From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 443E2C624DA for ; Wed, 2 Sep 2026 09:55:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=VVDspyZXkMh/nYRnw2K6t/1JNSoEqGFV53RtzhoE3O4=; b=ALsbt9IL/GA9syyQvMewL7oG2O PW79Fa/waPj+OYOUbNVqjON8STVLkTK6rZUnMHN3UuDruDCIqxYUsIwp1JHflAVKSeR6WRjL+jOw2 9SX7qj/gb7K7bqsBBtK3vV/+ZjxEU3Rz5u+EtQ5HEVpELk059VRgue6zErk7VuS0sBHu3sKVzuApn Yc0cj79B/zOMVoJtfgqahH3PNhePIkMnt61P6jcv595Ebhkv5nXiZCzxwQqqMoJfx2lw0rPsm0hL4 6dh7lpEHiXeIrH/0LNX9i3P+tvJjrhOKQiUF3RqbkNIsCDK/KPAQWTTdXv5pZ/kFcV+uz+BhR1qcg EJAaNsOQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1hga-0000000EHJV-2eYb; Wed, 02 Sep 2026 09:55:16 +0000 Received: from canpmsgout12.his.huawei.com ([113.46.200.227]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1hgW-0000000EHAI-0NhM for linux-arm-kernel@lists.infradead.org; Wed, 02 Sep 2026 09:55:13 +0000 dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=VVDspyZXkMh/nYRnw2K6t/1JNSoEqGFV53RtzhoE3O4=; b=c2XT/oxbuteWiqYFgGx9BPlFO3tVthSnQXHe1YobvHkJzVM9Sj1BQYQ0l5iHOaBGhLz9YWE+E nuOLPEvfqR2GeE95fW5LOTpqBf23rQ0BxHU+Y17LbkAFFG5/eDfOBiZIj48FJkWBlhTr6W33pRT rPkVlqOeKvTr4o/t4EWjBDc= Received: from mail.maildlp.com (unknown [172.19.163.163]) by canpmsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4hZd8p6p8fznTVv; Wed, 2 Sep 2026 17:43:54 +0800 (CST) Received: from dggpemf500011.china.huawei.com (unknown [7.185.36.131]) by mail.maildlp.com (Postfix) with ESMTPS id 2A1264057A; Wed, 2 Sep 2026 17:55:08 +0800 (CST) Received: from huawei.com (10.90.53.73) by dggpemf500011.china.huawei.com (7.185.36.131) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Wed, 2 Sep 2026 17:55:06 +0800 From: Jinjie Ruan To: , , , , , , , , , , , , , , , , , , , , CC: Subject: [PATCH v18 10/14] arm64: syscall: Use exit-specific flags check in el0_svc_common() Date: Wed, 2 Sep 2026 17:55:33 +0800 Message-ID: <20260902095537.602517-11-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260902095537.602517-1-ruanjinjie@huawei.com> References: <20260902095537.602517-1-ruanjinjie@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.90.53.73] X-ClientProxiedBy: kwepems100002.china.huawei.com (7.221.188.206) To dggpemf500011.china.huawei.com (7.185.36.131) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260902_025512_476023_24548DFD X-CRM114-Status: GOOD ( 13.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The syscall exit path in el0_svc_common() re-evaluates all _TIF_SYSCALL_WORK flags, but this mask contains flags that only matter on entry: - _TIF_SECCOMP: seccomp filtering is entry-only - _TIF_SYSCALL_EMU: PTRACE_SYSEMU skips the syscall on entry Re-checking them on exit is unnecessary and may trigger redundant work. Switch to _TIF_SYSCALL_EXIT_WORK for the exit-path re-check to evaluate only exit-relevant flags (_TIF_SYSCALL_TRACE, _TIF_SYSCALL_AUDIT, and _TIF_SYSCALL_TRACEPOINT). No functional change intended. Cc: Mark Rutland Cc: Will Deacon Cc: Catalin Marinas Cc: Ada Couprie Diaz Reviewed-by: Ada Couprie Diaz Reviewed-by: Linus Walleij Reviewed-by: Yeoreum Yun Signed-off-by: Jinjie Ruan --- arch/arm64/kernel/syscall.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index 0061fc63e7ba..a8e0bf8d362e 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -54,11 +54,6 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, syscall_set_return_value(current, regs, 0, ret); } -static inline bool has_syscall_work(unsigned long flags) -{ - return unlikely(flags & _TIF_SYSCALL_WORK); -} - static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, const syscall_fn_t syscall_table[]) { @@ -95,7 +90,7 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, return; } - if (has_syscall_work(flags)) { + if (unlikely(flags & _TIF_SYSCALL_WORK)) { /* * The de-facto standard way to skip a system call using ptrace * is to set the system call to -1 (NO_SYSCALL) and set x0 to a @@ -125,9 +120,9 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, * check again. However, if we were tracing entry, then we always trace * exit regardless, as the old entry assembly did. */ - if (!has_syscall_work(flags) && !IS_ENABLED(CONFIG_DEBUG_RSEQ)) { + if (!(unlikely(flags & _TIF_SYSCALL_WORK)) && !IS_ENABLED(CONFIG_DEBUG_RSEQ)) { flags = read_thread_flags(); - if (has_syscall_work(flags) || flags & _TIF_SINGLESTEP) + if (unlikely(flags & _TIF_SYSCALL_EXIT_WORK) || flags & _TIF_SINGLESTEP) arm64_syscall_exit_to_user_mode_work(regs); return; } -- 2.34.1