linux-kernel - [PATCH 05/35] x86/entry/32: Unshare NMI return path

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Message-Id: <1521228593-3820-6-git-send-email-joro@8bytes.org>
Date:   Fri, 16 Mar 2018 20:29:23 +0100
From:   Joerg Roedel <joro@...tes.org>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        "H . Peter Anvin" <hpa@...or.com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...el.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Juergen Gross <jgross@...e.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Borislav Petkov <bp@...en8.de>, Jiri Kosina <jkosina@...e.cz>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Brian Gerst <brgerst@...il.com>,
        David Laight <David.Laight@...lab.com>,
        Denys Vlasenko <dvlasenk@...hat.com>,
        Eduardo Valentin <eduval@...zon.com>,
        Greg KH <gregkh@...uxfoundation.org>,
        Will Deacon <will.deacon@....com>, aliguori@...zon.com,
        daniel.gruss@...k.tugraz.at, hughd@...gle.com, keescook@...gle.com,
        Andrea Arcangeli <aarcange@...hat.com>,
        Waiman Long <llong@...hat.com>, Pavel Machek <pavel@....cz>,
        jroedel@...e.de, joro@...tes.org
Subject: [PATCH 05/35] x86/entry/32: Unshare NMI return path

From: Joerg Roedel <jroedel@...e.de>

NMI will no longer use most of the shared return path,
because NMI needs special handling when the CR3 switches for
PTI are added. This patch prepares for that.

Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 arch/x86/entry/entry_32.S | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 0289bde..00ae759 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -1007,7 +1007,7 @@ ENTRY(nmi)
 
 	/* Not on SYSENTER stack. */
 	call	do_nmi
-	jmp	.Lrestore_all_notrace
+	jmp	.Lnmi_return
 
 .Lnmi_from_sysenter_stack:
 	/*
@@ -1018,7 +1018,11 @@ ENTRY(nmi)
 	movl	PER_CPU_VAR(cpu_current_top_of_stack), %esp
 	call	do_nmi
 	movl	%ebx, %esp
-	jmp	.Lrestore_all_notrace
+
+.Lnmi_return:
+	CHECK_AND_APPLY_ESPFIX
+	RESTORE_REGS 4
+	jmp	.Lirq_return
 
 #ifdef CONFIG_X86_ESPFIX32
 .Lnmi_espfix_stack:
-- 
2.7.4