[boot] Improve bootloader allocation accounting

The bootloader relied on the kernel to know which parts of memory to not
allocate over. For the future shift of having the init process load
other processes instead of the kernel, the bootloader needs a mechanism
to just hand the kernel a list of allocations. This is now done through
the new bootloader allocator, which all allocation goes through. Pool
memory will not be tracked, and so can be overwritten - this means the
args structure and its other structures like programs need to be handled
right away, or copied by the kernel.

- Add bootloader allocator
- Implement a new linked-list based set of pages that act as allocation
  registers
- Allow for operator new in the bootloader, which goes through the
  global allocator for pool memory
- Split memory map and frame accouting code in the bootloader into
  separate memory_map.* files
- Remove many includes that could be replaced by forward declaration in
  the bootloader
- Add a new global template type, `counted`, which replaces the
  bootloader's `buffer` type, and updated kernel args structure to use it.
- Move bootloader's pointer_manipulation.h to the global include dir
- Make offset_iterator try to return references instead of pointers to
  make it more consistent with static array iteration
- Implement a stub atexit() in the bootloader to satisfy clang

src/boot/memory_map.cpp

@@ -0,0 +1,303 @@
+#include <uefi/boot_services.h>
+#include <uefi/types.h>
+
+#include "allocator.h"
+#include "error.h"
+#include "kernel_memory.h"
+#include "memory.h"
+#include "memory_map.h"
+#include "paging.h"
+#include "status.h"
+
+namespace boot {
+namespace memory {
+
+using kernel::init::frame_block;
+using kernel::init::frames_per_block;
+using kernel::init::mem_entry;
+using kernel::init::mem_type;
+
+
+void
+efi_mem_map::update(uefi::boot_services &bs)
+{
+	size_t l = total;
+	uefi::status status = bs.get_memory_map(
+		&l, entries, &key, &size, &version);
+	length = l;
+
+	if (status == uefi::status::success)
+		return;
+
+	if (status != uefi::status::buffer_too_small)
+		error::raise(status, L"Error getting memory map size");
+
+	if (entries) {
+		try_or_raise(
+			bs.free_pool(reinterpret_cast<void*>(entries)),
+			L"Freeing previous memory map space");
+	}
+
+	total = length + 10 * size;
+
+	try_or_raise(
+		bs.allocate_pool(
+			uefi::memory_type::loader_data, total,
+			reinterpret_cast<void**>(&entries)),
+		L"Allocating space for memory map");
+
+	length = total;
+	try_or_raise(
+		bs.get_memory_map(&length, entries, &key, &size, &version),
+		L"Getting UEFI memory map");
+}
+
+static const wchar_t *memory_type_names[] = {
+	L"reserved memory type",
+	L"loader code",
+	L"loader data",
+	L"boot services code",
+	L"boot services data",
+	L"runtime services code",
+	L"runtime services data",
+	L"conventional memory",
+	L"unusable memory",
+	L"acpi reclaim memory",
+	L"acpi memory nvs",
+	L"memory mapped io",
+	L"memory mapped io port space",
+	L"pal code",
+	L"persistent memory"
+};
+
+static const wchar_t *kernel_memory_type_names[] = {
+	L"free",
+	L"pending",
+	L"acpi",
+	L"uefi_runtime",
+	L"mmio",
+	L"persistent"
+};
+
+static const wchar_t *
+memory_type_name(uefi::memory_type t)
+{
+	if (t < uefi::memory_type::max_memory_type)
+		return memory_type_names[static_cast<uint32_t>(t)];
+
+	return L"Bad Type Value";
+}
+
+static const wchar_t *
+kernel_memory_type_name(kernel::init::mem_type t)
+{
+	return kernel_memory_type_names[static_cast<uint32_t>(t)];
+}
+
+inline bool
+can_merge(mem_entry &prev, mem_type type, uefi::memory_descriptor &next)
+{
+	return
+		prev.type == type &&
+		prev.start + (page_size * prev.pages) == next.physical_start &&
+		prev.attr == (next.attribute & 0xffffffff);
+}
+
+counted<mem_entry>
+build_kernel_map(efi_mem_map &map)
+{
+	status_line status {L"Creating kernel memory map"};
+
+	size_t map_size = map.num_entries() * sizeof(mem_entry);
+	size_t num_pages = bytes_to_pages(map_size);
+	mem_entry *kernel_map = reinterpret_cast<mem_entry*>(
+		g_alloc.allocate_pages(num_pages, alloc_type::mem_map, true));
+
+	size_t nent = 0;
+	bool first = true;
+	for (auto &desc : map) {
+		/*
+		// EFI map dump
+		console::print(L"   eRange %lx (%lx) %x(%s) [%lu]\r\n",
+			desc.physical_start, desc.attribute, desc.type, memory_type_name(desc.type), desc.number_of_pages);
+		*/
+
+		mem_type type;
+		switch (desc.type) {
+			case uefi::memory_type::reserved:
+			case uefi::memory_type::unusable_memory:
+			case uefi::memory_type::acpi_memory_nvs:
+			case uefi::memory_type::pal_code:
+				continue;
+
+			case uefi::memory_type::loader_code:
+			case uefi::memory_type::boot_services_code:
+			case uefi::memory_type::boot_services_data:
+			case uefi::memory_type::conventional_memory:
+			case uefi::memory_type::loader_data:
+				type = mem_type::free;
+				break;
+
+			case uefi::memory_type::runtime_services_code:
+			case uefi::memory_type::runtime_services_data:
+				type = mem_type::uefi_runtime;
+				break;
+
+			case uefi::memory_type::acpi_reclaim_memory:
+				type = mem_type::acpi;
+				break;
+
+			case uefi::memory_type::memory_mapped_io:
+			case uefi::memory_type::memory_mapped_io_port_space:
+				type = mem_type::mmio;
+				break;
+
+			case uefi::memory_type::persistent_memory:
+				type = mem_type::persistent;
+				break;
+
+			default:
+				error::raise(
+					uefi::status::invalid_parameter,
+					L"Got an unexpected memory type from UEFI memory map");
+		}
+
+		// TODO: validate uefi's map is sorted
+		if (first) {
+			first = false;
+			mem_entry &ent = kernel_map[nent++];
+			ent.start = desc.physical_start;
+			ent.pages = desc.number_of_pages;
+			ent.type = type;
+			ent.attr = (desc.attribute & 0xffffffff);
+			continue;
+		}
+
+		mem_entry &prev = kernel_map[nent - 1];
+		if (can_merge(prev, type, desc)) {
+			prev.pages += desc.number_of_pages;
+		} else {
+			mem_entry &next = kernel_map[nent++];
+			next.start = desc.physical_start;
+			next.pages = desc.number_of_pages;
+			next.type = type;
+			next.attr = (desc.attribute & 0xffffffff);
+		}
+	}
+
+	/*
+	// kernel map dump
+	for (unsigned i = 0; i < nent; ++i) {
+		const mem_entry &e = kernel_map[i];
+		console::print(L"   kRange %lx (%lx) %x(%s) [%lu]\r\n",
+			e.start, e.attr, e.type, kernel_memory_type_name(e.type), e.pages);
+	}
+	*/
+
+	return { .pointer = kernel_map, .count = nent };
+}
+
+inline size_t bitmap_size(size_t frames) { return (frames + 63) / 64; }
+inline size_t num_blocks(size_t frames) { return (frames + (frames_per_block-1)) / frames_per_block; }
+
+counted<kernel::init::frame_block>
+build_frame_blocks(const counted<kernel::init::mem_entry> &kmap)
+{
+	status_line status {L"Creating kernel frame accounting map"};
+
+	size_t block_count = 0;
+	size_t total_bitmap_size = 0;
+	for (size_t i = 0; i < kmap.count; ++i) {
+		const mem_entry &ent = kmap[i];
+		if (ent.type != mem_type::free)
+			continue;
+
+		block_count += num_blocks(ent.pages);
+		total_bitmap_size += bitmap_size(ent.pages) * sizeof(uint64_t);
+	}
+
+	size_t total_size = block_count * sizeof(frame_block) + total_bitmap_size;
+
+	frame_block *blocks = reinterpret_cast<frame_block*>(
+		g_alloc.allocate_pages(bytes_to_pages(total_size), alloc_type::frame_map, true));
+
+	frame_block *next_block = blocks;
+	for (size_t i = 0; i < kmap.count; ++i) {
+		const mem_entry &ent = kmap[i];
+		if (ent.type != mem_type::free)
+			continue;
+
+		size_t page_count = ent.pages;
+		uintptr_t base_addr = ent.start;
+		while (page_count) {
+			frame_block *blk = next_block++;
+
+			blk->flags = static_cast<kernel::init::frame_flags>(ent.attr);
+			blk->base = base_addr;
+			base_addr += frames_per_block * page_size;
+
+			if (page_count >= frames_per_block) {
+				page_count -= frames_per_block;
+				blk->count = frames_per_block;
+				blk->map1 = ~0ull;
+				g_alloc.memset(blk->map2, sizeof(blk->map2), 0xff);
+			} else {
+				blk->count = page_count;
+				unsigned i = 0;
+
+				uint64_t b1 = (page_count + 4095) / 4096;
+				blk->map1 = (1 << b1) - 1;
+
+				uint64_t b2 = (page_count + 63) / 64;
+				uint64_t b2q = b2 / 64;
+				uint64_t b2r = b2 % 64;
+				g_alloc.memset(blk->map2, b2q, 0xff);
+				blk->map2[b2q] = (1 << b2r) - 1;
+				break;
+			}
+		}
+	}
+
+	uint64_t *bitmap = reinterpret_cast<uint64_t*>(next_block);
+	for (unsigned i = 0; i < block_count; ++i) {
+		frame_block &blk = blocks[i];
+		blk.bitmap = bitmap;
+
+		size_t b = blk.count / 64;
+		size_t r = blk.count % 64;
+		g_alloc.memset(blk.bitmap, b*8, 0xff);
+		blk.bitmap[b] = (1 << r) - 1;
+
+		bitmap += bitmap_size(blk.count);
+	}
+
+	return { .pointer = blocks, .count = block_count };
+}
+
+void
+fix_frame_blocks(kernel::init::args *args)
+{
+	counted<frame_block> &blocks = args->frame_blocks;
+
+	size_t size = blocks.count * sizeof(frame_block);
+	for (unsigned i = 0; i < blocks.count; ++i)
+		size += bitmap_size(blocks[i].count) * sizeof(uint64_t);
+
+	size_t pages = bytes_to_pages(size);
+	uintptr_t addr = reinterpret_cast<uintptr_t>(blocks.pointer);
+
+	// Map the frame blocks to the appropriate address
+	paging::map_pages(args, addr,
+		::memory::bitmap_start, pages, true, false);
+
+	uintptr_t offset = ::memory::bitmap_start - addr;
+
+	for (unsigned i = 0; i < blocks.count; ++i) {
+		frame_block &blk = blocks[i];
+		blk.bitmap = offset_ptr<uint64_t>(blk.bitmap, offset);
+	}
+}
+
+
+} // namespace memory
+} // namespace boot