Re: [PATCH 1/2] RISC-V: Add Zicclsm to cpufeature and hwprobe

[Charlie Jenkins <charlie@rivosinc.com>]

On Fri, Aug 09, 2024 at 12:22:39PM -0400, Jesse Taube wrote:
> > Zicclsm Misaligned loads and stores to main memory regions with both
> > the cacheability and coherence PMAs must be supported.
> > Note:
> > This introduces a new extension name for this feature.
> > This requires misaligned support for all regular load and store
> > instructions (including scalar and vector) but not AMOs or other
> > specialized forms of memory access. Even though mandated, misaligned
> > loads and stores might execute extremely slowly. Standard software
> > distributions should assume their existence only for correctness,
> > not for performance.

You left in the > characters.

Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Tested-by: Charlie Jenkins <charlie@rivosinc.com>

> 
> Signed-off-by: Jesse Taube <jesse@rivosinc.com>
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> Reviewed-by: Andy Chiu <andy.chiu@sifive.com>
> ---
> V1 -> V2:
>  - Add documentation for Zicclsm
>  - Move Zicclsm to correct location
> V2 -> V3:
>  - No changes
> V3 -> V4:
>  - Add definitions to hwprobe.rst
> V4 -> V5:
>  - No changes
> V5 -> V6:
>  - No changes
> V6 -> V7:
>  - No changes
> V7 -> V8:
>  - Rebase onto 2d1f51d8a4b0 (palmer/for-next)
>  - Change commit description
> ---
>  Documentation/arch/riscv/hwprobe.rst  | 5 +++++
>  arch/riscv/include/asm/hwcap.h        | 1 +
>  arch/riscv/include/uapi/asm/hwprobe.h | 1 +
>  arch/riscv/kernel/cpufeature.c        | 1 +
>  arch/riscv/kernel/sys_hwprobe.c       | 1 +
>  5 files changed, 9 insertions(+)
> 
> diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
> index 3db60a0911df..22c118df520b 100644
> --- a/Documentation/arch/riscv/hwprobe.rst
> +++ b/Documentation/arch/riscv/hwprobe.rst
> @@ -239,6 +239,11 @@ The following keys are defined:
>         ratified in commit 98918c844281 ("Merge pull request #1217 from
>         riscv/zawrs") of riscv-isa-manual.
>  
> +  * :c:macro:`RISCV_HWPROBE_EXT_ZICCLSM`:  The Zicclsm extension is supported as
> +        defined in the RISC-V RVA Profiles Specification. Misaligned support for
> +        all regular load and store instructions (including scalar and vector) but
> +        not AMOs or other specialized forms of memory access.
> +
>  * :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: A bitmask that contains performance
>    information about the selected set of processors.
>  
> diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
> index 5a0bd27fd11a..c93d957458f0 100644
> --- a/arch/riscv/include/asm/hwcap.h
> +++ b/arch/riscv/include/asm/hwcap.h
> @@ -92,6 +92,7 @@
>  #define RISCV_ISA_EXT_ZCF		83
>  #define RISCV_ISA_EXT_ZCMOP		84
>  #define RISCV_ISA_EXT_ZAWRS		85
> +#define RISCV_ISA_EXT_ZICCLSM		86
>  
>  #define RISCV_ISA_EXT_XLINUXENVCFG	127
>  
> diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
> index b706c8e47b02..a9370968fc9f 100644
> --- a/arch/riscv/include/uapi/asm/hwprobe.h
> +++ b/arch/riscv/include/uapi/asm/hwprobe.h
> @@ -72,6 +72,7 @@ struct riscv_hwprobe {
>  #define		RISCV_HWPROBE_EXT_ZCF		(1ULL << 46)
>  #define		RISCV_HWPROBE_EXT_ZCMOP		(1ULL << 47)
>  #define		RISCV_HWPROBE_EXT_ZAWRS		(1ULL << 48)
> +#define		RISCV_HWPROBE_EXT_ZICCLSM	(1ULL << 49)
>  #define RISCV_HWPROBE_KEY_CPUPERF_0	5
>  #define		RISCV_HWPROBE_MISALIGNED_UNKNOWN	(0 << 0)
>  #define		RISCV_HWPROBE_MISALIGNED_EMULATED	(1 << 0)
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 8f20607adb40..2f54d811a9b8 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -314,6 +314,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  					  riscv_ext_zicbom_validate),
>  	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts,
>  					  riscv_ext_zicboz_validate),
> +	__RISCV_ISA_EXT_DATA(zicclsm, RISCV_ISA_EXT_ZICCLSM),
>  	__RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR),
>  	__RISCV_ISA_EXT_DATA(zicond, RISCV_ISA_EXT_ZICOND),
>  	__RISCV_ISA_EXT_DATA(zicsr, RISCV_ISA_EXT_ZICSR),
> diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
> index 8d1b5c35d2a7..01eea29a56cd 100644
> --- a/arch/riscv/kernel/sys_hwprobe.c
> +++ b/arch/riscv/kernel/sys_hwprobe.c
> @@ -107,6 +107,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
>  		EXT_KEY(ZCB);
>  		EXT_KEY(ZCMOP);
>  		EXT_KEY(ZICBOZ);
> +		EXT_KEY(ZICCLSM);
>  		EXT_KEY(ZICOND);
>  		EXT_KEY(ZIHINTNTL);
>  		EXT_KEY(ZIHINTPAUSE);
> -- 
> 2.45.2
>