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[edk2] [PATCH v3 06/12] IntelFspWrapperPkg: Refine casting expression result to bigger size

Hao Wu posted 12 patches 7 years, 8 months ago
[edk2] [PATCH v3 06/12] IntelFspWrapperPkg: Refine casting expression result to bigger size
Posted by Hao Wu 7 years, 8 months ago 
There are cases that the operands of an expression are all with rank less
than UINT64/INT64 and the result of the expression is explicitly cast to
UINT64/INT64 to fit the target size.

An example will be:
UINT32 a,b;
// a and b can be any unsigned int type with rank less than UINT64, like
// UINT8, UINT16, etc.
UINT64 c;
c = (UINT64) (a + b);

Some static code checkers may warn that the expression result might
overflow within the rank of "int" (integer promotions) and the result is
then cast to a bigger size.

The commit refines codes by the following rules:
1). When the expression is possible to overflow the range of unsigned int/
int:
c = (UINT64)a + b;

2). When the expression will not overflow within the rank of "int", remove
the explicit type casts:
c = a + b;

3). When the expression will be cast to pointer of possible greater size:
UINT32 a,b;
VOID *c;
c = (VOID *)(UINTN)(a + b); --> c = (VOID *)((UINTN)a + b);

4). When one side of a comparison expression contains only operands with
rank less than UINT32:
UINT8 a;
UINT16 b;
UINTN c;
if ((UINTN)(a + b) > c) {...} --> if (((UINT32)a + b) > c) {...}

For rule 4), if we remove the 'UINTN' type cast like:
if (a + b > c) {...}
The VS compiler will complain with warning C4018 (signed/unsigned
mismatch, level 3 warning) due to promoting 'a + b' to type 'int'.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
---
 IntelFspWrapperPkg/FspNotifyDxe/LoadBelow4G.c        |  4 ++--
 IntelFspWrapperPkg/Library/BaseFspApiLib/FspApiLib.c | 12 ++++++------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/IntelFspWrapperPkg/FspNotifyDxe/LoadBelow4G.c b/IntelFspWrapperPkg/FspNotifyDxe/LoadBelow4G.c
index 6f06e24..089413c 100644
--- a/IntelFspWrapperPkg/FspNotifyDxe/LoadBelow4G.c
+++ b/IntelFspWrapperPkg/FspNotifyDxe/LoadBelow4G.c
@@ -1,6 +1,6 @@
 /** @file
 
-Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2015 - 2017, Intel Corporation. All rights reserved.<BR>
 
 This program and the accompanying materials
 are licensed and made available under the terms and conditions
@@ -115,7 +115,7 @@ RelocateImageUnder4GIfNeeded (
   // Align buffer on section boundary
   //
   ImageContext.ImageAddress += ImageContext.SectionAlignment - 1;
-  ImageContext.ImageAddress &= ~((EFI_PHYSICAL_ADDRESS)(ImageContext.SectionAlignment - 1));
+  ImageContext.ImageAddress &= ~((EFI_PHYSICAL_ADDRESS)ImageContext.SectionAlignment - 1);
   //
   // Load the image to our new buffer
   //
diff --git a/IntelFspWrapperPkg/Library/BaseFspApiLib/FspApiLib.c b/IntelFspWrapperPkg/Library/BaseFspApiLib/FspApiLib.c
index 162d244..accd6e4 100644
--- a/IntelFspWrapperPkg/Library/BaseFspApiLib/FspApiLib.c
+++ b/IntelFspWrapperPkg/Library/BaseFspApiLib/FspApiLib.c
@@ -1,7 +1,7 @@
 /** @file
   Provide FSP API related function.
 
-  Copyright (c) 2014 - 2015, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2014 - 2017, Intel Corporation. All rights reserved.<BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
@@ -98,7 +98,7 @@ CallFspInit (
   EFI_STATUS          Status;
   BOOLEAN             InterruptState;
 
-  FspInitApi = (FSP_INIT)(UINTN)(FspHeader->ImageBase + FspHeader->FspInitEntryOffset);
+  FspInitApi = (FSP_INIT)((UINTN)FspHeader->ImageBase + FspHeader->FspInitEntryOffset);
   InterruptState = SaveAndDisableInterrupts ();
   Status = Execute32BitCode ((UINTN)FspInitApi, (UINTN)FspInitParams);
   SetInterruptState (InterruptState);
@@ -125,7 +125,7 @@ CallFspNotifyPhase (
   EFI_STATUS          Status;
   BOOLEAN             InterruptState;
 
-  NotifyPhaseApi = (FSP_NOTIFY_PHASE)(UINTN)(FspHeader->ImageBase + FspHeader->NotifyPhaseEntryOffset);
+  NotifyPhaseApi = (FSP_NOTIFY_PHASE)((UINTN)FspHeader->ImageBase + FspHeader->NotifyPhaseEntryOffset);
   InterruptState = SaveAndDisableInterrupts ();
   Status = Execute32BitCode ((UINTN)NotifyPhaseApi, (UINTN)NotifyPhaseParams);
   SetInterruptState (InterruptState);
@@ -152,7 +152,7 @@ CallFspMemoryInit (
   EFI_STATUS          Status;
   BOOLEAN             InterruptState;
 
-  FspMemoryInitApi = (FSP_MEMORY_INIT)(UINTN)(FspHeader->ImageBase + FspHeader->FspMemoryInitEntryOffset);
+  FspMemoryInitApi = (FSP_MEMORY_INIT)((UINTN)FspHeader->ImageBase + FspHeader->FspMemoryInitEntryOffset);
   InterruptState = SaveAndDisableInterrupts ();
   Status = Execute32BitCode ((UINTN)FspMemoryInitApi, (UINTN)FspMemoryInitParams);
   SetInterruptState (InterruptState);
@@ -179,7 +179,7 @@ CallTempRamExit (
   EFI_STATUS          Status;
   BOOLEAN             InterruptState;
 
-  TempRamExitApi = (FSP_TEMP_RAM_EXIT)(UINTN)(FspHeader->ImageBase + FspHeader->TempRamExitEntryOffset);
+  TempRamExitApi = (FSP_TEMP_RAM_EXIT)((UINTN)FspHeader->ImageBase + FspHeader->TempRamExitEntryOffset);
   InterruptState = SaveAndDisableInterrupts ();
   Status = Execute32BitCode ((UINTN)TempRamExitApi, (UINTN)TempRamExitParam);
   SetInterruptState (InterruptState);
@@ -206,7 +206,7 @@ CallFspSiliconInit (
   EFI_STATUS          Status;
   BOOLEAN             InterruptState;
 
-  FspSiliconInitApi = (FSP_SILICON_INIT)(UINTN)(FspHeader->ImageBase + FspHeader->FspSiliconInitEntryOffset);
+  FspSiliconInitApi = (FSP_SILICON_INIT)((UINTN)FspHeader->ImageBase + FspHeader->FspSiliconInitEntryOffset);
   InterruptState = SaveAndDisableInterrupts ();
   Status = Execute32BitCode ((UINTN)FspSiliconInitApi, (UINTN)FspSiliconInitParam);
   SetInterruptState (InterruptState);
-- 
1.9.5.msysgit.0

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Re: [edk2] [PATCH v3 06/12] IntelFspWrapperPkg: Refine casting expression result to bigger size
Posted by Yao, Jiewen 7 years, 8 months ago 
Reviewed-by: jiewen.yao@intel.com

> -----Original Message-----
> From: Wu, Hao A
> Sent: Saturday, February 25, 2017 1:12 PM
> To: edk2-devel@lists.01.org
> Cc: Wu, Hao A <hao.a.wu@intel.com>; Yao, Jiewen <jiewen.yao@intel.com>
> Subject: [PATCH v3 06/12] IntelFspWrapperPkg: Refine casting expression result
> to bigger size
> 
> There are cases that the operands of an expression are all with rank less
> than UINT64/INT64 and the result of the expression is explicitly cast to
> UINT64/INT64 to fit the target size.
> 
> An example will be:
> UINT32 a,b;
> // a and b can be any unsigned int type with rank less than UINT64, like
> // UINT8, UINT16, etc.
> UINT64 c;
> c = (UINT64) (a + b);
> 
> Some static code checkers may warn that the expression result might
> overflow within the rank of "int" (integer promotions) and the result is
> then cast to a bigger size.
> 
> The commit refines codes by the following rules:
> 1). When the expression is possible to overflow the range of unsigned int/
> int:
> c = (UINT64)a + b;
> 
> 2). When the expression will not overflow within the rank of "int", remove
> the explicit type casts:
> c = a + b;
> 
> 3). When the expression will be cast to pointer of possible greater size:
> UINT32 a,b;
> VOID *c;
> c = (VOID *)(UINTN)(a + b); --> c = (VOID *)((UINTN)a + b);
> 
> 4). When one side of a comparison expression contains only operands with
> rank less than UINT32:
> UINT8 a;
> UINT16 b;
> UINTN c;
> if ((UINTN)(a + b) > c) {...} --> if (((UINT32)a + b) > c) {...}
> 
> For rule 4), if we remove the 'UINTN' type cast like:
> if (a + b > c) {...}
> The VS compiler will complain with warning C4018 (signed/unsigned
> mismatch, level 3 warning) due to promoting 'a + b' to type 'int'.
> 
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Hao Wu <hao.a.wu@intel.com>
> ---
>  IntelFspWrapperPkg/FspNotifyDxe/LoadBelow4G.c        |  4 ++--
>  IntelFspWrapperPkg/Library/BaseFspApiLib/FspApiLib.c | 12 ++++++------
>  2 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/IntelFspWrapperPkg/FspNotifyDxe/LoadBelow4G.c
> b/IntelFspWrapperPkg/FspNotifyDxe/LoadBelow4G.c
> index 6f06e24..089413c 100644
> --- a/IntelFspWrapperPkg/FspNotifyDxe/LoadBelow4G.c
> +++ b/IntelFspWrapperPkg/FspNotifyDxe/LoadBelow4G.c
> @@ -1,6 +1,6 @@
>  /** @file
> 
> -Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
> +Copyright (c) 2015 - 2017, Intel Corporation. All rights reserved.<BR>
> 
>  This program and the accompanying materials
>  are licensed and made available under the terms and conditions
> @@ -115,7 +115,7 @@ RelocateImageUnder4GIfNeeded (
>    // Align buffer on section boundary
>    //
>    ImageContext.ImageAddress += ImageContext.SectionAlignment - 1;
> -  ImageContext.ImageAddress &=
> ~((EFI_PHYSICAL_ADDRESS)(ImageContext.SectionAlignment - 1));
> +  ImageContext.ImageAddress &=
> ~((EFI_PHYSICAL_ADDRESS)ImageContext.SectionAlignment - 1);
>    //
>    // Load the image to our new buffer
>    //
> diff --git a/IntelFspWrapperPkg/Library/BaseFspApiLib/FspApiLib.c
> b/IntelFspWrapperPkg/Library/BaseFspApiLib/FspApiLib.c
> index 162d244..accd6e4 100644
> --- a/IntelFspWrapperPkg/Library/BaseFspApiLib/FspApiLib.c
> +++ b/IntelFspWrapperPkg/Library/BaseFspApiLib/FspApiLib.c
> @@ -1,7 +1,7 @@
>  /** @file
>    Provide FSP API related function.
> 
> -  Copyright (c) 2014 - 2015, Intel Corporation. All rights reserved.<BR>
> +  Copyright (c) 2014 - 2017, Intel Corporation. All rights reserved.<BR>
>    This program and the accompanying materials
>    are licensed and made available under the terms and conditions of the BSD
> License
>    which accompanies this distribution.  The full text of the license may be
> found at
> @@ -98,7 +98,7 @@ CallFspInit (
>    EFI_STATUS          Status;
>    BOOLEAN             InterruptState;
> 
> -  FspInitApi = (FSP_INIT)(UINTN)(FspHeader->ImageBase +
> FspHeader->FspInitEntryOffset);
> +  FspInitApi = (FSP_INIT)((UINTN)FspHeader->ImageBase +
> FspHeader->FspInitEntryOffset);
>    InterruptState = SaveAndDisableInterrupts ();
>    Status = Execute32BitCode ((UINTN)FspInitApi, (UINTN)FspInitParams);
>    SetInterruptState (InterruptState);
> @@ -125,7 +125,7 @@ CallFspNotifyPhase (
>    EFI_STATUS          Status;
>    BOOLEAN             InterruptState;
> 
> -  NotifyPhaseApi = (FSP_NOTIFY_PHASE)(UINTN)(FspHeader->ImageBase +
> FspHeader->NotifyPhaseEntryOffset);
> +  NotifyPhaseApi = (FSP_NOTIFY_PHASE)((UINTN)FspHeader->ImageBase +
> FspHeader->NotifyPhaseEntryOffset);
>    InterruptState = SaveAndDisableInterrupts ();
>    Status = Execute32BitCode ((UINTN)NotifyPhaseApi,
> (UINTN)NotifyPhaseParams);
>    SetInterruptState (InterruptState);
> @@ -152,7 +152,7 @@ CallFspMemoryInit (
>    EFI_STATUS          Status;
>    BOOLEAN             InterruptState;
> 
> -  FspMemoryInitApi = (FSP_MEMORY_INIT)(UINTN)(FspHeader->ImageBase +
> FspHeader->FspMemoryInitEntryOffset);
> +  FspMemoryInitApi = (FSP_MEMORY_INIT)((UINTN)FspHeader->ImageBase +
> FspHeader->FspMemoryInitEntryOffset);
>    InterruptState = SaveAndDisableInterrupts ();
>    Status = Execute32BitCode ((UINTN)FspMemoryInitApi,
> (UINTN)FspMemoryInitParams);
>    SetInterruptState (InterruptState);
> @@ -179,7 +179,7 @@ CallTempRamExit (
>    EFI_STATUS          Status;
>    BOOLEAN             InterruptState;
> 
> -  TempRamExitApi = (FSP_TEMP_RAM_EXIT)(UINTN)(FspHeader->ImageBase
> + FspHeader->TempRamExitEntryOffset);
> +  TempRamExitApi = (FSP_TEMP_RAM_EXIT)((UINTN)FspHeader->ImageBase
> + FspHeader->TempRamExitEntryOffset);
>    InterruptState = SaveAndDisableInterrupts ();
>    Status = Execute32BitCode ((UINTN)TempRamExitApi,
> (UINTN)TempRamExitParam);
>    SetInterruptState (InterruptState);
> @@ -206,7 +206,7 @@ CallFspSiliconInit (
>    EFI_STATUS          Status;
>    BOOLEAN             InterruptState;
> 
> -  FspSiliconInitApi = (FSP_SILICON_INIT)(UINTN)(FspHeader->ImageBase +
> FspHeader->FspSiliconInitEntryOffset);
> +  FspSiliconInitApi = (FSP_SILICON_INIT)((UINTN)FspHeader->ImageBase +
> FspHeader->FspSiliconInitEntryOffset);
>    InterruptState = SaveAndDisableInterrupts ();
>    Status = Execute32BitCode ((UINTN)FspSiliconInitApi,
> (UINTN)FspSiliconInitParam);
>    SetInterruptState (InterruptState);
> --
> 1.9.5.msysgit.0

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