From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1757392AbdLPVic (ORCPT <rfc822;w@1wt.eu>);
        Sat, 16 Dec 2017 16:38:32 -0500
Received: from Galois.linutronix.de ([146.0.238.70]:42077 "EHLO
        Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1757187AbdLPVi1 (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Sat, 16 Dec 2017 16:38:27 -0500
Message-Id: <20171216213138.883238323@linutronix.de>
User-Agent: quilt/0.63-1
Date: Sat, 16 Dec 2017 22:24:24 +0100
From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Linus Torvalds <torvalds@linux-foundation.org>,
        Andy Lutomirsky <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Dave Hansen <dave.hansen@intel.com>, Borislav Petkov <bpetkov@suse.de>,
        Greg KH <gregkh@linuxfoundation.org>, keescook@google.com,
        hughd@google.com, Brian Gerst <brgerst@gmail.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Denys Vlasenko <dvlasenk@redhat.com>, Rik van Riel <riel@redhat.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Juergen Gross <jgross@suse.com>,
        David Laight <David.Laight@aculab.com>,
        Eduardo Valentin <eduval@amazon.com>, aliguori@amazon.com,
        Will Deacon <will.deacon@arm.com>, daniel.gruss@iaik.tugraz.at,
        Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>
Subject: [patch V149 30/50] x86/mm/pti: Share cpu_entry_area PMDs
References: <20171216212354.120930222@linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-15
Content-Disposition: inline;
 filename=0039-x86-mm-pti-Share-cpu_entry_area-PMDs.patch
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Andy Lutomirski <luto@kernel.org>

Share the FIX_USR_SHARED PMDs so the user space and kernel space page
tables have the same PMD page.

[ tglx: Made it use the FIX_USR_SHARED range so later additions
	are covered automatically ]

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
---
 arch/x86/mm/pti.c |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -187,6 +187,23 @@ pti_clone_pmds(unsigned long start, unsi
 }
 
 /*
+ * Clone the populated PMDs of the user shared fixmaps into the user space
+ * visible page table.
+ */
+static void __init pti_clone_user_shared(void)
+{
+	unsigned long bot, top;
+
+	bot = __fix_to_virt(FIX_USR_SHARED_BOTTOM);
+	top = __fix_to_virt(FIX_USR_SHARED_TOP) + PAGE_SIZE;
+
+	/* Top of the user shared block must be PMD-aligned. */
+	WARN_ON(top & ~PMD_MASK);
+
+	pti_clone_pmds(bot, top, 0);
+}
+
+/*
  * Initialize kernel page table isolation
  */
 void __init pti_init(void)
@@ -195,4 +212,6 @@ void __init pti_init(void)
 		return;
 
 	pr_info("enabled\n");
+
+	pti_clone_user_shared();
 }