linux-kernel - [tip:x86/mm] x86/boot/efi: Cleanup initialization of GDT entries

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Date:   Tue, 13 Jun 2017 03:05:41 -0700
From:   "tip-bot for Kirill A. Shutemov" <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     luto@...nel.org, linux-kernel@...r.kernel.org, brgerst@...il.com,
        kirill.shutemov@...ux.intel.com, torvalds@...ux-foundation.org,
        tglx@...utronix.de, bp@...en8.de, dave.hansen@...el.com,
        peterz@...radead.org, jpoimboe@...hat.com, dvlasenk@...hat.com,
        luto@...capital.net, hpa@...or.com, matt@...eblueprint.co.uk,
        mingo@...nel.org, akpm@...ux-foundation.org
Subject: [tip:x86/mm] x86/boot/efi: Cleanup initialization of GDT entries

Commit-ID:  f8fceacbd1eaebe67997798867d177b36a0a6219
Gitweb:     http://git.kernel.org/tip/f8fceacbd1eaebe67997798867d177b36a0a6219
Author:     Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
AuthorDate: Tue, 6 Jun 2017 14:31:22 +0300
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 13 Jun 2017 08:56:51 +0200

x86/boot/efi: Cleanup initialization of GDT entries

This is preparation for following patches without changing semantics of the
code.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Reviewed-by: Matt Fleming <matt@...eblueprint.co.uk>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-arch@...r.kernel.org
Cc: linux-mm@...ck.org
Link: http://lkml.kernel.org/r/20170606113133.22974-4-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/boot/compressed/eboot.c | 39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index cbf4b87..1d5093d 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -1049,6 +1049,7 @@ struct boot_params *efi_main(struct efi_config *c,
 	/* The first GDT is a dummy and the second is unused. */
 	desc += 2;
 
+	/* __KERNEL_CS */
 	desc->limit0 = 0xffff;
 	desc->base0 = 0x0000;
 	desc->base1 = 0x0000;
@@ -1062,8 +1063,9 @@ struct boot_params *efi_main(struct efi_config *c,
 	desc->d = SEG_OP_SIZE_32BIT;
 	desc->g = SEG_GRANULARITY_4KB;
 	desc->base2 = 0x00;
-
 	desc++;
+
+	/* __KERNEL_DS */
 	desc->limit0 = 0xffff;
 	desc->base0 = 0x0000;
 	desc->base1 = 0x0000;
@@ -1077,24 +1079,25 @@ struct boot_params *efi_main(struct efi_config *c,
 	desc->d = SEG_OP_SIZE_32BIT;
 	desc->g = SEG_GRANULARITY_4KB;
 	desc->base2 = 0x00;
-
-#ifdef CONFIG_X86_64
-	/* Task segment value */
 	desc++;
-	desc->limit0 = 0x0000;
-	desc->base0 = 0x0000;
-	desc->base1 = 0x0000;
-	desc->type = SEG_TYPE_TSS;
-	desc->s = 0;
-	desc->dpl = 0;
-	desc->p = 1;
-	desc->limit = 0x0;
-	desc->avl = 0;
-	desc->l = 0;
-	desc->d = 0;
-	desc->g = SEG_GRANULARITY_4KB;
-	desc->base2 = 0x00;
-#endif /* CONFIG_X86_64 */
+
+	if (IS_ENABLED(CONFIG_X86_64)) {
+		/* Task segment value */
+		desc->limit0 = 0x0000;
+		desc->base0 = 0x0000;
+		desc->base1 = 0x0000;
+		desc->type = SEG_TYPE_TSS;
+		desc->s = 0;
+		desc->dpl = 0;
+		desc->p = 1;
+		desc->limit = 0x0;
+		desc->avl = 0;
+		desc->l = 0;
+		desc->d = 0;
+		desc->g = SEG_GRANULARITY_4KB;
+		desc->base2 = 0x00;
+		desc++;
+	}
 
 	asm volatile("cli");
 	asm volatile ("lgdt %0" : : "m" (*gdt));