From patchwork Tue Oct 12 00:00:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 12551211 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5BEF7C433F5 for ; Tue, 12 Oct 2021 00:07:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4444C60E54 for ; Tue, 12 Oct 2021 00:07:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235859AbhJLAJ0 (ORCPT ); Mon, 11 Oct 2021 20:09:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232494AbhJLAI2 (ORCPT ); Mon, 11 Oct 2021 20:08:28 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41099C06161C; Mon, 11 Oct 2021 17:06:27 -0700 (PDT) Message-ID: <20211011223610.404292507@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1633997183; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=EFhq4BlDAnV4q8GVsDZZiqlvWQFfxiu85EHWBzdICcc=; b=VCNQ0YYqHaHhvR6GAnFWkdWVKikPaplqds9wAmKjS/2xCPbmC63V4rn8t76+jiSQ6l3eJy zKR2EvMVeCS38BTAJjoIsebbL5ABSJU2Vp0CWS1ISyr3fAyPC0GKrHJuoUEyIbF9O3BB0d 5IXV36pdUaqQn3t+0mLaXE9LnrP2UHDfwqJsjmJsFDujew/+tbx7hZDX40iGAUh+CGKJnG ysXI2IFv9v2MkWz9583q8Jt3QxXZt/I63S91rGNyBsnjmXdjTjskbpH2+MqpBztw9NqLiS o+L+Rtq8iNi3gycnPsS60e9++9pkB/xFXN0ep9LxHqHiUDsc7958oKPUgvh6fw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1633997183; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=EFhq4BlDAnV4q8GVsDZZiqlvWQFfxiu85EHWBzdICcc=; b=CV8UjHd/t1bsVIIXwU4JXiPd5LH4dqDOMlNC0DxsNjXzgU5yx/iaLlGKXHXLDAJ2YQxGeL h5WoxoGIbEHGvSDg== From: Thomas Gleixner To: LKML Cc: x86@kernel.org, "Chang S. Bae" , Dave Hansen , Arjan van de Ven , kvm@vger.kernel.org, Paolo Bonzini Subject: [patch 02/31] x86/fpu: Update stale comments References: <20211011215813.558681373@linutronix.de> MIME-Version: 1.0 Date: Tue, 12 Oct 2021 02:00:00 +0200 (CEST) Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org copy_fpstate_to_sigframe() does not have a slow path anymore. Neither does the !ia32 restore in __fpu_restore_sig(). Update the comments accordingly. Signed-off-by: Thomas Gleixner --- arch/x86/kernel/fpu/signal.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -155,10 +155,8 @@ static inline int copy_fpregs_to_sigfram * buf == buf_fx for 64-bit frames and 32-bit fsave frame. * buf != buf_fx for 32-bit frames with fxstate. * - * Try to save it directly to the user frame with disabled page fault handler. - * If this fails then do the slow path where the FPU state is first saved to - * task's fpu->state and then copy it to the user frame pointed to by the - * aligned pointer 'buf_fx'. + * Save it directly to the user frame with disabled page fault handler. If + * that faults, try to clear the frame which handles the page fault. * * If this is a 32-bit frame with fxstate, put a fsave header before * the aligned state at 'buf_fx'. @@ -334,12 +332,7 @@ static bool __fpu_restore_sig(void __use } if (likely(!ia32_fxstate)) { - /* - * Attempt to restore the FPU registers directly from user - * memory. For that to succeed, the user access cannot cause page - * faults. If it does, fall back to the slow path below, going - * through the kernel buffer with the enabled pagefault handler. - */ + /* Restore the FPU registers directly from user memory. */ return restore_fpregs_from_user(buf_fx, user_xfeatures, fx_only, state_size); }