Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933244AbbG1KAi (ORCPT ); Tue, 28 Jul 2015 06:00:38 -0400 Received: from mx2.suse.de ([195.135.220.15]:57957 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755705AbbG1JxP (ORCPT ); Tue, 28 Jul 2015 05:53:15 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Maxime Coquelin , Mark Brown , Jiri Slaby Subject: [PATCH 3.12 108/124] regmap: Fix possible shift overflow in regmap_field_init() Date: Tue, 28 Jul 2015 11:52:49 +0200 Message-Id: <0e5220a40f655782e493f3aad6d869090258a6a3.1438076484.git.jslaby@suse.cz> X-Mailer: git-send-email 2.4.6 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1973 Lines: 59 From: Maxime Coquelin 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 921cc29473a0d7c109105c1876ddb432f4a4be7d upstream. The way the mask is generated in regmap_field_init() is wrong. Indeed, a field initialized with msb = 31 and lsb = 0 provokes a shift overflow while calculating the mask field. On some 32 bits architectures, such as x86, the generated mask is 0, instead of the expected 0xffffffff. This patch uses GENMASK() to fix the problem, as this macro is already safe regarding shift overflow. [-js: in 3.12, we do not have GENMASK for general access. Define locally as RM_GENMASK.] Signed-off-by: Maxime Coquelin Signed-off-by: Mark Brown Signed-off-by: Jiri Slaby --- drivers/base/regmap/regmap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index 45aec73d09bd..8ece0fe4033f 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -813,14 +813,16 @@ struct regmap *devm_regmap_init(struct device *dev, } EXPORT_SYMBOL_GPL(devm_regmap_init); +#define RM_GENMASK(h, l) \ + (((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h)))) + static void regmap_field_init(struct regmap_field *rm_field, struct regmap *regmap, struct reg_field reg_field) { - int field_bits = reg_field.msb - reg_field.lsb + 1; rm_field->regmap = regmap; rm_field->reg = reg_field.reg; rm_field->shift = reg_field.lsb; - rm_field->mask = ((BIT(field_bits) - 1) << reg_field.lsb); + rm_field->mask = RM_GENMASK(reg_field.msb, reg_field.lsb); } /** -- 2.4.6 -- 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/