[srv.init] Create init server and read init args

Create a new usermode program, srv.init, and have it read the initial
module_page args sent to it by the bootloader. Doesn't yet do anything
useful but sets up the way for loading the rest of the programs from
srv.init.

Other (mostly) related changes:

- bootloader: The allocator now has a function for allocating init
  modules out of a modules_page slab. Also changed how the allocator is
  initialized and passes the allocation register and modules_page list
  to efi_main().
- bootloader: Expose the simple wstrlen() to the rest of the program
- bootloader: Move check_cpu_supported() to hardware.cpp
- bootloader: Moved program_desc to loader.h and made the loader
  functions take it as an argument instead of paths.
- kernel: Rename the system_map_mmio syscall to system_map_phys, and
  stop having it default those VMAs to having the vm_flags::mmio flag.
  Added a new flag mask, vm_flags::driver_mask, so that drivers can be
  allowed to ask for the MMIO flag.
- kernel: Rename load_simple_process() to load_init_server() and got rid
  of all the stack setup routines in memory_bootstrap.cpp and task.s
- Fixed formatting in config/debug.toml, undefined __linux and other
  linux-specific defines, and got rid of _LIBCPP_HAS_THREAD_API_EXTERNAL
  because that's just not true.

src/boot/main.cpp

@@ -9,7 +9,6 @@
 
 #include "allocator.h"
 #include "console.h"
-#include "cpu/cpu_id.h"
 #include "error.h"
 #include "fs.h"
 #include "hardware.h"
@@ -30,19 +29,12 @@ namespace init = kernel::init;
 
 namespace boot {
 
-constexpr int max_modules = 5; // Max modules to allocate room for
-constexpr int max_programs = 5; // Max programs to allocate room for
+const loader::program_desc kern_desc = {L"kernel", L"jsix.elf"};
+const loader::program_desc init_desc = {L"init server", L"srv.init.elf"};
+const loader::program_desc fb_driver = {L"UEFI framebuffer driver", L"drv.uefi_fb.elf"};
 
-struct program_desc
-{
-	const wchar_t *name;
-	const wchar_t *path;
-};
-
-const program_desc program_list[] = {
-	{L"kernel", L"jsix.elf"},
+const loader::program_desc extra_programs[] = {
 	{L"test application", L"testapp.elf"},
-	{L"UEFI framebuffer driver", L"drv.uefi_fb.elf"},
 };
 
 /// Change a pointer to point to the higher-half linear-offset version
@@ -53,40 +45,6 @@ void change_pointer(T *&pointer)
 	pointer = offset_ptr<T>(pointer, kernel::memory::page_offset);
 }
 
-/// Add a module to the kernel args list
-inline void
-add_module(init::args *args, init::mod_type type, buffer &data)
-{
-	init::module &m = args->modules[args->modules.count++];
-	m.type = type;
-	m.location = data.pointer;
-	m.size = data.count;
-
-	change_pointer(m.location);
-}
-
-/// Check that all required cpu features are supported
-void
-check_cpu_supported()
-{
-	status_line status {L"Checking CPU features"};
-
-	cpu::cpu_id cpu;
-	uint64_t missing = cpu.missing();
-	if (missing) {
-#define CPU_FEATURE_OPT(...)
-#define CPU_FEATURE_REQ(name, ...) \
-		if (!cpu.has_feature(cpu::feature::name)) { \
-			status::fail(L"CPU required feature " L ## #name, uefi::status::unsupported); \
-		}
-#include "cpu/features.inc"
-#undef CPU_FEATURE_REQ
-#undef CPU_FEATURE_OPT
-
-		error::raise(uefi::status::unsupported, L"CPU not supported");
-	}
-}
-
 /// The main procedure for the portion of the loader that runs while
 /// UEFI is still in control of the machine. (ie, while the loader still
 /// has access to boot services.)
@@ -98,13 +56,11 @@ uefi_preboot(uefi::handle image, uefi::system_table *st)
 
 	status_line status {L"Performing UEFI pre-boot"};
 
-	check_cpu_supported();
+	hw::check_cpu_supported();
 	memory::init_pointer_fixup(bs, rs);
 
 	init::args *args = new init::args;
 	g_alloc.zero(args, sizeof(init::args));
-	args->programs.pointer = new init::program[5];
-	args->modules.pointer = new init::module[5];
 
 	args->magic = init::args_magic;
 	args->version = init::args_version;
@@ -114,21 +70,32 @@ uefi_preboot(uefi::handle image, uefi::system_table *st)
 
 	paging::allocate_tables(args);
 
+	return args;
+}
+
+/// Load the kernel and other programs from disk
+void
+load_resources(init::args *args, video::screen *screen, uefi::handle image, uefi::boot_services *bs)
+{
+	status_line status {L"Loading programs"};
+
 	fs::file disk = fs::get_boot_volume(image, bs);
 
-	buffer symbols = loader::load_file(disk, L"symbol table", L"symbol_table.dat");
-	add_module(args, init::mod_type::symbol_table, symbols);
-
-	for (auto &desc : program_list) {
-		buffer buf = loader::load_file(disk, desc.name, desc.path);
-		init::program &program = args->programs[args->programs.count++];
-		loader::load_program(program, desc.name, buf);
+	if (screen) {
+		video::make_module(screen);
+		loader::load_module(disk, fb_driver);
 	}
 
-    // First program *must* be the kernel
-    loader::verify_kernel_header(args->programs[0]);
+	args->symbol_table = loader::load_file(disk, {L"symbol table", L"symbol_table.dat"});
+
+	args->kernel = loader::load_program(disk, kern_desc, true);
+	args->init = loader::load_program(disk, init_desc);
+
+	for (auto &desc : extra_programs)
+		loader::load_module(disk, desc);
+
+    loader::verify_kernel_header(*args->kernel);
 
-	return args;
 }
 
 memory::efi_mem_map
@@ -141,7 +108,6 @@ uefi_exit(init::args *args, uefi::handle image, uefi::boot_services *bs)
 
 	args->mem_map = memory::build_kernel_map(map);
 	args->frame_blocks = memory::build_frame_blocks(args->mem_map);
-	args->allocations = g_alloc.get_register();
 
 	map.update(*bs);
 	try_or_raise(
@@ -162,17 +128,24 @@ efi_main(uefi::handle image, uefi::system_table *st)
 	uefi::boot_services *bs = st->boot_services;
 	console con(st->con_out);
 
-	memory::init_allocator(bs);
+	init::allocation_register *allocs = nullptr;
+	init::modules_page *modules = nullptr;
+	memory::allocator::init(allocs, modules, bs);
+
 	video::screen *screen = video::pick_mode(bs);
 	con.announce();
 
 	init::args *args = uefi_preboot(image, st);
+	load_resources(args, screen, image, bs);
 	memory::efi_mem_map map = uefi_exit(args, image, st->boot_services);
 
+	args->allocations = allocs;
+	args->modules = reinterpret_cast<uintptr_t>(modules);
+
 	status_bar status {screen}; // Switch to fb status display
 
 	// Map the kernel to the appropriate address
-	init::program &kernel = args->programs[0];
+	init::program &kernel = *args->kernel;
 	for (auto &section : kernel.sections)
 		paging::map_section(args, section);
 
@@ -180,20 +153,22 @@ efi_main(uefi::handle image, uefi::system_table *st)
 
 	init::entrypoint kentry =
 		reinterpret_cast<init::entrypoint>(kernel.entrypoint);
-	status.next();
+	//status.next();
 
 	hw::setup_control_regs();
 	memory::virtualize(args->pml4, map, st->runtime_services);
-	status.next();
+	//status.next();
 
 	change_pointer(args);
 	change_pointer(args->pml4);
-	change_pointer(args->modules.pointer);
-	change_pointer(args->programs.pointer);
-	for (auto &program : args->programs)
-		change_pointer(program.sections.pointer);
+	change_pointer(args->symbol_table.pointer);
 
-	status.next();
+	change_pointer(args->kernel);
+	change_pointer(args->kernel->sections.pointer);
+	change_pointer(args->init);
+	change_pointer(args->init->sections.pointer);
+
+	//status.next();
 
 	kentry(args);
 	debug_break();