From nobody Fri Sep 20 20:25:26 2024 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A9BEC77B6C for ; Thu, 13 Apr 2023 07:34:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229968AbjDMHeu (ORCPT ); Thu, 13 Apr 2023 03:34:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47070 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229830AbjDMHet (ORCPT ); Thu, 13 Apr 2023 03:34:49 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 687745FFE for ; Thu, 13 Apr 2023 00:34:46 -0700 (PDT) X-UUID: a6841290d9cd11eda9a90f0bb45854f4-20230413 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:Content-Transfer-Encoding:MIME-Version:Message-ID:Date:Subject:CC:To:From; bh=YaTPAzl/heZ+h8rUiiBKWDbrCg55o/k0t045jGrMKak=; b=CeZatF4CNK5FW1Fpj7uBv4tQ0/9JuA2rBP/2JqPf+LbZBj7jNMhkZWrwrp4nAMBEKmRkP7cp0C+HXfpTQDLqlAs8TmFeFf6bzRHW69GpLGDFZVtRDXMqpfrxzBBCT9FvP0UafNKhMPstMDWGzioT4j5GIQFOzpAbDKCUHKOe14E=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.22,REQID:d772b1ba-b5e0-4fa7-ab55-46bfb18b0364,IP:0,U RL:0,TC:0,Content:-25,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTIO N:release,TS:-25 X-CID-META: VersionHash:120426c,CLOUDID:c2f7d2ea-db6f-41fe-8b83-13fe7ed1ef52,B ulkID:nil,BulkQuantity:0,Recheck:0,SF:102,TC:nil,Content:0,EDM:-3,IP:nil,U RL:11|1,File:nil,Bulk:nil,QS:nil,BEC:nil,COL:0,OSI:0,OSA:0,AV:0 X-CID-BVR: 0,NGT X-CID-BAS: 0,NGT,0,_ X-UUID: a6841290d9cd11eda9a90f0bb45854f4-20230413 Received: from mtkmbs11n1.mediatek.inc [(172.21.101.185)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 1883800672; Thu, 13 Apr 2023 15:34:40 +0800 Received: from mtkmbs13n2.mediatek.inc (172.21.101.108) by mtkmbs11n2.mediatek.inc (172.21.101.187) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.25; Thu, 13 Apr 2023 15:34:39 +0800 Received: from mszsdtlt102.gcn.mediatek.inc (10.16.4.142) by mtkmbs13n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.1118.25 via Frontend Transport; Thu, 13 Apr 2023 15:34:38 +0800 From: Haibo Li To: Russell King , Linus Walleij , , CC: Matthias Brugger , AngeloGioacchino Del Regno , Haibo Li , , Russell King , Alex Sverdlin , , , , , Subject: [PATCH v2] ARM:unwind:fix unwind abort for uleb128 case Date: Thu, 13 Apr 2023 15:34:29 +0800 Message-ID: <20230413073429.40050-1-haibo.li@mediatek.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When unwind instruction is 0xb2,the subsequent instructions are uleb128 bytes. For now,it uses only the first uleb128 byte in code. For vsp increments of 0x204~0x400,use one uleb128 byte like below: 0xc06a00e4 : 0x80b27fac Compact model index: 0 0xb2 0x7f vsp =3D vsp + 1024 0xac pop {r4, r5, r6, r7, r8, r14} For vsp increments larger than 0x400,use two uleb128 bytes like below: 0xc06a00e4 : @0xc0cc9e0c Compact model index: 1 0xb2 0x81 0x01 vsp =3D vsp + 1032 0xac pop {r4, r5, r6, r7, r8, r14} The unwind works well since the decoded uleb128 byte is also 0x81. For vsp increments larger than 0x600,use two uleb128 bytes like below: 0xc06a00e4 : @0xc0cc9e0c Compact model index: 1 0xb2 0x81 0x02 vsp =3D vsp + 1544 0xac pop {r4, r5, r6, r7, r8, r14} In this case,the decoded uleb128 result is 0x101(vsp=3D0x204+(0x101<<2)). While the uleb128 used in code is 0x81(vsp=3D0x204+(0x81<<2)). The unwind aborts at this frame since it gets incorrect vsp. To fix this,add uleb128 decode to cover all the above case. Signed-off-by: Haibo Li Reviewed-by: Alexandre Mergnat Reviewed-by: AngeloGioacchino Del Regno Reviewed-by: Linus Walleij --- v2: - As Linus Walleij and Alexandre Mergnat suggested,add comments for unwind_= decode_uleb128 - As Alexandre Mergnat suggested,change variables declaration in Alphabetic= al order --- arch/arm/kernel/unwind.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c index 53be7ea6181b..f37e55fcf81d 100644 --- a/arch/arm/kernel/unwind.c +++ b/arch/arm/kernel/unwind.c @@ -308,6 +308,29 @@ static int unwind_exec_pop_subset_r0_to_r3(struct unwi= nd_ctrl_block *ctrl, return URC_OK; } =20 +static unsigned long unwind_decode_uleb128(struct unwind_ctrl_block *ctrl) +{ + unsigned long bytes =3D 0; + unsigned long insn; + unsigned long result =3D 0; + + /* unwind_get_byte() will advance ctrl one instruction at a time, + * we loop until we get an instruction byte where bit 7 is not set. + * Note:It decodes max 4 bytes to output 28bits data. + * 28bits data(0xfffffff) covers vsp increments of 1073742336. + * It is sufficent for unwinding stack. + */ + do { + insn =3D unwind_get_byte(ctrl); + result |=3D (insn & 0x7f) << (bytes * 7); + bytes++; + if (bytes =3D=3D sizeof(result)) + break; + } while (!!(insn & 0x80)); + + return result; +} + /* * Execute the current unwind instruction. */ @@ -361,7 +384,7 @@ static int unwind_exec_insn(struct unwind_ctrl_block *c= trl) if (ret) goto error; } else if (insn =3D=3D 0xb2) { - unsigned long uleb128 =3D unwind_get_byte(ctrl); + unsigned long uleb128 =3D unwind_decode_uleb128(ctrl); =20 ctrl->vrs[SP] +=3D 0x204 + (uleb128 << 2); } else { --=20 2.25.1