Fixed TSS setup.

diff --git a/src/boot.S b/src/boot.S
index d63fb7d2ffcad08f7fd40068e38f19afa743adf7..9faf67a8891587cd09c580a19f360a3ae5c6ccec 100644 (file)
--- 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