powerpc/interrupt: Refactor interrupt_exit_user_prepare()

interrupt_exit_user_prepare() is a superset of
interrupt_exit_user_prepare_main().

Refactor to avoid code duplication.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210617155116.2167984-15-npiggin@gmail.com

arch/powerpc/kernel/interrupt.c

@@ -404,9 +404,7 @@ notrace unsigned long syscall_exit_restart(unsigned long r3, struct pt_regs *reg
 
 notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs)
 {
-	unsigned long ti_flags;
-	unsigned long flags;
-	unsigned long ret = 0;
+	unsigned long ret;
 
 	if (!IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x))
 		BUG_ON(!(regs->msr & MSR_RI));
@@ -420,63 +418,14 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs)
 	 */
 	kuap_assert_locked();
 
-	local_irq_save(flags);
-
-again:
-	ti_flags = READ_ONCE(current_thread_info()->flags);
-	while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
-		local_irq_enable(); /* returning to user: may enable */
-		if (ti_flags & _TIF_NEED_RESCHED) {
-			schedule();
-		} else {
-			if (ti_flags & _TIF_SIGPENDING)
-				ret |= _TIF_RESTOREALL;
-			do_notify_resume(regs, ti_flags);
-		}
-		local_irq_disable();
-		ti_flags = READ_ONCE(current_thread_info()->flags);
-	}
-
-	if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && IS_ENABLED(CONFIG_PPC_FPU)) {
-		if (IS_ENABLED(CONFIG_PPC_TRANSACTIONAL_MEM) &&
-				unlikely((ti_flags & _TIF_RESTORE_TM))) {
-			restore_tm_state(regs);
-		} else {
-			unsigned long mathflags = MSR_FP;
-
-			if (cpu_has_feature(CPU_FTR_VSX))
-				mathflags |= MSR_VEC | MSR_VSX;
-			else if (cpu_has_feature(CPU_FTR_ALTIVEC))
-				mathflags |= MSR_VEC;
-
-			/* See above restore_math comment */
-			if ((regs->msr & mathflags) != mathflags)
-				restore_math(regs);
-		}
-	}
-
-	if (!prep_irq_for_user_exit()) {
-		local_irq_enable();
-		local_irq_disable();
-		goto again;
-	}
-
-	booke_load_dbcr0();
-
-#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
-	local_paca->tm_scratch = regs->msr;
-#endif
+	local_irq_disable();
 
-	account_cpu_user_exit();
+	ret = interrupt_exit_user_prepare_main(0, regs);
 
 #ifdef CONFIG_PPC64
 	regs->exit_result = ret;
 #endif
 
-	/* Restore user access locks last */
-	kuap_user_restore(regs);
-	kuep_unlock();
-
 	return ret;
 }