From patchwork Sat Feb 29 13:15:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Josh Poimboeuf X-Patchwork-Id: 11413835 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E297914B4 for ; Sat, 29 Feb 2020 13:15:45 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BA91B2468E for ; Sat, 29 Feb 2020 13:15:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GoAdX/XB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BA91B2468E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 010DC6E332; Sat, 29 Feb 2020 13:15:45 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from us-smtp-delivery-1.mimecast.com (us-smtp-2.mimecast.com [205.139.110.61]) by gabe.freedesktop.org (Postfix) with ESMTPS id E4DD16E332 for ; Sat, 29 Feb 2020 13:15:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582982142; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=RCYWHBxLPOdlW57S3eZdORk1KAVBLC2yFlcjTiBScDs=; b=GoAdX/XB8Bym80wHloXgCXnHBQii/jVIFOsFm48LQf/7D9UJhf3e2kG50cIrqu62b7fAnc FF0+P8hpXQRbK7otyo7pbGX3Gebe6jBrQA3/0bCQd+FrmXYgDFl1YEFsEr0oqn34qXg62V +6eyNQrIXCPyZGYRwQr/yrynz/CKUzU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-260-mKMc4NI0Mpi2LoTiS2PCRA-1; Sat, 29 Feb 2020 08:15:38 -0500 X-MC-Unique: mKMc4NI0Mpi2LoTiS2PCRA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E547C801E5C; Sat, 29 Feb 2020 13:15:36 +0000 (UTC) Received: from treble.redhat.com (ovpn-120-211.rdu2.redhat.com [10.10.120.211]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2114187B08; Sat, 29 Feb 2020 13:15:34 +0000 (UTC) From: Josh Poimboeuf To: Andrew Morton Date: Sat, 29 Feb 2020 07:15:26 -0600 Message-Id: <740179324b2b18b750b16295c48357f00b5fa9ed.1582982020.git.jpoimboe@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Subject: [Intel-gfx] [PATCH] bitops: Always inline sign extension helpers X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Zijlstra , intel-gfx@lists.freedesktop.org, Randy Dunlap , linux-kernel@vger.kernel.org, Al Viro Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" With CONFIG_CC_OPTIMIZE_FOR_SIZE, objtool reports: drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: i915_gem_execbuffer2_ioctl()+0x5b7: call to gen8_canonical_addr() with UACCESS enabled This means i915_gem_execbuffer2_ioctl() is calling gen8_canonical_addr() from the user_access_begin/end critical region (i.e, with SMAP disabled). While it's probably harmless in this case, in general we like to avoid extra function calls in SMAP-disabled regions because it can open up inadvertent security holes. Fix the warning by changing the sign extension helpers to __always_inline. This convinces GCC to inline gen8_canonical_addr(). The sign extension functions are trivial anyway, so it makes sense to always inline them. With my test optimize-for-size-based config, this actually shrinks the text size of i915_gem_execbuffer.o by 45 bytes -- and no change for vmlinux. Reported-by: Randy Dunlap Signed-off-by: Josh Poimboeuf --- include/linux/bitops.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/bitops.h b/include/linux/bitops.h index 47f54b459c26..9acf654f0b19 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -162,7 +162,7 @@ static inline __u8 ror8(__u8 word, unsigned int shift) * * This is safe to use for 16- and 8-bit types as well. */ -static inline __s32 sign_extend32(__u32 value, int index) +static __always_inline __s32 sign_extend32(__u32 value, int index) { __u8 shift = 31 - index; return (__s32)(value << shift) >> shift; @@ -173,7 +173,7 @@ static inline __s32 sign_extend32(__u32 value, int index) * @value: value to sign extend * @index: 0 based bit index (0<=index<64) to sign bit */ -static inline __s64 sign_extend64(__u64 value, int index) +static __always_inline __s64 sign_extend64(__u64 value, int index) { __u8 shift = 63 - index; return (__s64)(value << shift) >> shift;