[PATCH 2/2] BaseTools/tools_def AARCH64: avoid SIMD register in XIP code

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

XIP code may execute with the MMU off, in which case all memory accesses
should be strictly aligned to their size. Some versions of GCC violate
this restriction even when -mstrict-align is passed, when performing
loads and stores that involve SIMD registers. This is clearly a bug in
the compiler, but we can easily work around it by avoiding SIMD registers
altogether when building code that may execute in such a context. So add
-mgeneral-regs-only to the AARCH64 XIP CC flags.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@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 128da5131d01..cdc9df44d97d 100755
--- a/BaseTools/Conf/tools_def.template
+++ b/BaseTools/Conf/tools_def.template
@@ -4342,7 +4342,7 @@ DEFINE GCC_IPF_CC_FLAGS            = DEF(GCC_ALL_CC_FLAGS) -minline-int-divide-m
 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 -ffixed-x18
-DEFINE GCC_AARCH64_CC_XIPFLAGS     = -mstrict-align
+DEFINE GCC_AARCH64_CC_XIPFLAGS     = -mstrict-align -mgeneral-regs-only
 DEFINE GCC_DLINK_FLAGS_COMMON      = -nostdlib --pie
 DEFINE GCC_DLINK2_FLAGS_COMMON     = -Wl,--script=$(EDK_TOOLS_PATH)/Scripts/GccBase.lds
 DEFINE GCC_IA32_X64_DLINK_COMMON   = DEF(GCC_DLINK_FLAGS_COMMON) --gc-sections
-- 
2.9.3