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Subject[PATCH 76/76] ACPI throttling: fix endian bug in acpi_read_throttling_status()
Date
From: Dan Carpenter <dan.carpenter@oracle.com>

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>
---
drivers/acpi/processor_throttling.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 605a295..1d02b7b 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -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);
--
1.7.10.rc2.19.gfae9d


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