On Wed, May 01, 2024 at 11:46:07AM +0100, Conor Dooley wrote:
On Fri, Apr 26, 2024 at 02:29:19PM -0700, Charlie Jenkins wrote:
Separate vendor extensions out into one struct per vendor instead of adding vendor extensions onto riscv_isa_ext.
Add a hidden config RISCV_ISA_VENDOR_EXT to conditionally include this code.
The xtheadvector vendor extension is added using these changes.
This mostly looks good to me, thanks for the updates. There's one thing that I think is wrong, but I need to test and will get back to you on...
Signed-off-by: Charlie Jenkins charlie@rivosinc.com
arch/riscv/Kconfig | 2 + arch/riscv/Kconfig.vendor | 19 ++++++ arch/riscv/include/asm/cpufeature.h | 18 ++++++ arch/riscv/include/asm/vendor_extensions.h | 26 ++++++++ arch/riscv/include/asm/vendor_extensions/thead.h | 19 ++++++ arch/riscv/kernel/Makefile | 2 + arch/riscv/kernel/cpufeature.c | 77 ++++++++++++++++++------ arch/riscv/kernel/vendor_extensions.c | 18 ++++++ arch/riscv/kernel/vendor_extensions/Makefile | 3 + arch/riscv/kernel/vendor_extensions/thead.c | 36 +++++++++++ 10 files changed, 200 insertions(+), 20 deletions(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index be09c8836d56..fec86fba3acd 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -759,6 +759,8 @@ config RISCV_EFFICIENT_UNALIGNED_ACCESS endchoice +source "arch/riscv/Kconfig.vendor"
endmenu # "Platform type" menu "Kernel features" diff --git a/arch/riscv/Kconfig.vendor b/arch/riscv/Kconfig.vendor new file mode 100644 index 000000000000..4fc86810af1d --- /dev/null +++ b/arch/riscv/Kconfig.vendor @@ -0,0 +1,19 @@ +menu "Vendor extensions"
+config RISCV_ISA_VENDOR_EXT
- bool
+menu "T-Head" +config RISCV_ISA_VENDOR_EXT_THEAD
- bool "T-Head vendor extension support"
- select RISCV_ISA_VENDOR_EXT
- default y
- help
Say N here if you want to disable all T-Head vendor extensionsupport. This will cause any T-Head vendor extensions that arerequested to be ignored.What does "requested to be ignored" mean to a punter configuring a kernel? I'd expect this to be something like:
"Say N here to disable detection of and support for all T-Head vendor extensions. Without this option enabled, T-Head vendor extensions will not be detected at boot and their presence not reported to userspace."
Sounds great I will change to that.
- Charlie
In general, I'd expect something that needs some support in the kernel (like vector) to function to have a dedicated option, but the likes of their Zba variant could be detected and reported via hwprobe et al once RISCV_ISA_VENDOR_EXT_THEAD is enabled.
Cheers, Conor.