From nobody Wed Sep 10 05:32:06 2025 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 02BFB31D750; Mon, 8 Sep 2025 23:00:17 +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=1757372419; cv=none; b=FNo/QlJ6KiNB+g+m87PCiCxHikN4be/YsvEWcjpmQ8Wyd+offpcgv6wN8b+vw2BJVAaU+h4KUFrlW0PGlKNMkiPQ0uBsngQyv+HC+JqIpvyGNh9rFAbipzA3ZQRIwwuwe1bhO17dtCXf9FKafGxzapoQDyzytidFg+jz3DQ5GDk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757372419; c=relaxed/simple; bh=RhXdOrpmvWhEXZAJBOlVp00/Ibtc92pO9VfibfnzKL4=; h=Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type:Date; b=KUugInjhnz43cy3go5JNMSP5SvKf5gat3t05eo2CLdwBnalJNuKA+bUrG1yxeLpXSEmR1pvUcCA4hv/Tx6MyQWi+y1CYjLWdjIYwMAl63O+YMFNR6Wz/AamSOHXLQ26NMloH5wNMbT/0qtFbljwWhBgRRU6ftwhwjYoF0eh3Z+o= 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=4VHy6Q4Z; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=K5DH7yM5; 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="4VHy6Q4Z"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="K5DH7yM5" Message-ID: <20250908225753.269052052@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1757372415; 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=gQFvLoA+8aqRp49/IJYirlydqYT+cxE6z9BZ2w2sdfQ=; b=4VHy6Q4Z+X7wotuWb5XH/oWzf2xQ8Gd0gQPu9ssvBPHM4VT7QrOyzhbx/QFgz8+y1QHeEw mSVVzXvAy/FjkHbMaik6gBQGNW5pPxF9+/gUJhWjPU5nF1BHHiUCoFFQsFISIfiqQCqTmG rHS0xtst6Lvm/5H6SOWcFSp1R2yJUgOM4Is+pMwMESCCvBD1/6EA8XYPV9uuSlGhObgW1c NAPjqtd62loFd4ip+aTKUsvCIupJbv9ghvFNCoXmfU8YRIjWt1NSF8BBgpPHLy284UJ2kl NkLBzghgN5rvqfZvuP38Ja/1PaRWtas2T9O9vvHoHFLvYAVHI7GrU/7ykFf/DA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1757372415; 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=gQFvLoA+8aqRp49/IJYirlydqYT+cxE6z9BZ2w2sdfQ=; b=K5DH7yM5WVkWYaguBKpIUFa6o5NWJVq4gdxsJ+b5yQadggpnnNZGAnPlkUFbkqokkTKa6G 75xOkj58B796zzBQ== From: Thomas Gleixner To: LKML Cc: Mathieu Desnoyers , Peter Zijlstra , "Paul E. McKenney" , Boqun Feng , Peter Zilstra , Jonathan Corbet , Prakash Sangappa , Madadi Vineeth Reddy , K Prateek Nayak , Steven Rostedt , Sebastian Andrzej Siewior , Arnd Bergmann , linux-arch@vger.kernel.org Subject: [patch 11/12] entry: Hook up rseq time slice extension References: <20250908225709.144709889@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Tue, 9 Sep 2025 01:00:14 +0200 (CEST) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Wire the grant decision function up in exit_to_user_mode_loop() Signed-off-by: Thomas Gleixner Cc: Mathieu Desnoyers Cc: Peter Zijlstra Cc: "Paul E. McKenney" Cc: Boqun Feng --- kernel/entry/common.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -17,6 +17,14 @@ void __weak arch_do_signal_or_restart(st #define EXIT_TO_USER_MODE_WORK_LOOP (EXIT_TO_USER_MODE_WORK) #endif =20 +/* TIF bits, which prevent a time slice extension. */ +#ifdef CONFIG_PREEMPT_RT +# define TIF_SLICE_EXT_SCHED (_TIF_NEED_RESCHED_LAZY) +#else +# define TIF_SLICE_EXT_SCHED (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY) +#endif +#define TIF_SLICE_EXT_DENY (EXIT_TO_USER_MODE_WORK & ~TIF_SLICE_EXT_SCHED) + static __always_inline unsigned long __exit_to_user_mode_loop(struct pt_re= gs *regs, unsigned long ti_work) { @@ -28,8 +36,10 @@ static __always_inline unsigned long __e =20 local_irq_enable_exit_to_user(ti_work); =20 - if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) - schedule(); + if (ti_work & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) { + if (!rseq_grant_slice_extension(ti_work & TIF_SLICE_EXT_DENY)) + schedule(); + } =20 if (ti_work & _TIF_UPROBE) uprobe_notify_resume(regs);