x86/ibt,sev: Annotations

No IBT on AMD so far.. probably correct, who knows.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154318.995109889@infradead.org

Author: Peter Zijlstra

arch/x86/entry/entry_64.S

@@ -95,6 +95,7 @@ SYM_CODE_START(entry_SYSCALL_64)
 	movq	PER_CPU_VAR(cpu_current_top_of_stack), %rsp
 
 SYM_INNER_LABEL(entry_SYSCALL_64_safe_stack, SYM_L_GLOBAL)
+	ANNOTATE_NOENDBR
 
 	/* Construct struct pt_regs on stack */
 	pushq	$__USER_DS				/* pt_regs->ss */

arch/x86/entry/entry_64_compat.S

@@ -214,6 +214,7 @@ SYM_CODE_START(entry_SYSCALL_compat)
 	movq	PER_CPU_VAR(cpu_current_top_of_stack), %rsp
 
 SYM_INNER_LABEL(entry_SYSCALL_compat_safe_stack, SYM_L_GLOBAL)
+	ANNOTATE_NOENDBR
 
 	/* Construct struct pt_regs on stack */
 	pushq	$__USER32_DS		/* pt_regs->ss */

arch/x86/kernel/head_64.S

@@ -332,6 +332,7 @@ SYM_CODE_END(start_cpu0)
  */
 SYM_CODE_START_NOALIGN(vc_boot_ghcb)
 	UNWIND_HINT_IRET_REGS offset=8
+	ENDBR
 
 	/* Build pt_regs */
 	PUSH_AND_CLEAR_REGS
@@ -439,6 +440,7 @@ SYM_CODE_END(early_idt_handler_common)
  */
 SYM_CODE_START_NOALIGN(vc_no_ghcb)
 	UNWIND_HINT_IRET_REGS offset=8
+	ENDBR
 
 	/* Build pt_regs */
 	PUSH_AND_CLEAR_REGS