From nobody Fri Feb 13 17:33:59 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61133E7D0AA for ; Thu, 21 Sep 2023 20:37:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232075AbjIUUhj (ORCPT ); Thu, 21 Sep 2023 16:37:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47638 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231708AbjIUUhZ (ORCPT ); Thu, 21 Sep 2023 16:37:25 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3C1E81FFD; Thu, 21 Sep 2023 10:36:34 -0700 (PDT) Date: Thu, 21 Sep 2023 17:36:05 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1695317766; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BdlegKqSx1sFXYsl6OPUIPVsYZjue2Sou5wwaOjYFwE=; b=N6Ne6cKwyMO1FBjjffxoMh36OXm6HwtL+9ZZbTEj5vme1MTSni/wzqHsVtxk0e+On5iE3Y giAkdR93fYh9DDWjZiy/XIIfbhLPXobPq7cntEST+Vq1ZBJxUf3AId3L3pSmxdSIp4rDDU zvVnBXLZJ2KQ3eUpgke3fHhRWL82ND+FvkZk9EUChUhQYiC0/EZoW8+dX8IvUjWuyK6mXr lr5RUdWALBFZ+ySAx1E+Xj1L53cGSa60c1sRYdXLjSvn4TcspXgNzQn2EHDhsnwFLIN8bB VkDKkegayO6HmcZVA+CEWGlR6fvj8Xe34NyvnDqLIJ6+2i5ia3DkF5uOPkxlIQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1695317766; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BdlegKqSx1sFXYsl6OPUIPVsYZjue2Sou5wwaOjYFwE=; b=w/r0GLzYM8z+AgGBS/FJTA2A86kOH3teS/zTZ1WA4e27OORUGq5+LLGKS6v/UvILtIOgTy QrAd28T+KxMqrCBA== From: "tip-bot2 for peterz@infradead.org" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: locking/core] futex: Flag conversion Cc: "Peter Zijlstra (Intel)" , Thomas Gleixner , andrealmeid@igalia.com, x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20230921105247.722140574@noisy.programming.kicks-ass.net> References: <20230921105247.722140574@noisy.programming.kicks-ass.net> MIME-Version: 1.0 Message-ID: <169531776573.27769.5454262358398654731.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the locking/core branch of tip: Commit-ID: 5694289ce183bc3336407a78c8c722a0b9208f9b Gitweb: https://git.kernel.org/tip/5694289ce183bc3336407a78c8c722a0b= 9208f9b Author: peterz@infradead.org AuthorDate: Thu, 21 Sep 2023 12:45:08 +02:00 Committer: Peter Zijlstra CommitterDate: Thu, 21 Sep 2023 19:22:05 +02:00 futex: Flag conversion Futex has 3 sets of flags: - legacy futex op bits - futex2 flags - internal flags Add a few helpers to convert from the API flags into the internal flags. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Thomas Gleixner Reviewed-by: Andr=C3=A9 Almeida Link: https://lore.kernel.org/r/20230921105247.722140574@noisy.programming.= kicks-ass.net --- kernel/futex/futex.h | 63 ++++++++++++++++++++++++++++++++++++++-- kernel/futex/syscalls.c | 24 +++++---------- kernel/futex/waitwake.c | 4 +-- 3 files changed, 71 insertions(+), 20 deletions(-) diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h index b5379c0..68fc052 100644 --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -5,6 +5,7 @@ #include #include #include +#include =20 #ifdef CONFIG_PREEMPT_RT #include @@ -16,8 +17,15 @@ * Futex flags used to encode options to functions and preserve them across * restarts. */ +#define FLAGS_SIZE_8 0x00 +#define FLAGS_SIZE_16 0x01 +#define FLAGS_SIZE_32 0x02 +#define FLAGS_SIZE_64 0x03 + +#define FLAGS_SIZE_MASK 0x03 + #ifdef CONFIG_MMU -# define FLAGS_SHARED 0x01 +# define FLAGS_SHARED 0x10 #else /* * NOMMU does not have per process address space. Let the compiler optimize @@ -25,8 +33,57 @@ */ # define FLAGS_SHARED 0x00 #endif -#define FLAGS_CLOCKRT 0x02 -#define FLAGS_HAS_TIMEOUT 0x04 +#define FLAGS_CLOCKRT 0x20 +#define FLAGS_HAS_TIMEOUT 0x40 +#define FLAGS_NUMA 0x80 + +/* FUTEX_ to FLAGS_ */ +static inline unsigned int futex_to_flags(unsigned int op) +{ + unsigned int flags =3D FLAGS_SIZE_32; + + if (!(op & FUTEX_PRIVATE_FLAG)) + flags |=3D FLAGS_SHARED; + + if (op & FUTEX_CLOCK_REALTIME) + flags |=3D FLAGS_CLOCKRT; + + return flags; +} + +/* FUTEX2_ to FLAGS_ */ +static inline unsigned int futex2_to_flags(unsigned int flags2) +{ + unsigned int flags =3D flags2 & FUTEX2_SIZE_MASK; + + if (!(flags2 & FUTEX2_PRIVATE)) + flags |=3D FLAGS_SHARED; + + if (flags2 & FUTEX2_NUMA) + flags |=3D FLAGS_NUMA; + + return flags; +} + +static inline unsigned int futex_size(unsigned int flags) +{ + return 1 << (flags & FLAGS_SIZE_MASK); +} + +static inline bool futex_flags_valid(unsigned int flags) +{ + /* Only 64bit futexes for 64bit code */ + if (!IS_ENABLED(CONFIG_64BIT) || in_compat_syscall()) { + if ((flags & FLAGS_SIZE_MASK) =3D=3D FLAGS_SIZE_64) + return false; + } + + /* Only 32bit futexes are implemented -- for now */ + if ((flags & FLAGS_SIZE_MASK) !=3D FLAGS_SIZE_32) + return false; + + return true; +} =20 #ifdef CONFIG_FAIL_FUTEX extern bool should_fail_futex(bool fshared); diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c index 953f0a4..948ac24 100644 --- a/kernel/futex/syscalls.c +++ b/kernel/futex/syscalls.c @@ -1,6 +1,5 @@ // SPDX-License-Identifier: GPL-2.0-or-later =20 -#include #include #include =20 @@ -85,15 +84,12 @@ err_unlock: long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, u32 __user *uaddr2, u32 val2, u32 val3) { + unsigned int flags =3D futex_to_flags(op); int cmd =3D op & FUTEX_CMD_MASK; - unsigned int flags =3D 0; =20 - if (!(op & FUTEX_PRIVATE_FLAG)) - flags |=3D FLAGS_SHARED; - - if (op & FUTEX_CLOCK_REALTIME) { - flags |=3D FLAGS_CLOCKRT; - if (cmd !=3D FUTEX_WAIT_BITSET && cmd !=3D FUTEX_WAIT_REQUEUE_PI && + if (flags & FLAGS_CLOCKRT) { + if (cmd !=3D FUTEX_WAIT_BITSET && + cmd !=3D FUTEX_WAIT_REQUEUE_PI && cmd !=3D FUTEX_LOCK_PI2) return -ENOSYS; } @@ -201,21 +197,19 @@ static int futex_parse_waitv(struct futex_vector *fut= exv, unsigned int i; =20 for (i =3D 0; i < nr_futexes; i++) { + unsigned int flags; + if (copy_from_user(&aux, &uwaitv[i], sizeof(aux))) return -EFAULT; =20 if ((aux.flags & ~FUTEX2_VALID_MASK) || aux.__reserved) return -EINVAL; =20 - if (!IS_ENABLED(CONFIG_64BIT) || in_compat_syscall()) { - if ((aux.flags & FUTEX2_SIZE_MASK) =3D=3D FUTEX2_SIZE_U64) - return -EINVAL; - } - - if ((aux.flags & FUTEX2_SIZE_MASK) !=3D FUTEX2_SIZE_U32) + flags =3D futex2_to_flags(aux.flags); + if (!futex_flags_valid(flags)) return -EINVAL; =20 - futexv[i].w.flags =3D aux.flags; + futexv[i].w.flags =3D flags; futexv[i].w.val =3D aux.val; futexv[i].w.uaddr =3D aux.uaddr; futexv[i].q =3D futex_q_init; diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c index ba01b94..fa97577 100644 --- a/kernel/futex/waitwake.c +++ b/kernel/futex/waitwake.c @@ -419,11 +419,11 @@ static int futex_wait_multiple_setup(struct futex_vec= tor *vs, int count, int *wo */ retry: for (i =3D 0; i < count; i++) { - if ((vs[i].w.flags & FUTEX_PRIVATE_FLAG) && retry) + if (!(vs[i].w.flags & FLAGS_SHARED) && retry) continue; =20 ret =3D get_futex_key(u64_to_user_ptr(vs[i].w.uaddr), - !(vs[i].w.flags & FUTEX_PRIVATE_FLAG), + vs[i].w.flags & FLAGS_SHARED, &vs[i].q.key, FUTEX_READ); =20 if (unlikely(ret))