From: Maxime Coquelin Date: Tue, 16 Jun 2015 11:53:19 +0000 (+0200) Subject: regmap: Fix possible shift overflow in regmap_field_init() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=921cc29473a0d7c109105c1876ddb432f4a4be7d;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git regmap: Fix possible shift overflow in regmap_field_init() 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. Signed-off-by: Maxime Coquelin Signed-off-by: Mark Brown Cc: stable@vger.kernel.org --- diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index 6273ff072f3e..e5194f698d66 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -945,11 +945,10 @@ EXPORT_SYMBOL_GPL(devm_regmap_init); 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 = GENMASK(reg_field.msb, reg_field.lsb); rm_field->id_size = reg_field.id_size; rm_field->id_offset = reg_field.id_offset; }