[PATCH v2 0/7] ISA based RISC-V tune implementation

Mark Hatle
2025-06-17T23:39:57Z

The following implements the risc-v processor tune based on the ISA approach
as documented in the oe-architecture post:

https://lists.openembedded.org/g/openembedded-architecture/message/2155

This set also attempts to make u-boot and kernel configurations dynamic
based on the TUNE_FEATURES.

For the linux-yocto, I suspect that the config fragments should be
sent to the kmeta (kernel-cache), but I'd like a review from Bruce and
others before I do this.

Additionally, this enables a new (optional) features_check for TUNE_FEATURES.

I've found numerous items in the system have certain RISC-V ISA expectations
that may need to be addressed over time, however the obvious one is the
Linux kernel requires ima_zicsr_zifencei. Since it has it's own -march=
setting this will ensure the processor defintion will be compatible.

Also dynamically configure the QEMU cpu based on the tune_features. This
is nice to ensure that what we're actually building should be able to run
on real hardware. However, it does highlight some of the (extension)
limitations in the current design. (limitations as in extension not yet
enabled.)

Note: OpenSBI _requires_ the 'c' extension or it will not execute. I
suspect this can be fixed, but it's beyond my capabilities at this time.

v2:

- Note: the linux-yocto change still needs further rework (noted in commit)
(if everything else is merged, it will still work fine)

- Change the TUNE_FEATURES check to kernel.bbclass per review comments

- Add 7/7 patch for RUST configuration.

Mark Hatle (7):
riscv tunes: ISA Implementation of RISC-V tune features
linux-yocto: Enable risc-v TUNE_FEATURES ISA selections ** DO NOT
MERGE **
u-boot: Dynamic RISC-V ISA configuration
qemuriscv: Dynamically configure qemu CPU
features_check.bbclass: Add support for required TUNE_FEATURES
kernel.bbclass: State riscv required tune_features for Linux
rust-target-config.bbclass: Update for new riscv TUNE_FEATURES

meta/classes-recipe/features_check.bbclass | 2 +-
meta/classes-recipe/kernel.bbclass | 6 +-
.../classes-recipe/rust-target-config.bbclass | 65 ++++++---
meta/conf/machine/include/riscv/README | 122 ++++++++++++++++
.../conf/machine/include/riscv/arch-riscv.inc | 138 +++++++++++++++++-
meta/conf/machine/include/riscv/qemuriscv.inc | 31 +++-
.../conf/machine/include/riscv/tune-riscv.inc | 40 ++---
meta/conf/machine/qemuriscv32.conf | 4 +-
meta/lib/oe/__init__.py | 2 +-
meta/lib/oe/rust.py | 2 -
meta/lib/oe/tune.py | 81 ++++++++++
.../u-boot/files/u-boot-riscv-isa_a.cfg | 1 +
.../u-boot/files/u-boot-riscv-isa_c.cfg | 1 +
.../u-boot/files/u-boot-riscv-isa_clear.cfg | 6 +
.../u-boot/files/u-boot-riscv-isa_d.cfg | 1 +
.../u-boot/files/u-boot-riscv-isa_f.cfg | 1 +
.../u-boot/files/u-boot-riscv-isa_zbb.cfg | 1 +
.../u-boot/files/u-boot-riscv-isa_zicbom.cfg | 1 +
meta/recipes-bsp/u-boot/u-boot-common.inc | 12 ++
.../linux/files/risc-v-isa-c.cfg | 1 +
.../linux/files/risc-v-isa-clear.cfg | 9 ++
.../linux/files/risc-v-isa-fpu.cfg | 1 +
.../linux/files/risc-v-isa-rv32i.cfg | 2 +
.../linux/files/risc-v-isa-rv64i.cfg | 2 +
.../linux/files/risc-v-isa-v.cfg | 1 +
.../linux/files/risc-v-isa-zbb.cfg | 1 +
.../linux/files/risc-v-isa-zicbom.cfg | 1 +
meta/recipes-kernel/linux/linux-yocto.inc | 14 ++
28 files changed, 480 insertions(+), 69 deletions(-)
create mode 100644 meta/conf/machine/include/riscv/README
create mode 100644 meta/lib/oe/tune.py
create mode 100644 meta/recipes-bsp/u-boot/files/u-boot-riscv-isa_a.cfg
create mode 100644 meta/recipes-bsp/u-boot/files/u-boot-riscv-isa_c.cfg
create mode 100644 meta/recipes-bsp/u-boot/files/u-boot-riscv-isa_clear.cfg
create mode 100644 meta/recipes-bsp/u-boot/files/u-boot-riscv-isa_d.cfg
create mode 100644 meta/recipes-bsp/u-boot/files/u-boot-riscv-isa_f.cfg
create mode 100644 meta/recipes-bsp/u-boot/files/u-boot-riscv-isa_zbb.cfg
create mode 100644 meta/recipes-bsp/u-boot/files/u-boot-riscv-isa_zicbom.cfg
create mode 100644 meta/recipes-kernel/linux/files/risc-v-isa-c.cfg
create mode 100644 meta/recipes-kernel/linux/files/risc-v-isa-clear.cfg
create mode 100644 meta/recipes-kernel/linux/files/risc-v-isa-fpu.cfg
create mode 100644 meta/recipes-kernel/linux/files/risc-v-isa-rv32i.cfg
create mode 100644 meta/recipes-kernel/linux/files/risc-v-isa-rv64i.cfg
create mode 100644 meta/recipes-kernel/linux/files/risc-v-isa-v.cfg
create mode 100644 meta/recipes-kernel/linux/files/risc-v-isa-zbb.cfg
create mode 100644 meta/recipes-kernel/linux/files/risc-v-isa-zicbom.cfg

--
2.34.1