Re: [PATCH v10 00/14] riscv: Add support for xtheadvector

[Charlie Jenkins <charlie@rivosinc.com>]

On Mon, Sep 30, 2024 at 12:07:23AM +0800, Aoba K wrote:
> 
> On 2024/9/12 13:55, Charlie Jenkins wrote:
> > xtheadvector is a custom extension that is based upon riscv vector
> > version 0.7.1 [1]. All of the vector routines have been modified to
> > support this alternative vector version based upon whether xtheadvector
> > was determined to be supported at boot.
> > 
> > vlenb is not supported on the existing xtheadvector hardware, so a
> > devicetree property thead,vlenb is added to provide the vlenb to Linux.
> > 
> > There is a new hwprobe key RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0 that is
> > used to request which thead vendor extensions are supported on the
> > current platform. This allows future vendors to allocate hwprobe keys
> > for their vendor.
> > 
> > Support for xtheadvector is also added to the vector kselftests.
> > 
> > Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
> > 
> > [1] https://github.com/T-head-Semi/thead-extension-spec/blob/95358cb2cca9489361c61d335e03d3134b14133f/xtheadvector.adoc
> > 
> > ---
> > This series is a continuation of a different series that was fragmented
> > into two other series in an attempt to get part of it merged in the 6.10
> > merge window. The split-off series did not get merged due to a NAK on
> > the series that added the generic riscv,vlenb devicetree entry. This
> > series has converted riscv,vlenb to thead,vlenb to remedy this issue.
> > 
> > The original series is titled "riscv: Support vendor extensions and
> > xtheadvector" [3].
> > 
> > The series titled "riscv: Extend cpufeature.c to detect vendor
> > extensions" is still under development and this series is based on that
> > series! [4]
> > 
> > I have tested this with an Allwinner Nezha board. I used SkiffOS [1] to
> > manage building the image, but upgraded the U-Boot version to Samuel
> > Holland's more up-to-date version [2] and changed out the device tree
> > used by U-Boot with the device trees that are present in upstream linux
> > and this series. Thank you Samuel for all of the work you did to make
> > this task possible.
> > 
> > [1] https://github.com/skiffos/SkiffOS/tree/master/configs/allwinner/nezha
> > [2] https://github.com/smaeul/u-boot/commit/2e89b706f5c956a70c989cd31665f1429e9a0b48
> > [3] https://lore.kernel.org/all/20240503-dev-charlie-support_thead_vector_6_9-v6-0-cb7624e65d82@rivosinc.com/
> > [4] https://lore.kernel.org/lkml/20240719-support_vendor_extensions-v3-4-0af7587bbec0@rivosinc.com/T/
> > 
> > ---
> > Changes in v10:
> > - In DT probing disable vector with new function to clear vendor
> >    extension bits for xtheadvector
> > - Add ghostwrite mitigations for c9xx CPUs. This disables xtheadvector
> >    unless mitigations=off is set as a kernel boot arg
> > - Link to v9: https://lore.kernel.org/r/20240806-xtheadvector-v9-0-62a56d2da5d0@rivosinc.com
> > 
> > Changes in v9:
> > - Rebase onto palmer's for-next
> > - Fix sparse error in arch/riscv/kernel/vendor_extensions/thead.c
> > - Fix maybe-uninitialized warning in arch/riscv/include/asm/vendor_extensions/vendor_hwprobe.h
> > - Wrap some long lines
> > - Link to v8: https://lore.kernel.org/r/20240724-xtheadvector-v8-0-cf043168e137@rivosinc.com
> > 
> > Changes in v8:
> > - Rebase onto palmer's for-next
> > - Link to v7: https://lore.kernel.org/r/20240724-xtheadvector-v7-0-b741910ada3e@rivosinc.com
> > 
> > Changes in v7:
> > - Add defs for has_xtheadvector_no_alternatives() and has_xtheadvector()
> >    when vector disabled. (Palmer)
> > - Link to v6: https://lore.kernel.org/r/20240722-xtheadvector-v6-0-c9af0130fa00@rivosinc.com
> > 
> > Changes in v6:
> > - Fix return type of is_vector_supported()/is_xthead_supported() to be bool
> > - Link to v5: https://lore.kernel.org/r/20240719-xtheadvector-v5-0-4b485fc7d55f@rivosinc.com
> > 
> > Changes in v5:
> > - Rebase on for-next
> > - Link to v4: https://lore.kernel.org/r/20240702-xtheadvector-v4-0-2bad6820db11@rivosinc.com
> > 
> > Changes in v4:
> > - Replace inline asm with C (Samuel)
> > - Rename VCSRs to CSRs (Samuel)
> > - Replace .insn directives with .4byte directives
> > - Link to v3: https://lore.kernel.org/r/20240619-xtheadvector-v3-0-bff39eb9668e@rivosinc.com
> > 
> > Changes in v3:
> > - Add back Heiko's signed-off-by (Conor)
> > - Mark RISCV_HWPROBE_KEY_VENDOR_EXT_THEAD_0 as a bitmask
> > - Link to v2: https://lore.kernel.org/r/20240610-xtheadvector-v2-0-97a48613ad64@rivosinc.com
> > 
> > Changes in v2:
> > - Removed extraneous references to "riscv,vlenb" (Jess)
> > - Moved declaration of "thead,vlenb" into cpus.yaml and added
> >    restriction that it's only applicable to thead cores (Conor)
> > - Check CONFIG_RISCV_ISA_XTHEADVECTOR instead of CONFIG_RISCV_ISA_V for
> >    thead,vlenb (Jess)
> > - Fix naming of hwprobe variables (Evan)
> > - Link to v1: https://lore.kernel.org/r/20240609-xtheadvector-v1-0-3fe591d7f109@rivosinc.com
> > 
> > ---
> > Charlie Jenkins (13):
> >        dt-bindings: riscv: Add xtheadvector ISA extension description
> >        dt-bindings: cpus: add a thead vlen register length property
> >        riscv: dts: allwinner: Add xtheadvector to the D1/D1s devicetree
> >        riscv: Add thead and xtheadvector as a vendor extension
> >        riscv: vector: Use vlenb from DT for thead
> >        riscv: csr: Add CSR encodings for CSR_VXRM/CSR_VXSAT
> >        riscv: Add xtheadvector instruction definitions
> >        riscv: vector: Support xtheadvector save/restore
> >        riscv: hwprobe: Add thead vendor extension probing
> >        riscv: hwprobe: Document thead vendor extensions and xtheadvector extension
> >        selftests: riscv: Fix vector tests
> >        selftests: riscv: Support xtheadvector in vector tests
> >        riscv: Add ghostwrite vulnerability
> > 
> > Heiko Stuebner (1):
> >        RISC-V: define the elements of the VCSR vector CSR
> > 
> >   Documentation/arch/riscv/hwprobe.rst               |  10 +
> >   Documentation/devicetree/bindings/riscv/cpus.yaml  |  19 ++
> >   .../devicetree/bindings/riscv/extensions.yaml      |  10 +
> >   arch/riscv/Kconfig.errata                          |  11 +
> >   arch/riscv/Kconfig.vendor                          |  26 ++
> >   arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi      |   3 +-
> >   arch/riscv/errata/thead/errata.c                   |  28 ++
> >   arch/riscv/include/asm/bugs.h                      |  22 ++
> >   arch/riscv/include/asm/cpufeature.h                |   2 +
> >   arch/riscv/include/asm/csr.h                       |  15 +
> >   arch/riscv/include/asm/errata_list.h               |   3 +-
> >   arch/riscv/include/asm/hwprobe.h                   |   3 +-
> >   arch/riscv/include/asm/switch_to.h                 |   2 +-
> >   arch/riscv/include/asm/vector.h                    | 225 +++++++++++----
> >   arch/riscv/include/asm/vendor_extensions/thead.h   |  48 ++++
> >   .../include/asm/vendor_extensions/thead_hwprobe.h  |  19 ++
> >   .../include/asm/vendor_extensions/vendor_hwprobe.h |  37 +++
> >   arch/riscv/include/uapi/asm/hwprobe.h              |   3 +-
> >   arch/riscv/include/uapi/asm/vendor/thead.h         |   3 +
> >   arch/riscv/kernel/Makefile                         |   2 +
> >   arch/riscv/kernel/bugs.c                           |  55 ++++
> >   arch/riscv/kernel/cpufeature.c                     |  58 +++-
> >   arch/riscv/kernel/kernel_mode_vector.c             |   8 +-
> >   arch/riscv/kernel/process.c                        |   4 +-
> >   arch/riscv/kernel/signal.c                         |   6 +-
> >   arch/riscv/kernel/sys_hwprobe.c                    |   5 +
> >   arch/riscv/kernel/vector.c                         |  24 +-
> >   arch/riscv/kernel/vendor_extensions.c              |  10 +
> >   arch/riscv/kernel/vendor_extensions/Makefile       |   2 +
> >   arch/riscv/kernel/vendor_extensions/thead.c        |  29 ++
> >   .../riscv/kernel/vendor_extensions/thead_hwprobe.c |  19 ++
> >   drivers/base/cpu.c                                 |   3 +
> >   include/linux/cpu.h                                |   1 +
> >   tools/testing/selftests/riscv/vector/.gitignore    |   3 +-
> >   tools/testing/selftests/riscv/vector/Makefile      |  17 +-
> >   .../selftests/riscv/vector/v_exec_initval_nolibc.c |  94 +++++++
> >   tools/testing/selftests/riscv/vector/v_helpers.c   |  68 +++++
> >   tools/testing/selftests/riscv/vector/v_helpers.h   |   8 +
> >   tools/testing/selftests/riscv/vector/v_initval.c   |  22 ++
> >   .../selftests/riscv/vector/v_initval_nolibc.c      |  68 -----
> >   .../selftests/riscv/vector/vstate_exec_nolibc.c    |  20 +-
> >   .../testing/selftests/riscv/vector/vstate_prctl.c  | 305 +++++++++++++--------
> >   42 files changed, 1048 insertions(+), 272 deletions(-)
> > ---
> > base-commit: 0e3f3649d44bf1b388a7613ade14c29cbdedf075
> > change-id: 20240530-xtheadvector-833d3d17b423
> 
> 
> Hello Charlie,
> 
> 
> Apologize for the last email, when dealing with pastebin it deleted the last
> version...
> 
> tl,dr for the last email: Patches not boot on Sipeed Lichee RV Dock (with
> same D1 SoC).
> 
> Logs here:
> 
> https://fars.ee/XFzR
> 
> (the board resets without kernel panic)

Apologies, this thread slipped by me. This looks to be the same issue as was experienced here [1] and fixed here [2].

[1] https://lore.kernel.org/linux-riscv/ZoydV7vad5JWIcZb@ghost/
[2] https://lore.kernel.org/linux-riscv/20240820034850.3189912-1-apatel@ventanamicro.com/

Since you are on 6.11-rc2 that patch is probably not in your tree, as it
was merged in 6.11-rc4 unfortunately. Can you try updating your kernel
to include that patch?

- Charlie


> 
> 
> Cheers,
> 
> Aoba K