[PATCH v2 09/13] ACPICA: Executer: Introduce a set of macros to handle bit width mask generation

Lv Zheng
2016-05-05T04:58:45Z

ACPICA commit c23034a3a09d5ed79f1827d51f43cfbccf68ab64

A regression was reported to the shift offset >= width of type.
This patch fixes this issue. BZ 1270.
This is a part of the fix because the order of the patches are modified for
Linux upstream, containing the cleanups for the old code. Lv Zheng.

Link: https://github.com/acpica/acpica/commit/c23034a3
Link: https://bugs.acpica.org/show_bug.cgi?id=1270
Reported-by: Sascha Wildner <swildner@gmail.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
---
drivers/acpi/acpica/acmacros.h | 12 ++++++++++++
drivers/acpi/acpica/exfldio.c | 12 ++----------
2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/acpi/acpica/acmacros.h b/drivers/acpi/acpica/acmacros.h
index ecbaaba..a3b9543 100644
--- a/drivers/acpi/acpica/acmacros.h
+++ b/drivers/acpi/acpica/acmacros.h
@@ -270,9 +270,21 @@
* Bit positions start at zero.
* MASK_BITS_ABOVE creates a mask starting AT the position and above
* MASK_BITS_BELOW creates a mask starting one bit BELOW the position
+ * MASK_BITS_ABOVE/BELOW accpets a bit offset to create a mask
+ * MASK_BITS_ABOVE/BELOW_32/64 accpets a bit width to create a mask
+ * Note: The ACPI_INTEGER_BIT_SIZE check is used to bypass compiler
+ * differences with the shift operator
*/
#define ACPI_MASK_BITS_ABOVE(position) (~((ACPI_UINT64_MAX) << ((u32) (position))))
#define ACPI_MASK_BITS_BELOW(position) ((ACPI_UINT64_MAX) << ((u32) (position)))
+#define ACPI_MASK_BITS_ABOVE_32(width) ((u32) ACPI_MASK_BITS_ABOVE(width))
+#define ACPI_MASK_BITS_BELOW_32(width) ((u32) ACPI_MASK_BITS_BELOW(width))
+#define ACPI_MASK_BITS_ABOVE_64(width) ((width) == ACPI_INTEGER_BIT_SIZE ? \
+ ACPI_UINT64_MAX : \
+ ACPI_MASK_BITS_ABOVE(width))
+#define ACPI_MASK_BITS_BELOW_64(width) ((width) == ACPI_INTEGER_BIT_SIZE ? \
+ (u64) 0 : \
+ ACPI_MASK_BITS_BELOW(width))

/* Bitfields within ACPI registers */

diff --git a/drivers/acpi/acpica/exfldio.c b/drivers/acpi/acpica/exfldio.c
index 72f9176..ee76d29 100644
--- a/drivers/acpi/acpica/exfldio.c
+++ b/drivers/acpi/acpica/exfldio.c
@@ -897,17 +897,9 @@ acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,

access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width);

- /*
- * Create the bitmasks used for bit insertion.
- * Note: This if/else is used to bypass compiler differences with the
- * shift operator
- */
- if (access_bit_width == ACPI_INTEGER_BIT_SIZE) {
- width_mask = ACPI_UINT64_MAX;
- } else {
- width_mask = ACPI_MASK_BITS_ABOVE(access_bit_width);
- }
+ /* Create the bitmasks used for bit insertion */

+ width_mask = ACPI_MASK_BITS_ABOVE_64(access_bit_width);
mask = width_mask &
ACPI_MASK_BITS_BELOW(obj_desc->common_field.start_field_bit_offset);

--
1.7.10