Move PML4 initialization into the VirtualMemory class.

zion/loader/elf_loader.cpp

@@ -48,7 +48,7 @@ typedef struct {
 
 }  // namespace
 
-uint64_t LoadElfProgram(uint64_t cr3, uint64_t base, uint64_t offset) {
+uint64_t LoadElfProgram(Process& dest_proc, uint64_t base, uint64_t offset) {
   Elf64Header* header = reinterpret_cast<Elf64Header*>(base);
   dbgln("phoff: %u phnum: %u", header->phoff, header->phnum);
   Elf64ProgramHeader* programs =
@@ -60,7 +60,7 @@ uint64_t LoadElfProgram(uint64_t cr3, uint64_t base, uint64_t offset) {
         "filesz: %u, memsz: %u, align: %u",
         program.type, program.flags, program.offset, program.vaddr,
         program.paddr, program.filesz, program.memsz, program.align);
-    CopyIntoNonResidentProcess(base + program.offset, program.filesz, cr3,
+    CopyIntoNonResidentProcess(base + program.offset, program.filesz, dest_proc,
                                program.vaddr);
   }
   return header->entry;

zion/loader/elf_loader.h

@@ -2,5 +2,7 @@
 
 #include <stdint.h>
 
+#include "scheduler/process.h"
+
 // Loads the elf program and returns its entry point.
-uint64_t LoadElfProgram(uint64_t cr3, uint64_t base, uint64_t length);
+uint64_t LoadElfProgram(Process& dest_proc, uint64_t base, uint64_t length);

zion/loader/init_loader.cpp

@@ -43,12 +43,11 @@ void LoadInitProgram() {
   SharedPtr<Process> proc = MakeShared<Process>();
   gProcMan->InsertProcess(proc);
 
-  uint64_t entry =
-      LoadElfProgram(proc->cr3(), reinterpret_cast<uint64_t>(init_prog.address),
-                     init_prog.size);
+  uint64_t entry = LoadElfProgram(
+      *proc, reinterpret_cast<uint64_t>(init_prog.address), init_prog.size);
 
   CopyIntoNonResidentProcess(reinterpret_cast<uint64_t>(prog2.address),
-                             prog2.size, proc->cr3(),
+                             prog2.size, *proc,
                              proc->vmm().GetNextMemMapAddr(prog2.size));
 
   proc->CreateThread(entry);

zion/memory/paging_util.cpp

@@ -174,15 +174,15 @@ void EnsureResident(uint64_t addr, uint64_t size) {
   }
 }
 
-void CopyIntoNonResidentProcess(uint64_t base, uint64_t size, uint64_t dest_cr3,
-                                uint64_t dest_virt) {
+void CopyIntoNonResidentProcess(uint64_t base, uint64_t size,
+                                Process& dest_proc, uint64_t dest_virt) {
   if (size > 0x1000) {
     panic("Unimplemented NR copy > 1 page");
   }
   if (dest_virt & 0xFFF) {
     panic("Unimplemented NR copy to non page aligned");
   }
-  uint64_t phys = AllocatePageIfNecessary(dest_virt, dest_cr3);
+  uint64_t phys = AllocatePageIfNecessary(dest_virt, dest_proc.vmm().cr3());
   uint8_t* src = reinterpret_cast<uint8_t*>(base);
   uint8_t* dest =
       reinterpret_cast<uint8_t*>(phys + boot::GetHigherHalfDirectMap());

zion/memory/paging_util.h

@@ -2,10 +2,12 @@
 
 #include <stdint.h>
 
+#include "scheduler/process.h"
+
 void InitializePml4(uint64_t pml4_physical_addr);
 
 uint64_t AllocatePageIfNecessary(uint64_t addr, uint64_t cr3 = 0);
 void EnsureResident(uint64_t addr, uint64_t size);
 
-void CopyIntoNonResidentProcess(uint64_t base, uint64_t size, uint64_t dest_cr3,
-                                uint64_t dest_virt);
+void CopyIntoNonResidentProcess(uint64_t base, uint64_t size,
+                                Process& dest_proc, uint64_t dest_virt);

zion/memory/virtual_memory.cpp

@@ -1,9 +1,22 @@
 #include "memory/virtual_memory.h"
 
 #include "memory/kernel_stack_manager.h"
+#include "memory/paging_util.h"
+#include "memory/physical_memory.h"
 
 extern KernelStackManager* gKernelStackManager;
 
+VirtualMemory VirtualMemory::ForRoot() {
+  uint64_t cr3 = 0;
+  asm volatile("mov %%cr3, %0;" : "=r"(cr3));
+  return {cr3};
+}
+
+VirtualMemory::VirtualMemory() {
+  cr3_ = phys_mem::AllocatePage();
+  InitializePml4(cr3_);
+}
+
 uint64_t* VirtualMemory::AllocateKernelStack() {
   return gKernelStackManager->AllocateKernelStack();
 }

zion/memory/virtual_memory.h

@@ -38,16 +38,21 @@ class VirtualMemory {
     KERNEL_STACK,
   };
 
-  VirtualMemory() {}
+  static VirtualMemory ForRoot();
+
+  VirtualMemory();
   VirtualMemory(const VirtualMemory&) = delete;
   VirtualMemory(VirtualMemory&&) = delete;
 
+  uint64_t cr3() { return cr3_; }
+
   uint64_t GetNextMemMapAddr(uint64_t size);
 
   // Kernel
   uint64_t* AllocateKernelStack();
 
  private:
+  VirtualMemory(uint64_t cr3) : cr3_(cr3) {}
   uint64_t cr3_ = 0;
 
   uint64_t next_memmap_addr_ = 0x20'00000000;

zion/scheduler/process.cpp

@@ -13,19 +13,14 @@ static uint64_t gNextId = 1;
 }
 
 SharedPtr<Process> Process::RootProcess() {
-  uint64_t pml4_addr = 0;
-  asm volatile("mov %%cr3, %0;" : "=r"(pml4_addr));
-  SharedPtr<Process> proc(new Process(0, pml4_addr));
+  SharedPtr<Process> proc(new Process(0));
   proc->threads_.PushBack(Thread::RootThread(*proc));
   proc->next_thread_id_ = 1;
 
   return proc;
 }
 
-Process::Process() : id_(gNextId++), state_(RUNNING) {
-  cr3_ = phys_mem::AllocatePage();
-  InitializePml4(cr3_);
-}
+Process::Process() : id_(gNextId++), state_(RUNNING) {}
 
 void Process::CreateThread(uint64_t entry) {
   Thread* thread = new Thread(*this, next_thread_id_++, entry);

zion/scheduler/process.h

@@ -21,7 +21,6 @@ class Process {
   Process();
 
   uint64_t id() const { return id_; }
-  uint64_t cr3() const { return cr3_; }
   VirtualMemory& vmm() { return vmm_; }
 
   void CreateThread(uint64_t entry);
@@ -34,10 +33,9 @@ class Process {
   State GetState() { return state_; }
 
  private:
-  Process(uint64_t id, uint64_t cr3) : id_(id), cr3_(cr3) {}
+  Process(uint64_t id) : id_(id), vmm_(VirtualMemory::ForRoot()) {}
   uint64_t id_;
   VirtualMemory vmm_;
-  uint64_t cr3_;
   State state_;
 
   uint64_t next_thread_id_ = 0;

zion/scheduler/thread.cpp

@@ -34,7 +34,7 @@ Thread::Thread(Process& proc, uint64_t tid, uint64_t entry)
   *(stack_ptr - 5) = reinterpret_cast<uint64_t>(stack_ptr + 1);
   // 6-15: rsi, rdi, r8, r9, r10, r11, r12, r13, r14, r15
   // 16: cr3
-  *(stack_ptr - 16) = proc.cr3();
+  *(stack_ptr - 16) = proc.vmm().cr3();
   rsp0_ = reinterpret_cast<uint64_t>(stack_ptr - 16);
   rsp0_start_ = reinterpret_cast<uint64_t>(stack_ptr);
 }

zion/syscall/syscall.cpp

@@ -60,7 +60,7 @@ uint64_t ProcessSpawn(ZProcessSpawnReq* req) {
   dbgln("Proc spawn: %u:%u", req->elf_base, req->elf_size);
   SharedPtr<Process> proc = MakeShared<Process>();
   gProcMan->InsertProcess(proc);
-  uint64_t entry = LoadElfProgram(proc->cr3(), req->elf_base, req->elf_size);
+  uint64_t entry = LoadElfProgram(*proc, req->elf_base, req->elf_size);
   proc->CreateThread(entry);
   return 0;
 }