[PATCH RFC x86/asm] Make serialize __always_inline

Recent mainline has been getting objtool complaints:

vmlinux.o: warning: objtool: __static_call_update_early+0x33: call to serialize() leaves .noinstr.text section

Bisection converged to a nonsensical commit, and reverting that commit
did not get rid of the complaints.

So fix this by inspection, marking serialize() __always_inline to match
the call from sync_core().

This silences the objtool complaint, but of course might not be the
proper patch.

Signed-off-by: Paul E. McKenney <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>

diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
index aec6e2d3aa1d5..98bfc097389c4 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -217,7 +217,7 @@ static inline int write_user_shstk_64(u64 __user *addr, u64 val)
 
 #define nop() asm volatile ("nop")
 
-static inline void serialize(void)
+static __always_inline void serialize(void)
 {
 	/* Instruction opcode for SERIALIZE; supported in binutils >= 2.35. */
 	asm volatile(".byte 0xf, 0x1, 0xe8" ::: "memory");