1 files changed, 27 insertions, 38 deletions
diff --git a/src/vmm.cc b/src/vmm.cc
index 483f02f..3c90c48 100644
--- a/src/vmm.cc
+++ b/src/vmm.cc
@@ -1,5 +1,4 @@
 #include "vmm.h"
-#include <stdlib.h>
 
 typedef void (*constructor)();
 
@@ -49,51 +48,41 @@ void dump_address() {
 }
 }  // extern "C"
 
-/* boot.S page directory and kernel page table */
+/* boot.S externs */
 extern uint32_t kernel_pagedir;
 extern uint32_t kernel_ptable0;
+extern uint32_t VADDR_OFFSET;
 
-constexpr uint32_t to_vma(uint32_t page_dir_address) {
-  page_dir_address &= 0xfffff000;
-  page_dir_address += 0xc0000000;
-  page_dir_address -= 0x00400000;
-  return page_dir_address;
-}
-
-vmm::vmm(uint32_t* addr) : directory{(addr == nullptr) ? &kernel_pagedir : addr} {
-  printk("page directory is at ", uhex{reinterpret_cast<uint32_t>(directory)}, '\n');
-  printk("page table 768       ", uhex{reinterpret_cast<uint32_t>(directory[768])}, '\n');
-  printk("page table 768 vma   ", uhex{to_vma(reinterpret_cast<uint32_t>(directory[768]))}, '\n');
-  printk("kernel_ptable0 is at ", uhex{reinterpret_cast<uint32_t>(&kernel_ptable0)}, '\n');
-
-  uint32_t* page = reinterpret_cast<uint32_t*>(&kernel_ptable0);
-  for (size_t i = 0; i < 32; ++i) {
-    printk(uhex{page[i] & 0xfffff000}, ' ');
-    if (i % 4 == 3) printk('\n');
-  }
-}
+/* vmm */
+static_assert(sizeof(vmm::address) == 4);
+static_assert(vmm::address(0xc03ff000) == 0xc03ff000);
+static_assert(vmm::address(0xc03ff000).table_idx == 768);
+static_assert(vmm::address(0xc03ff000).page_idx == 1023);
+static_assert(vmm::address(0xc03ff000).offset == 0);
 
-uint32_t vmm::map(uint32_t phys_addr, uint32_t dest) {
-  const auto phys_offset = phys_addr % 4096;
-  const auto phys_page = phys_addr - phys_offset;
+vmm::vmm(uint32_t* addr) : directory{(addr == nullptr) ? &kernel_pagedir : addr} {}
 
-  const auto table = table_id(dest);
-  const auto page = page_id(dest - table * 4 * 1024 * 1024);
+Result<uint32_t, vmm::Error> vmm::map(uint32_t addr, const vmm::address dest) {
+  const auto phys_offset = addr % 4096;
+  const auto phys_paddr = addr & 0xfffff000;
 
-  printk("phys_addr page: ", uhex{phys_page}, '\n');
-  printk("        offset: ", uhex{phys_offset}, '\n');
-  printk("         table: ", table, '\n');
-  printk("          page: ", page, '\n');
+  // TODO allocate page table
+  if (directory[dest.table_idx] == 0) return Result<uint32_t, vmm::Error>{vmm::TableNotAllocated};
 
-  if (directory[table] == 0) return 0;
+  page_table table{directory[dest.table_idx]};
 
-  uint32_t* page_table = reinterpret_cast<uint32_t*>(to_vma(reinterpret_cast<uint32_t>(directory[table])));
-  if (page_table[page] != 0) return 0;
-  page_table[page] = phys_page | 0x003;
+  if (table.set(dest.page_idx, phys_paddr)) {
+    vmm::reload();
+    return Result<uint32_t, vmm::Error>{dest + phys_offset};
+  } else
+    return Result<uint32_t, vmm::Error>{vmm::AddressAlreadyMapped};
+}
 
-  uint32_t cr0;
-  asm volatile("mov %%cr0, %0" : "=r"(cr0));
-  asm volatile("mov %0, %%cr0" : : "r"(cr0));
+vmm::page_table::page_table(uint32_t from) {
+  // TODO get flags
+  // convert physical address to a virtual address so we can read it
+  from &= 0xfffff000;  // discard flags
+  from += reinterpret_cast<uint32_t>(&VADDR_OFFSET);
 
-  return table * 4 * 1024 * 1024 + page * 4 * 1024 + phys_offset;
+  pages = reinterpret_cast<uint32_t*>(from);
 }