From nobody Thu Apr 2 09:30:13 2026 Received: from canpmsgout06.his.huawei.com (canpmsgout06.his.huawei.com [113.46.200.221]) (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 ACE6935F19C for ; Fri, 20 Mar 2026 10:25:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.221 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774002350; cv=none; b=kzmif3cUCx57rf9vXSqBob2PUE5VXTjLLDZN03epNKrV/RNnts/WEpFE5ZDbNOZh9oBEdjHgIosIDmi96lKF9NRcpObLokJ+a9vXFLpRrARQmYfV8bIORAFLqW21k/2N030LlWeC8u4QCZdB9empMpqsfdAWe1jbxrNuffSnV4I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774002350; c=relaxed/simple; bh=H27AODbt5KdR+CJ0X8OuALpL6ghhtknUKujeSjbP1Fw=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=G1JQ/5miqMSlLGr7LZRsJF5sDXyyFR+ZZ49iPaLEnxyG6qNb8fMQ1vLAUSl64AWwyQf4yjr1nOZVLe8OoWFGyc23cJAnbAn6O+lecsOIDA2xLXjdyPWyiEwhzPohwgXLD0QgYAv5IY9e7FPVfUD8bDUaiXvBXgHXZ34ZcKvF9ek= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=DpZ8NIt+; arc=none smtp.client-ip=113.46.200.221 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="DpZ8NIt+" 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> 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 X-ClientProxiedBy: kwepems100002.china.huawei.com (7.221.188.206) To dggpemf500011.china.huawei.com (7.185.36.131) Content-Type: text/plain; charset="utf-8" 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/sysc= all.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; } =20 +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); =20 #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, unsign= ed long flags) return ret ? : syscall; } =20 -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); =20 if (flags & _TIF_SYSCALL_TRACEPOINT) @@ -2467,6 +2465,16 @@ void syscall_trace_exit(struct pt_regs *regs, unsign= ed long flags) report_syscall_exit(regs); } =20 +void syscall_exit_to_user_mode_work(struct pt_regs *regs) +{ + unsigned long flags =3D 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, unsigne= d int scno, choose_random_kstack_offset(get_random_u16()); } =20 -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 s= cno, int sc_nr, } =20 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 =3D read_thread_flags(); - if (!has_syscall_work(flags) && !(flags & _TIF_SINGLESTEP)) - return; - } - trace_exit: - flags =3D read_thread_flags(); - syscall_trace_exit(regs, flags); + syscall_exit_to_user_mode_work(regs); } =20 void do_el0_svc(struct pt_regs *regs) --=20 2.34.1