linux-kernel - [PATCH] xtensa: rearrange NMI exit path

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Date:   Sat, 19 Mar 2022 13:12:54 -0700
From:   Max Filippov <jcmvbkbc@...il.com>
To:     linux-xtensa@...ux-xtensa.org
Cc:     Chris Zankel <chris@...kel.net>, linux-kernel@...r.kernel.org,
        Max Filippov <jcmvbkbc@...il.com>
Subject: [PATCH] xtensa: rearrange NMI exit path

NMI exit path to userspace should neither check TIF_DB_DISABLED nor call
check_tlb_sanity because NMI shouldn't touch anything related to
userspace. Drop kernel/userspace check in NMI exit path.

Signed-off-by: Max Filippov <jcmvbkbc@...il.com>
---
 arch/xtensa/kernel/entry.S | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index 77a7c8da3ff5..8d671898d582 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -488,9 +488,10 @@ KABI_W	or	a3, a3, a2
 common_exception_return:
 
 #if XTENSA_FAKE_NMI
-	l32i	a2, a1, PT_EXCCAUSE
-	movi	a3, EXCCAUSE_MAPPED_NMI
-	beq	a2, a3, .LNMIexit
+	l32i	abi_tmp0, a1, PT_EXCCAUSE
+	movi	abi_tmp1, EXCCAUSE_MAPPED_NMI
+	l32i	abi_saved1, a1, PT_PS
+	beq	abi_tmp0, abi_tmp1, 4f
 #endif
 1:
 	irq_save a2, a3
@@ -550,12 +551,6 @@ common_exception_return:
 	j	4f
 #endif
 
-#if XTENSA_FAKE_NMI
-.LNMIexit:
-	l32i	abi_saved1, a1, PT_PS
-	_bbci.l	abi_saved1, PS_UM_BIT, 4f
-#endif
-
 5:
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 	_bbci.l	a4, TIF_DB_DISABLED, 7f
-- 
2.30.2