linux-kernel - [PATCH v3 1/5] x86/mm: surround level4_kernel_pgt with #ifdef CONFIG_X86

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Date:   Sun,  6 May 2018 08:20:12 +0800
From:   changbin.du@...el.com
To:     yamada.masahiro@...ionext.com, michal.lkml@...kovi.net,
        tglx@...utronix.de, mingo@...hat.com, akpm@...ux-foundation.org
Cc:     rostedt@...dmis.org, rdunlap@...radead.org, x86@...nel.org,
        lgirdwood@...il.com, broonie@...nel.org, arnd@...db.de,
        linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org, Changbin Du <changbin.du@...el.com>
Subject: [PATCH v3 1/5] x86/mm: surround level4_kernel_pgt with #ifdef CONFIG_X86_5LEVEL...#endif

From: Changbin Du <changbin.du@...el.com>

The level4_kernel_pgt is only defined when X86_5LEVEL is enabled. So
surround level4_kernel_pgt with #ifdef CONFIG_X86_5LEVEL...#endif to
make code correct.

Signed-off-by: Changbin Du <changbin.du@...el.com>
---
 arch/x86/include/asm/pgtable_64.h |  2 ++
 arch/x86/kernel/head64.c          | 13 ++++++-------
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h
index 877bc27..9e7f667 100644
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -15,7 +15,9 @@
 #include <linux/bitops.h>
 #include <linux/threads.h>
 
+#ifdef CONFIG_X86_5LEVEL
 extern p4d_t level4_kernel_pgt[512];
+#endif
 extern p4d_t level4_ident_pgt[512];
 extern pud_t level3_kernel_pgt[512];
 extern pud_t level3_ident_pgt[512];
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 0c408f8..775d7a6 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -143,16 +143,15 @@ unsigned long __head __startup_64(unsigned long physaddr,
 
 	pgd = fixup_pointer(&early_top_pgt, physaddr);
 	p = pgd + pgd_index(__START_KERNEL_map);
-	if (la57)
-		*p = (unsigned long)level4_kernel_pgt;
-	else
-		*p = (unsigned long)level3_kernel_pgt;
-	*p += _PAGE_TABLE_NOENC - __START_KERNEL_map + load_delta;
-
+#ifdef CONFIG_X86_5LEVEL
 	if (la57) {
+		*p = (unsigned long)level4_kernel_pgt;
 		p4d = fixup_pointer(&level4_kernel_pgt, physaddr);
 		p4d[511] += load_delta;
-	}
+	} else
+#endif
+		*p = (unsigned long)level3_kernel_pgt;
+	*p += _PAGE_TABLE_NOENC - __START_KERNEL_map + load_delta;
 
 	pud = fixup_pointer(&level3_kernel_pgt, physaddr);
 	pud[510] += load_delta;
-- 
2.7.4