added paging support

1 files changed, 127 insertions, 19 deletions

diff --git a/kernel/vmem.c b/kernel/vmem.c
index 9d34810..b1ecfa1 100644
--- a/kernel/vmem.c
+++ b/kernel/vmem.c
@@ -1,5 +1,12 @@
+// http://www.brokenthorn.com/Resources/OSDev18.html
+
 #include "kernel.h"
+#include "x86.h"
+#include "../lib/logger/log.h"	// logger facilities
+#define FOOLOS_MODULE_NAME "vmem"
+
 
+// TODO : why is the frame not 0xfffff??
 enum PAGE_PTE_FLAGS {
  
     I86_PTE_PRESENT		=	1,		//0000000000000000000000000000001
@@ -12,7 +19,7 @@ enum PAGE_PTE_FLAGS {
     I86_PTE_PAT			=	0x80,		//0000000000000000000000010000000
     I86_PTE_CPU_GLOBAL		=	0x100,		//0000000000000000000000100000000
     I86_PTE_LV4_GLOBAL		=	0x200,		//0000000000000000000001000000000
-    I86_PTE_FRAME		=	0x7FFFF000 	//1111111111111111111000000000000
+    I86_PTE_FRAME		=	0xFFFFF000 	//1111111111111111111000000000000
 };
 
 enum PAGE_PDE_FLAGS {
@@ -27,7 +34,7 @@ enum PAGE_PDE_FLAGS {
     I86_PDE_4MB			=	0x80,		//0000000000000000000000010000000
     I86_PDE_CPU_GLOBAL		=	0x100,		//0000000000000000000000100000000
     I86_PDE_LV4_GLOBAL		=	0x200,		//0000000000000000000001000000000
-    I86_PDE_FRAME		=	0x7FFFF000 	//1111111111111111111000000000000
+    I86_PDE_FRAME		=	0xFFFFF000 	//1111111111111111111000000000000
 };
 
 //! page table entry
@@ -62,53 +69,65 @@ typedef uint8_t bool;
 #define PAGE_SIZE 4096
  
 //! page table
-struct ptable {
+typedef struct ptable_struct {
  
     pt_entry m_entries[PAGES_PER_TABLE];
-};
+}ptable ;
  
 //! page directory
-struct pdirectory {
+typedef struct pdirectory_struct {
  
     pd_entry m_entries[PAGES_PER_DIR];
-};
+}pdirectory;
 
-void 		pt_entry_add_attrib (pt_entry* e, uint32_t attrib)
+void pt_entry_add_attrib (pt_entry* e, uint32_t attrib)
 {
+    *e|=attrib;
 }
-void 		pt_entry_del_attrib (pt_entry* e, uint32_t attrib)
+void pt_entry_del_attrib (pt_entry* e, uint32_t attrib)
 {
+    *e&=~attrib;
 }
-void 		pt_entry_set_frame (pt_entry* e , physical_addr addr)
+void pt_entry_set_frame (pt_entry* e , physical_addr addr)
 {
+     //          *e = (*e & ~I86_PTE_FRAME) | addr;                               
+
+    *e|=I86_PTE_FRAME&addr;
+
 }
-bool 		pt_entry_is_present (pt_entry e)
+bool pt_entry_is_present (pt_entry e)
 {
-    return 1;
+    return e&I86_PTE_PRESENT;
 }
-bool 		pt_entry_is_writable (pt_entry e)
+
+bool pt_entry_is_writable (pt_entry e)
 {
-    return 1;
+    return e&I86_PTE_WRITABLE;
 }
-physical_addr	pt_entry_pfn (pt_entry e)
+
+physical_addr pt_entry_pfn (pt_entry e)
 {
-    return 1;
+    return e&I86_PTE_FRAME;
 }
 
 void		pd_entry_add_attrib (pd_entry* e, uint32_t attrib)
 {
+    *e|=attrib;
 }
 
 void		pd_entry_del_attrib (pd_entry* e, uint32_t attrib)
 {
+    *e&=~attrib;
 }
 void		pd_entry_set_frame (pd_entry* e, physical_addr add)
 {
+    *e|=I86_PDE_FRAME&add;
 }
 bool		pd_entry_is_present (pd_entry e)
 {
-    return 1;
+    return e&I86_PDE_PRESENT;
 }
+/*
 bool		pd_entry_is_user (pd_entry e)
 {
     return 1;
@@ -118,20 +137,23 @@ bool		pd_entry_is_4mb (pd_entry e)
 {
     return 1;
 }
+*/
 
 bool		pd_entry_is_writable (pd_entry e)
 {
-    return 1;
+    return e&I86_PDE_WRITABLE;
 }
 
 physical_addr	pd_entry_pfn (pd_entry e)
 {
-    return 1;
+    return e&I86_PDE_FRAME;
 }
 
+/*
 void		pd_entry_enable_global (pd_entry e)
 {
 }
+*/
 
 uint8_t vmmngr_alloc_page (pt_entry* e) 
 {
@@ -148,8 +170,94 @@ uint8_t vmmngr_alloc_page (pt_entry* e)
 	return 1;
 }
 
-void vmem_init()
+void vmmngr_free_page (pt_entry* e) 
+{
+    void* p = (void*)pt_entry_pfn (*e);
+    if (p)
+	pmmngr_free_block (p);
+ 
+    pt_entry_del_attrib (e, I86_PTE_PRESENT);
+}
+
+pt_entry* vmmngr_ptable_lookup_entry (ptable* p, virtual_addr addr) 
+{
+ 
+    if (p)
+	return &p->m_entries[ PAGE_TABLE_INDEX (addr) ];
+
+    return 0;
+}
+
+// TODO !?  http://www.brokenthorn.com/Resources/OSDev18.html
+void vmmngr_map_page (void* phys, void* virt) 
+{
+
+}
+
+void vmem_init(uint32_t vesa_physbase)
 {
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"init paging (vesa base: 0x%08x)",vesa_physbase);
+
+    ptable* table1 = (ptable*) pmmngr_alloc_block ();
+
+    if (!table1)panic(FOOLOS_MODULE_NAME,"unable to alloc table1");
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"table1: 0x%X",table1);
+ 
+    ptable* table2 = (ptable*) pmmngr_alloc_block ();
+
+    if (!table1)panic(FOOLOS_MODULE_NAME,"unable to alloc table2");
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"table2: 0x%X",table2);
+
+    // TODO: 3blocks? 
+    pdirectory*	dir = (pdirectory*) pmmngr_alloc_block ();
+    if (!dir)panic(FOOLOS_MODULE_NAME,"unable to alloc pdirectory");
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"pdirectory: 0x%X",dir);
+
+    //! map 1mb to 3gb (where we are at)
+    for (int i=0, frame=vesa_physbase, virt=vesa_physbase; i<1024; i++, frame+=4096, virt+=4096) {
+
+	//! create a new page
+	pt_entry page=0;
+	pt_entry_add_attrib (&page, I86_PTE_PRESENT);
+	pt_entry_set_frame (&page, frame);
+
+	//! ...and add it to the page table
+	table1->m_entries [PAGE_TABLE_INDEX (virt) ] = page;
+    }
+
+    //! 1st 4mb are idenitity mapped
+    for (int i=0, frame=0x0, virt=0x00000000; i<1024; i++, frame+=4096, virt+=4096) 
+    {
+
+	//! create a new page
+	pt_entry page=0;
+	pt_entry_add_attrib (&page, I86_PTE_PRESENT);
+	pt_entry_set_frame (&page, frame);
+
+	//! ...and add it to the page table
+	table2->m_entries [PAGE_TABLE_INDEX (virt) ] = page;
+    }
+
+   
+    pd_entry* entry = &dir->m_entries [PAGE_DIRECTORY_INDEX (vesa_physbase) ];
+    *entry=0;
+    pd_entry_add_attrib (entry, I86_PDE_PRESENT);
+    pd_entry_add_attrib (entry, I86_PDE_WRITABLE);
+    pd_entry_set_frame (entry, (physical_addr)table1);
+    
+
+    pd_entry* entry2 = &dir->m_entries [PAGE_DIRECTORY_INDEX (0x00000000) ];
+    *entry2=0;
+    pd_entry_add_attrib (entry2, I86_PDE_PRESENT);
+    pd_entry_add_attrib (entry2, I86_PDE_WRITABLE);
+    pd_entry_set_frame (entry2, (physical_addr)table2);
+
+
+    x86_set_pdbr(dir);
+
+    log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"enabling paging...");
+    x86_paging_enable();
+
 
 }