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 X-Spam-Level: X-Spam-Status: No, score=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72EE8C48BC2 for ; Wed, 23 Jun 2021 22:10:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 56F06613F1 for ; Wed, 23 Jun 2021 22:10:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230411AbhFWWMQ (ORCPT ); Wed, 23 Jun 2021 18:12:16 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:40054 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230152AbhFWWLc (ORCPT ); Wed, 23 Jun 2021 18:11:32 -0400 Date: Wed, 23 Jun 2021 22:09:12 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1624486153; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Lj9aNjPI8t22BSqFKqWgFFZyNu0nwu4GYA/y+TSipZA=; b=s+EfkOyl/hdK3wD0Eb1RHnG4XGiqqvaDtQrBeR7mXdrF6nATKDG/OJomREAmsJU776lF+R K5wXQRy3BcdxB7n0qRLyqQM2EcpioK4NytA/Cs3lWXvp1qALTsLk0XzY1U1J0Arl3cnrGi PmFl1KPHanTZVOHnwXqjXhKGG55XbUf+wVc/YaHSUMLJaLI7os0VzobbYXzZcWvC6gt3z8 9ru8F4VsTvY06l4Yy9w9jBhN70Bvwca9waTI/K3xCz64X+yOGugOSi4iwOCy6totMz2LmL 0vXywK4/xIt97eNksJ5gPpn9IyS25aWlFWxGhacUc0VqDUv9vm2Y8CwM5rn3IQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1624486153; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Lj9aNjPI8t22BSqFKqWgFFZyNu0nwu4GYA/y+TSipZA=; b=GeurjUvjWAOjC9CYsR/jnHmRKb94CreBrDn4XshCL7VHIQqmbI7QyrLGl7VGs4dEX/4aaZ s2G4FYb5gE/0leCg== From: "tip-bot2 for Thomas Gleixner" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/fpu] x86/fpu: Rename and sanitize fpu__save/copy() Cc: Thomas Gleixner , Borislav Petkov , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20210623121455.196727450@linutronix.de> References: <20210623121455.196727450@linutronix.de> MIME-Version: 1.0 Message-ID: <162448615236.395.4081108305345528808.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/fpu branch of tip: Commit-ID: b2681e791dbcee6acb1dca7a5076a0285109ac4c Gitweb: https://git.kernel.org/tip/b2681e791dbcee6acb1dca7a5076a0285109ac4c Author: Thomas Gleixner AuthorDate: Wed, 23 Jun 2021 14:02:06 +02:00 Committer: Borislav Petkov CommitterDate: Wed, 23 Jun 2021 18:55:56 +02:00 x86/fpu: Rename and sanitize fpu__save/copy() Both function names are a misnomer. fpu__save() is actually about synchronizing the hardware register state into the task's memory state so that either coredump or a math exception handler can inspect the state at the time where the problem happens. The function guarantees to preserve the register state, while "save" is a common terminology for saving the current state so it can be modified and restored later. This is clearly not the case here. Rename it to fpu_sync_fpstate(). fpu__copy() is used to clone the current task's FPU state when duplicating task_struct. While the register state is a copy the rest of the FPU state is not. Name it accordingly and remove the really pointless @src argument along with the warning which comes along with it. Nothing can ever copy the FPU state of a non-current task. It's clearly just a consequence of arch_dup_task_struct(), but it makes no sense to proliferate that further. Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Reviewed-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210623121455.196727450@linutronix.de --- arch/x86/include/asm/fpu/internal.h | 6 ++++-- arch/x86/kernel/fpu/core.c | 17 ++++++++--------- arch/x86/kernel/fpu/regset.c | 2 +- arch/x86/kernel/process.c | 3 +-- arch/x86/kernel/traps.c | 5 +++-- 5 files changed, 17 insertions(+), 16 deletions(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 3558cd0..f5da2e9 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -26,14 +26,16 @@ /* * High level FPU state handling functions: */ -extern void fpu__save(struct fpu *fpu); extern int fpu__restore_sig(void __user *buf, int ia32_frame); extern void fpu__drop(struct fpu *fpu); -extern int fpu__copy(struct task_struct *dst, struct task_struct *src); extern void fpu__clear_user_states(struct fpu *fpu); extern void fpu__clear_all(struct fpu *fpu); extern int fpu__exception_code(struct fpu *fpu, int trap_nr); +extern void fpu_sync_fpstate(struct fpu *fpu); + +extern int fpu_clone(struct task_struct *dst); + /* * Boot time FPU initialization functions: */ diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 4a59e0f..8762b1a 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -159,11 +159,10 @@ void kernel_fpu_end(void) EXPORT_SYMBOL_GPL(kernel_fpu_end); /* - * Save the FPU state (mark it for reload if necessary): - * - * This only ever gets called for the current task. + * Sync the FPU register state to current's memory register state when the + * current task owns the FPU. The hardware register state is preserved. */ -void fpu__save(struct fpu *fpu) +void fpu_sync_fpstate(struct fpu *fpu) { WARN_ON_FPU(fpu != ¤t->thread.fpu); @@ -221,18 +220,18 @@ void fpstate_init(union fpregs_state *state) } EXPORT_SYMBOL_GPL(fpstate_init); -int fpu__copy(struct task_struct *dst, struct task_struct *src) +/* Clone current's FPU state on fork */ +int fpu_clone(struct task_struct *dst) { + struct fpu *src_fpu = ¤t->thread.fpu; struct fpu *dst_fpu = &dst->thread.fpu; - struct fpu *src_fpu = &src->thread.fpu; + /* The new task's FPU state cannot be valid in the hardware. */ dst_fpu->last_cpu = -1; - if (!static_cpu_has(X86_FEATURE_FPU)) + if (!cpu_feature_enabled(X86_FEATURE_FPU)) return 0; - WARN_ON_FPU(src_fpu != ¤t->thread.fpu); - /* * Don't let 'init optimized' areas of the XSAVE area * leak into the child task: diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c index 892aec1..4575796 100644 --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -41,7 +41,7 @@ int regset_xregset_fpregs_active(struct task_struct *target, const struct user_r static void sync_fpstate(struct fpu *fpu) { if (fpu == ¤t->thread.fpu) - fpu__save(fpu); + fpu_sync_fpstate(fpu); } /* diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 5e1f381..af3db53 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -87,8 +87,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) #ifdef CONFIG_VM86 dst->thread.vm86 = NULL; #endif - - return fpu__copy(dst, src); + return fpu_clone(dst); } /* diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 853ea7a..4c9c4aa 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -1046,9 +1046,10 @@ static void math_error(struct pt_regs *regs, int trapnr) } /* - * Save the info for the exception handler and clear the error. + * Synchronize the FPU register state to the memory register state + * if necessary. This allows the exception handler to inspect it. */ - fpu__save(fpu); + fpu_sync_fpstate(fpu); task->thread.trap_nr = trapnr; task->thread.error_code = 0;