[PATCH v6 0/4] riscv, mm: detect svnapot cpu support at runtime

[panqinglin2020 at iscas.ac.cn]

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 Linux Kernel's boot process
and hugetlb fs.

This patchset adds a Kconfig item for using Svnapot in
"Platform type"->"SVNAPOT extension support". Its default value is off,
and people can set it on if they 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


Qinglin Pan (4):
  riscv: mm: modify pte format for Svnapot
  riscv: mm: support Svnapot in physical page linear-mapping
  riscv: mm: support Svnapot in hugetlb page
  riscv: mm: support Svnapot in huge vmap

 arch/riscv/Kconfig                  |  17 +-
 arch/riscv/include/asm/hugetlb.h    |  37 +++-
 arch/riscv/include/asm/hwcap.h      |   4 +
 arch/riscv/include/asm/page.h       |   2 +-
 arch/riscv/include/asm/pgtable-64.h |  13 ++
 arch/riscv/include/asm/pgtable.h    |  69 +++++++-
 arch/riscv/include/asm/vmalloc.h    |  28 ++++
 arch/riscv/kernel/cpu.c             |   1 +
 arch/riscv/kernel/cpufeature.c      |   1 +
 arch/riscv/mm/hugetlbpage.c         | 250 +++++++++++++++++++++++++++-
 arch/riscv/mm/init.c                |  30 +++-
 11 files changed, 440 insertions(+), 12 deletions(-)

-- 
2.35.1