From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753487AbdJFI5y (ORCPT ); Fri, 6 Oct 2017 04:57:54 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:50198 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753450AbdJFI5v (ORCPT ); Fri, 6 Oct 2017 04:57:51 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paul Burton , linux-mips@linux-mips.org, Ralf Baechle , Sasha Levin Subject: [PATCH 4.4 06/50] MIPS: Ensure bss section ends on a long-aligned address Date: Fri, 6 Oct 2017 10:52:54 +0200 Message-Id: <20171006083706.190458864@linuxfoundation.org> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171006083705.157012217@linuxfoundation.org> References: <20171006083705.157012217@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paul Burton [ Upstream commit 3f00f4d8f083bc61005d0a1ef592b149f5c88bbd ] When clearing the .bss section in kernel_entry we do so using LONG_S instructions, and branch whilst the current write address doesn't equal the end of the .bss section minus the size of a long integer. The .bss section always begins at a long-aligned address and we always increment the write pointer by the size of a long integer - we therefore rely upon the .bss section ending at a long-aligned address. If this is not the case then the long-aligned write address can never be equal to the non-long-aligned end address & we will continue to increment past the end of the .bss section, attempting to zero the rest of memory. Despite this requirement that .bss end at a long-aligned address we pass 0 as the end alignment requirement to the BSS_SECTION macro and thus don't guarantee any particular alignment, allowing us to hit the error condition described above. Fix this by instead passing 8 bytes as the end alignment argument to the BSS_SECTION macro, ensuring that the end of the .bss section is always at least long-aligned. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14526/ Signed-off-by: Ralf Baechle Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/mips/kernel/vmlinux.lds.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/mips/kernel/vmlinux.lds.S +++ b/arch/mips/kernel/vmlinux.lds.S @@ -159,7 +159,7 @@ SECTIONS * Force .bss to 64K alignment so that .bss..swapper_pg_dir * gets that alignment. .sbss should be empty, so there will be * no holes after __init_end. */ - BSS_SECTION(0, 0x10000, 0) + BSS_SECTION(0, 0x10000, 8) _end = . ;