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Date:   Wed, 04 Oct 2023 07:07:11 -0700 (PDT)
Subject:     Re: [PATCH v3 2/6] RISC-V: Detect Zicond from ISA string
In-Reply-To: <20231003035226.1945725-3-apatel@ventanamicro.com>
CC:     pbonzini@redhat.com, atishp@atishpatra.org,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Conor Dooley <conor@kernel.org>, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, shuah@kernel.org,
        ajones@ventanamicro.com, mchitale@ventanamicro.com,
        devicetree@vger.kernel.org, kvm@vger.kernel.org,
        kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
        apatel@ventanamicro.com, Conor Dooley <conor.dooley@microchip.com>
From:   Palmer Dabbelt <palmer@dabbelt.com>
To:     apatel@ventanamicro.com
Message-ID: <mhng-4ec1093a-4542-429e-a9f0-8a976cff9ac4@palmer-ri-x1c9>
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On Mon, 02 Oct 2023 20:52:22 PDT (-0700), apatel@ventanamicro.com wrote:
> The RISC-V integer conditional (Zicond) operation extension defines
> standard conditional arithmetic and conditional-select/move operations
> which are inspired from the XVentanaCondOps extension. In fact, QEMU
> RISC-V also has support for emulating Zicond extension.
>
> Let us detect Zicond extension from ISA string available through
> DT or ACPI.
>
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>  arch/riscv/include/asm/hwcap.h | 1 +
>  arch/riscv/kernel/cpufeature.c | 1 +
>  2 files changed, 2 insertions(+)
>
> diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
> index 0f520f7d058a..6fc51c1b34cf 100644
> --- a/arch/riscv/include/asm/hwcap.h
> +++ b/arch/riscv/include/asm/hwcap.h
> @@ -59,6 +59,7 @@
>  #define RISCV_ISA_EXT_ZIFENCEI		41
>  #define RISCV_ISA_EXT_ZIHPM		42
>  #define RISCV_ISA_EXT_SMSTATEEN		43
> +#define RISCV_ISA_EXT_ZICOND		44
>
>  #define RISCV_ISA_EXT_MAX		64
>
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 3755a8c2a9de..e3803822ab5a 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -167,6 +167,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
>  	__RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM),
>  	__RISCV_ISA_EXT_DATA(zicboz, RISCV_ISA_EXT_ZICBOZ),
>  	__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),
>  	__RISCV_ISA_EXT_DATA(zifencei, RISCV_ISA_EXT_ZIFENCEI),
>  	__RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),

Acked-by: Palmer Dabbelt <palmer@rivosinc.com>

Can we do a shared tag, though?  These will conflict.