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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 <maxime.coquelin@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
hifive-unleashed-5.1
Maxime Coquelin 2015-06-16 13:53:19 +02:00 committed by Mark Brown
parent b787f68c36
commit 921cc29473
1 changed files with 1 additions and 2 deletions
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3
drivers/base/regmap/regmap.c
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@ -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;
}