[PATCH 4.9 26/38] ARM: Do not use NOCROSSREFS directive with ld.lld

[Greg Kroah-Hartman]

From: Nathan Chancellor <nathan@xxxxxxxxxx>

commit 36168e387fa7d0f1fe0cd5cf76c8cea7aee714fa upstream.

ld.lld does not support the NOCROSSREFS directive at the moment, which
breaks the build after commit b9baf5c8c5c3 ("ARM: Spectre-BHB
workaround"):

  ld.lld: error: ./arch/arm/kernel/vmlinux.lds:34: AT expected, but got NOCROSSREFS

Support for this directive will eventually be implemented, at which
point a version check can be added. To avoid breaking the build in the
meantime, just define NOCROSSREFS to nothing when using ld.lld, with a
link to the issue for tracking.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: b9baf5c8c5c3 ("ARM: Spectre-BHB workaround")
Link: https://github.com/ClangBuiltLinux/linux/issues/1609
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/arm/kernel/vmlinux-xip.lds.S |    8 ++++++++
 arch/arm/kernel/vmlinux.lds.S     |    8 ++++++++
 2 files changed, 16 insertions(+)

--- a/arch/arm/kernel/vmlinux-xip.lds.S
+++ b/arch/arm/kernel/vmlinux-xip.lds.S
@@ -12,6 +12,14 @@
 #include <asm/memory.h>
 #include <asm/page.h>
 
+/*
+ * ld.lld does not support NOCROSSREFS:
+ * https://github.com/ClangBuiltLinux/linux/issues/1609
+ */
+#ifdef CONFIG_LD_IS_LLD
+#define NOCROSSREFS
+#endif
+
 /* Set start/end symbol names to the LMA for the section */
 #define ARM_LMA(sym, section)						\
 	sym##_start = LOADADDR(section);				\
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -14,6 +14,14 @@
 #include <asm/page.h>
 #include <asm/pgtable.h>
 
+/*
+ * ld.lld does not support NOCROSSREFS:
+ * https://github.com/ClangBuiltLinux/linux/issues/1609
+ */
+#ifdef CONFIG_LD_IS_LLD
+#define NOCROSSREFS
+#endif
+
 /* Set start/end symbol names to the LMA for the section */
 #define ARM_LMA(sym, section)						\
 	sym##_start = LOADADDR(section);				\