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ACPI throttling: fix endian bug in acpi_read_throttling_status() 

Using a u64 here creates an endian bug.  We store a u32 number in the
top byte which is a larger number than intended on big endian systems.
There is no reason to use a 64 bit data type here, I guess it was just
an oversight.

I removed the initialization to zero as well.  It's needed with a u64
but with a u32, the variable gets initialized properly inside the call
to acpi_os_read_port().

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Dan Carpenter 2012-03-07 14:57:36 +03:00 committed by Len Brown
parent c264c651fd
commit 344e222edf
1 changed files with 2 additions and 3 deletions
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5
drivers/acpi/processor_throttling.c
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@ -769,7 +769,7 @@ static int acpi_read_throttling_status(struct acpi_processor *pr,
u64 *value)
{
u32 bit_width, bit_offset;
u64 ptc_value;
u32 ptc_value;
u64 ptc_mask;
struct acpi_processor_throttling *throttling;
int ret = -1;
@ -777,12 +777,11 @@ static int acpi_read_throttling_status(struct acpi_processor *pr,
throttling = &pr->throttling;
switch (throttling->status_register.space_id) {
case ACPI_ADR_SPACE_SYSTEM_IO:
ptc_value = 0;
bit_width = throttling->status_register.bit_width;
bit_offset = throttling->status_register.bit_offset;
acpi_os_read_port((acpi_io_address) throttling->status_register.
address, (u32 *) &ptc_value,
address, &ptc_value,
(u32) (bit_width + bit_offset));
ptc_mask = (1 << bit_width) - 1;
*value = (u64) ((ptc_value >> bit_offset) & ptc_mask);