ++
>   include/linux/sizes.h                         |   2 +
>   mm/mmap.c                                     |  43 +--
>   mm/util.c                                     |   2 +-
>   31 files changed, 185 insertions(+), 535 deletions(-)
>   delete mode 100644 arch/powerpc/include/asm/slice.h
>   rename arch/powerpc/mm/{ => book3s64}/slice.c (91%)
>   delete mode 100644 arch/powerpc/mm/mmap.c
>