From 344e222edf486bf42da1ced137e36df7a345b0ad Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 7 Mar 2012 14:57:36 +0300 Subject: [PATCH] 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 Signed-off-by: Len Brown --- 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 605a2954ef17..1d02b7b5ade0 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);