Commit bbf92368 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

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



Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.638561109@infradead.org
parent c8c301ab

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

+9 −1
Original line number Diff line number Diff line
@@ -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));