From fb69c7b05894cee2b8bb691ead948798a0674059 Mon Sep 17 00:00:00 2001
From: Loic Guegan <manzerbredes@mailbox.org>
Date: Fri, 30 Apr 2021 10:43:44 +0200
Subject: Setup TSS segment

---
 src/boucane.cc | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

(limited to 'src/boucane.cc')

diff --git a/src/boucane.cc b/src/boucane.cc
index 060f9cd..96c9ba7 100644
--- a/src/boucane.cc
+++ b/src/boucane.cc
@@ -19,8 +19,33 @@ u64 kvar_terminus_psf_start;
 u64 kvar_terminus_psf_end;
 u64 kvar_logo_bmp_start;
 u64 kvar_logo_bmp_end;
+TSS kvar_tss;
 
 void (*printk)(char *str,...)=printf;
+extern u64 gdt64_tss;
+
+void configure_tss(){
+    u64 tss_addr=(u64)&kvar_tss;
+    u32 desc1=(tss_addr&0xFFFF)<<16|(sizeof(TSS)&0xFFFF);
+    tss_addr>>=16;
+    u32 desc2=(tss_addr&0xFF)|((tss_addr>>8)<<24);
+    tss_addr>>=16;
+    u32 desc3=tss_addr;
+
+    // Options
+    u32 options=0b1001; // 64-bits TSS type
+    options|=(0b1000<<4); // Present
+
+    // Configure GDT
+    u32 *gdt_entry=(u32*)&gdt64_tss;
+    gdt_entry[0]=desc1;
+    gdt_entry[1]=desc2|(options<<8);
+    gdt_entry[2]=desc3;
+    gdt_entry[3]=0;
+
+    // Configure segment
+    kvar_tss.rsp0=(u64)VIRT(kvar_stack_pma);
+}
 
 extern "C" void boucane(u64 mb_info){
     // Init linker variables
@@ -35,6 +60,7 @@ extern "C" void boucane(u64 mb_info){
     asm volatile ("movq $res_binary_res_logo_bmp_end, %0":"=m"(kvar_logo_bmp_end));
 
     // Init data structures
+    configure_tss();
     asm volatile ("call load_gdt");
     paging_enable();
     memtext_init();
@@ -74,5 +100,8 @@ extern "C" void boucane(u64 mb_info){
         mem/=1024;
         printk("RAM:%dMB\n", mem);
     }
+
+    printk("%x",&kvar_tss);
+    DUMP(&gdt64_tss);
     while(1);
 }
\ No newline at end of file
-- 
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