Save kernel stack top to TSS

arch/init.c

@@ -9,6 +9,7 @@ extern char _kernel_offset;
 extern char _kernel_size;
 extern char _kernel_phys_base;
 extern char _kernel_virt_base;
+extern char _kernel_stack_top;
 
 static struct KernelMQ_Info kinfo;
 
@@ -35,6 +36,8 @@ const struct KernelMQ_Info *init(unsigned long multiboot_magic, unsigned long mu
 
     kinfo.kernel_and_modules_total_size = kinfo.kernel_size + kinfo.modules_total_size;
 
+    kinfo.kernel_stack_top = (unsigned long)&_kernel_stack_top;
+
     paging_clear();
     paging_identity();
     /* kinfo.freepde_start = */ paging_mapkernel(&kinfo);

arch/main.c

@@ -58,7 +58,7 @@ void main(const struct KernelMQ_Info *const kinfo_ptr)
 
     memory_initialize(&kinfo);
 
-    protected_initialize();
+    protected_initialize(&kinfo);
 
     // Set up a new post-relocate bootstrap pagetable so that
     // we can map in VM, and we no longer rely on pre-relocated

arch/protected.c

@@ -53,7 +53,7 @@ static void idt_set_gate(unsigned char num, unsigned int base, unsigned short se
 void gdt_flush(const struct GdtPointer *pointer);
 void idt_flush(const struct IdtPointer *pointer);
 
-void protected_initialize()
+void protected_initialize(const struct KernelMQ_Info *const kinfo)
 {
     logger_info("Remap the IRQ table.");
 
@@ -76,7 +76,7 @@ void protected_initialize()
     gdt_set_gate(GDT_USER_CS_INDEX,   0, 0xFFFFFFFF, 0xFA, 0xCF);
     gdt_set_gate(GDT_USER_DS_INDEX,   0, 0xFFFFFFFF, 0xF2, 0xCF);
 
-    tss_write_to_gdt(&gdt_entries[GDT_TSS_INDEX]);
+    tss_write_to_gdt(kinfo, &gdt_entries[GDT_TSS_INDEX]);
 
     logger_info("Setup IDT.");
 

arch/protected.h

@@ -1,6 +1,8 @@
 #ifndef KERNELMQ_INCLUDED_PROTECTED
 #define KERNELMQ_INCLUDED_PROTECTED 1
 
-void protected_initialize();
+#include <kernelmq/info.h>
+
+void protected_initialize(const struct KernelMQ_Info *kinfo);
 
 #endif

arch/start.s

@@ -14,9 +14,10 @@
 
 .section .bss
 .align 16
-stack_bottom:
 .skip 16384 # 16 KiB
-stack_top:
+_kernel_stack_top:
+
+.global _kernel_stack_top
 
 .section .text
 
@@ -27,13 +28,13 @@ stack_top:
 .type halt,   @function
 
 _start:
-    mov $stack_top, %esp // Initialize stack
+    mov $_kernel_stack_top, %esp // Initialize stack
 
     push %ebx // Multiboot information pointer
     push %eax // Multiboot magic number
     call init
 
-    mov $stack_top, %esp // Initialize stack
+    mov $_kernel_stack_top, %esp // Initialize stack
 
     push %eax // Kernel information pointer
     call main

arch/tss.c

@@ -56,7 +56,7 @@ __attribute__((packed));
 
 static struct tss_entry tss;
 
-void tss_write_to_gdt(void *gdt_entry_ptr)
+void tss_write_to_gdt(const struct KernelMQ_Info *const kinfo, void *gdt_entry_ptr)
 {
     struct gdt_entry_bits *const g = gdt_entry_ptr;
 
@@ -84,5 +84,5 @@ void tss_write_to_gdt(void *gdt_entry_ptr)
     kmemset(&tss, 0, sizeof(tss));
 
     tss.ss0 = GDT_KERNEL_DS_SELECTOR;
-    tss.esp0 = 0; // TODO: get from kinfo
+    tss.esp0 = kinfo->kernel_stack_top;
 }

arch/tss.h

@@ -1,6 +1,8 @@
 #ifndef KERNELMQ_INCLUDED_TSS
 #define KERNELMQ_INCLUDED_TSS 1
 
-void tss_write_to_gdt(void *gdt_entry);
+#include <kernelmq/info.h>
+
+void tss_write_to_gdt(const struct KernelMQ_Info *kinfo, void *gdt_entry);
 
 #endif

include/kernelmq/info.h

@@ -47,6 +47,8 @@ struct KernelMQ_Info {
 
     unsigned long modules_total_size;
     unsigned long kernel_and_modules_total_size;
+
+    unsigned long kernel_stack_top;
 };
 
 unsigned char kernelmq_info_validate_and_copy(struct KernelMQ_Info *dest, const struct KernelMQ_Info *src);