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Commit 344e222e authored by Dan Carpenter's avatar Dan Carpenter Committed by Len Brown
Browse files

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: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent c264c651

drivers/acpi/processor_throttling.c

+2 −3
Original line number Diff line number Diff line
@@ -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);