diff options
Diffstat (limited to 'Source/Kernel/MemoryManager/GDT.ns.cpp')
| -rw-r--r-- | Source/Kernel/MemoryManager/GDT.ns.cpp | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Source/Kernel/MemoryManager/GDT.ns.cpp b/Source/Kernel/MemoryManager/GDT.ns.cpp index 0bb606d..f1f5c94 100644 --- a/Source/Kernel/MemoryManager/GDT.ns.cpp +++ b/Source/Kernel/MemoryManager/GDT.ns.cpp @@ -1,6 +1,9 @@ #include "GDT.ns.h" extern "C" void gdt_flush(u32int); +extern "C" void tss_flush(); + +using namespace CMem; //For memset #define GDT_ENTRIES 6 @@ -8,6 +11,7 @@ namespace GDT { gdt_entry_t gdt_entries[GDT_ENTRIES]; gdt_ptr_t gdt_ptr; +tss_entry_t tss_entry; void setGate(s32int num, u32int base, u32int limit, u8int access, u8int gran) { gdt_entries[num].base_low = (base & 0xFFFF); @@ -20,6 +24,22 @@ void setGate(s32int num, u32int base, u32int limit, u8int access, u8int gran) { gdt_entries[num].access = access; } +void writeTSS(s32int num, u16int ss0, u32int esp0) { + u32int base = (u32int)&tss_entry; + u32int limit = base + sizeof(tss_entry); + + setGate(num, base, limit, 0xE9, 0x00); + + memset((u8int*)&tss_entry, 0, sizeof(tss_entry_t)); + + tss_entry.ss0 = ss0; + tss_entry.esp0 = esp0; + + tss_entry.cs = 0x0B; //0x0B = Kernel code segment + RPL=3 (meaning it is supposed to be called from user mode) + //0x13 = Kernel data segment + RPL=3 (meaning to be called from ring3) + tss_entry.ss = tss_entry.ds = tss_entry.es = tss_entry.fs = tss_entry.gs = 0x13; +} + void init() { gdt_ptr.limit = (sizeof(gdt_entry_t) * GDT_ENTRIES) - 1; gdt_ptr.base = (u32int)&gdt_entries; @@ -29,8 +49,10 @@ void init() { setGate(2, 0, 0xFFFFFFFF, 0x92, 0xCF); //Kernel data segment setGate(3, 0, 0xFFFFFFFF, 0xFA, 0xCF); //User code segment setGate(4, 0, 0xFFFFFFFF, 0xF2, 0xCF); //User data segment + writeTSS(5, 0x10, 0x0); gdt_flush((u32int)&gdt_ptr); + tss_flush(); } } |