From nobody Mon Feb 9 00:20:39 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC622347BCF; Wed, 22 Oct 2025 12:49:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761137369; cv=none; b=f/zAwQXRmHk80Meaorhln7cF3OGQdv36jTGyNAir2VgWBg0p9aZSwK+m4D7kD619qNk0FpQhs3OQu/sMe/P43ZljpFMa3kQ+gCARfBtruljLLZjC4qzc0Bn4e5G4uyXnvtxvdx+yWZ8xTdE/642E5d5YtS178wCPI3lK3ewcqhE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761137369; c=relaxed/simple; bh=XFbP7c4oWTMLAjnLkkeDQLOvFLNhdk14vwJ7xtqtbVU=; h=Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type:Date; b=olEOwaQDM0+dqo2eCwjyz5JLm/LVZZ4WEsGkN+wx30gUBv5dXmgh3ennfZ2hK14fVeMT7gU3lU6POavjQNY9C546lIqUg123PskbtUW7Nj4vAXzboBJqHX1FP7AAN2+0zDdt6UYxb2j1iCcZSy5u5BNDUE7u3V16Do15/PPD5To= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=sE058jY4; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=LCpBggbX; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="sE058jY4"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="LCpBggbX" Message-ID: <20251022103112.539017094@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1761137356; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=uuF1PbflRL7G3epzTRJvFK2AzVPBYAY82eKYUINaU84=; b=sE058jY4nU6VsrYvJYJGWz0GnmS2zddKt81kyGurkLnKI3lTj4IAfwcC7vb0GQE2MKAIC9 06bYY0LlPsompS+ICNa3F0PddkENSI1sjP6uhPMX8hRgmC4QtXBo0vzsziPIKkEfKLUxRz e78CSOuQNN3Z0MNphVxMCQu15iLvF0NdT6dFANIPGRsh1693eM6rjQmEsxH7SYRE9EXGNs aJ1tZ74jsYpp+Dr7L+Q4UvLxfDGI4CvODwLqZcPoIb4kFWxVKbAkhaHmpA/QT/7i7q48Gk i6f0dFKptvOHQUJs1yizaeIwBhEXcT5MWnhDxQOY/prkjd4IGXRTuOAeBOIfPQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1761137356; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=uuF1PbflRL7G3epzTRJvFK2AzVPBYAY82eKYUINaU84=; b=LCpBggbX1O1nqs3aE6YLPbmxhfEEsetgCmtO5LHIcdjPiL9+7YVxy6NLO1LLLCxGKuvIYc NMSIIhJLPzxbI5Dw== From: Thomas Gleixner To: LKML Cc: x86@kernel.org, kernel test robot , Russell King , linux-arm-kernel@lists.infradead.org, Linus Torvalds , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , linuxppc-dev@lists.ozlabs.org, Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org, Heiko Carstens , Christian Borntraeger , Sven Schnelle , linux-s390@vger.kernel.org, Mathieu Desnoyers , Andrew Cooper , David Laight , Julia Lawall , Nicolas Palix , Peter Zijlstra , Darren Hart , Davidlohr Bueso , =?UTF-8?q?Andr=C3=A9=20Almeida?= , Alexander Viro , Christian Brauner , Jan Kara , linux-fsdevel@vger.kernel.org Subject: [patch V4 11/12] x86/futex: Convert to scoped user access References: <20251022102427.400699796@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Wed, 22 Oct 2025 14:49:15 +0200 (CEST) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Replace the open coded implementation with the scoped user access guards No functional change intended. Signed-off-by: Thomas Gleixner Cc: x86@kernel.org --- V4: Rename once more Use asm_inline - Andrew V3: Adapt to scope changes V2: Convert to scoped masked access Use RW access functions - Christophe --- arch/x86/include/asm/futex.h | 75 ++++++++++++++++++--------------------= ----- 1 file changed, 33 insertions(+), 42 deletions(-) --- --- a/arch/x86/include/asm/futex.h +++ b/arch/x86/include/asm/futex.h @@ -46,38 +46,31 @@ do { \ } while(0) =20 static __always_inline int arch_futex_atomic_op_inuser(int op, int oparg, = int *oval, - u32 __user *uaddr) + u32 __user *uaddr) { - if (can_do_masked_user_access()) - uaddr =3D masked_user_access_begin(uaddr); - else if (!user_access_begin(uaddr, sizeof(u32))) - return -EFAULT; - - switch (op) { - case FUTEX_OP_SET: - unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault); - break; - case FUTEX_OP_ADD: - unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval, - uaddr, oparg, Efault); - break; - case FUTEX_OP_OR: - unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault); - break; - case FUTEX_OP_ANDN: - unsafe_atomic_op2("andl %4, %3", oval, uaddr, ~oparg, Efault); - break; - case FUTEX_OP_XOR: - unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault); - break; - default: - user_access_end(); - return -ENOSYS; + scoped_user_rw_access(uaddr, Efault) { + switch (op) { + case FUTEX_OP_SET: + unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault); + break; + case FUTEX_OP_ADD: + unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval, uaddr, oparg, Efaul= t); + break; + case FUTEX_OP_OR: + unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault); + break; + case FUTEX_OP_ANDN: + unsafe_atomic_op2("andl %4, %3", oval, uaddr, ~oparg, Efault); + break; + case FUTEX_OP_XOR: + unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault); + break; + default: + return -ENOSYS; + } } - user_access_end(); return 0; Efault: - user_access_end(); return -EFAULT; } =20 @@ -86,21 +79,19 @@ static inline int futex_atomic_cmpxchg_i { int ret =3D 0; =20 - if (can_do_masked_user_access()) - uaddr =3D masked_user_access_begin(uaddr); - else if (!user_access_begin(uaddr, sizeof(u32))) - return -EFAULT; - asm volatile("\n" - "1:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" - "2:\n" - _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0) \ - : "+r" (ret), "=3Da" (oldval), "+m" (*uaddr) - : "r" (newval), "1" (oldval) - : "memory" - ); - user_access_end(); - *uval =3D oldval; + scoped_user_rw_access(uaddr, Efault) { + asm_inline volatile("\n" + "1:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" + "2:\n" + _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0) + : "+r" (ret), "=3Da" (oldval), "+m" (*uaddr) + : "r" (newval), "1" (oldval) + : "memory"); + *uval =3D oldval; + } return ret; +Efault: + return -EFAULT; } =20 #endif