[bootproto] Create new bootproto lib

This is a rather large commit that is widely focused on cleaning things
out of the 'junk drawer' that is src/include. Most notably, several
things that were put in there because they needed somewhere where both
the kernel, boot, and init could read them have been moved to a new lib,
'bootproto'.

- Moved kernel_args.h and init_args.h to bootproto as kernel.h and
  init.h, respectively.

- Moved counted.h and pointer_manipulation.h into util, renaming the
  latter to util/pointers.h.

- Created a new src/include/arch for very arch-dependent definitions,
  and moved some kernel_memory.h constants like frame size, page table
  entry count, etc to arch/amd64/memory.h. Also created arch/memory.h
  which detects platform and includes the former.

- Got rid of kernel_memory.h entirely in favor of a new, cog-based
  approach. The new definitions/memory_layout.csv lists memory regions
  in descending order from the top of memory, their sizes, and whether
  they are shared outside the kernel (ie, boot needs to know them). The
  new header bootproto/memory.h exposes the addresses of the shared
  regions, while the kernel's memory.h gains the start and size of all
  the regions. Also renamed the badly-named page-offset area the linear
  area.

- The python build scripts got a few new features: the ability to parse
  the csv mentioned above in a new memory.py module; the ability to add
  dependencies to existing source files (The list of files that I had to
  pull out of the main list just to add them with the dependency on
  memory.h was getting too large. So I put them back into the sources
  list, and added the dependency post-hoc.); and the ability to
  reference 'source_root', 'build_root', and 'module_root' variables in
  .module files.

- Some utility functions that were in the kernel's memory.h got moved to
  util/pointers.h and util/misc.h, and misc.h's byteswap was renamed
  byteswap32 to be more specific.

src/boot/paging.cpp

@@ -1,4 +1,7 @@
-#include "kernel_memory.h"
+#include <arch/memory.h>
+#include <bootproto/memory.h>
+#include <util/counted.h>
+#include <util/pointers.h>
 
 #include "allocator.h"
 #include "console.h"
@@ -6,7 +9,6 @@
 #include "loader.h"
 #include "memory.h"
 #include "paging.h"
-#include "pointer_manipulation.h"
 #include "status.h"
 
 namespace boot {
@@ -14,8 +16,6 @@ namespace paging {
 
 using memory::alloc_type;
 using memory::page_size;
-using ::memory::pml4e_kernel;
-using ::memory::table_entries;
 
 // Flags: 0 0 0 1  0 0 0 0  0 0 0 1 = 0x0101
 //         IGN  |  | | | |  | | | +- Present
@@ -58,13 +58,13 @@ constexpr uint64_t table_flags = 0x003;
 
 
 inline void *
-pop_pages(counted<void> &pages, size_t count)
+pop_pages(util::counted<void> &pages, size_t count)
 {
     if (count > pages.count)
         error::raise(uefi::status::out_of_resources, L"Page table cache empty", 0x7ab1e5);
 
     void *next = pages.pointer;
-    pages.pointer = offset_ptr<void>(pages.pointer, count*page_size);
+    pages.pointer = util::offset_pointer(pages.pointer, count*page_size);
     pages.count -= count;
     return next;
 }
@@ -81,7 +81,7 @@ public:
     page_entry_iterator(
             uintptr_t virt,
             page_table *pml4,
-            counted<void> &pages) :
+            util::counted<void> &pages) :
         m_pages(pages)
     {
         m_table[0] = pml4;
@@ -137,17 +137,17 @@ private:
         }
     }
 
-    counted<void> &m_pages;
+    util::counted<void> &m_pages;
     page_table *m_table[D];
     uint16_t m_index[D];
 };
 
 
 static void
-add_offset_mappings(page_table *pml4, counted<void> &pages)
+add_offset_mappings(page_table *pml4, util::counted<void> &pages)
 {
     uintptr_t phys = 0;
-    uintptr_t virt = ::memory::page_offset; // Start of offset-mapped area
+    uintptr_t virt = bootproto::mem::linear_offset; // Start of offset-mapped area
     size_t page_count = 64 * 1024; // 64 TiB of 1 GiB pages
     constexpr size_t GiB = 0x40000000ull;
 
@@ -164,9 +164,12 @@ add_offset_mappings(page_table *pml4, counted<void> &pages)
 }
 
 static void
-add_kernel_pds(page_table *pml4, counted<void> &pages)
+add_kernel_pds(page_table *pml4, util::counted<void> &pages)
 {
-    for (unsigned i = pml4e_kernel; i < table_entries; ++i)
+    constexpr unsigned start = arch::kernel_root_index; 
+    constexpr unsigned end = arch::table_entries; 
+
+    for (unsigned i = start; i < end; ++i)
         pml4->set(i, pop_pages(pages, 1), table_flags);
 }
 
@@ -178,7 +181,8 @@ add_current_mappings(page_table *new_pml4)
     asm volatile ( "mov %%cr3, %0" : "=r" (old_pml4) );
 
     // Only copy mappings in the lower half
-    for (int i = 0; i < ::memory::pml4e_kernel; ++i) {
+    constexpr unsigned halfway = arch::kernel_root_index; 
+    for (int i = 0; i < halfway; ++i) {
         uint64_t entry = old_pml4->entries[i];
         if (entry & 1)
             new_pml4->entries[i] = entry;
@@ -186,7 +190,7 @@ add_current_mappings(page_table *new_pml4)
 }
 
 void
-allocate_tables(kernel::init::args *args)
+allocate_tables(bootproto::args *args)
 {
     status_line status(L"Allocating initial page tables");
 
@@ -221,7 +225,7 @@ constexpr bool has_flag(E set, E flag) {
 
 void
 map_pages(
-    kernel::init::args *args,
+    bootproto::args *args,
     uintptr_t phys, uintptr_t virt,
     size_t count, bool write_flag, bool exe_flag)
 {
@@ -251,10 +255,10 @@ map_pages(
 
 void
 map_section(
-    kernel::init::args *args,
-    const kernel::init::program_section &section)
+    bootproto::args *args,
+    const bootproto::program_section &section)
 {
-    using kernel::init::section_flags;
+    using bootproto::section_flags;
 
     map_pages(
         args,
@@ -267,8 +271,8 @@ map_section(
 
 void
 map_program(
-    kernel::init::args *args,
-    kernel::init::program &program)
+    bootproto::args *args,
+    bootproto::program &program)
 {
     for (auto &section : program.sections)
         paging::map_section(args, section);