[PATCH v3 32/75] x86/head/64: Reload GDT after switch to virtual addresses

Joerg Roedel
2020-04-28T15:22:36Z

From: Joerg Roedel <jroedel@suse.de>

Reload the GDT after switching to virtual addresses to make sure it will
not go away when the lower mappings are removed. This will also reload
the GDT for booting APs, which will need a working GDT too to handle #VC
exceptions.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/kernel/head_64.S | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 11a28c1fb51f..20a9df062088 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -163,6 +163,11 @@ SYM_CODE_START(secondary_startup_64)
1:
UNWIND_HINT_EMPTY

+ /* Setup boot GDT descriptor and load boot GDT */
+ leaq boot_gdt(%rip), %rax
+ movq %rax, boot_gdt_base(%rip)
+ lgdt boot_gdt_descr(%rip)
+
/* Check if nx is implemented */
movl $0x80000001, %eax
cpuid
--
2.17.1