Patrick Georgi submitted this change.

View Change

mmio: Fix failure in bit field macro when accessing >30 bits

For bit fields with 31 bits (e.g: DEFINE_BITFIELD(MYREG, 30, 0) ),
the calculation of mask value will go overflow:
 "error: integer overflow in expression '-2147483648 - 1' of
  type 'int' results in '2147483647'".

And for bit fields with 32 bits (e.g: DEFINE_BITFIELD(MYREG, 31, 0) ),
the error will be:
 "error: left shift count >= width of type [-Werror=shift-count-overflow]"

To fix these issues, the bit field macros should always use unsigned
integers, and use 64bit integer when creating mask value.

Change-Id: Ie3cddf9df60b83de4e21243bfde6b79729fb06ef
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40404
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
---
M src/include/device/mmio.h
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/include/device/mmio.h b/src/include/device/mmio.h
index b4f2ab6..a725a62 100644
--- a/src/include/device/mmio.h
+++ b/src/include/device/mmio.h
@@ -131,10 +131,10 @@
 #define DEFINE_BIT(name, bit) DEFINE_BITFIELD(name, bit, bit)
 
 #define _BF_MASK(name, value) \
-	(((1 << name##_BITFIELD_SIZE) - 1) << name##_BITFIELD_SHIFT)
+	((u32)((1ULL << name##_BITFIELD_SIZE) - 1) << name##_BITFIELD_SHIFT)
 
 #define _BF_VALUE(name, value) \
-	((value) << name##_BITFIELD_SHIFT)
+	(((u32)(value) << name##_BITFIELD_SHIFT) & _BF_MASK(name, 0))
 
 #define _BF_APPLY1(op, name, value, ...) (op(name, value))
 #define _BF_APPLY2(op, name, value, ...) ((op(name, value)) | \

To view, visit change 40404. To unsubscribe, or for help writing mail filters, visit settings.