From mboxrd@z Thu Jan 1 00:00:00 1970 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 1FC0BC7EE43 for ; Wed, 7 Jun 2023 20:54:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235068AbjFGUyE (ORCPT ); Wed, 7 Jun 2023 16:54:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235397AbjFGUxl (ORCPT ); Wed, 7 Jun 2023 16:53:41 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93CBD212B for ; Wed, 7 Jun 2023 13:53:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 17FE1647A8 for ; Wed, 7 Jun 2023 20:53:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A215C433EF; Wed, 7 Jun 2023 20:53:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686171208; bh=PrAnEKQM8ba/kaH3fVF6IzMwaMifVuJ1DuyslPXnVho=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qHL8v/uexbOo7K9FBIqXxvEstaYCGJhcK1iNl+jV1BGnvgOhy8HRChqu4iK5baxLh ZcRG2TH615heVmExsf0VXnDB1FCCnq+3qxOX9YVsmk9TGbYpB22H0X661JDWkH/ez8 EpCk7ryZtxltlNMTZu7Tvgieq1PCC56b+IVCy6T4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Haibo Li , Linus Walleij , Alexandre Mergnat , AngeloGioacchino Del Regno , "Russell King (Oracle)" , Sasha Levin Subject: [PATCH 5.4 30/99] ARM: 9295/1: unwind:fix unwind abort for uleb128 case Date: Wed, 7 Jun 2023 22:16:22 +0200 Message-ID: <20230607200901.203913414@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230607200900.195572674@linuxfoundation.org> References: <20230607200900.195572674@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Haibo Li [ Upstream commit fa3eeb638de0c1a9d2d860e5b48259facdd65176 ] 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 Reviewed-by: Linus Walleij Reviewed-by: Alexandre Mergnat Reviewed-by: AngeloGioacchino Del Regno Signed-off-by: Russell King (Oracle) Signed-off-by: Sasha Levin --- 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 4574e6aea0a52..f321c2aa94e1c 100644 --- a/arch/arm/kernel/unwind.c +++ b/arch/arm/kernel/unwind.c @@ -300,6 +300,29 @@ 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. */ @@ -353,7 +376,7 @@ 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 { -- 2.39.2