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 442A3C61DD6 for ; Wed, 2 Sep 2026 09:55:32 +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=FoI1sraNn1QtgUyY5YxVLEE/KvAwSlgQcF2bwSxIYEo=; b=q3IXyumwdIU+k1q0WkyMTALDuf yyJR1eOREfxFyNx6miHLKDM+IctFs/hScorXQDF1nm1KTJ3XDyvQVmMqkCvXp77mfiABHCl2ZUHS4 Kze2MscArT/cHUoC5isxC9N0rbNadBCApsyTNBF1o7k8fsTiafNwrmlfKkXd/CBTDg77PuRZRE1Yt puFQLqqDzq+MGJ95kKEvbcSs3EJeto2kZEDsWUHgH6vzEpEGGJ3ryQWAZwi4Up9JKP4nDAeIQXjTK PO/e0qxNltggGa/jSVO7PNeA94rVVB7yHrjA9v40ns+sWumgnnWc1zXKosFufzoXay/rj9KnkYhM1 /UPhK7mw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1hge-0000000EHPf-3cHi; Wed, 02 Sep 2026 09:55:20 +0000 Received: from canpmsgout09.his.huawei.com ([113.46.200.224]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1hgW-0000000EHBu-35wj for linux-arm-kernel@lists.infradead.org; Wed, 02 Sep 2026 09:55:16 +0000 dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=FoI1sraNn1QtgUyY5YxVLEE/KvAwSlgQcF2bwSxIYEo=; b=1j4u8TZQMf60kmx3fG2CyJhZ7O8gLyM6g8RTCKpEgY8TlVYHN9G4jAgilb1cNlK8pbQZ5ujKc nUxmzolF/yrZah8kZNyd0f3ZtqGbFE2qdimpmQ4Vtt1Dhz2eYOA6PHCOyTMWyT/JKfgW4lSNDhR u0vBk3yLLuf5ABGd0gAM1no= Received: from mail.maildlp.com (unknown [172.19.162.92]) by canpmsgout09.his.huawei.com (SkyGuard) with ESMTPS id 4hZd9K1zdnz1cyVf; Wed, 2 Sep 2026 17:44:21 +0800 (CST) Received: from dggpemf500011.china.huawei.com (unknown [7.185.36.131]) by mail.maildlp.com (Postfix) with ESMTPS id 9E4A240565; Wed, 2 Sep 2026 17:55:10 +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 17:55:09 +0800 From: Jinjie Ruan To: , , , , , , , , , , , , , , , , , , , , CC: Subject: [PATCH v18 12/14] arm64: ptrace: Make return type of arm64_syscall_trace_enter() bool Date: Wed, 2 Sep 2026 17:55:35 +0800 Message-ID: <20260902095537.602517-13-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_025513_101307_7FA88D15 X-CRM114-Status: GOOD ( 15.46 ) 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 In preparation for migrating arm64 to the generic entry infrastructure, decouple the decision to execute the syscall from the syscall number itself. The ptrace and seccomp now returns a boolean flag rather than overloading NO_SYSCALL (-1). Changes: - arm64_syscall_trace_enter() returns bool: - false: abort syscall execution - true: proceed, with syscall number reread from regs - If we decide to execute the syscall, reread the syscall number and check if it is NO_SYSCALL again. Because when a tracer sets the syscall number to -1 and provides a custom return value in x0, this avoids calling invoke_syscall() which would overwrite the custom value with -ENOSYS by sys_ni_syscall(). Behavioral impact (unchanged): - User-issued syscall(-1): unchanged, returns -ENOSYS. - Tracer skip with custom x0: unchanged, returns custom x0 - Tracer skip without setting x0: unchanged, returns original argument (garbage) - Normal syscalls and seccomp rejects: unaffected No functional changes. Cc: Mark Rutland Cc: Will Deacon Cc: Catalin Marinas Cc: Ada Couprie Diaz Reviewed-by: Linus Walleij Signed-off-by: Jinjie Ruan --- arch/arm64/include/asm/syscall.h | 2 +- arch/arm64/kernel/ptrace.c | 8 ++++---- arch/arm64/kernel/syscall.c | 6 +++++- 3 files changed, 10 insertions(+), 6 deletions(-) diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h index 7cc872fde019..f19d4a8824ba 100644 --- a/arch/arm64/include/asm/syscall.h +++ b/arch/arm64/include/asm/syscall.h @@ -121,7 +121,7 @@ static inline int syscall_get_arch(struct task_struct *task) return AUDIT_ARCH_AARCH64; } -int arm64_syscall_trace_enter(struct pt_regs *regs, unsigned long flags); +bool arm64_syscall_trace_enter(struct pt_regs *regs, unsigned long flags); void arm64_syscall_exit_work(struct pt_regs *regs, unsigned long flags); static __always_inline void arm64_syscall_exit_to_user_mode_work(struct pt_regs *regs) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 08d2c39ae2ba..9825f4aff187 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -2468,14 +2468,14 @@ static inline void syscall_enter_audit(struct pt_regs *regs) } #endif -int arm64_syscall_trace_enter(struct pt_regs *regs, unsigned long flags) +bool arm64_syscall_trace_enter(struct pt_regs *regs, unsigned long flags) { int ret; if (flags & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE)) { ret = report_syscall_entry(regs); if (ret || (flags & _TIF_SYSCALL_EMU)) - return NO_SYSCALL; + return false; /* ptrace might have changed thread flags */ flags = read_thread_flags(); @@ -2484,7 +2484,7 @@ int arm64_syscall_trace_enter(struct pt_regs *regs, unsigned long flags) /* Do the secure computing after ptrace; failures should be fast. */ if (unlikely(flags & _TIF_SECCOMP)) { if (!__seccomp_permit_syscall()) - return NO_SYSCALL; + return false; } if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) @@ -2493,7 +2493,7 @@ int arm64_syscall_trace_enter(struct pt_regs *regs, unsigned long flags) if (unlikely(audit_context())) syscall_enter_audit(regs); - return syscall_get_nr(current, regs); + return true; } static inline bool report_single_step(unsigned long flags) diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index 3488afd45d20..72c6e8b7ab21 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -108,7 +108,11 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, */ if (scno == NO_SYSCALL) syscall_set_return_value(current, regs, -ENOSYS, 0); - scno = arm64_syscall_trace_enter(regs, read_thread_flags()); + if (!arm64_syscall_trace_enter(regs, read_thread_flags())) + goto trace_exit; + + /* Reread the syscall number as it might have been modified */ + scno = syscall_get_nr(current, regs); if (scno == NO_SYSCALL) goto trace_exit; } -- 2.34.1