x86/text-patching: Make text_gen_insn() play nice with ANNOTATE_NOENDBR

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.638561109@infradead.org

arch/x86/include/asm/text-patching.h

@@ -101,13 +101,21 @@ void *text_gen_insn(u8 opcode, const void *addr, const void *dest)
 	static union text_poke_insn insn; /* per instance */
 	int size = text_opcode_size(opcode);
 
+	/*
+	 * Hide the addresses to avoid the compiler folding in constants when
+	 * referencing code, these can mess up annotations like
+	 * ANNOTATE_NOENDBR.
+	 */
+	OPTIMIZER_HIDE_VAR(addr);
+	OPTIMIZER_HIDE_VAR(dest);
+
 	insn.opcode = opcode;
 
 	if (size > 1) {
 		insn.disp = (long)dest - (long)(addr + size);
 		if (size == 2) {
 			/*
-			 * Ensure that for JMP9 the displacement
+			 * Ensure that for JMP8 the displacement
 			 * actually fits the signed byte.
 			 */
 			BUG_ON((insn.disp >> 31) != (insn.disp >> 7));