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Tue, 13 Oct 2026 09:59:13 -0700 (PDT) Date: Tue, 13 Oct 2026 11:59:12 -0500 From: Andy Chiu To: Samuel Holland Cc: Paul Walmsley , Anup Patel , Atish Patra , Palmer Dabbelt , linux-kernel@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH 1/3] riscv: Drop CONFIG_RISCV_ISA_V_DEFAULT_ENABLE Message-ID: References: <20261007085126.222688-1-samuel.holland@sifive.com> <20261007085126.222688-2-samuel.holland@sifive.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261007085126.222688-2-samuel.holland@sifive.com> On Wed, Oct 07, 2026 at 01:51:16AM -0700, Samuel Holland wrote: > The ability to prevent userspace from executing vector instructions was > provided as a escape hatch for software that was broken by adding vector > state to the signal context. This appears to be unused in practice, and > creates confusion in the extension support returned by hwprobe(), as in > this one special case an extension reported as present by hwprobe() is > unusable. > > Since we believe it is safe to always allow vector usage, start removing > this functionality by dropping the Kconfig option. It is possible to get > equivalent behavior by setting the sysctl at boot via the kernel command > line, but that method will also soon be deprecated. > > Signed-off-by: Samuel Holland Reviewed-by: Andy Chiu Thanks! > --- > > arch/riscv/Kconfig | 11 ----------- > arch/riscv/kernel/vector.c | 2 +- > 2 files changed, 1 insertion(+), 12 deletions(-) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index d6c2dbf8455ce..e26450f0d38fb 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -650,17 +650,6 @@ config RISCV_ISA_V > > If you don't know what to do here, say Y. > > -config RISCV_ISA_V_DEFAULT_ENABLE > - bool "Enable userspace Vector by default" > - depends on RISCV_ISA_V > - default y > - help > - Say Y here if you want to enable Vector in userspace by default. > - Otherwise, userspace has to make explicit prctl() call to enable > - Vector, or enable it via the sysctl interface. > - > - If you don't know what to do here, say Y. > - > config RISCV_ISA_V_UCOPY_THRESHOLD > int "Threshold size for vectorized user copies" > depends on RISCV_ISA_V > diff --git a/arch/riscv/kernel/vector.c b/arch/riscv/kernel/vector.c > index b112166d51e9f..9641343732782 100644 > --- a/arch/riscv/kernel/vector.c > +++ b/arch/riscv/kernel/vector.c > @@ -20,7 +20,7 @@ > #include > #include > > -static bool riscv_v_implicit_uacc = IS_ENABLED(CONFIG_RISCV_ISA_V_DEFAULT_ENABLE); > +static bool riscv_v_implicit_uacc = true; > static struct kmem_cache *riscv_v_user_cachep; > #ifdef CONFIG_RISCV_ISA_V_PREEMPTIVE > static struct kmem_cache *riscv_v_kernel_cachep; > -- > 2.52.0 >