arm64: entry: Refactor and modernise annotation for ret_to_user

As part of an effort to clarify and clean up the assembler annotations
new macros have been introduced which annotate the start and end of blocks
of code in assembler files. Currently ret_to_user has an out of line slow
path work_pending placed above the main function which makes annotating the
start and end of these blocks of code awkward.

Since work_pending is only referenced from within ret_to_user try to make
things a bit clearer by moving it after the current ret_to_user and then
marking both ret_to_user and work_pending as part of a single ret_to_user
code block.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200501115430.37315-2-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

arch/arm64/kernel/entry.S

@@ -727,21 +727,10 @@ el0_error_naked:
 	b	ret_to_user
 SYM_CODE_END(el0_error)
 
-/*
- * Ok, we need to do extra processing, enter the slow path.
- */
-work_pending:
-	mov	x0, sp				// 'regs'
-	bl	do_notify_resume
-#ifdef CONFIG_TRACE_IRQFLAGS
-	bl	trace_hardirqs_on		// enabled while in userspace
-#endif
-	ldr	x1, [tsk, #TSK_TI_FLAGS]	// re-check for single-step
-	b	finish_ret_to_user
 /*
  * "slow" syscall return path.
  */
-ret_to_user:
+SYM_CODE_START_LOCAL(ret_to_user)
 	disable_daif
 	gic_prio_kentry_setup tmp=x3
 	ldr	x1, [tsk, #TSK_TI_FLAGS]
@@ -753,7 +742,19 @@ finish_ret_to_user:
 	bl	stackleak_erase
 #endif
 	kernel_exit 0
-ENDPROC(ret_to_user)
+
+/*
+ * Ok, we need to do extra processing, enter the slow path.
+ */
+work_pending:
+	mov	x0, sp				// 'regs'
+	bl	do_notify_resume
+#ifdef CONFIG_TRACE_IRQFLAGS
+	bl	trace_hardirqs_on		// enabled while in userspace
+#endif
+	ldr	x1, [tsk, #TSK_TI_FLAGS]	// re-check for single-step
+	b	finish_ret_to_user
+SYM_CODE_END(ret_to_user)
 
 	.popsection				// .entry.text