[PATCH v9 0/3] riscv, mm: detect svnapot cpu support at runtime

panqinglin2020
2022-12-04T14:12:19Z

From: Qinglin Pan <panqinglin2020@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

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 | 16 +-
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 | 297 +++++++++++++++++++++++++++
11 files changed, 510 insertions(+), 13 deletions(-)

--
2.37.4