From patchwork Wed Sep 21 17:32:31 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Konrad Rzeszutek Wilk X-Patchwork-Id: 9344009 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 3B8FD6077A for ; Wed, 21 Sep 2016 17:35:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 296EB2A83D for ; Wed, 21 Sep 2016 17:35:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1E1E52A846; Wed, 21 Sep 2016 17:35:32 +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, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 821842A83D for ; Wed, 21 Sep 2016 17:35:31 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bmlOW-0003uv-Cy; Wed, 21 Sep 2016 17:33:16 +0000 Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bmlOV-0003m5-4q for xen-devel@lists.xenproject.org; Wed, 21 Sep 2016 17:33:15 +0000 Received: from [85.158.139.211] by server-12.bemta-5.messagelabs.com id B3/C1-09561-A54C2E75; Wed, 21 Sep 2016 17:33:14 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrFLMWRWlGSWpSXmKPExsUyZ7p8oG7UkUf hBms3SFp83zKZyYHR4/CHKywBjFGsmXlJ+RUJrBlvf75lKXgoV3HvxxPGBsYW0S5GLg4hgYlM EqtWHmOGcP4ySmyYdZwNwtnIKPFr7mH2LkZOIGcWo8TTp+ldjBwcbAImEm9WOYLUiAj0MUpsv PqbDaSGGcTZd5oZxBYWcJSYvaIPzGYRUJV4sWsLWA2vgLtEx++pjCBzJATkJZ7drgcJcwKF7z w6wgyxyk3ibv9DVhBbQsBQ4vPGpcwTGPkWMDKsYlQvTi0qSy3SNdRLKspMzyjJTczM0TU0MNX LTS0uTkxPzUlMKtZLzs/dxAgMk3oGBsYdjE29zocYJTmYlER5u7c8ChfiS8pPqcxILM6ILyrN SS0+xCjDwaEkwatzGCgnWJSanlqRlpkDDFiYtAQHj5IIrwJImre4IDG3ODMdInWKUVFKnNcDJ CEAksgozYNrg0XJJUZZKWFeRgYGBiGegtSi3MwSVPlXjOIcjErCvI8PAU3hycwrgZv+CmgxE9 DiLT8fgCwuSURISTUw+pswJXKd0jN7fsd2tdGOSXeSXKb92ce3+H+P8eGw1idWdo/6j72/nB+ 4d5bxXg5Rvui6tvPG6zQilz/5HFRycC/3ROuHyQmqFs/SBCSff2ny5G+/zrW5NDHt2D/1maXs KmsP5Mmwm5lzP0u/VrL1tbHEXz1/91f6u3UjTx+7o3a/pClCcYKkEktxRqKhFnNRcSIABGc3l I0CAAA= X-Env-Sender: konrad.wilk@oracle.com X-Msg-Ref: server-9.tower-206.messagelabs.com!1474479192!60891712!1 X-Originating-IP: [156.151.31.81] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogMTU2LjE1MS4zMS44MSA9PiAyODgzMzk=\n X-StarScan-Received: X-StarScan-Version: 8.84; banners=-,-,- X-VirusChecked: Checked Received: (qmail 36135 invoked from network); 21 Sep 2016 17:33:14 -0000 Received: from userp1040.oracle.com (HELO userp1040.oracle.com) (156.151.31.81) by server-9.tower-206.messagelabs.com with DHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 21 Sep 2016 17:33:14 -0000 Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id u8LHX6l8022046 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 21 Sep 2016 17:33:07 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userv0022.oracle.com (8.14.4/8.13.8) with ESMTP id u8LHX6NE017129 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 21 Sep 2016 17:33:06 GMT Received: from abhmp0012.oracle.com (abhmp0012.oracle.com [141.146.116.18]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id u8LHX67w015234; Wed, 21 Sep 2016 17:33:06 GMT Received: from localhost.localdomain.localdomain (/172.58.216.202) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 21 Sep 2016 10:33:05 -0700 From: Konrad Rzeszutek Wilk To: konrad@kernel.org, xen-devel@lists.xenproject.org, ross.lagerwall@citrix.com, sstabellini@kernel.org, julien.grall@arm.com Date: Wed, 21 Sep 2016 13:32:31 -0400 Message-Id: <1474479154-20991-14-git-send-email-konrad.wilk@oracle.com> X-Mailer: git-send-email 2.4.11 In-Reply-To: <1474479154-20991-1-git-send-email-konrad.wilk@oracle.com> References: <1474479154-20991-1-git-send-email-konrad.wilk@oracle.com> X-Source-IP: userv0022.oracle.com [156.151.31.74] Cc: Andrew Cooper , Jan Beulich , Konrad Rzeszutek Wilk Subject: [Xen-devel] [PATCH v5 13/16] bug/x86/arm: Align bug_frames sections. X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP Most of the WARN_ON or BUG_ON sections are properly aligned on x86. However on ARM and on x86 assembler the macros don't include any alignment information - hence they end up being the default byte granularity. On ARM32 it is paramount that the alignment is word-size (4) otherwise if one tries to use (uint32_t*) access (such as livepatch ELF relocations) we get a Data Abort. Enforcing bug_frames to have the proper alignment across all architectures and in both C and x86 makes them all the same. Furthermore on x86 the bloat-o-meter detects that with this change: add/remove: 0/0 grow/shrink: 0/0 up/down: 0/0 (0) function old new delta On ARM32: add/remove: 1/0 grow/shrink: 0/1 up/down: 384/-288 (96) function old new delta gnttab_unpopulate_status_frames - 384 +384 do_grant_table_op 10808 10520 -288 And ARM64: add/remove: 1/2 grow/shrink: 0/1 up/down: 4164/-4236 (-72) function old new delta gnttab_map_grant_ref - 4164 +4164 do_grant_table_op 9892 9836 -56 grant_map_exists 300 - -300 __gnttab_map_grant_ref 3880 - -3880 Reviewed-by: Julien Grall Acked-by: Jan Beulich [x86 parts] Signed-off-by: Konrad Rzeszutek Wilk --- Cc: Julien Grall Cc: Stefano Stabellini Cc: Jan Beulich Cc: Andrew Cooper v3: First submission. Replaces the "livepatch/elf: Adjust section aligment to word" patch. v4: Remove the .ALIGN(4) in xen.lds.S for x86 (the only place needing that change). Update the commit description with correct x86 results Remove the . = ALIGN(4); in linker filer on x86 [the only file needing the change] v5: Add Jan's Ack on x86 parts. v6: Added Julien's Reviewed-by s/aligment/alignment/ s/align 4/p2align 2/ as the align semnatics varies by platforms, while p2align is the same across all of them. --- xen/arch/x86/xen.lds.S | 1 - xen/include/asm-arm/bug.h | 1 + xen/include/asm-x86/bug.h | 1 + 3 files changed, 2 insertions(+), 1 deletion(-) diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S index d903c31..7676de9 100644 --- a/xen/arch/x86/xen.lds.S +++ b/xen/arch/x86/xen.lds.S @@ -79,7 +79,6 @@ SECTIONS .rodata : { _srodata = .; /* Bug frames table */ - . = ALIGN(4); __start_bug_frames = .; *(.bug_frames.0) __stop_bug_frames_0 = .; diff --git a/xen/include/asm-arm/bug.h b/xen/include/asm-arm/bug.h index 68353e1..4704e2d 100644 --- a/xen/include/asm-arm/bug.h +++ b/xen/include/asm-arm/bug.h @@ -52,6 +52,7 @@ struct bug_frame { ".popsection\n" \ ".pushsection .bug_frames." __stringify(type) ", \"a\", %progbits\n"\ "4:\n" \ + ".p2align 2\n" \ ".long (1b - 4b)\n" \ ".long (2b - 4b)\n" \ ".long (3b - 4b)\n" \ diff --git a/xen/include/asm-x86/bug.h b/xen/include/asm-x86/bug.h index c5d2d4c..9bb4a19 100644 --- a/xen/include/asm-x86/bug.h +++ b/xen/include/asm-x86/bug.h @@ -98,6 +98,7 @@ extern const struct bug_frame __start_bug_frames[], .popsection .pushsection .bug_frames.\type, "a", @progbits + .p2align 2 .L\@bf: .long (.L\@ud - .L\@bf) + \ ((\line >> BUG_LINE_LO_WIDTH) << BUG_DISP_WIDTH)