Re: [PATCH 1/3] MdePkg/BaseMemoryLibOptDxe ARM: add missing function annotations

[Laszlo Ersek <lersek@redhat.com>]

On 12/12/18 11:33, Ard Biesheuvel wrote:
> ARM uses the low order bit of a branch target address to decide in
> which execution mode (ARM or Thumb) a function needs to be called.
> In order for this to work across object files, ELF function symbols
> will have the low bit set if they were emitted in Thumb mode and
> cleared otherwise. This annotation is only emitted if the ELF symbols
> are annotated as function, since taking the address of some data
> symbol (e.g., a literal) should not produce a value with the low bit
> set, even if it appears in an object file containing Thumb code.
> 
> This means that all functions coded in assembler must have this
> function annotation, or they may end up getting called in the
> wrong mode, crashing the program.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  MdePkg/Library/BaseMemoryLibOptDxe/Arm/CompareGuid.S | 1 +
>  MdePkg/Library/BaseMemoryLibOptDxe/Arm/CompareMem.S  | 1 +
>  MdePkg/Library/BaseMemoryLibOptDxe/Arm/CopyMem.S     | 1 +
>  MdePkg/Library/BaseMemoryLibOptDxe/Arm/SetMem.S      | 5 +++++
>  4 files changed, 8 insertions(+)
> 
> diff --git a/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CompareGuid.S b/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CompareGuid.S
> index 6d0089049d48..b74056fa1f5f 100644
> --- a/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CompareGuid.S
> +++ b/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CompareGuid.S
> @@ -30,6 +30,7 @@
>      .thumb
>      .syntax unified
>      .align  5
> +    .type   ASM_PFX(InternalMemCompareGuid), %function
>  ASM_GLOBAL ASM_PFX(InternalMemCompareGuid)
>  ASM_PFX(InternalMemCompareGuid):
>      push    {r4, lr}
> diff --git a/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CompareMem.S b/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CompareMem.S
> index 9483aab61a0c..25a9a0994524 100644
> --- a/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CompareMem.S
> +++ b/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CompareMem.S
> @@ -46,6 +46,7 @@
>      .thumb
>      .syntax unified
>      .align  5
> +    .type   ASM_PFX(InternalMemCompareMem), %function
>  ASM_GLOBAL ASM_PFX(InternalMemCompareMem)
>  ASM_PFX(InternalMemCompareMem):
>      push    {r4-r8, lr}
> diff --git a/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CopyMem.S b/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CopyMem.S
> index 195a0b23f770..e1543f3c2a43 100644
> --- a/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CopyMem.S
> +++ b/MdePkg/Library/BaseMemoryLibOptDxe/Arm/CopyMem.S
> @@ -42,6 +42,7 @@ InternalMemCopyMem (
>    IN      UINTN                     Length
>    )
>  **/
> +    .type   ASM_PFX(InternalMemCopyMem), %function
>  ASM_GLOBAL ASM_PFX(InternalMemCopyMem)
>  ASM_PFX(InternalMemCopyMem):
>      push    {r4-r11, lr}
> diff --git a/MdePkg/Library/BaseMemoryLibOptDxe/Arm/SetMem.S b/MdePkg/Library/BaseMemoryLibOptDxe/Arm/SetMem.S
> index 2d8f4d5b8621..928c1a12d558 100644
> --- a/MdePkg/Library/BaseMemoryLibOptDxe/Arm/SetMem.S
> +++ b/MdePkg/Library/BaseMemoryLibOptDxe/Arm/SetMem.S
> @@ -16,6 +16,7 @@
>      .thumb
>      .syntax unified
>      .align  5
> +    .type   ASM_PFX(InternalMemSetMem16), %function
>  ASM_GLOBAL ASM_PFX(InternalMemSetMem16)
>  ASM_PFX(InternalMemSetMem16):
>      uxth    r2, r2
> @@ -23,17 +24,20 @@ ASM_PFX(InternalMemSetMem16):
>      orr     r2, r2, r2, lsl #16
>      b       0f
>  
> +    .type   ASM_PFX(InternalMemSetMem32), %function
>  ASM_GLOBAL ASM_PFX(InternalMemSetMem32)
>  ASM_PFX(InternalMemSetMem32):
>      lsl     r1, r1, #2
>      b       0f
>  
> +    .type   ASM_PFX(InternalMemSetMem64), %function
>  ASM_GLOBAL ASM_PFX(InternalMemSetMem64)
>  ASM_PFX(InternalMemSetMem64):
>      lsl     r1, r1, #3
>      b       1f
>  
>      .align  5
> +    .type   ASM_PFX(InternalMemSetMem), %function
>  ASM_GLOBAL ASM_PFX(InternalMemSetMem)
>  ASM_PFX(InternalMemSetMem):
>      uxtb    r2, r2
> @@ -41,6 +45,7 @@ ASM_PFX(InternalMemSetMem):
>      orr     r2, r2, r2, lsl #16
>      b       0f
>  
> +    .type   ASM_PFX(InternalMemZeroMem), %function
>  ASM_GLOBAL ASM_PFX(InternalMemZeroMem)
>  ASM_PFX(InternalMemZeroMem):
>      movs    r2, #0
> 

Acked-by: Laszlo Ersek <lersek@redhat.com>