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

Kirill A. Shutemov
2017-06-06T11:31:22Z

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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