Remove high memory kernel and needless prints

3 files changed, 48 insertions, 118 deletions

diff --git a/arch/x86_64/scripts/kernel.ld b/arch/x86_64/scripts/kernel.ld
index 943266c..31d8be3 100644
--- a/arch/x86_64/scripts/kernel.ld
+++ b/arch/x86_64/scripts/kernel.ld
@@ -3,7 +3,6 @@ ENTRY(_start)
 /*****************************************************************************
  * Virtual and linear start addresses of the TeachOS kernel
  *****************************************************************************/
-TEACHOS_HIGH = -2048M;
 TEACHOS_LOW = 1M;
 
 PHDRS {
@@ -31,7 +30,7 @@ SECTIONS
    * symbols at the beginning.
    ***************************************************************************/
   _start_linear = .;
-  _start_virtual = . + TEACHOS_HIGH;
+  _start_virtual = .;
 
   /***************************************************************************
    * The bootstrapping infratructure goes first. We first place the read-only
@@ -66,9 +65,8 @@ SECTIONS
    * also make sure to align the loaded data onto a page boundary.
    ***************************************************************************/
   . = ALIGN(4K);
-  . += TEACHOS_HIGH;
 
-  .init ALIGN(4K) : AT(ADDR (.init) - TEACHOS_HIGH)
+  .init ALIGN(4K) : AT(ADDR (.init))
   {
     /* 
      * Make sure that the crt code is wrapped around the compiler generated
@@ -79,7 +77,7 @@ SECTIONS
     KEEP(*crtn.s.o*(.init))
   } :text
 
-  .fini ALIGN(4K) : AT(ADDR (.fini) - TEACHOS_HIGH)
+  .fini ALIGN(4K) : AT(ADDR (.fini))
   {
     /* 
      * Make sure that the crt code is wrapped around the compiler generated
@@ -90,18 +88,18 @@ SECTIONS
     KEEP(*crtn.s.o*(.fini))
   }
 
-  .text ALIGN(4K) : AT(ADDR (.text) - TEACHOS_HIGH)
+  .text ALIGN(4K) : AT(ADDR (.text))
   {
     *(.text*)
   }
 
-  .rodata ALIGN(4K) : AT (ADDR (.rodata) - TEACHOS_HIGH)
+  .rodata ALIGN(4K) : AT (ADDR (.rodata))
   {
     *(.rodata)
     *(.rodata.*)
   } :rodata
 
-  .ctors ALIGN(4K) : AT (ADDR (.ctors) - TEACHOS_HIGH)
+  .ctors ALIGN(4K) : AT (ADDR (.ctors))
   {
     KEEP(*crtbegin.o(.ctors))
     KEEP(*(EXCLUDE_FILE (*crtend.o) .ctors))
@@ -109,7 +107,7 @@ SECTIONS
     KEEP(*crtend.o(.ctors))
   } :data
 
-  .dtors ALIGN(4K) : AT (ADDR (.dtors) - TEACHOS_HIGH)
+  .dtors ALIGN(4K) : AT (ADDR (.dtors))
   {
     KEEP(*crtbegin.o(.dtors))
     KEEP(*(EXCLUDE_FILE (*crtend.o) .dtors))
@@ -117,12 +115,12 @@ SECTIONS
     KEEP(*crtend.o(.dtors))
   }
 
-  .data ALIGN(4K) : AT (ADDR (.data) - TEACHOS_HIGH)
+  .data ALIGN(4K) : AT (ADDR (.data))
   {
     *(.data*)
   }
 
-  .bss ALIGN(4K) : AT (ADDR (.bss) - TEACHOS_HIGH)
+  .bss ALIGN(4K) : AT (ADDR (.bss))
   {
     *(COMMON)
     *(.bss*)
@@ -133,7 +131,7 @@ SECTIONS
    * symbols to mark the end of our loaded image.
    ***************************************************************************/
   _end_virtual = ADDR(.bss) + SIZEOF(.bss);
-  _end_linear = _end_virtual - TEACHOS_HIGH;
+  _end_linear = _end_virtual;
 
   /DISCARD/ : { *(.comment) }
 }
diff --git a/arch/x86_64/src/boot/boot.s b/arch/x86_64/src/boot/boot.s
index 7b4e193..0c21c66 100644
--- a/arch/x86_64/src/boot/boot.s
+++ b/arch/x86_64/src/boot/boot.s
@@ -17,8 +17,8 @@
  *
  * We need:
  *   - A single PML 4 (since we will only use 4-level paging)
- *   - 2 PML 3s (since we need to map high (-2GiB) and low (1+MiB) memory)
- *   - 2 PML 2s (since we need to map high (-2GiB) and low (1+MiB) memory)
+ *   - 2 PML 3s (since we need to map low (1+MiB) memory)
+ *   - 2 PML 2s (since we need to map low (1+MiB) memory)
  */
 
 .global page_map_level_4
@@ -26,13 +26,9 @@ page_map_level_4: .skip 512 * 8
 
 .global page_map_level_3_low
 page_map_level_3_low: .skip 512 * 8
-.global page_map_level_3_high
-page_map_level_3_high: .skip 512 * 8
 
 .global page_map_level_2_low
 page_map_level_2_low: .skip 512 * 8
-.global page_map_level_2_high
-page_map_level_2_high: .skip 512 * 8
 
 /**
  * Reserve some space for the Multiboot 2 information pointer.
@@ -306,10 +302,7 @@ enable_sse:
  *
  * We map all physical memory we were loaded in plus one additional page. The
  * mapping is done in terms of huge pages (2 MiB per page) to save on required
- * page map entries. Note that we also map memory both in the low and high
- * virtual address ranges, giving us two ways of accessing it. We need to do
- * this, because the bootstrapping code lives in low memory, while the rest of
- * the kernel will reside on the high end.
+ * page map entries.
  */
 prepare_page_maps:
     /* Add an entry to the PML4, pointing to the low PML3 */
@@ -317,21 +310,11 @@ prepare_page_maps:
     or $0x3, %eax
     mov %eax, (page_map_level_4 + ((0x0000000000100000 >> 39) & 0x1ff) * 8)
 
-    /* Add an entry to the PML4, pointing to the high PML3 */
-    mov $page_map_level_3_high, %eax
-    or $0x3, %eax
-    mov %eax, (page_map_level_4 + ((0xffffffff80100000 >> 39) & 0x1ff) * 8)
-
     /* Add an entry to the low PML3, pointing to the low PML2 */
     mov $page_map_level_2_low, %eax
     or $0x3, %eax
     mov %eax, (page_map_level_3_low + ((0x0000000000100000 >> 30) & 0x1ff) * 8)
 
-    /* Add an entry to the high PML3, pointing to the high PML2 */
-    mov $page_map_level_2_high, %eax
-    or $0x3, %eax
-    mov %eax, (page_map_level_3_high + ((0xffffffff80100000 >> 30) & 0x1ff) * 8)
-
     xor %ecx, %ecx
 
     mov $_end_linear, %esi
@@ -343,7 +326,6 @@ prepare_page_maps:
     mul %ecx
     or $((1 << 0) | (1 << 1) | (1 << 7)), %eax
     mov %eax, page_map_level_2_low(,%ecx,8)
-    mov %eax, page_map_level_2_high(,%ecx,8)
 
     inc %ecx
     cmp %esi, %ecx
diff --git a/arch/x86_64/src/kernel/main.cpp b/arch/x86_64/src/kernel/main.cpp
index 4d6296a..e867bad 100644
--- a/arch/x86_64/src/kernel/main.cpp
+++ b/arch/x86_64/src/kernel/main.cpp
@@ -9,47 +9,28 @@ namespace teachos::arch::kernel
   auto print_mem_info(arch::memory::memory_info * mem_info) -> void
   {
     using namespace video::vga;
-
     auto mem_lower = mem_info->mem_lower;
-    text::write("Lower memory (kB): ", text::common_attributes::green_on_black);
-    text::write_number(mem_lower, text::common_attributes::green_on_black);
-
     auto mem_upper = mem_info->mem_upper;
-    text::write("Upper memory (kB): ", text::common_attributes::green_on_black);
-    text::write_number(mem_upper, text::common_attributes::green_on_black);
   }
 
   auto print_memory_map(arch::memory::memory_map * mminfo) -> void
   {
     using namespace video::vga;
 
-    uint32_t const entry_size = mminfo->entry_size;
-    text::write("Entry Size: ", text::common_attributes::green_on_black);
-    text::write_number(entry_size, text::common_attributes::green_on_black);
-
-    uint32_t const entry_version = mminfo->entry_version;
-    text::write("Version: ", text::common_attributes::green_on_black);
-    text::write_number(entry_version, text::common_attributes::green_on_black);
-
-    uint32_t const remaining_size = mminfo->tag.size - (4 * sizeof(uint32_t));
-    uint32_t const entry_amount = remaining_size / entry_size;
+    auto entry_size = mminfo->entry_size;
+    auto entry_version = mminfo->entry_version;
+    auto remaining_size = mminfo->tag.size - (4 * sizeof(uint32_t));
+    auto entry_amount = remaining_size / entry_size;
 
     auto begin = &mminfo->entries;
     auto end = begin + entry_amount;
-    for (auto entry = begin; entry != end; ++entry)
+    for (auto entry = begin; entry != end;
+         entry = (teachos::arch::memory::memory_area *)(((uint8_t *)entry) + ((entry_size + 7) & ~7)))
     {
-      text::write("Base Address: ", text::common_attributes::green_on_black);
-      text::write_number(entry->base_addr, text::common_attributes::green_on_black);
-
-      text::write("Length: ", text::common_attributes::green_on_black);
-      text::write_number(entry->length, text::common_attributes::green_on_black);
-
-      text::write("Type: ", text::common_attributes::green_on_black);
-      text::write_number(static_cast<std::underlying_type<arch::memory::memory_area_type>::type>(entry->type),
-                         text::common_attributes::green_on_black);
-
-      text::write("Reserved: ", text::common_attributes::green_on_black);
-      text::write_number(entry->reserved, text::common_attributes::green_on_black);
+      auto base_addr = entry->base_addr;
+      auto length = entry->length;
+      auto type = entry->type;
+      auto reserved = entry->reserved;
     }
   }
 
@@ -57,61 +38,33 @@ namespace teachos::arch::kernel
   {
     using namespace video::vga;
 
-    uint16_t const num = symbol->num;
-    text::write("Number of entries: ", text::common_attributes::green_on_black);
-    text::write_number(num, text::common_attributes::green_on_black);
-
-    uint16_t const entsize = symbol->entsize;
-    text::write("Entry Size: ", text::common_attributes::green_on_black);
-    text::write_number(entsize, text::common_attributes::green_on_black);
-
-    uint16_t const shndx = symbol->shndx;
-    text::write("Section index: ", text::common_attributes::green_on_black);
-    text::write_number(shndx, text::common_attributes::green_on_black);
+    auto num = symbol->num;
+    auto entsize = symbol->entsize;
+    auto shndx = symbol->shndx;
 
     auto begin = &symbol->sections;
     auto end = begin + num;
-    for (auto section = begin; section != end; ++section)
-    {
-      uint32_t const sh_name = section->sh_name;
-      text::write("Section name: ", text::common_attributes::green_on_black);
-      text::write_number(sh_name, text::common_attributes::green_on_black);
-
-      uint32_t const sh_type = section->sh_type;
-      text::write("Section type: ", text::common_attributes::green_on_black);
-      text::write_number(sh_type, text::common_attributes::green_on_black);
-
-      uint64_t const sh_flags = section->sh_flags;
-      text::write("Section flags: ", text::common_attributes::green_on_black);
-      text::write_number(sh_flags, text::common_attributes::green_on_black);
 
-      uint64_t const sh_addr = section->sh_addr;
-      text::write("Section address: ", text::common_attributes::green_on_black);
-      text::write_number(sh_addr, text::common_attributes::green_on_black);
-
-      uint64_t const sh_offset = section->sh_offset;
-      text::write("Section offset: ", text::common_attributes::green_on_black);
-      text::write_number(sh_offset, text::common_attributes::green_on_black);
-
-      uint64_t const sh_size = section->sh_size;
-      text::write("Section size: ", text::common_attributes::green_on_black);
-      text::write_number(sh_size, text::common_attributes::green_on_black);
-
-      uint32_t const sh_link = section->sh_link;
-      text::write("Section link: ", text::common_attributes::green_on_black);
-      text::write_number(sh_link, text::common_attributes::green_on_black);
-
-      uint32_t const sh_info = section->sh_info;
-      text::write("Section info: ", text::common_attributes::green_on_black);
-      text::write_number(sh_info, text::common_attributes::green_on_black);
-
-      uint64_t const sh_addralign = section->sh_addralign;
-      text::write("Section address align: ", text::common_attributes::green_on_black);
-      text::write_number(sh_addralign, text::common_attributes::green_on_black);
-
-      uint64_t const sh_entsize = section->sh_entsize;
-      text::write("Section entry size: ", text::common_attributes::green_on_black);
-      text::write_number(sh_entsize, text::common_attributes::green_on_black);
+    /*
+     * Loop over the elf section to access the information needed.
+     * Sections are defined in the header file and are padded so that each
+     * Section starts at an 8-bytes aligned adress.
+     *
+     * The increment part aligns the size to an 8-byte address.
+     */
+    for (auto section = begin; section != end;
+         section = (teachos::arch::memory::elf_section_header *)(((uint8_t *)section) + ((entsize + 7) & ~7)))
+    {
+      auto sh_name = section->sh_name;
+      auto sh_type = section->sh_type;
+      auto sh_flags = section->sh_flags;
+      auto sh_addr = section->sh_addr;
+      auto sh_offset = section->sh_offset;
+      auto sh_size = section->sh_size;
+      auto sh_link = section->sh_link;
+      auto sh_info = section->sh_info;
+      auto sh_addralign = section->sh_addralign;
+      auto sh_entsize = section->sh_entsize;
     }
   }
 
@@ -127,11 +80,8 @@ namespace teachos::arch::kernel
         (arch::memory::multi_boot_info *)arch::boot::multiboot_information_pointer;
     auto multiboot_tag = &(multiboot_information_pointer->tags);
 
-    text::write("Multiboot Start: ", text::common_attributes::green_on_black);
-    text::write_number(arch::boot::multiboot_information_pointer, text::common_attributes::green_on_black);
-    text::write("Multiboot End: ", text::common_attributes::green_on_black);
-    text::write_number(arch::boot::multiboot_information_pointer + multiboot_information_pointer->total_size,
-                       text::common_attributes::green_on_black);
+    auto multiboot_start = arch::boot::multiboot_information_pointer;
+    auto multiboot_end = arch::boot::multiboot_information_pointer + multiboot_information_pointer->total_size;
 
     /*
      * Loop over the multiboot2 tags to access the information needed.