From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 25 Jul 2017 21:27:00 +0200 (CEST) Received: from mail.linuxfoundation.org ([140.211.169.12]:36330 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23993974AbdGYTUqwX70n (ORCPT ); Tue, 25 Jul 2017 21:20:46 +0200 Received: from localhost (rrcs-64-183-28-114.west.biz.rr.com [64.183.28.114]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 3B969ACA; Tue, 25 Jul 2017 19:20:40 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, James Hogan , linux-mips@linux-mips.org, Ralf Baechle Subject: [PATCH 4.4 60/83] MIPS: Save static registers before sysmips Date: Tue, 25 Jul 2017 12:19:24 -0700 Message-Id: <20170725191717.889385594@linuxfoundation.org> X-Mailer: git-send-email 2.13.3 In-Reply-To: <20170725191708.449126292@linuxfoundation.org> References: <20170725191708.449126292@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 59250 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: gregkh@linuxfoundation.org Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: James Hogan commit 49955d84cd9ccdca5a16a495e448e1a06fad9e49 upstream. The MIPS sysmips system call handler may return directly from the MIPS_ATOMIC_SET case (mips_atomic_set()) to syscall_exit. This path restores the static (callee saved) registers, however they won't have been saved on entry to the system call. Use the save_static_function() macro to create a __sys_sysmips wrapper function which saves the static registers before calling sys_sysmips, so that the correct static register state is restored by syscall_exit. Fixes: f1e39a4a616c ("MIPS: Rewrite sysmips(MIPS_ATOMIC_SET, ...) in C with inline assembler") Signed-off-by: James Hogan Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16149/ Signed-off-by: Ralf Baechle Signed-off-by: Greg Kroah-Hartman --- arch/mips/kernel/scall32-o32.S | 2 +- arch/mips/kernel/scall64-64.S | 2 +- arch/mips/kernel/scall64-n32.S | 2 +- arch/mips/kernel/scall64-o32.S | 2 +- arch/mips/kernel/syscall.c | 6 ++++++ 5 files changed, 10 insertions(+), 4 deletions(-) --- a/arch/mips/kernel/scall32-o32.S +++ b/arch/mips/kernel/scall32-o32.S @@ -372,7 +372,7 @@ EXPORT(sys_call_table) PTR sys_writev PTR sys_cacheflush PTR sys_cachectl - PTR sys_sysmips + PTR __sys_sysmips PTR sys_ni_syscall /* 4150 */ PTR sys_getsid PTR sys_fdatasync --- a/arch/mips/kernel/scall64-64.S +++ b/arch/mips/kernel/scall64-64.S @@ -312,7 +312,7 @@ EXPORT(sys_call_table) PTR sys_sched_getaffinity PTR sys_cacheflush PTR sys_cachectl - PTR sys_sysmips + PTR __sys_sysmips PTR sys_io_setup /* 5200 */ PTR sys_io_destroy PTR sys_io_getevents --- a/arch/mips/kernel/scall64-n32.S +++ b/arch/mips/kernel/scall64-n32.S @@ -298,7 +298,7 @@ EXPORT(sysn32_call_table) PTR compat_sys_sched_getaffinity PTR sys_cacheflush PTR sys_cachectl - PTR sys_sysmips + PTR __sys_sysmips PTR compat_sys_io_setup /* 6200 */ PTR sys_io_destroy PTR compat_sys_io_getevents --- a/arch/mips/kernel/scall64-o32.S +++ b/arch/mips/kernel/scall64-o32.S @@ -367,7 +367,7 @@ EXPORT(sys32_call_table) PTR compat_sys_writev PTR sys_cacheflush PTR sys_cachectl - PTR sys_sysmips + PTR __sys_sysmips PTR sys_ni_syscall /* 4150 */ PTR sys_getsid PTR sys_fdatasync --- a/arch/mips/kernel/syscall.c +++ b/arch/mips/kernel/syscall.c @@ -202,6 +202,12 @@ static inline int mips_atomic_set(unsign unreachable(); } +/* + * mips_atomic_set() normally returns directly via syscall_exit potentially + * clobbering static registers, so be sure to preserve them. + */ +save_static_function(sys_sysmips); + SYSCALL_DEFINE3(sysmips, long, cmd, long, arg1, long, arg2) { switch (cmd) {