application loading

1 files changed, 56 insertions, 84 deletions

diff --git a/kernel/entry.cpp b/kernel/entry.cpp
index 445d560..f7ba71d 100644
--- a/kernel/entry.cpp
+++ b/kernel/entry.cpp
@@ -1,5 +1,6 @@
 #include <mercury/kernel/storage/bd/memory.hpp>
 #include <mercury/kernel/storage/fs/tarfs.hpp>
+#include <mercury/kernel/application.hpp>
 #include <mercury/kernel/framebuffer.hpp>
 #include <mercury/kernel/terminal.hpp>
 #include <mercury/kernel/limine.hpp>
@@ -103,6 +104,8 @@ uint64_t initfs_len;
 
 [[noreturn]] static void with_kernel_p4();
 
+extern "C" void load_gdt_and_idt();
+
 extern "C" [[noreturn]] void entry() {
 
   //TODO?: maybe we should check if the limine requests were
@@ -113,9 +116,9 @@ extern "C" [[noreturn]] void entry() {
   paging::mark_all_pram_used();
   auto memmap = memmap_request.response;
   for (uint64_t i = 0; i < memmap->entry_count; ++i) {
-    //we don't start allocating physical pages until after we are done using
-    //limine structures (specifically at the call to paging::map_kernel_stack),
-    //so we consider bootloader reclaimable to be free. usable and bootloader
+    //we don't allocate any physical pages until after we are done using limine
+    //structures (specifically at the call to paging::map_kernel_stacks), so
+    //we consider bootloader reclaimable to be free. usable and bootloader
     //reclaimable are guaranteed by limine spec to be page-aligned.
     auto entry = memmap->entries[i];
     if (entry->type == LIMINE_MEMMAP_USABLE ||
@@ -175,79 +178,29 @@ extern "C" [[noreturn]] void entry() {
 
   //switch to kernel p4
 
-  paging::map_kernel_stack();
+  paging::map_kernel_stacks();
+  load_gdt_and_idt();
   switch_to_kernel_p4(&with_kernel_p4);
 
 }
 
+static void print_mem() {
+  uint64_t used_vram_mib = (paging::get_used_vram_page_count() + 128) / 256;
+  uint64_t free_pram_mib = (paging::get_free_pram_page_count() + 128) / 256;
+  terminal::put_int_decimal(used_vram_mib);
+  terminal::put_string_sz(" MiB kernel memory mapped.\n");
+  terminal::put_int_decimal(free_pram_mib);
+  terminal::put_string_sz(" MiB physical memory free.\n");
+}
+
 [[noreturn]] static void print_and_halt(const char *msg) {
   terminal::put_string_sz(msg);
   while (1)
     asm ("hlt");
 }
 
-static void draw_indent(unsigned indent) {
-  for (unsigned i = 0; i < indent; ++i)
-    terminal::put_char(' ');
-}
-
-static void dir_tree(
-  const vfile::vfile &root, const vfile::vfile &f, unsigned indent
-) {
-
-  draw_indent(indent);
-  terminal::put_string(f.dir_entry.name);
-  terminal::put_char('\n');
-
-  std::optional<vfile::vfile> followed;
-  utility::vector<vfile::vfile> children;
-
-  switch (f.dir_entry.type) {
-
-    case storage::file_type::regular_file:
-      draw_indent(indent + 2);
-      terminal::put_string_sz("type: regular file\n");
-      draw_indent(indent + 2);
-      terminal::put_string_sz("length: ");
-      terminal::put_int_decimal(f.dir_entry.length);
-      terminal::put_string_sz(" bytes\n");
-      break;
-
-    case storage::file_type::symlink:
-      draw_indent(indent + 2);
-      terminal::put_string_sz("type: symlink\n");
-      draw_indent(indent + 2);
-      terminal::put_string_sz("target: ");
-      terminal::put_string(f.dir_entry.target);
-      terminal::put_char('\n');
-      if (f.follow_symlinks(root, followed) != storage::fs_result::success)
-        print_and_halt("failed to follow symlink.");
-      if (!followed) {
-        draw_indent(indent + 4);
-        terminal::put_string_sz("[broken]\n");
-      }
-      dir_tree(root, *followed, indent + 4);
-      break;
-
-    case storage::file_type::directory:
-      if (f.get_children(children) != storage::fs_result::success)
-        print_and_halt("failed to get children.");
-      draw_indent(indent + 2);
-      terminal::put_string_sz("type: directory\n");
-      draw_indent(indent + 2);
-      terminal::put_string_sz("children:\n");
-      if (children.count == 0) {
-        draw_indent(indent + 4);
-        terminal::put_string_sz("[empty]\n");
-      }
-      else
-        for (unsigned i = 0; i < children.count; ++i)
-          dir_tree(root, children.buffer[i], indent + 4);
-      break;
-
-  }
-
-}
+extern "C" [[noreturn]] void start_user_mode(
+  uint64_t rip, uint64_t rsp, uint64_t p4_paddr);
 
 [[noreturn]] static void with_kernel_p4() {
 
@@ -257,27 +210,46 @@ static void dir_tree(
   storage::fs::tarfs_instance initfs_fs(&initfs_bd);
   initfs_bd.mounted_as = &initfs_fs;
 
-  terminal::put_string_sz("kernel initialization complete.\n");
-
-  int used_vram_kib = paging::get_used_vram_page_count() * 4;
-  int free_pram_kib = paging::get_free_pram_page_count() * 4;
+  vfile::vfile vfs_root;
+  vfs_root.bd = &initfs_bd;
+  vfs_root.dir_entry.type = storage::file_type::directory;
+  vfs_root.path.absolute = true;
 
-  terminal::put_int_decimal(used_vram_kib);
-  terminal::put_string_sz(" kiB kernel memory mapped.\n");
-  terminal::put_int_decimal(free_pram_kib);
-  terminal::put_string_sz(" kiB physical memory free.\n");
+  if (initfs_fs.get_root_node(vfs_root.dir_entry.node) !=
+      storage::fs_result::success)
+    print_and_halt("failed to get root node of initfs.");
 
-  vfile::vfile root;
-  root.bd = &initfs_bd;
-  root.dir_entry.type = storage::file_type::directory;
-  root.path.absolute = true;
+  utility::string init_path_string("/bin/init.elf", 13);
+  vfile::canon_path init_path;
+  vfile::canonize_path(init_path_string, init_path);
 
-  if (initfs_fs.get_root_node(root.dir_entry.node) !=
+  std::optional<vfile::vfile> init_file;
+  if (vfile::lookup_path(vfs_root, init_path, init_file) !=
       storage::fs_result::success)
-    print_and_halt("failed to get root node.");
-
-  terminal::put_string_sz("initfs");
-  dir_tree(root, root, 0);
-  print_and_halt("halting.");
+    print_and_halt("failed to look up /bin/init.elf.");
+  if (!init_file)
+    print_and_halt("/bin/init.elf does not exist.");
+
+  terminal::put_string_sz("/bin/init.elf is ");
+  terminal::put_int_decimal(init_file->dir_entry.length);
+  terminal::put_string_sz(" bytes long.\n");
+
+  application::app_instance *init;
+  if (application::create_app(*init_file, init) !=
+      application::create_app_result::success)
+    print_and_halt("failed to parse /bin/init.elf.");
+
+  terminal::put_string_sz("/bin/init.elf loaded:\n  instruction pointer 0x");
+  terminal::put_int_hex(init->saved_regs.rip, 8);
+  terminal::put_string_sz("\n  stack pointer 0x");
+  terminal::put_int_hex(init->saved_regs.rsp, 8);
+  terminal::put_string_sz("\n  ");
+  terminal::put_int_decimal(init->count_mapped_vram_pages() * 2);
+  terminal::put_string_sz(" MiB userspace memory used\n");
+
+  print_mem();
+  terminal::put_string_sz("switching to /bin/init.elf.\n");
+  application::running_app = init;
+  start_user_mode(init->saved_regs.rip, init->saved_regs.rsp, init->p4_paddr);
 
 }