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

diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index b742178..1c4cfb1 100644 (file)
--- a/arch/x86/include/asm/text-patching.h
+++ b/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));