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 67EC9C3ABC0 for ; Thu, 8 May 2025 14:07:28 +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-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jOw5GC4YFh89wwgYDL9nl+Wzcb0DQGniIFsqjncK9IU=; b=GOmCHPVCxw+4Ipqx/Ks3zhFf3h R0JQ1Js9mTaraMLBrwL0Q51Hj2GRH2p8mCev6NRw2ddnIWzUCeNGc7glQYv1NrCVmBAMK6oNGKGVy sBmiazSyGVNaa2AnAQoi/wdGc59Btvb28GDz1Q/zIJXBYZOV2/MAXU1CUbEx9gEzeSGnvBTfm7lxF e1wVskOqfsvsD69fALjehPGnOYJCk7lr7PVr0uATD8dt2v5eFqXK5E16xO+F7n7AQL2EhpIX9+I2U Tmw+ajOf5xIvrgq9tOR4BwPnhJbvf7yrFfUQ8BJLjf5oMKrhzfpc+//CbT1HQMlzjSpu7oYTVbFL4 BUYpbWdQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uD1uC-00000000rIZ-3LIH; Thu, 08 May 2025 14:07:20 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uD1ID-00000000kYP-1AAy for linux-arm-kernel@lists.infradead.org; Thu, 08 May 2025 13:28:06 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8642D106F; Thu, 8 May 2025 06:27:54 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 854B93F58B; Thu, 8 May 2025 06:28:02 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Cc: broonie@kernel.org, catalin.marinas@arm.com, daniel.kiss@arm.com, david.spickett@arm.com, luis.machado@arm.com, mark.rutland@arm.com, maz@kernel.org, richard.sandiford@arm.com, sander.desmalen@arm.com, tabba@google.com, tamas.petz@arm.com, tkjos@google.com, will@kernel.org, yury.khrustalev@arm.com Subject: [PATCH v2 18/24] arm64/fpsimd: ptrace: Mandate SVE payload for streaming-mode state Date: Thu, 8 May 2025 14:26:38 +0100 Message-Id: <20250508132644.1395904-19-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20250508132644.1395904-1-mark.rutland@arm.com> References: <20250508132644.1395904-1-mark.rutland@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250508_062805_356421_5D34018B X-CRM114-Status: GOOD ( 13.27 ) 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 When a task has PSTATE.SM==1, reads of NT_ARM_SSVE are required to always present a header with SVE_PT_REGS_SVE, and register data in SVE format. Reads of NT_ARM_SSVE must never present register data in FPSIMD format. Within the kernel, we always expect streaming SVE data to be stored in SVE format. Currently a user can write to NT_ARM_SSVE with a header presenting SVE_PT_REGS_FPSIMD rather than SVE_PT_REGS_SVE, placing the task's FPSIMD/SVE data into an invalid state. To fix this we can either: (a) Forbid such writes. (b) Accept such writes, and immediately convert data into SVE format. Take the simple option and forbid such writes. Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers") Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: David Spickett Cc: Luis Machado Cc: Marc Zyngier Cc: Mark Brown Cc: Will Deacon Reviewed-by: Mark Brown --- arch/arm64/kernel/ptrace.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index a2075e1df27c6..cff72b420eab8 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -890,6 +890,7 @@ static int sve_set_common(struct task_struct *target, struct user_sve_header header; unsigned int vq; unsigned long start, end; + bool fpsimd; /* Header */ if (count < sizeof(header)) @@ -899,6 +900,15 @@ static int sve_set_common(struct task_struct *target, if (ret) goto out; + /* + * Streaming SVE data is always stored and presented in SVE format. + * Require the user to provide SVE formatted data for consistency, and + * to avoid the risk that we configure the task into an invalid state. + */ + fpsimd = (header.flags & SVE_PT_REGS_MASK) == SVE_PT_REGS_FPSIMD; + if (fpsimd && type == ARM64_VEC_SME) + return -EINVAL; + /* * Apart from SVE_PT_REGS_MASK, all SVE_PT_* flags are consumed by * vec_set_vector_length(), which will also validate them for us: @@ -945,7 +955,7 @@ static int sve_set_common(struct task_struct *target, /* Registers: FPSIMD-only case */ BUILD_BUG_ON(SVE_PT_FPSIMD_OFFSET != sizeof(header)); - if ((header.flags & SVE_PT_REGS_MASK) == SVE_PT_REGS_FPSIMD) { + if (fpsimd) { clear_tsk_thread_flag(target, TIF_SVE); target->thread.fp_type = FP_STATE_FPSIMD; ret = __fpr_set(target, regset, pos, count, kbuf, ubuf, -- 2.30.2