BaseTools/tools_def AARCH64: mark register x18 as reserved

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>

diff --git a/BaseTools/Conf/tools_def.template b/BaseTools/Conf/tools_def.template
index 7d3f54218461d1cb5620b797d52538368643f01a..128da5131d013d6e14f3e54e3899779c64c52134 100755 (executable)
--- 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\r
 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\r
 DEFINE GCC_ARM_CC_XIPFLAGS         = -mno-unaligned-access\r
 DEFINE GCC_IPF_CC_FLAGS            = DEF(GCC_ALL_CC_FLAGS) -minline-int-divide-min-latency\r
 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\r
 DEFINE GCC_ARM_CC_XIPFLAGS         = -mno-unaligned-access\r

-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\r
+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\r

 DEFINE GCC_AARCH64_CC_XIPFLAGS     = -mstrict-align\r
 DEFINE GCC_DLINK_FLAGS_COMMON      = -nostdlib --pie\r
 DEFINE GCC_DLINK2_FLAGS_COMMON     = -Wl,--script=$(EDK_TOOLS_PATH)/Scripts/GccBase.lds\r
 DEFINE GCC_AARCH64_CC_XIPFLAGS     = -mstrict-align\r
 DEFINE GCC_DLINK_FLAGS_COMMON      = -nostdlib --pie\r
 DEFINE GCC_DLINK2_FLAGS_COMMON     = -Wl,--script=$(EDK_TOOLS_PATH)/Scripts/GccBase.lds\r