linux-kernel - [tip:x86/mm] x86/xen: Provide pre-built page tables only for CONFIG_XEN_PV=y and CONFIG_XEN

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Date:   Fri, 20 Oct 2017 05:28:38 -0700
From:   "tip-bot for Kirill A. Shutemov" <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     gorcunov@...nvz.org, torvalds@...ux-foundation.org,
        tglx@...utronix.de, mingo@...nel.org, peterz@...radead.org,
        bp@...e.de, jgross@...e.com, linux-kernel@...r.kernel.org,
        kirill.shutemov@...ux.intel.com, luto@...capital.net,
        hpa@...or.com, akpm@...ux-foundation.org
Subject: [tip:x86/mm] x86/xen: Provide pre-built page tables only for
 CONFIG_XEN_PV=y and CONFIG_XEN_PVH=y

Commit-ID:  4375c29985f155d7eb2346615d84e62d1b673682
Gitweb:     https://git.kernel.org/tip/4375c29985f155d7eb2346615d84e62d1b673682
Author:     Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
AuthorDate: Fri, 29 Sep 2017 17:08:19 +0300
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Fri, 20 Oct 2017 13:07:10 +0200

x86/xen: Provide pre-built page tables only for CONFIG_XEN_PV=y and CONFIG_XEN_PVH=y

Looks like we only need pre-built page tables in the CONFIG_XEN_PV=y and
CONFIG_XEN_PVH=y cases.

Let's not provide them for other configurations.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Reviewed-by: Juergen Gross <jgross@...e.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Borislav Petkov <bp@...e.de>
Cc: Cyrill Gorcunov <gorcunov@...nvz.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-mm@...ck.org
Link: http://lkml.kernel.org/r/20170929140821.37654-5-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kernel/head_64.S | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 513cbb0..2be7d1e 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -37,11 +37,12 @@
  *
  */
 
-#define p4d_index(x)	(((x) >> P4D_SHIFT) & (PTRS_PER_P4D-1))
 #define pud_index(x)	(((x) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
 
+#if defined(CONFIG_XEN_PV) || defined(CONFIG_XEN_PVH)
 PGD_PAGE_OFFSET = pgd_index(__PAGE_OFFSET_BASE)
 PGD_START_KERNEL = pgd_index(__START_KERNEL_map)
+#endif
 L3_START_KERNEL = pud_index(__START_KERNEL_map)
 
 	.text
@@ -361,10 +362,7 @@ NEXT_PAGE(early_dynamic_pgts)
 
 	.data
 
-#ifndef CONFIG_XEN
-NEXT_PAGE(init_top_pgt)
-	.fill	512,8,0
-#else
+#if defined(CONFIG_XEN_PV) || defined(CONFIG_XEN_PVH)
 NEXT_PAGE(init_top_pgt)
 	.quad   level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC
 	.org    init_top_pgt + PGD_PAGE_OFFSET*8, 0
@@ -381,6 +379,9 @@ NEXT_PAGE(level2_ident_pgt)
 	 * Don't set NX because code runs from these pages.
 	 */
 	PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD)
+#else
+NEXT_PAGE(init_top_pgt)
+	.fill	512,8,0
 #endif
 
 #ifdef CONFIG_X86_5LEVEL