From patchwork Fri Apr 14 06:10:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Haibo Li X-Patchwork-Id: 13210994 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7F6E4C77B70 for ; Fri, 14 Apr 2023 06:10:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:Message-ID:Date:Subject:CC:To:From: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=K5oB4l0Vb3M1xYybDiOMAFZ9n2MsdIcmscCAPi5IQEM=; b=2Ii1bMRmUKOEYoZ+GxmJZu7MSO yQRErEf7W6L3GsN87I150N0F/p1Zhmg66y5jOrigC/aNtOXnNgbIVuWX0ebod5RkVByRu57s47zUZ oUG/F1am4o6gJ5xG7IEd6zwE55pkFuSQK9cGM2LTbW8Hb7INj2lp52K3Yv8dIDQS4PSa8aRTD0/YD 1Xc/PVJ4yNhA3BFQLZl3KdUwG+9NGSCJBRov/6qMW3mhWgVj+5Fa7xSVEpaFWWKcm9R8z3TMPhdte 5cmbwZ5f7pq2NBmfqF1+I3N8aruFCqPHQpNmFiSN6dpD0cEhhlk21zExecYumCQf0PAoeHtxuef8j PfQ6hkWQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pnCdw-008R9s-34; Fri, 14 Apr 2023 06:10:44 +0000 Received: from mailgw01.mediatek.com ([216.200.240.184]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pnCdu-008R8S-03; Fri, 14 Apr 2023 06:10:43 +0000 X-UUID: 123e99a2da8b11edb7d8d11f642b8e78-20230413 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=K5oB4l0Vb3M1xYybDiOMAFZ9n2MsdIcmscCAPi5IQEM=; b=Eh9yAyYCQRAG0NKyCrc8G7tklHDdIPrmWIJWgzrmVg8seCrTIIwtoUdQY5fKjRXb8Yp3V71rt6Vn7D2YRhLxmzjZ4ThEjfSE1b5Ectj5kuddrNSEE0gXD1cIJg9M/hwN4+UEiL0ZlynZTsDNIxiodDXdCskZqIKTbsxbZtxn8Pg=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.22,REQID:ce22d748-d392-4ccd-b10c-c54a2a7757d1,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:454af0ea-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: 123e99a2da8b11edb7d8d11f642b8e78-20230413 Received: from mtkmbs11n2.mediatek.inc [(172.21.101.187)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 1120280521; Thu, 13 Apr 2023 23:10:35 -0700 Received: from mtkmbs11n2.mediatek.inc (172.21.101.187) 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; Fri, 14 Apr 2023 14:10:33 +0800 Received: from mszsdtlt102.gcn.mediatek.inc (10.16.4.142) by mtkmbs11n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.1118.25 via Frontend Transport; Fri, 14 Apr 2023 14:10:33 +0800 From: Haibo Li To: Russell King , AngeloGioacchino Del Regno , Linus Walleij , , CC: Matthias Brugger , Haibo Li , , Russell King , Alex Sverdlin , , , , , Subject: [PATCH v3] ARM:unwind:fix unwind abort for uleb128 case Date: Fri, 14 Apr 2023 14:10:31 +0800 Message-ID: <20230414061031.141430-1-haibo.li@mediatek.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230413_231042_081989_7DC650FA X-CRM114-Status: GOOD ( 16.51 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org 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 = 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 = 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 = vsp + 1544 0xac pop {r4, r5, r6, r7, r8, r14} In this case,the decoded uleb128 result is 0x101(vsp=0x204+(0x101<<2)). While the uleb128 used in code is 0x81(vsp=0x204+(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 --- v3: -As AngeloGioacchino Del Regno suggested,improve the comment and compress the code v2: - As Linus Walleij and Alexandre Mergnat suggested,add comments for unwind_decode_uleb128 - As Alexandre Mergnat suggested,change variables declaration in Alphabetical 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..9d2192156087 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 unwind_ctrl_block *ctrl, return URC_OK; } +static unsigned long unwind_decode_uleb128(struct unwind_ctrl_block *ctrl) +{ + unsigned long bytes = 0; + unsigned long insn; + unsigned long result = 0; + + /* + * unwind_get_byte() will advance `ctrl` one instruction at a time, so + * loop until we get an instruction byte where bit 7 is not set. + * + * Note: This decodes a maximum of 4 bytes to output 28 bits data where + * max is 0xfffffff: that will cover a vsp increment of 1073742336, hence + * it is sufficient for unwinding the stack. + */ + do { + insn = unwind_get_byte(ctrl); + result |= (insn & 0x7f) << (bytes * 7); + bytes++; + } while (!!(insn & 0x80) && (bytes != sizeof(result))); + + return result; +} + /* * Execute the current unwind instruction. */ @@ -361,7 +384,7 @@ static int unwind_exec_insn(struct unwind_ctrl_block *ctrl) if (ret) goto error; } else if (insn == 0xb2) { - unsigned long uleb128 = unwind_get_byte(ctrl); + unsigned long uleb128 = unwind_decode_uleb128(ctrl); ctrl->vrs[SP] += 0x204 + (uleb128 << 2); } else {