From nobody Mon Feb 9 13:36:02 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 6CF3FC001B0 for ; Fri, 14 Jul 2023 14:16:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235438AbjGNOQ4 (ORCPT ); Fri, 14 Jul 2023 10:16:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33314 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235510AbjGNOQn (ORCPT ); Fri, 14 Jul 2023 10:16:43 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C50B730C0; Fri, 14 Jul 2023 07:16:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=98fwNtpV0Bbvya3mBoauq7smkVWN16/6yjAoJPAxLCQ=; b=k0AkkJTwfkefz5URce2ntHKAIC 6CkN91KKm1sEDmU8seNl1uV4Im1FILXye+5BHlydSaZELYf9BNA3/k7+QifPdr1WwzxLzYcvHvf6T P1AJrThlTJ4nWZgI8kec0ij5yNMrSO/t5B/BJ5VDAX+AR7E+PAaN9ykyCq7vT6csjBMqdhA19nELp lEz1sIwnXytxoy8hFGNf0qkpI0+Ch+wz56SHgu5eT13eNOFZ9pHKXoHl5VNSgkeZfGyJrfRhvnzkm 2UMzg2C3u8KfvGSkocm2zB5m0xp474j8eyUMo0BZX3hXkqvYrbCtZ7F7zHwbFS4yTB9IgE5FV80uX dly3b80w==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qKJah-006Iiw-21; Fri, 14 Jul 2023 14:16:16 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id A0834300362; Fri, 14 Jul 2023 16:16:13 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 691B3213728B7; Fri, 14 Jul 2023 16:16:13 +0200 (CEST) Message-ID: <20230714141218.813185695@infradead.org> User-Agent: quilt/0.66 Date: Fri, 14 Jul 2023 15:39:02 +0200 From: Peter Zijlstra To: tglx@linutronix.de, axboe@kernel.dk Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@redhat.com, dvhart@infradead.org, dave@stgolabs.net, andrealmeid@igalia.com, Andrew Morton , urezki@gmail.com, hch@infradead.org, lstoakes@gmail.com, Arnd Bergmann , linux-api@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, malteskarupke@web.de Subject: [RFC][PATCH 03/10] futex: Flag conversion References: <20230714133859.305719029@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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) --- kernel/futex/futex.h | 48 +++++++++++++++++++++++++++++++++++++++++++= ++--- kernel/futex/syscalls.c | 21 +++++++++++++-------- kernel/futex/waitwake.c | 4 ++-- 3 files changed, 60 insertions(+), 13 deletions(-) --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -16,8 +16,15 @@ * 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 +32,43 @@ */ # 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_64; + + 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) +{ + unsigned int size =3D flags & FLAGS_SIZE_MASK; + return 1 << size; /* {0,1,2,3} -> {1,2,4,8} */ +} =20 #ifdef CONFIG_FAIL_FUTEX extern bool should_fail_futex(bool fshared); --- a/kernel/futex/syscalls.c +++ b/kernel/futex/syscalls.c @@ -85,15 +85,12 @@ SYSCALL_DEFINE3(get_robust_list, int, pi 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; } @@ -201,6 +198,8 @@ static int futex_parse_waitv(struct fute unsigned int i; =20 for (i =3D 0; i < nr_futexes; i++) { + unsigned int bits, flags; + if (copy_from_user(&aux, &uwaitv[i], sizeof(aux))) return -EFAULT; =20 @@ -210,7 +209,13 @@ static int futex_parse_waitv(struct fute if ((aux.flags & FUTEX2_64) !=3D FUTEX2_32) return -EINVAL; =20 - futexv[i].w.flags =3D aux.flags; + flags =3D futex2_to_flags(aux.flags); + bits =3D 8 * futex_size(flags); + + if (bits < 64 && aux.val >> bits) + return -EINVAL; + + 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; --- a/kernel/futex/waitwake.c +++ b/kernel/futex/waitwake.c @@ -419,11 +419,11 @@ static int futex_wait_multiple_setup(str */ 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))