Re: [PATCH 1/2] BaseTools/tools_def AARCH64: mark register x18 as reserved

[Leif Lindholm <leif.lindholm@linaro.org>]

On Thu, Jul 13, 2017 at 01:48:43PM +0100, Ard Biesheuvel wrote:
> The AArch64 ABI classifies register x18 as a platform register, which
> means it should not be used unless the code is guaranteed to run on a
> platform that doesn't use it in such a capacity.
> 
> GCC does not honour this requirement by default, and so we need to tell
> it not to touch it explicitly, by passing the -ffixed-x18 command line
> option.
> 
> Link: https://bugzilla.tianocore.org/show_bug.cgi?id=625
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

> ---
>  BaseTools/Conf/tools_def.template | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/BaseTools/Conf/tools_def.template b/BaseTools/Conf/tools_def.template
> index 7d3f54218461..128da5131d01 100755
> --- a/BaseTools/Conf/tools_def.template
> +++ b/BaseTools/Conf/tools_def.template
> @@ -4341,7 +4341,7 @@ DEFINE GCC_X64_CC_FLAGS            = DEF(GCC_ALL_CC_FLAGS) -mno-red-zone -Wno-ad
>  DEFINE GCC_IPF_CC_FLAGS            = DEF(GCC_ALL_CC_FLAGS) -minline-int-divide-min-latency
>  DEFINE GCC_ARM_CC_FLAGS            = DEF(GCC_ALL_CC_FLAGS) -mlittle-endian -mabi=aapcs -fno-short-enums -funsigned-char -ffunction-sections -fdata-sections -fomit-frame-pointer -Wno-address -mthumb -mfloat-abi=soft -fno-pic -fno-pie
>  DEFINE GCC_ARM_CC_XIPFLAGS         = -mno-unaligned-access
> -DEFINE GCC_AARCH64_CC_FLAGS        = DEF(GCC_ALL_CC_FLAGS) -mlittle-endian -fno-short-enums -fverbose-asm -funsigned-char  -ffunction-sections -fdata-sections -Wno-address -fno-asynchronous-unwind-tables -fno-pic -fno-pie
> +DEFINE GCC_AARCH64_CC_FLAGS        = DEF(GCC_ALL_CC_FLAGS) -mlittle-endian -fno-short-enums -fverbose-asm -funsigned-char  -ffunction-sections -fdata-sections -Wno-address -fno-asynchronous-unwind-tables -fno-pic -fno-pie -ffixed-x18
>  DEFINE GCC_AARCH64_CC_XIPFLAGS     = -mstrict-align
>  DEFINE GCC_DLINK_FLAGS_COMMON      = -nostdlib --pie
>  DEFINE GCC_DLINK2_FLAGS_COMMON     = -Wl,--script=$(EDK_TOOLS_PATH)/Scripts/GccBase.lds
> -- 
> 2.9.3
>