arm64: Disable LLD linker ASSERT()s for the time being

It turns out [1] that the way LLD handles ASSERT()s in the linker script
can result in spurious failures, so disable them for the newly
introduced BSS symbol export checks. Since we're not aware of any issues
with the existing assertions in vmlinux.lds.S, leave those alone for now
so that they can continue to provide useful coverage.

A linker fix [2] is due to land in version 21 of LLD.

Link: https://lore.kernel.org/r/[email protected] [1]
Link: llvm/llvm-project@5859863bab7f [2]
Link: ClangBuiltLinux/linux#2094
Signed-off-by: Ard Biesheuvel <[email protected]>
Tested-by: Arnd Bergmann <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

Author: ardbiesheuvel

arch/arm64/kernel/image-vars.h

@@ -10,6 +10,10 @@
 #error This file should only be included in vmlinux.lds.S
 #endif
 
+#if defined(CONFIG_LD_IS_LLD) && CONFIG_LLD_VERSION < 210000
+#define ASSERT(...)
+#endif
+
 #define PI_EXPORT_SYM(sym)		\
 	__PI_EXPORT_SYM(sym, __pi_ ## sym, Cannot export BSS symbol sym to startup code)
 #define __PI_EXPORT_SYM(sym, pisym, msg)\
@@ -142,4 +146,6 @@ KVM_NVHE_ALIAS(kvm_protected_mode_initialized);
 _kernel_codesize = ABSOLUTE(__inittext_end - _text);
 #endif
 
+#undef ASSERT
+
 #endif /* __ARM64_KERNEL_IMAGE_VARS_H */