[PATCH v11 0/3] riscv, mm: detect svnapot cpu support at runtime

[Palmer Dabbelt]

On Thu, 15 Dec 2022 22:21:06 PST (-0800), panqinglin2020 at iscas.ac.cn wrote:
> From: Qinglin Pan <panqinglin2020 at iscas.ac.cn>
>
> Svnapot is a RISC-V extension for marking contiguous 4K pages as a non-4K
> page. This patch set is for using Svnapot in hugetlb fs and huge vmap.
>
> This patchset adds a Kconfig item for using Svnapot in
> "Platform type"->"SVNAPOT extension support". Its default value is on,
> and people can set it off if they don't allow kernel to detect Svnapot
> hardware support and leverage it.
>
> Tested on:
>   - qemu rv64 with "Svnapot support" off and svnapot=true.
>   - qemu rv64 with "Svnapot support" on and svnapot=true.
>   - qemu rv64 with "Svnapot support" off and svnapot=false.
>   - qemu rv64 with "Svnapot support" on and svnapot=false.
>
>
> Changes in v2:
>   - detect Svnapot hardware support at boot time.
> Changes in v3:
>   - do linear mapping again if has_svnapot
> Changes in v4:
>   - fix some errors/warns reported by checkpatch.pl, thanks @Conor
> Changes in v5:
>   - modify code according to @Conor and @Heiko
> Changes in v6:
>   - use static key insead of alternative errata
> Changes in v7:
>   - add napot_cont_order for possible more napot order in the future
>   - remove linear mapping related code from this patchset to another patch
>   - refactor hugetlb code for svnapot according to thanks @Andrew @Conor
>   - use tools/testing/selftests/vm/map_hugetlb as hugetlb testing program
>   - support svnapot in huge vmap on newer for-next branch
> Changes in v8:
>   - fix compilation errors in rv32_defconfig
>   - insert some lines of whitespace according to @Conor's suggestion
> Changes in v9:
>   - use alternative to avoid using static branches inside heavily used
>     inline functions
>   - change napot_cont_mask definition
>   - post test_vmalloc modification about testing vmalloc_huge
> Changes in v10:
>   - fix some nits caught by @Andrew
>   - collect Reviewed-by/Acked-by
>   - add memory leak warning in KConfig text
>   - replace test_vmalloc patch link with the standard one
> Changes in v11:
>   - add more detailed warning about HUGETLBFS and SVNAPOT in KConfig text
>   - fix missing reverse-xmas tree
>
>
> Qinglin Pan (3):
>   riscv: mm: modify pte format for Svnapot
>   riscv: mm: support Svnapot in hugetlb page
>   riscv: mm: support Svnapot in huge vmap
>
>  arch/riscv/Kconfig                   |  21 +-
>  arch/riscv/include/asm/errata_list.h |  15 +-
>  arch/riscv/include/asm/hugetlb.h     |  34 ++-
>  arch/riscv/include/asm/hwcap.h       |   2 +-
>  arch/riscv/include/asm/page.h        |   5 -
>  arch/riscv/include/asm/pgtable-64.h  |  34 +++
>  arch/riscv/include/asm/pgtable.h     |  43 +++-
>  arch/riscv/include/asm/vmalloc.h     |  61 +++++-
>  arch/riscv/kernel/cpu.c              |   1 +
>  arch/riscv/kernel/cpufeature.c       |  15 ++
>  arch/riscv/mm/hugetlbpage.c          | 301 +++++++++++++++++++++++++++
>  11 files changed, 519 insertions(+), 13 deletions(-)

This is triggering some build failures.  I sent along a fix before 
realizing they're actually coming from this patch set: 
https://lore.kernel.org/all/20230214201358.10647-1-palmer@rivosinc.com/ 
.  If it's OK I'll just squash that in here, so I can avoid a broken 
build.