Re: [PATCH] ArmVirtPkg/ArmVirtPrePiUniCoreRelocatable: deal with relaxed XIP alignment

[Laszlo Ersek <lersek@redhat.com>]

On 08/02/16 12:17, Ard Biesheuvel wrote:
> Commit b89919ee8f8c ("BaseTools AARCH64: override XIP module linker
> alignment to 32 bytes") updated the various AARCH64 toolchain definitions
> to allow SEC, PEI_CORE and PEIM modules to be built with minimal alignment
> requirements even when using the AArch64 small code model which normally
> requires 4 KB section alignment.
> 
> This involves conversion of ADRP instructions into ADR instructions, which
> can only be done reliably if the ELF and the PE/COFF sections appear at
> the same offset modulo 4 KB.
> 
> The ArmVirtPrePiUniCoreRelocatable linker script did not yet take this
> into account, so update it by starting the .text section at the next
> appropriately aligned offset PECOFF_HEADER_SIZE bytes into the image.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> 
> This fixes the ArmVirtQemuKernel and ArmVirtXen platforms, which are currently
> broken when using DEBUG_GCC49, DEBUG_GCC5 or *_CLANG35 (all of which received
> the linker alignment treatment mentioned above)
> 
> Symptoms: many occurrences of
> ...
> GenFw: ERROR 3000: Invalid
>   WriteSections64(): <../ArmVirtPrePiUniCoreRelocatable.dll> AARCH64 small
>      code model requires identical ELF and PE/COFF section offsets modulo 4 KB.
> ...
> 
> and a failed build.
> 
>  ArmVirtPkg/PrePi/Scripts/PrePi-PIE.lds | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/ArmVirtPkg/PrePi/Scripts/PrePi-PIE.lds b/ArmVirtPkg/PrePi/Scripts/PrePi-PIE.lds
> index 44df7840adfd..492a8fff380f 100644
> --- a/ArmVirtPkg/PrePi/Scripts/PrePi-PIE.lds
> +++ b/ArmVirtPkg/PrePi/Scripts/PrePi-PIE.lds
> @@ -14,9 +14,10 @@
>  
>  SECTIONS
>  {
> -  .text 0x0 : ALIGN(CONSTANT(COMMONPAGESIZE)) {
> -    PROVIDE(__reloc_base = .);
> +  PROVIDE(__reloc_base = .);
>  
> +  . = PECOFF_HEADER_SIZE;
> +  .text : ALIGN(CONSTANT(COMMONPAGESIZE)) {
>      *(.text .text*)
>      *(.got .got*)
>      *(.rodata .rodata*)
> 

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