From patchwork Thu Jan 12 11:26:07 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Martin X-Patchwork-Id: 9513063 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8EE0B601E5 for ; Thu, 12 Jan 2017 11:29:06 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8042E28649 for ; Thu, 12 Jan 2017 11:29:06 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 74F55286C3; Thu, 12 Jan 2017 11:29:06 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id CFF9A286D0 for ; Thu, 12 Jan 2017 11:29:05 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cRdZ0-0004BD-Pa; Thu, 12 Jan 2017 11:29:02 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cRdX4-0001CU-Fl for linux-arm-kernel@lists.infradead.org; Thu, 12 Jan 2017 11:27:09 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id AB46F165C; Thu, 12 Jan 2017 03:26:34 -0800 (PST) Received: from e103592.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B2FF63F24D; Thu, 12 Jan 2017 03:26:32 -0800 (PST) From: Dave Martin To: linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH 08/10] arm64/sve: ptrace: Wire up vector length control and reporting Date: Thu, 12 Jan 2017 11:26:07 +0000 Message-Id: <1484220369-23970-9-git-send-email-Dave.Martin@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1484220369-23970-1-git-send-email-Dave.Martin@arm.com> References: <1484220369-23970-1-git-send-email-Dave.Martin@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170112_032703_181412_4E1612BD X-CRM114-Status: GOOD ( 13.88 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, Florian Weimer , libc-alpha@sourceware.org, Ard Biesheuvel , Marc Zyngier , gdb@sourceware.org, Yao Qi , Szabolcs Nagy , Joseph Myers , Alan Hayward , Torvald Riegel , Christoffer Dall MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP This patch adds support for manipulating a task's vector length at runtime via ptrace. As a simplification, we turn the task back into an FPSIMD-only task when changing the vector length. If the register data is written too, we then turn the task back into an SVE task, with changed task_struct layout for the SVE data, before the actual data writing is done. Because the vector length is now variable, sve_get() now needs to return the real maximum for user_sve_header.max_vl, since .vl may be less than this (that's the whole point). Signed-off-by: Dave Martin --- arch/arm64/include/asm/fpsimd.h | 1 + arch/arm64/include/uapi/asm/ptrace.h | 5 +++++ arch/arm64/kernel/ptrace.c | 25 +++++++++++++++---------- 3 files changed, 21 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h index 1ec2363..0f1b068 100644 --- a/arch/arm64/include/asm/fpsimd.h +++ b/arch/arm64/include/asm/fpsimd.h @@ -105,6 +105,7 @@ extern void sve_load_state(void const *state, u32 const *pfpsr, extern unsigned int sve_get_vl(void); extern int sve_set_vector_length(struct task_struct *task, unsigned long vl, unsigned long flags); +extern int sve_max_vl; /* * FPSIMD/SVE synchronisation helpers for ptrace: diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h index 48b57a0..bcb542d 100644 --- a/arch/arm64/include/uapi/asm/ptrace.h +++ b/arch/arm64/include/uapi/asm/ptrace.h @@ -64,6 +64,8 @@ #ifndef __ASSEMBLY__ +#include + /* * User structures for general purpose, floating point and debug registers. */ @@ -108,6 +110,9 @@ struct user_sve_header { #define SVE_PT_REGS_FPSIMD 0 #define SVE_PT_REGS_SVE SVE_PT_REGS_MASK +#define SVE_PT_VL_THREAD PR_SVE_SET_VL_THREAD +#define SVE_PT_VL_INHERIT PR_SVE_SET_VL_INHERIT + /* * The remainder of the SVE state follows struct user_sve_header. The diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 32debb8..7e40039 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -741,14 +741,15 @@ static int sve_get(struct task_struct *target, BUG_ON(!sve_vl_valid(header.vl)); vq = sve_vq_from_vl(header.vl); - /* Until runtime or per-task vector length changing is supported: */ - header.max_vl = header.vl; + BUG_ON(!sve_vl_valid(sve_max_vl)); + header.max_vl = sve_max_vl; header.flags = test_tsk_thread_flag(target, TIF_SVE) ? SVE_PT_REGS_SVE : SVE_PT_REGS_FPSIMD; header.size = SVE_PT_SIZE(vq, header.flags); - header.max_size = SVE_PT_SIZE(vq, SVE_PT_REGS_SVE); + header.max_size = SVE_PT_SIZE(sve_vq_from_vl(header.max_vl), + SVE_PT_REGS_SVE); ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &header, 0, sizeof(header)); @@ -830,14 +831,18 @@ static int sve_set(struct task_struct *target, if (ret) goto out; - if (header.vl != target->thread.sve_vl) - return -EINVAL; - - BUG_ON(!sve_vl_valid(header.vl)); - vq = sve_vq_from_vl(header.vl); + /* + * Apart from PT_SVE_REGS_MASK, all PT_SVE_* flags are consumed by + * sve_set_vector_length(), which will also validate them for us: + */ + ret = sve_set_vector_length(target, header.vl, + header.flags & ~SVE_PT_REGS_MASK); + if (ret) + goto out; - if (header.flags & ~SVE_PT_REGS_MASK) - return -EINVAL; + /* Actual VL set may be less than the user asked for: */ + BUG_ON(!sve_vl_valid(target->thread.sve_vl)); + vq = sve_vq_from_vl(target->thread.sve_vl); /* Registers: FPSIMD-only case */