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 C5BB4108B8ED for ; Fri, 20 Mar 2026 10:25:57 +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:To:From:Reply-To:Cc:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=UyUAjH5aWCCCGKq0gjvpfn/bS7b3FTk3IuM2tMQEVWM=; b=H7RpVB5oHJwFQj/fHmWu8wpFUC MccO1YWufEiW5YZFKVfUvMomSXs7801KrVG6IP9B6nrJJEgHyBy2E3MSthgErnaCYgzVhulafrAub jinFVNxlvy94yKTdo9v/XlejnQFo6r7vsWfMEVcXGTerK5KIfFzGiYbix+DSYt8iMpNZuTFQ7LRrs M75rXTk7LbA6etXyrPc0HFLkRY1x3KY7xqaR5AYhvndKRSa8G57KsOHkYtwTcafV/6G11W4OcA8To dLwk0DlCvZzQsqKglRcfxrNk31nM7Dx4RyN1U+SpkAFHpyyGK+npNG5/7D3hDEimzNepmZjN653Zk 0wKYpe8Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w3X3B-0000000CaP1-2HiB; Fri, 20 Mar 2026 10:25:53 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w3X2v-0000000CaHM-23Uh for linux-arm-kernel@bombadil.infradead.org; Fri, 20 Mar 2026 10:25:37 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:Content-Transfer-Encoding :MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:To:From:Sender: Reply-To:Cc:Content-ID:Content-Description; bh=UyUAjH5aWCCCGKq0gjvpfn/bS7b3FTk3IuM2tMQEVWM=; b=GfDHv8gCbvQKz/4h641H7Gkss/ M5165MOnNyO9LEgyg4AMt8tCGvidLYIdmvab/lTBJDxeHy9g4/S4Mdap3aMuYv90t5ccO22HIJ0iD KkGYQ7E5hiug+Oyg9e704bAelOs2h2rQNrk9rQ4wRFzm9OFwYKMteLe87moiODySUi5o5IPZ7c1Zy buXWLCyOD49nizvbmaAFbuV+ldKqtcdRw8gPndwI+l+E1N7us/lYsYNseksgK+ZZiD3+unByyF2OM SflyXxZ1dUG7UzP9rv/8xZyeWkXDKA3Y44y93sEcVDjgAjmdXrofZzeG/1L/Rm+ufpFzDQPQTl7t2 K1JgXn2A==; Received: from canpmsgout06.his.huawei.com ([113.46.200.221]) by desiato.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w3X2q-0000000FJlj-3HW7 for linux-arm-kernel@lists.infradead.org; Fri, 20 Mar 2026 10:25:36 +0000 dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=UyUAjH5aWCCCGKq0gjvpfn/bS7b3FTk3IuM2tMQEVWM=; b=DpZ8NIt+MVM3bhRbGAoCCo43vX/T4rBVIbDp8XhQhnPwOU/C6l3cSrXuyBmscWHieKrIuMCD+ S8lMKraU8sP/70H9UFvlMFNCeO6lWZ3BD64iuN4juabMVXu3njGxUozXGQog8puGmHIBldMkad1 sCsVUHBLyZyrWMzBM/mx+mY= Received: from mail.maildlp.com (unknown [172.19.163.0]) by canpmsgout06.his.huawei.com (SkyGuard) with ESMTPS id 4fcdqc0S3vzRhR3; Fri, 20 Mar 2026 18:20:28 +0800 (CST) Received: from dggpemf500011.china.huawei.com (unknown [7.185.36.131]) by mail.maildlp.com (Postfix) with ESMTPS id 116D24056B; Fri, 20 Mar 2026 18:25:28 +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; Fri, 20 Mar 2026 18:25:26 +0800 From: Jinjie Ruan To: , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH v14 06/10] arm64: syscall: Introduce syscall_exit_to_user_mode_work() Date: Fri, 20 Mar 2026 18:26:16 +0800 Message-ID: <20260320102620.1336796-7-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260320102620.1336796-1-ruanjinjie@huawei.com> References: <20260320102620.1336796-1-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 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260320_102533_511758_D2A4C1D1 X-CRM114-Status: GOOD ( 16.46 ) 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 Refactor the system call exit path to align with the generic entry framework. This consolidates thread flag checking, rseq handling, and syscall tracing into a structure that mirrors the generic syscall_exit_to_user_mode_work() implementation. [Rationale] The generic entry code employs a hierarchical approach for syscall exit work: 1. syscall_exit_to_user_mode_work(): The entry point that handles rseq and checks if further exit work (tracing/audit) is required. 2. syscall_exit_work(): Performs the actual tracing, auditing, and ptrace reporting. [Changes] - Rename and Encapsulate: Rename syscall_trace_exit() to syscall_exit_work() and make it static, as it is now an internal helper for the exit path. - New Entry Point: Implement syscall_exit_to_user_mode_work() to replace the manual flag-reading logic in el0_svc_common(). This function now encapsulates the rseq_syscall() call and the conditional execution of syscall_exit_work(). - Simplify el0_svc_common(): Remove the complex conditional checks for tracing and CONFIG_DEBUG_RSEQ at the end of the syscall path, delegating this responsibility to the new helper. - Helper Migration: Move has_syscall_work() to asm/syscall.h to allow its reuse across ptrace.c and syscall.c. - Clean up RSEQ: Remove the explicit IS_ENABLED(CONFIG_DEBUG_RSEQ) check in the caller, as rseq_syscall() is already a no-op when the config is disabled. Cc: Will Deacon Cc: Catalin Marinas Reviewed-by: Linus Walleij Reviewed-by: Yeoreum Yun Reviewed-by: Kevin Brodsky Signed-off-by: Jinjie Ruan --- arch/arm64/include/asm/syscall.h | 7 ++++++- arch/arm64/kernel/ptrace.c | 14 +++++++++++--- arch/arm64/kernel/syscall.c | 20 +------------------- 3 files changed, 18 insertions(+), 23 deletions(-) diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h index 30b203ef156b..c469d09a7964 100644 --- a/arch/arm64/include/asm/syscall.h +++ b/arch/arm64/include/asm/syscall.h @@ -120,7 +120,12 @@ static inline int syscall_get_arch(struct task_struct *task) return AUDIT_ARCH_AARCH64; } +static inline bool has_syscall_work(unsigned long flags) +{ + return unlikely(flags & _TIF_SYSCALL_WORK); +} + int syscall_trace_enter(struct pt_regs *regs, unsigned long flags); -void syscall_trace_exit(struct pt_regs *regs, unsigned long flags); +void syscall_exit_to_user_mode_work(struct pt_regs *regs); #endif /* __ASM_SYSCALL_H */ diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 8245d1ae61cf..2c97de8a097c 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -2454,10 +2454,8 @@ int syscall_trace_enter(struct pt_regs *regs, unsigned long flags) return ret ? : syscall; } -void syscall_trace_exit(struct pt_regs *regs, unsigned long flags) +static void syscall_exit_work(struct pt_regs *regs, unsigned long flags) { - rseq_syscall(regs); - audit_syscall_exit(regs); if (flags & _TIF_SYSCALL_TRACEPOINT) @@ -2467,6 +2465,16 @@ void syscall_trace_exit(struct pt_regs *regs, unsigned long flags) report_syscall_exit(regs); } +void syscall_exit_to_user_mode_work(struct pt_regs *regs) +{ + unsigned long flags = read_thread_flags(); + + rseq_syscall(regs); + + if (has_syscall_work(flags) || flags & _TIF_SINGLESTEP) + syscall_exit_work(regs, flags); +} + /* * SPSR_ELx bits which are always architecturally RES0 per ARM DDI 0487D.a. * We permit userspace to set SSBS (AArch64 bit 12, AArch32 bit 23) which is diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index e8fd0d60ab09..66d4da641d97 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -65,11 +65,6 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, choose_random_kstack_offset(get_random_u16()); } -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[]) { @@ -130,21 +125,8 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, } invoke_syscall(regs, scno, sc_nr, syscall_table); - - /* - * The tracing status may have changed under our feet, so we have to - * 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)) { - flags = read_thread_flags(); - if (!has_syscall_work(flags) && !(flags & _TIF_SINGLESTEP)) - return; - } - trace_exit: - flags = read_thread_flags(); - syscall_trace_exit(regs, flags); + syscall_exit_to_user_mode_work(regs); } void do_el0_svc(struct pt_regs *regs) -- 2.34.1