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gpio / ACPI: Prevent potential wrap of GPIO value on OpRegion read

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Dan Carpenter's static code checker reports:

 The patch 473ed7be0d: "gpio / ACPI: Add support for ACPI GPIO
 operation regions" from Mar 14, 2014, leads to the following static
 checker warning:

  drivers/gpio/gpiolib-acpi.c:454 acpi_gpio_adr_space_handler()
  warn: should 'gpiod_get_raw_value(desc) << i' be a 64 bit type?

This is due the fact that *value is of type u64 and gpiod_get_raw_value()
returns int. Since i can be larger than 31, it is possible that the value
returned gets wrapped.

Fix this by casting the return of gpiod_get_raw_value() to u64 first before
shift.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Mika Westerberg 2014-04-01 13:03:00 +03:00 committed by Linus Walleij
parent e9595f84a6
commit b5539fa2d5
1 changed files with 1 additions and 1 deletions
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2
drivers/gpio/gpiolib-acpi.c
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@ -451,7 +451,7 @@ acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
if (function == ACPI_WRITE)
gpiod_set_raw_value(desc, !!((1 << i) & *value));
else
*value |= gpiod_get_raw_value(desc) << i;
*value |= (u64)gpiod_get_raw_value(desc) << i;
}
out: