[tip: x86/boot] x86/boot: Fix incorrect startup_gdt_descr.size

[tip-bot2 for Yuntao Wang]

The following commit has been merged into the x86/boot branch of tip:

Commit-ID:     001470fed5959d01faecbd57fcf2f60294da0de1
Gitweb:        https://git.kernel.org/tip/001470fed5959d01faecbd57fcf2f60294da0de1
Author:        Yuntao Wang <ytcoode@xxxxxxxxx>
AuthorDate:    Mon, 07 Aug 2023 16:45:47 +08:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 03 Oct 2023 10:28:29 +02:00

x86/boot: Fix incorrect startup_gdt_descr.size

Since the size value is added to the base address to yield the last valid
byte address of the GDT, the current size value of startup_gdt_descr is
incorrect (too large by one), fix it.

[ mingo: This probably never mattered, because startup_gdt[] is only used
         in a very controlled fashion - but make it consistent nevertheless. ]

Fixes: 866b556efa12 ("x86/head/64: Install startup GDT")
Signed-off-by: Yuntao Wang <ytcoode@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230807084547.217390-1-ytcoode@xxxxxxxxx
---
 arch/x86/kernel/head64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 49f7629..bbc2179 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -80,7 +80,7 @@ static struct desc_struct startup_gdt[GDT_ENTRIES] = {
  * while the kernel still uses a direct mapping.
  */
 static struct desc_ptr startup_gdt_descr = {
-	.size = sizeof(startup_gdt),
+	.size = sizeof(startup_gdt)-1,
 	.address = 0,
 };