Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754059AbaLOPIs (ORCPT ); Mon, 15 Dec 2014 10:08:48 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:38403 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752431AbaLOO1m (ORCPT ); Mon, 15 Dec 2014 09:27:42 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Maxime Coquelin , "Peter Zijlstra (Intel)" , linux@rasmusvillemoes.dk, gong.chen@linux.intel.com, John Sullivan , Linus Torvalds , "Paul E. McKenney" , "Theodore Ts'o" , Ingo Molnar , Luis Henriques Subject: [PATCH 3.16.y-ckt 027/168] bitops: Fix shift overflow in GENMASK macros Date: Mon, 15 Dec 2014 14:24:41 +0000 Message-Id: <1418653622-21105-28-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.3 In-Reply-To: <1418653622-21105-1-git-send-email-luis.henriques@canonical.com> References: <1418653622-21105-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt3 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Maxime COQUELIN commit 00b4d9a14125f1e51874def2b9de6092e007412d upstream. On some 32 bits architectures, including x86, GENMASK(31, 0) returns 0 instead of the expected ~0UL. This is the same on some 64 bits architectures with GENMASK_ULL(63, 0). This is due to an overflow in the shift operand, 1 << 32 for GENMASK, 1 << 64 for GENMASK_ULL. Reported-by: Eric Paire Suggested-by: Rasmus Villemoes Signed-off-by: Maxime Coquelin Signed-off-by: Peter Zijlstra (Intel) Cc: linux@rasmusvillemoes.dk Cc: gong.chen@linux.intel.com Cc: John Sullivan Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Theodore Ts'o Fixes: 10ef6b0dffe4 ("bitops: Introduce a more generic BITMASK macro") Link: http://lkml.kernel.org/r/1415267659-10563-1-git-send-email-maxime.coquelin@st.com Signed-off-by: Ingo Molnar Signed-off-by: Luis Henriques --- include/linux/bitops.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/include/linux/bitops.h b/include/linux/bitops.h index cbc5833fb221..38b5f5c88c18 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -18,8 +18,11 @@ * position @h. For example * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000. */ -#define GENMASK(h, l) (((U32_C(1) << ((h) - (l) + 1)) - 1) << (l)) -#define GENMASK_ULL(h, l) (((U64_C(1) << ((h) - (l) + 1)) - 1) << (l)) +#define GENMASK(h, l) \ + (((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h)))) + +#define GENMASK_ULL(h, l) \ + (((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h)))) extern unsigned int __sw_hweight8(unsigned int w); extern unsigned int __sw_hweight16(unsigned int w); -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/