Move paging out of memory

kernel/include/paging.hpp

@@ -0,0 +1,22 @@
+//=======================================================================
+// Copyright Baptiste Wicht 2013.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt)
+//=======================================================================
+
+#ifndef PAGING_H
+#define PAGING_H
+
+#include "types.hpp"
+
+namespace paging {
+
+const int PAGE_SIZE = 4096;
+
+bool identity_map(void* physical);
+bool identity_map(void* physical, size_t pages);
+
+} //end of namespace paging
+
+#endif

kernel/src/acpi.cpp

@@ -9,6 +9,7 @@
 #include "types.hpp"
 #include "kernel_utils.hpp"
 #include "timer.hpp"
+#include "paging.hpp"
 
 #include "console.hpp"
 
@@ -200,8 +201,15 @@ int init_acpi(){
 
    k_printf("%h\n", reinterpret_cast<uintptr_t>(ptr));
 
+   if(!paging::identity_map(ptr, 16)){
+       k_print_line("Impossible to map the ACPI tables");
+
+       return -1;
+   }
+
    // check if address is correct  ( if acpi is available on this pc )
    if (ptr && check_header(ptr, "RSDT") == 0){
+      //k_print_line("2");
       // the RSDT contains an unknown number of pointers to acpi tables
       int entrys = *(ptr + 1);
       entrys = (entrys-36) /4;

kernel/src/memory.cpp

@@ -85,23 +85,6 @@ uint64_t pdpt_index = 0;
 uint64_t pdt_index = 0;
 uint64_t pt_index = 256;
 
-void identity_map(void* physical){
-    //Find the correct indexes inside the paging table for the physical address
-    auto table = (reinterpret_cast<uintptr_t>(physical) >> 12) & 0x1FF;
-    auto directory = (reinterpret_cast<uintptr_t>(physical) >> 21) & 0x1FF;
-    auto directory_ptr = (reinterpret_cast<uintptr_t>(physical) >> 30) & 0x1FF;
-    auto pml4 = (reinterpret_cast<uintptr_t>(physical) >> 39) & 0x1FF;
-
-    //Find the entries
-    pml4t_t pml4t = reinterpret_cast<pml4t_t>(0x70000);
-    auto pdpt = reinterpret_cast<pdpt_t>(reinterpret_cast<uintptr_t>(pml4t[pml4]) & ~0xFFF);
-    auto pdt = reinterpret_cast<pdt_t>(reinterpret_cast<uintptr_t>(pdpt[directory_ptr]) & ~0xFFF);
-    auto pt = reinterpret_cast<pt_t>(reinterpret_cast<uintptr_t>(pdt[directory]) & ~0xFFF);
-
-    //Identity map  the physical address
-    pt[table] = reinterpret_cast<page_entry>(reinterpret_cast<uintptr_t>(physical) | 0x3);
-}
-
 uint64_t* allocate_block(uint64_t blocks){
     if(!current_mmap_entry){
         for(uint64_t i = 0; i < entry_count; ++i){

kernel/src/paging.cpp

@@ -0,0 +1,62 @@
+//=======================================================================
+// Copyright Baptiste Wicht 2013.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt)
+//=======================================================================
+
+#include "paging.hpp"
+#include "types.hpp"
+
+namespace {
+
+typedef uint64_t* page_entry;
+typedef page_entry* pt_t;
+typedef pt_t* pdt_t;
+typedef pdt_t* pdpt_t;
+typedef pdpt_t* pml4t_t;
+
+} //end of anonymous namespace
+
+bool paging::identity_map(void* physical){
+    //The address must be page-aligned
+    if(reinterpret_cast<uintptr_t>(physical) % PAGE_SIZE != 0){
+        return false;
+    }
+
+    //Find the correct indexes inside the paging table for the physical address
+    auto table = (reinterpret_cast<uintptr_t>(physical) >> 12) & 0x1FF;
+    auto directory = (reinterpret_cast<uintptr_t>(physical) >> 21) & 0x1FF;
+    auto directory_ptr = (reinterpret_cast<uintptr_t>(physical) >> 30) & 0x1FF;
+    auto pml4 = (reinterpret_cast<uintptr_t>(physical) >> 39) & 0x1FF;
+
+    //Find the entries
+    pml4t_t pml4t = reinterpret_cast<pml4t_t>(0x70000);
+    auto pdpt = reinterpret_cast<pdpt_t>(reinterpret_cast<uintptr_t>(pml4t[pml4]) & ~0xFFF);
+    auto pdt = reinterpret_cast<pdt_t>(reinterpret_cast<uintptr_t>(pdpt[directory_ptr]) & ~0xFFF);
+    auto pt = reinterpret_cast<pt_t>(reinterpret_cast<uintptr_t>(pdt[directory]) & ~0xFFF);
+
+    //Identity map  the physical address
+    pt[table] = reinterpret_cast<page_entry>(reinterpret_cast<uintptr_t>(physical) | 0x3);
+
+    //TODO Check if pt[table] is already used and if so, return false
+
+    return true;
+}
+
+bool paging::identity_map(void* physical, size_t pages){
+    //The address must be page-aligned
+    if(reinterpret_cast<uintptr_t>(physical) % PAGE_SIZE != 0){
+        return false;
+    }
+
+    //TODO This should first check each page for the present bit
+
+    for(size_t page = 0; page < pages; ++page){
+        if(!identity_map(reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(physical) + page * PAGE_SIZE))){
+            return false;
+        }
+    }
+
+    return true;
+}