On Fri, Aug 23, 2019 at 11:55:37 +0100, 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>
Reviewed-by: Leif Lindholm <leif.lindh...@linaro.org>
Apologies for missing this set.
> ---
> 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;
> }
> --
> 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'
>
>
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