[PATCH 1/3] kcsan: Don't expect 64 bits atomic builtins from 32 bits architectures

[Christophe Leroy]

Activating KCSAN on a 32 bits architecture leads to the following
link-time failure:

    LD      .tmp_vmlinux.kallsyms1
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_load':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_load_8'
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_store':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_store_8'
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_exchange':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_exchange_8'
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_fetch_add':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_fetch_add_8'
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_fetch_sub':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_fetch_sub_8'
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_fetch_and':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_fetch_and_8'
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_fetch_or':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_fetch_or_8'
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_fetch_xor':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_fetch_xor_8'
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_fetch_nand':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_fetch_nand_8'
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_compare_exchange_strong':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_compare_exchange_8'
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_compare_exchange_weak':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_compare_exchange_8'
  powerpc64-linux-ld: kernel/kcsan/core.o: in function `__tsan_atomic64_compare_exchange_val':
  kernel/kcsan/core.c:1273: undefined reference to `__atomic_compare_exchange_8'

32 bits architectures don't have 64 bits atomic builtins. Only
include DEFINE_TSAN_ATOMIC_OPS(64) on 64 bits architectures.

Fixes: 0f8ad5f2e934 ("kcsan: Add support for atomic builtins")
Suggested-by: Marco Elver <elver@xxxxxxxxxx>
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
 kernel/kcsan/core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c
index 5a60cc52adc0..8a7baf4e332e 100644
--- a/kernel/kcsan/core.c
+++ b/kernel/kcsan/core.c
@@ -1270,7 +1270,9 @@ static __always_inline void kcsan_atomic_builtin_memorder(int memorder)
 DEFINE_TSAN_ATOMIC_OPS(8);
 DEFINE_TSAN_ATOMIC_OPS(16);
 DEFINE_TSAN_ATOMIC_OPS(32);
+#ifdef CONFIG_64BIT
 DEFINE_TSAN_ATOMIC_OPS(64);
+#endif
 
 void __tsan_atomic_thread_fence(int memorder);
 void __tsan_atomic_thread_fence(int memorder)
-- 
2.40.1