jump_label,noinstr: Avoid instrumentation for JUMP_LABEL=n builds
authorPeter Zijlstra <peterz@infradead.org>
Mon, 2 May 2022 10:30:20 +0000 (12:30 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 14 Jun 2022 16:36:23 +0000 (18:36 +0200)
[ Upstream commit 656d054e0a15ec327bd82801ccd58201e59f6896 ]

When building x86_64 with JUMP_LABEL=n it's possible for
instrumentation to sneak into noinstr:

vmlinux.o: warning: objtool: exit_to_user_mode+0x14: call to static_key_count.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: syscall_exit_to_user_mode+0x2d: call to static_key_count.constprop.0() leaves .noinstr.text section
vmlinux.o: warning: objtool: irqentry_exit_to_user_mode+0x1b: call to static_key_count.constprop.0() leaves .noinstr.text section

Switch to arch_ prefixed atomic to avoid the explicit instrumentation.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
include/linux/jump_label.h

index 48b9b2a82767d74ec95f102ab1470f5fa79cc97d..019e55c13248b54d65cc7ebbb3d834b4ceb87aa9 100644 (file)
@@ -261,9 +261,9 @@ extern void static_key_disable_cpuslocked(struct static_key *key);
 #include <linux/atomic.h>
 #include <linux/bug.h>
 
-static inline int static_key_count(struct static_key *key)
+static __always_inline int static_key_count(struct static_key *key)
 {
-       return atomic_read(&key->enabled);
+       return arch_atomic_read(&key->enabled);
 }
 
 static __always_inline void jump_label_init(void)