From: Amelia Coutard <eliottulio.coutard@gmail.com>
Date: Mon, 10 Oct 2022 20:56:19 +0000 (+0200)
Subject: Fixed TSS setup.
X-Git-Url: https://git.ameliathe1st.gay/?a=commitdiff_plain;h=1a3d191551372206eeb9aef5a9161ffca03a5d3e;p=voyage-au-centre-des-fichiers.git

Fixed TSS setup.
---

diff --git a/src/boot.S b/src/boot.S
index d63fb7d..9faf67a 100644
--- a/src/boot.S
+++ b/src/boot.S
@@ -57,13 +57,16 @@ GDT:
 	.byte 0b11111010 # Access: present | readable | ring3
 	.byte 0b10101111 # Flags: page_gran | long_mode, Limit[16:20]
 	.byte 0x00 # Base[24:32]
+.globl GDT.TSS
 .set GDT.TSS, . - GDT
-	.short TSS_SIZE & 0xFFFF # Limit[0:16]
+	.short (TSS_SIZE - 1) & 0xFFFF # Limit[0:16]
 	.short 0x0000 # Base[0:16] # TSS & 0xFFFF
 	.byte 0x00 # Base[16:24] # (TSS >> 16) & 0xFF
 	.byte 0b10001001 # Access
-	.byte (0b0000 << 4) | ((TSS_SIZE >> 16) & 0xF) # Flags, Limit[16:20]
+	.byte (0b0000 << 4) | (((TSS_SIZE - 1) >> 16) & 0xF) # Flags, Limit[16:20]
 	.byte 0x00 # Base[24:32] # (TSS >> 24) & 0xFF
+	.int 0 # Base[32:63] # (TSS >> 32) & 0xFFFFFFFF
+	.int 0 # reserved
 GDT.PTR:
 	.short . - GDT - 1
 	.quad GDT - KERNEL_VMA
@@ -184,20 +187,6 @@ _start:
 	or $1 << 31, %eax
 	mov %eax, %cr0
 
-	# Setup TSS address in GDT
-	mov $TSS - KERNEL_VMA, %eax
-	shr $0, %eax
-	and $0xFFFF, %eax
-	mov %ax, GDT.TSS + GDT - KERNEL_VMA + 2
-	mov $TSS - KERNEL_VMA, %eax
-	shr $16, %eax
-	and $0xFF, %eax
-	mov %al, GDT.TSS + GDT - KERNEL_VMA + 4
-	mov $TSS - KERNEL_VMA, %eax
-	shr $24, %eax
-	and $0xFF, %eax
-	mov %al, GDT.TSS + GDT - KERNEL_VMA + 7
-
 	# Jump to 64 bits:
 	lgdt (GDT.PTR - KERNEL_VMA)
 	jmp $GDT.KERNEL_CODE, $.trampoline
@@ -241,6 +230,23 @@ _start:
 	mov $PML4T - KERNEL_VMA, %rax
 	mov %rax, %cr3
 
+	# Setup TSS address in GDT
+	movabs $TSS, %rax
+	shr $0, %rax
+	and $0xFFFF, %rax
+	mov %ax, GDT.TSS + GDT + 2
+	movabs $TSS, %rax
+	shr $16, %rax
+	and $0xFF, %rax
+	mov %al, GDT.TSS + GDT + 4
+	movabs $TSS, %rax
+	shr $24, %rax
+	and $0xFF, %rax
+	mov %al, GDT.TSS + GDT + 7
+	movabs $TSS, %rax
+	shr $32, %rax
+	mov %rax, GDT.TSS + GDT + 8
+
 	call _init
 
 	mov %r14, %rsi