On 8/23/19 12:55 PM, Sami Mujawar wrote:
The VS2017 compiler reports 'warning C4244: '=': conversion
from 'UINT64' to 'UINT32', possible loss of data' for the
calculation of the UART Divisor value.
Fix this warning by adding appropriate typecast and a validation
that ensures that the UART divisor value generated does not exceed
MAX_UINT32.
Signed-off-by: Sami Mujawar <sami.muja...@arm.com>
---
ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c
b/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c
index
801990d9551a638c17d560d4226137b8a3ee47bb..2d3c279cce49304959953ec4a34b50e09a7d0045
100644
--- a/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c
+++ b/ArmPlatformPkg/Library/PL011UartLib/PL011UartLib.c
@@ -2,7 +2,7 @@
Serial I/O Port library functions with no library constructor/destructor
Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
- Copyright (c) 2011 - 2016, ARM Ltd. All rights reserved.<BR>
+ Copyright (c) 2011 - 2019, ARM Ltd. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
@@ -78,6 +78,7 @@ PL011UartInitializePort (
UINT32 Integer;
UINT32 Fractional;
UINT32 HardwareFifoDepth;
+ UINT64 DivisorValue;
HardwareFifoDepth = (PL011_UARTPID2_VER (MmioRead32 (UartBase + UARTPID2)) \
> PL011_VER_R1P4) \
@@ -188,7 +189,12 @@ PL011UartInitializePort (
return RETURN_INVALID_PARAMETER;
}
- Divisor = (UartClkInHz * 4) / *BaudRate;
+ DivisorValue = (((UINT64)UartClkInHz * 4) / *BaudRate);
+ if (DivisorValue > MAX_UINT32) {
+ return RETURN_INVALID_PARAMETER;
+ }
+
+ Divisor = (UINT32)DivisorValue;
Integer = Divisor >> FRACTION_PART_SIZE_IN_BITS;
Fractional = Divisor & FRACTION_PART_MASK;
}
Reviewed-by: Philippe Mathieu-Daude <phi...@redhat.com>
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