From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752841Ab0EFVip (ORCPT ); Thu, 6 May 2010 17:38:45 -0400 Received: from mail.digidescorp.com ([66.244.163.200]:11210 "EHLO digidescorp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751423Ab0EFVio (ORCPT ); Thu, 6 May 2010 17:38:44 -0400 X-Spam-Processed: digidescorp.com, Thu, 06 May 2010 16:38:43 -0500 X-Authenticated-Sender: steve@digidescorp.com X-Return-Path: prvs=17422c4580=steve@digidescorp.com X-Envelope-From: steve@digidescorp.com X-MDaemon-Deliver-To: linux-kernel@vger.kernel.org From: "Steven J. Magnani" To: microblaze-uclinux@itee.uq.edu.au Cc: monstr@monstr.eu, linux-kernel@vger.kernel.org, "Steven J. Magnani" Subject: [PATCH] microblaze: fix get_user/put_user side-effects Date: Thu, 6 May 2010 16:38:33 -0500 Message-Id: <1273181913-888-1-git-send-email-steve@digidescorp.com> X-Mailer: git-send-email 1.6.0.6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The Microblaze implementations of get_user() and (MMU) put_user() evaluate the address argument more than once. This causes unexpected side-effects for invocations that include increment operators, i.e. get_user(foo, bar++). This patch also removes the distinction between MMU and noMMU put_user(). Without the patch: $ echo 1234567890 > /proc/sys/kernel/core_pattern $ cat /proc/sys/kernel/core_pattern 12345 Signed-off-by: Steven J. Magnani --- diff -uprN a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h --- a/arch/microblaze/include/asm/uaccess.h 2010-04-27 10:14:33.000000000 -0500 +++ b/arch/microblaze/include/asm/uaccess.h 2010-05-06 16:21:02.000000000 -0500 @@ -182,6 +182,39 @@ extern long __user_bad(void); * Returns zero on success, or -EFAULT on error. * On error, the variable @x is set to zero. */ +#define get_user(x, ptr) \ + __get_user_check((x), (ptr), sizeof(*(ptr))) + +#define __get_user_check(x, ptr, size) \ +({ \ + unsigned long __gu_val = 0; \ + const typeof(*(ptr)) __user *__gu_addr = (ptr); \ + int __gu_err = 0; \ + \ + if (access_ok(VERIFY_READ, __gu_addr, size)) { \ + switch (size) { \ + case 1: \ + __get_user_asm("lbu", __gu_addr, __gu_val, \ + __gu_err); \ + break; \ + case 2: \ + __get_user_asm("lhu", __gu_addr, __gu_val, \ + __gu_err); \ + break; \ + case 4: \ + __get_user_asm("lw", __gu_addr, __gu_val, \ + __gu_err); \ + break; \ + default: \ + __gu_err = __user_bad(); \ + break; \ + } \ + } else { \ + __gu_err = -EFAULT; \ + } \ + x = (typeof(*(ptr)))__gu_val; \ + __gu_err; \ +}) #define __get_user(x, ptr) \ ({ \ @@ -206,12 +239,6 @@ extern long __user_bad(void); }) -#define get_user(x, ptr) \ -({ \ - access_ok(VERIFY_READ, (ptr), sizeof(*(ptr))) \ - ? __get_user((x), (ptr)) : -EFAULT; \ -}) - #define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err) \ ({ \ __asm__ __volatile__ ( \ @@ -266,6 +293,42 @@ extern long __user_bad(void); * * Returns zero on success, or -EFAULT on error. */ +#define put_user(x, ptr) \ + __put_user_check((x), (ptr), sizeof(*(ptr))) + +#define __put_user_check(x, ptr, size) \ +({ \ + typeof(*(ptr)) __pu_val; \ + typeof(*(ptr)) __user *__pu_addr = (ptr); \ + int __pu_err = 0; \ + \ + __pu_val = (x); \ + if (access_ok(VERIFY_WRITE, __pu_addr, size)) { \ + switch (size) { \ + case 1: \ + __put_user_asm("sb", __pu_addr, __pu_val, \ + __pu_err); \ + break; \ + case 2: \ + __put_user_asm("sh", __pu_addr, __pu_val, \ + __pu_err); \ + break; \ + case 4: \ + __put_user_asm("sw", __pu_addr, __pu_val, \ + __pu_err); \ + break; \ + case 8: \ + __put_user_asm_8(__pu_addr, __pu_val, __pu_err);\ + break; \ + default: \ + __pu_err = __user_bad(); \ + break; \ + } \ + } else { \ + __pu_err = -EFAULT; \ + } \ + __pu_err; \ +}) #define __put_user(x, ptr) \ ({ \ @@ -290,18 +353,6 @@ extern long __user_bad(void); __gu_err; \ }) -#ifndef CONFIG_MMU - -#define put_user(x, ptr) __put_user((x), (ptr)) - -#else /* CONFIG_MMU */ - -#define put_user(x, ptr) \ -({ \ - access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) \ - ? __put_user((x), (ptr)) : -EFAULT; \ -}) -#endif /* CONFIG_MMU */ /* copy_to_from_user */ #define __copy_from_user(to, from, n) \