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Groups > linux.kernel > #1658670

[PATCHv7 03/14] x86/boot/efi: Cleanup initialization of GDT entries

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

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
---
 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 cbf4b87f55b9..1d5093d1f319 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));
-- 
2.11.0

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[PATCHv7 00/14] x86: 5-level paging enabling for v4.13, Part 4 "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-06-06 13:40 +0200
  [PATCHv7 03/14] x86/boot/efi: Cleanup initialization of GDT entries "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-06-06 13:40 +0200
  [PATCHv7 06/14] x86/boot/compressed: Enable 5-level paging during decompression stage "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-06-06 13:40 +0200
  [PATCHv7 04/14] x86/boot/efi: Fix __KERNEL_CS definition of GDT entry on 64-bit configuration "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-06-06 13:40 +0200

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