From: Peter Zijlstra <peterz@infradead.org>
Date: Wed, 20 Nov 2019 12:05:06 +0000 (+0100)
Subject: x86/entry/32: Fix IRET exception
X-Git-Tag: v5.4.1~48
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0fbd1f06b635139a7616ad831deb4fd79cdb8c86;p=platform%2Fkernel%2Flinux-rpi.git

x86/entry/32: Fix IRET exception

commit 40ad2199580e248dce2a2ebb722854180c334b9e upstream.

As reported by Lai, the commit 3c88c692c287 ("x86/stackframe/32:
Provide consistent pt_regs") wrecked the IRET EXTABLE entry by making
.Lirq_return not point at IRET.

Fix this by placing IRET_FRAME in RESTORE_REGS, to mirror how
FIXUP_FRAME is part of SAVE_ALL.

Fixes: 3c88c692c287 ("x86/stackframe/32: Provide consistent pt_regs")
Reported-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 019dbac6fe9d..f4335ac9692f 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -357,6 +357,7 @@
 2:	popl	%es
 3:	popl	%fs
 	POP_GS \pop
+	IRET_FRAME
 .pushsection .fixup, "ax"
 4:	movl	$0, (%esp)
 	jmp	1b
@@ -1075,7 +1076,6 @@ restore_all:
 	/* Restore user state */
 	RESTORE_REGS pop=4			# skip orig_eax/error_code
 .Lirq_return:
-	IRET_FRAME
 	/*
 	 * ARCH_HAS_MEMBARRIER_SYNC_CORE rely on IRET core serialization
 	 * when returning from IPI handler and when returning from