Re: [PATCH V4 0/2] riscv: add RISC-V Svpbmt Standard Extension supports

From: Jisheng Zhang
Date: Mon Nov 29 2021 - 10:28:40 EST


On Mon, 29 Nov 2021 09:40:05 +0800
wefu@xxxxxxxxxx wrote:

> From: Fu Wei <wefu@xxxxxxxxxx>
>
> This patch follows the RISC-V standard Svpbmt extension in
> privilege spec to solve the non-coherent SOC DMA synchronization
> issues.
>
> The svpbmt PTE format:
> | 63 | 62-61 | 60-8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
> N MT RSW D A G U X W R V
> ^
>
> Of the Reserved bits [63:54] in a leaf PTE, the bits [62:61] are used as
> the MT (aka MemType) field. This field specifies one of three memory types
> as shown in the following table:
> MemType RISC-V Description
> ---------- ------------------------------------------------
> 00 - PMA Normal Cacheable, No change to implied PMA memory type
> 01 - NC Non-cacheable, idempotent, weakly-ordered Main Memory
> 10 - IO Non-cacheable, non-idempotent, strongly-ordered I/O memory
> 11 - Rsvd Reserved for future standard use
>
> The standard protection_map[] needn't be modified because the "PMA"
> type keeps the highest bits zero.
> And the whole modification is limited in the arch/riscv/* and using
> a global variable(__svpbmt) as _PAGE_MASK/IO/NOCACHE for pgprot_noncached
> (&writecombine) in pgtable.h. We also add _PAGE_CHG_MASK to filter
> PFN than before.
>
> Enable it in devicetree - (Add "riscv,svpbmt" in the mmu of cpu node)
> - mmu:
> riscv,svpmbt
>

I noticed that this series goes up to v4 but changes history is missing.
Will you add it?


> Wei Fu (2):
> dt-bindings: riscv: add MMU Standard Extensions support for Svpbmt
> riscv: add RISC-V Svpbmt extension supports
>
> .../devicetree/bindings/riscv/cpus.yaml | 10 +++++
> arch/riscv/include/asm/fixmap.h | 2 +-
> arch/riscv/include/asm/pgtable-64.h | 21 ++++++++--
> arch/riscv/include/asm/pgtable-bits.h | 39 ++++++++++++++++++-
> arch/riscv/include/asm/pgtable.h | 39 ++++++++++++++-----
> arch/riscv/kernel/cpufeature.c | 35 +++++++++++++++++
> arch/riscv/mm/init.c | 5 +++
> 7 files changed, 136 insertions(+), 15 deletions(-)
>