xtensa: enable KCSAN

Prefix arch-specific barrier macros with '__' to make use of instrumented
generic macros.
Prefix arch-specific bitops with 'arch_' to make use of instrumented
generic functions.
Provide stubs for 64-bit atomics when building with KCSAN.
Disable KCSAN instrumentation in arch/xtensa/boot.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Marco Elver <elver@google.com>

2 files changed, 56 insertions, 0 deletions

diff --git a/arch/xtensa/lib/Makefile b/arch/xtensa/lib/Makefile
index 5848c133f7ea..d4e9c397e3fd 100644
--- a/arch/xtensa/lib/Makefile
+++ b/arch/xtensa/lib/Makefile
@@ -8,3 +8,5 @@ lib-y	+= memcopy.o memset.o checksum.o \
 	   divsi3.o udivsi3.o modsi3.o umodsi3.o mulsi3.o \
 	   usercopy.o strncpy_user.o strnlen_user.o
 lib-$(CONFIG_PCI) += pci-auto.o
+lib-$(CONFIG_KCSAN) += kcsan-stubs.o
+KCSAN_SANITIZE_kcsan-stubs.o := n
diff --git a/arch/xtensa/lib/kcsan-stubs.c b/arch/xtensa/lib/kcsan-stubs.c
new file mode 100644
index 000000000000..2b08faa62b86
--- /dev/null
+++ b/arch/xtensa/lib/kcsan-stubs.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bug.h>
+#include <linux/types.h>
+
+void __atomic_store_8(volatile void *p, u64 v, int i)
+{
+	BUG();
+}
+
+u64 __atomic_load_8(const volatile void *p, int i)
+{
+	BUG();
+}
+
+u64 __atomic_exchange_8(volatile void *p, u64 v, int i)
+{
+	BUG();
+}
+
+bool __atomic_compare_exchange_8(volatile void *p1, void *p2, u64 v, bool b, int i1, int i2)
+{
+	BUG();
+}
+
+u64 __atomic_fetch_add_8(volatile void *p, u64 v, int i)
+{
+	BUG();
+}
+
+u64 __atomic_fetch_sub_8(volatile void *p, u64 v, int i)
+{
+	BUG();
+}
+
+u64 __atomic_fetch_and_8(volatile void *p, u64 v, int i)
+{
+	BUG();
+}
+
+u64 __atomic_fetch_or_8(volatile void *p, u64 v, int i)
+{
+	BUG();
+}
+
+u64 __atomic_fetch_xor_8(volatile void *p, u64 v, int i)
+{
+	BUG();
+}
+
+u64 __atomic_fetch_nand_8(volatile void *p, u64 v, int i)
+{
+	BUG();
+}