[PATCH v2 1/1] ArmPkg/ArmMmuLibb: Fix implicit cast

[PATCH v2 1/1] ArmPkg/ArmMmuLibb: Fix implicit cast

[PierreGondois]

From: Pierre Gondois <pierre.gondois@arm.com>

While building with the following command line:
build -b DEBUG -a AARCH64 -t VS2017 -p
edk2\MdeModulePkg\MdeModulePkg.dsc

A missing cast triggers the following warning,
then triggering an error:
edk2/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c(652):
warning C4152: nonstandard extension, function/data pointer
conversion in expression

This patch first casts the function pointer to (UINTN),
then to (VOID*), followowing the C99 standard s6.3.2.3
"Pointer", paragraphs 5 and 6. This allows to remove the
warning.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
---

The changes can be seen at: https://github.com/PierreARM/edk2/commits/831_Fix_implicit_cast_v2

Notes:
    v1:
     - Add (void*) cast. [Pierre]
    v2:
     - First cast to (UINTN) to conform to c99 specification. [Lazlo]

 ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
index 222ff817956feb738325fc78fbaf064de98802a9..5fcd410061f0f0940cd761819ab49f598e2b4b00 100644
--- a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
+++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
@@ -649,7 +649,7 @@ ArmMmuBaseLibConstructor (
   // The ArmReplaceLiveTranslationEntry () helper function may be invoked
   // with the MMU off so we have to ensure that it gets cleaned to the PoC
   //
-  WriteBackDataCacheRange (ArmReplaceLiveTranslationEntry,
+  WriteBackDataCacheRange ((VOID*)(UINTN)ArmReplaceLiveTranslationEntry,
     ArmReplaceLiveTranslationEntrySize);
 
   return RETURN_SUCCESS;
-- 
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'

Re: [PATCH v2 1/1] ArmPkg/ArmMmuLibb: Fix implicit cast

[Ard Biesheuvel]

On 6/26/20 5:28 PM, PierreGondois wrote:
> From: Pierre Gondois <pierre.gondois@arm.com>
> 
> While building with the following command line:
> build -b DEBUG -a AARCH64 -t VS2017 -p
> edk2\MdeModulePkg\MdeModulePkg.dsc
> 
> A missing cast triggers the following warning,
> then triggering an error:
> edk2/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c(652):
> warning C4152: nonstandard extension, function/data pointer
> conversion in expression
> 
> This patch first casts the function pointer to (UINTN),
> then to (VOID*), followowing the C99 standard s6.3.2.3
> "Pointer", paragraphs 5 and 6. This allows to remove the
> warning.
> 
> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>

Merged as #731

Thanks,

> ---
> 
> The changes can be seen at: https://github.com/PierreARM/edk2/commits/831_Fix_implicit_cast_v2
> 
> Notes:
>      v1:
>       - Add (void*) cast. [Pierre]
>      v2:
>       - First cast to (UINTN) to conform to c99 specification. [Lazlo]
> 
>   ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
> index 222ff817956feb738325fc78fbaf064de98802a9..5fcd410061f0f0940cd761819ab49f598e2b4b00 100644
> --- a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
> +++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
> @@ -649,7 +649,7 @@ ArmMmuBaseLibConstructor (
>     // The ArmReplaceLiveTranslationEntry () helper function may be invoked
>     // with the MMU off so we have to ensure that it gets cleaned to the PoC
>     //
> -  WriteBackDataCacheRange (ArmReplaceLiveTranslationEntry,
> +  WriteBackDataCacheRange ((VOID*)(UINTN)ArmReplaceLiveTranslationEntry,
>       ArmReplaceLiveTranslationEntrySize);
>   
>     return RETURN_SUCCESS;
>