Re: [PATCH v2 1/2] MdePkg/BaseLib: Fix unaligned API prototypes


Michael D Kinney
 

Hi Marvin,

Can you provide an example of which C compiler is flagging this as
an error and what error message is generated.

Please enter a BZ with this background information and add link to the
BZ in the commit message.

This is a change to the BaseLib class, so we need to make sure there
are no impacts to any existing code. I looks like a safe change
because changing from a pointer to a fixed size type to VOID *
should be compatible. Please add that analysis to the background
in the BZ as well.

Thanks,

Mike

-----Original Message-----
From: Marvin Häuser <mhaeuser@...>
Sent: Monday, August 9, 2021 2:51 AM
To: devel@edk2.groups.io
Cc: Kinney, Michael D <michael.d.kinney@...>; Liming Gao <gaoliming@...>; Liu, Zhiguang
<zhiguang.liu@...>; Vitaly Cheptsov <vit9696@...>
Subject: [PATCH v2 1/2] MdePkg/BaseLib: Fix unaligned API prototypes

C prohibits not only dereferencing but also casting to unaligned
pointers. Thus, the current set of unaligned APIs cannot be called
safely. Update their prototypes to take VOID * pointers, which must
be able to represent any valid pointer.

Cc: Michael D Kinney <michael.d.kinney@...>
Cc: Liming Gao <gaoliming@...>
Cc: Zhiguang Liu <zhiguang.liu@...>
Cc: Vitaly Cheptsov <vit9696@...>
Signed-off-by: Marvin Häuser <mhaeuser@...>
---
MdePkg/Library/BaseLib/Arm/Unaligned.c | 14 ++++-----
MdePkg/Library/BaseLib/Unaligned.c | 32 ++++++++++----------
MdePkg/Include/Library/BaseLib.h | 16 +++++-----
3 files changed, 31 insertions(+), 31 deletions(-)

diff --git a/MdePkg/Library/BaseLib/Arm/Unaligned.c b/MdePkg/Library/BaseLib/Arm/Unaligned.c
index e9934e7003cb..57f19fc44e0b 100644
--- a/MdePkg/Library/BaseLib/Arm/Unaligned.c
+++ b/MdePkg/Library/BaseLib/Arm/Unaligned.c
@@ -59,7 +59,7 @@ ReadUnaligned16 (
UINT16

EFIAPI

WriteUnaligned16 (

- OUT UINT16 *Buffer,

+ OUT VOID *Buffer,

IN UINT16 Value

)

{

@@ -87,7 +87,7 @@ WriteUnaligned16 (
UINT32

EFIAPI

ReadUnaligned24 (

- IN CONST UINT32 *Buffer

+ IN CONST VOID *Buffer

)

{

ASSERT (Buffer != NULL);

@@ -116,7 +116,7 @@ ReadUnaligned24 (
UINT32

EFIAPI

WriteUnaligned24 (

- OUT UINT32 *Buffer,

+ OUT VOID *Buffer,

IN UINT32 Value

)

{

@@ -143,7 +143,7 @@ WriteUnaligned24 (
UINT32

EFIAPI

ReadUnaligned32 (

- IN CONST UINT32 *Buffer

+ IN CONST VOID *Buffer

)

{

UINT16 LowerBytes;

@@ -175,7 +175,7 @@ ReadUnaligned32 (
UINT32

EFIAPI

WriteUnaligned32 (

- OUT UINT32 *Buffer,

+ OUT VOID *Buffer,

IN UINT32 Value

)

{

@@ -202,7 +202,7 @@ WriteUnaligned32 (
UINT64

EFIAPI

ReadUnaligned64 (

- IN CONST UINT64 *Buffer

+ IN CONST VOID *Buffer

)

{

UINT32 LowerBytes;

@@ -234,7 +234,7 @@ ReadUnaligned64 (
UINT64

EFIAPI

WriteUnaligned64 (

- OUT UINT64 *Buffer,

+ OUT VOID *Buffer,

IN UINT64 Value

)

{

diff --git a/MdePkg/Library/BaseLib/Unaligned.c b/MdePkg/Library/BaseLib/Unaligned.c
index a419cb85e53c..3041adcde606 100644
--- a/MdePkg/Library/BaseLib/Unaligned.c
+++ b/MdePkg/Library/BaseLib/Unaligned.c
@@ -26,12 +26,12 @@
UINT16

EFIAPI

ReadUnaligned16 (

- IN CONST UINT16 *Buffer

+ IN CONST VOID *Buffer

)

{

ASSERT (Buffer != NULL);



- return *Buffer;

+ return *(CONST UINT16 *) Buffer;

}



/**

@@ -52,13 +52,13 @@ ReadUnaligned16 (
UINT16

EFIAPI

WriteUnaligned16 (

- OUT UINT16 *Buffer,

+ OUT VOID *Buffer,

IN UINT16 Value

)

{

ASSERT (Buffer != NULL);



- return *Buffer = Value;

+ return *(UINT16 *) Buffer = Value;

}



/**

@@ -77,12 +77,12 @@ WriteUnaligned16 (
UINT32

EFIAPI

ReadUnaligned24 (

- IN CONST UINT32 *Buffer

+ IN CONST VOID *Buffer

)

{

ASSERT (Buffer != NULL);



- return *Buffer & 0xffffff;

+ return *(CONST UINT32 *) Buffer & 0xffffff;

}



/**

@@ -103,13 +103,13 @@ ReadUnaligned24 (
UINT32

EFIAPI

WriteUnaligned24 (

- OUT UINT32 *Buffer,

+ OUT VOID *Buffer,

IN UINT32 Value

)

{

ASSERT (Buffer != NULL);



- *Buffer = BitFieldWrite32 (*Buffer, 0, 23, Value);

+ *(UINT32 *) Buffer = BitFieldWrite32 (*(CONST UINT32 *) Buffer, 0, 23, Value);

return Value;

}



@@ -129,12 +129,12 @@ WriteUnaligned24 (
UINT32

EFIAPI

ReadUnaligned32 (

- IN CONST UINT32 *Buffer

+ IN CONST VOID *Buffer

)

{

ASSERT (Buffer != NULL);



- return *Buffer;

+ return *(CONST UINT32 *) Buffer;

}



/**

@@ -155,13 +155,13 @@ ReadUnaligned32 (
UINT32

EFIAPI

WriteUnaligned32 (

- OUT UINT32 *Buffer,

+ OUT VOID *Buffer,

IN UINT32 Value

)

{

ASSERT (Buffer != NULL);



- return *Buffer = Value;

+ return *(UINT32 *) Buffer = Value;

}



/**

@@ -180,12 +180,12 @@ WriteUnaligned32 (
UINT64

EFIAPI

ReadUnaligned64 (

- IN CONST UINT64 *Buffer

+ IN CONST VOID *Buffer

)

{

ASSERT (Buffer != NULL);



- return *Buffer;

+ return *(CONST UINT64 *) Buffer;

}



/**

@@ -206,11 +206,11 @@ ReadUnaligned64 (
UINT64

EFIAPI

WriteUnaligned64 (

- OUT UINT64 *Buffer,

+ OUT VOID *Buffer,

IN UINT64 Value

)

{

ASSERT (Buffer != NULL);



- return *Buffer = Value;

+ return *(UINT64 *) Buffer = Value;

}

diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
index 2452c1d92e51..4d30f0539c6b 100644
--- a/MdePkg/Include/Library/BaseLib.h
+++ b/MdePkg/Include/Library/BaseLib.h
@@ -3420,7 +3420,7 @@ DivS64x64Remainder (
UINT16

EFIAPI

ReadUnaligned16 (

- IN CONST UINT16 *Buffer

+ IN CONST VOID *Buffer

);





@@ -3442,7 +3442,7 @@ ReadUnaligned16 (
UINT16

EFIAPI

WriteUnaligned16 (

- OUT UINT16 *Buffer,

+ OUT VOID *Buffer,

IN UINT16 Value

);



@@ -3463,7 +3463,7 @@ WriteUnaligned16 (
UINT32

EFIAPI

ReadUnaligned24 (

- IN CONST UINT32 *Buffer

+ IN CONST VOID *Buffer

);





@@ -3485,7 +3485,7 @@ ReadUnaligned24 (
UINT32

EFIAPI

WriteUnaligned24 (

- OUT UINT32 *Buffer,

+ OUT VOID *Buffer,

IN UINT32 Value

);



@@ -3506,7 +3506,7 @@ WriteUnaligned24 (
UINT32

EFIAPI

ReadUnaligned32 (

- IN CONST UINT32 *Buffer

+ IN CONST VOID *Buffer

);





@@ -3528,7 +3528,7 @@ ReadUnaligned32 (
UINT32

EFIAPI

WriteUnaligned32 (

- OUT UINT32 *Buffer,

+ OUT VOID *Buffer,

IN UINT32 Value

);



@@ -3549,7 +3549,7 @@ WriteUnaligned32 (
UINT64

EFIAPI

ReadUnaligned64 (

- IN CONST UINT64 *Buffer

+ IN CONST VOID *Buffer

);





@@ -3571,7 +3571,7 @@ ReadUnaligned64 (
UINT64

EFIAPI

WriteUnaligned64 (

- OUT UINT64 *Buffer,

+ OUT VOID *Buffer,

IN UINT64 Value

);



--
2.31.1

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