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 10C2AC3ABBE for ; Tue, 6 May 2025 19:48:19 +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=YI8bMXQ8oBHCNNoFtceLOPQaHkJDoK7p1mJ62OjA7pc=; b=19v/8wYZp19PG/A907uMtQvRUB f6HCXaQq53G5XHGQaOuCWJOpGyBQ5j8SCYoajM5Ofj5pwqUzssBCJaWob9Q79zoeIikoKwzlxB781 14YRhonPZDZLY8cNQkCQyWYDWm0RrmV+p5l1DGcHvyO/Sig4ifg6dAU6tL8BXCOMuARTBNiWX/JoS Oa6r0u2KaQsTZfJFg+566l6G4EcD6GJ1WxLUSBD5BiSMRDw09vi9SRHvvCiND1nXS6qrRNR+2YRw1 3WpxrvSk7rWvAPfJbqzLs1kn52o4xS/Al/W9yVGh96TjHEf9JsfP7tqvRM9SUskilho60rWLQM6cU dUu5PiOQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uCOGv-0000000DGhm-0LgS; Tue, 06 May 2025 19:48:09 +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 1uCKBk-0000000CUbB-3Kzy for linux-arm-kernel@lists.infradead.org; Tue, 06 May 2025 15:26:33 +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 B8674339; Tue, 6 May 2025 08:26:22 -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 0B1D93F58B; Tue, 6 May 2025 08:26:29 -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 18/20] arm64/fpsimd: ptrace: Mandate SVE payload for streaming-mode state Date: Tue, 6 May 2025 16:25:21 +0100 Message-Id: <20250506152523.1107431-19-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20250506152523.1107431-1-mark.rutland@arm.com> References: <20250506152523.1107431-1-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-20250506_082632_873192_B433585D X-CRM114-Status: GOOD ( 13.18 ) 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 --- 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