From nobody Sat Oct 11 04:18:11 2025 Received: from mail-ed1-f48.google.com (mail-ed1-f48.google.com [209.85.208.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CC1D625BEED for ; Wed, 11 Jun 2025 11:49:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.48 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749642542; cv=none; b=pQ0Zzq9k94JP2aXO6ThEwWdluhfkMTpZnvoMw9erwhtQDG4IHv8GKgA6mypKIgib/Zy1GLFhucfa8Bg/EmkUETv1DniyZ5ijuumfNRvbl//2LBQDpop/ynY/+9kfHbscgm0QdFh9LJI1EbbMr3gMWx6ty0rTCwidOYBv08XW7Q0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749642542; c=relaxed/simple; bh=35M5gOyWlSaqL6iH1KU+YV0U7S6wgKSwxLGbs4KIhfE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=OA9nYEqdFDOlKCHun0emcd42hxOjpekNdc1mbWQxUnoIiVvqb8DTfdfkA1mE263ASX4YZwRjL8uXoVfrNrBlN4Gw94vr7llPOXgxUOjnzPu/0EYywzqfagE2QDaXEfkLIgsu37Ywn4cose6NvCh5GC81VdCMR15/MpfNNvtlH38= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=C9ghENme; arc=none smtp.client-ip=209.85.208.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="C9ghENme" Received: by mail-ed1-f48.google.com with SMTP id 4fb4d7f45d1cf-60794c43101so6871108a12.1 for ; Wed, 11 Jun 2025 04:49:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1749642539; x=1750247339; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=LSRjpysjkvUqzPQa+4DtR1H7++BicgArTKa2t6hjtGY=; b=C9ghENmeToVUF/KYUew990rIk9SrUTkgGjpP12pJl7qXlQLp+y4NweVUlamKaSsMjr 2zHl013HMcukEUKqOBOUlE9DmJJ8K1NADum6QEgjHFr3+Xsxl7EaWr1KCTc7earcwBAv TXh+0iU/lcd87q9yNkTaWDFu4/5jDw4Dfl6CyToMhlie0Mi7S7Xn1Ndc85AwJdLJEMcC /IBWDysgXbsDwiJcYR9JSOajoncc8ZdHrRc4+w+VXT3SeRG9tmBpLluEpvVcNliYEugi T7hsNKFhcr1OUQIcPilvxsG6fuM4BHNHcb5PLMPnDr6s03EpAPRb9DjldjbsfO3NtyKx H2hQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749642539; x=1750247339; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=LSRjpysjkvUqzPQa+4DtR1H7++BicgArTKa2t6hjtGY=; b=ikQTvjnZjVaoFLzUmS8C4Kx0EY6QzpkAOWBXZRsteobeeg98djJg8Yk20+5ef6QRaV lYrFc+Z+KwYHo1CjJDyqGt3xwTEPLo6dD5mcVH13X+9rSdJ/dhM7EMIA3YFYYSlnMaTK MROTPEdOZFHUoRvkCwRMuTaJ0py692GWQslgm9As+4VxsrKssDwBNV28X9b7DGGku/a2 cj31E9oRT0lRWJf41Z75m5USgEJtIbkzrlH8kQF7c7CN1IVeaulje7H78NhuMiPxTd4T Hkx+JvCiYUzVIaytC1iTrWp556wDY/e/Pidp8PBHuIw0bb728EzSMU8BoB5zFPhFmB0y YqzQ== X-Gm-Message-State: AOJu0YwBGwHZLAgTE+yFK6ViHuCiB2pPlXnNsA8dN9Gn/Kq85ScxrRQ9 Qwncf9BmHLxpAz+/M3JUQJLjbtUGkz4Vfo+KyXJx+uCy92hC0HisFi0z X-Gm-Gg: ASbGncsnnssYYBBUZz/hYUJdoKgOOGowmvEbiymvHFjMJn0Lp0UKmRSfbipQKEww2Ie sgdLJ0CdIb+3tC4heexlHAcIR8kuXUfmWzrZKTrpVjmrhgOVt1vdKz3ML4Ri9lHKSr88QyIDASr 66ogneBYMwA6+2udKRC15xhprfrCf9on7JH9kebfzs7F7dFUGrXqJT6NRoiyqBC3yUZ/T7ya+VI ExN+m0HhPOI2DNu4O0REV/gzE2+KrXDGlzC1Kg5t9ev2wymez6IEzaO9/nbagSFuAsOQRqY3tX0 5OBxrhItobUoySeJ5ezQJXgbIEJu9QgM3Zyku4sVCbUdSbE7UjFZGIAHS4taHaEcnAVMH//l/WZ iag== X-Google-Smtp-Source: AGHT+IFvMMhhCIH4jalpWwB+920r18WVhja2oWWNtYf6uMWbIL0d0FmohQk/xL8AYQFH9BE5Ruxc9w== X-Received: by 2002:a17:906:f581:b0:ad2:15c4:e23f with SMTP id a640c23a62f3a-ade8946222dmr282933066b.13.1749642538835; Wed, 11 Jun 2025 04:48:58 -0700 (PDT) Received: from localhost.localdomain ([41.79.198.22]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ade33c09594sm787588566b.97.2025.06.11.04.48.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Jun 2025 04:48:58 -0700 (PDT) From: Khalid Ali X-Google-Original-From: Khalid Ali Subject: [PATCH] kernel/entry: Remove some redundancy checks on syscall works Date: Wed, 11 Jun 2025 11:43:53 +0000 Message-ID: <20250611114810.785-1-khaliidcaliy@gmail.com> X-Mailer: git-send-email 2.49.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" There is a redundant checks of thread syscall work. After we read thread syscall work we are checking the work bits using SYSCALL_WORK_ENTER and SYSCALL_WORK_EXIT on syscall entry and exit respectively, and at the same time syscall_trace_enter() and syscall_exit_work() checking bits one by one, the bits we already checked. This is redundancy. So either we need to check the work bits one by one as I did, or check as whole. On my prespective, i think the way code is implemented now checking work bits one by one is simpler and gives us more granular control. I also checking if SYSCALL_WORK_SYSCALL_AUDIT is set on work as other part. Thus we don't need SYSCALL_WORK_ENTER and SYSCALL_WORK_EXIT anymore. We may need on the future, so we can safely let them be there. Signed-off-by: Khalid Ali --- include/linux/entry-common.h | 9 ++------- kernel/entry/common.c | 8 +++++--- 2 files changed, 7 insertions(+), 10 deletions(-) diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index f94f3fdf15fc..60a6741d5c5a 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -165,11 +165,7 @@ long syscall_trace_enter(struct pt_regs *regs, long sy= scall, static __always_inline long syscall_enter_from_user_mode_work(struct pt_re= gs *regs, long syscall) { unsigned long work =3D READ_ONCE(current_thread_info()->syscall_work); - - if (work & SYSCALL_WORK_ENTER) - syscall =3D syscall_trace_enter(regs, syscall, work); - - return syscall; + return syscall_trace_enter(regs, syscall, work); } =20 /** @@ -408,8 +404,7 @@ static __always_inline void syscall_exit_to_user_mode_w= ork(struct pt_regs *regs) * enabled, we want to run them exactly once per syscall exit with * interrupts enabled. */ - if (unlikely(work & SYSCALL_WORK_EXIT)) - syscall_exit_work(regs, work); + syscall_exit_work(regs, work); local_irq_disable_exit_to_user(); exit_to_user_mode_prepare(regs); } diff --git a/kernel/entry/common.c b/kernel/entry/common.c index e774dc9e7eaf..9accf5fde8e7 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -64,8 +64,9 @@ long syscall_trace_enter(struct pt_regs *regs, long sysca= ll, */ syscall =3D syscall_get_nr(current, regs); } - - syscall_enter_audit(regs, syscall); +=09 + if (work & SYSCALL_WORK_SYSCALL_AUDIT) + syscall_enter_audit(regs, syscall); =20 return ret ? : syscall; } @@ -162,7 +163,8 @@ void syscall_exit_work(struct pt_regs *regs, unsigned l= ong work) } } =20 - audit_syscall_exit(regs); + if (work & SYSCALL_WORK_SYSCALL_AUDIT) + audit_syscall_exit(regs); =20 if (work & SYSCALL_WORK_SYSCALL_TRACEPOINT) trace_sys_exit(regs, syscall_get_return_value(current, regs)); --=20 2.49.0