Remove the addition of USER_ACCESSIBLE flag to every entry created

11 files changed, 38 insertions, 88 deletions

diff --git a/arch/x86_64/include/arch/memory/paging/active_page_table.hpp b/arch/x86_64/include/arch/memory/paging/active_page_table.hpp
index 9e91a8c..a4a5b64 100644
--- a/arch/x86_64/include/arch/memory/paging/active_page_table.hpp
+++ b/arch/x86_64/include/arch/memory/paging/active_page_table.hpp
@@ -89,7 +89,7 @@ namespace teachos::arch::memory::paging
       arch::exception_handling::assert(!level1_entry.contains_flags(entry::HUGE_PAGE),
                                        "[Page Mapper] Unable to map huge pages");
       arch::exception_handling::assert(level1_entry.is_unused(), "[Page Mapper] Page table entry is already used");
-      level1_entry.set_entry(frame, flags.to_ulong() | entry::PRESENT);
+      level1_entry.set_entry(frame, flags.to_ulong() | entry::PRESENT | entry::USER_ACCESSIBLE);
     }
 
     /**
diff --git a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
index 8d36fde..09e9bf4 100644
--- a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
+++ b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
@@ -81,11 +81,12 @@ namespace teachos::arch::memory::paging
           kernel::cpu::read_control_register(kernel::cpu::control_register::CR3));
       auto page_table_level4 = temporary_page.map_table_frame(backup, active_table);
 
-      active_table[511].set_entry(inactive_table.page_table_level_4_frame, entry::PRESENT | entry::WRITABLE);
+      active_table[511].set_entry(inactive_table.page_table_level_4_frame,
+                                  entry::PRESENT | entry::WRITABLE | entry::USER_ACCESSIBLE);
       kernel::cpu::tlb_flush_all();
       map_elf_kernel_sections(active_table);
 
-      page_table_level4[511].set_entry(backup, entry::PRESENT | entry::WRITABLE);
+      page_table_level4[511].set_entry(backup, entry::PRESENT | entry::WRITABLE | entry::USER_ACCESSIBLE);
       kernel::cpu::tlb_flush_all();
       temporary_page.unmap_page(active_table);
     }
@@ -136,7 +137,14 @@ namespace teachos::arch::memory::paging
         allocator::frame_container::iterator const begin{start_frame};
         allocator::frame_container::iterator const end{end_frame};
         allocator::frame_container const frames{begin, end};
-        entry const entry{section.flags};
+        entry entry{section.flags};
+
+        // TODO: Only set this if we are in the .user_text section.
+        // address: 0000000000216000, offset: 013000, size: varies depending on code not a a good idea
+        // Alternatively index Nr. 8 could be used to detect section, can also change if we add more section
+        entry.set_user_accesible();
+
+        // TODO: Entering User Mode still works, but then attempting to execute an instruction immedatiately fails.
 
         for (auto const & frame : frames)
         {
@@ -146,7 +154,7 @@ namespace teachos::arch::memory::paging
 
       auto const vga_buffer_frame =
           allocator::physical_frame::containing_address(video::vga::text::DEFAULT_VGA_TEXT_BUFFER_ADDRESS);
-      active_table.identity_map(allocator, vga_buffer_frame, entry::WRITABLE);
+      active_table.identity_map(allocator, vga_buffer_frame, entry::WRITABLE | entry::USER_ACCESSIBLE);
     }
 
     T & allocator;
diff --git a/arch/x86_64/include/arch/memory/paging/page_entry.hpp b/arch/x86_64/include/arch/memory/paging/page_entry.hpp
index ef4fe61..5cba1bc 100644
--- a/arch/x86_64/include/arch/memory/paging/page_entry.hpp
+++ b/arch/x86_64/include/arch/memory/paging/page_entry.hpp
@@ -72,6 +72,12 @@ namespace teachos::arch::memory::paging
     auto set_unused() -> void;
 
     /**
+     * @brief Marks the page as accessible in User mode, meaning the underlying std::bitset has the 2nd bit aditonally
+     * set.
+     */
+    auto set_user_accesible() -> void;
+
+    /**
      * @brief Calculates the physical frame this entry is pointing too, can be null if the page is not present in
      * memory.
      *
diff --git a/arch/x86_64/include/arch/memory/paging/page_table.hpp b/arch/x86_64/include/arch/memory/paging/page_table.hpp
index 60a0a2f..db7ba6c 100644
--- a/arch/x86_64/include/arch/memory/paging/page_table.hpp
+++ b/arch/x86_64/include/arch/memory/paging/page_table.hpp
@@ -94,7 +94,8 @@ namespace teachos::arch::memory::paging
       {
         auto const allocated_frame = allocator.allocate_frame();
         exception_handling::assert(allocated_frame.has_value(), "[Page mapper] Unable to allocate frame");
-        this->operator[](table_index).set_entry(allocated_frame.value(), entry::PRESENT | entry::WRITABLE);
+        this->operator[](table_index)
+            .set_entry(allocated_frame.value(), entry::PRESENT | entry::WRITABLE | entry::USER_ACCESSIBLE);
         // There should now be an entry at the previously not existent index, therefore we can simply access it again.
         next_handle = next_table(table_index);
         exception_handling::assert(next_handle.has_value(), "[Page mapper] Unable to create new entry into page table");
diff --git a/arch/x86_64/include/arch/user/main.hpp b/arch/x86_64/include/arch/user/main.hpp
index 4f1d005..ba30864 100644
--- a/arch/x86_64/include/arch/user/main.hpp
+++ b/arch/x86_64/include/arch/user/main.hpp
@@ -3,6 +3,11 @@
 
 namespace teachos::arch::user
 {
+  /**
+   * @brief User Main method. If this method finishes there is no code left to run and the whole OS will shut down.
+   * Additionally this main method is executed at Ring 3 and accessing CPU Registers or Kernel level functionality can
+   * only be done over syscalls and not directly anymore.
+   */
   auto main() -> void;
 
 }  // namespace teachos::arch::user
diff --git a/arch/x86_64/src/memory/main.cpp b/arch/x86_64/src/memory/main.cpp
index bd094e0..4cccabb 100644
--- a/arch/x86_64/src/memory/main.cpp
+++ b/arch/x86_64/src/memory/main.cpp
@@ -31,7 +31,8 @@ namespace teachos::arch::memory
 
       for (auto const & page : pages)
       {
-        active_table.map_page_to_next_free_frame(allocator, page, paging::entry::WRITABLE);
+        active_table.map_page_to_next_free_frame(allocator, page,
+                                                 paging::entry::WRITABLE | paging::entry::USER_ACCESSIBLE);
       }
     }
   }  // namespace
diff --git a/arch/x86_64/src/memory/paging/inactive_page_table.cpp b/arch/x86_64/src/memory/paging/inactive_page_table.cpp
index 4e0610e..780f12c 100644
--- a/arch/x86_64/src/memory/paging/inactive_page_table.cpp
+++ b/arch/x86_64/src/memory/paging/inactive_page_table.cpp
@@ -14,7 +14,7 @@ namespace teachos::arch::memory::paging
   {
     auto table = temporary_page.map_table_frame(page_table_level_4_frame, active_page_table);
     table.zero_entries();
-    table[511].set_entry(page_table_level_4_frame, entry::PRESENT | entry::WRITABLE);
+    table[511].set_entry(page_table_level_4_frame, entry::PRESENT | entry::WRITABLE | entry::USER_ACCESSIBLE);
     temporary_page.unmap_page(active_page_table);
   }
 }  // namespace teachos::arch::memory::paging
diff --git a/arch/x86_64/src/memory/paging/page_entry.cpp b/arch/x86_64/src/memory/paging/page_entry.cpp
index 3a0f03f..c76c673 100644
--- a/arch/x86_64/src/memory/paging/page_entry.cpp
+++ b/arch/x86_64/src/memory/paging/page_entry.cpp
@@ -10,7 +10,7 @@ namespace teachos::arch::memory::paging
   }  // namespace
 
   entry::entry(uint64_t flags)
-      : flags(flags | entry::USER_ACCESSIBLE)  // TODO: Temporarily make all entries user accessible
+      : flags(flags)
   {
     // Nothing to do.
   }
@@ -31,15 +31,14 @@ namespace teachos::arch::memory::paging
     {
       flags |= entry::EXECUTING_CODE_FORBIDDEN;
     }
-
-    // TODO: Temporarily make all entries user accessible
-    flags |= entry::USER_ACCESSIBLE;
   }
 
   auto entry::is_unused() const -> bool { return flags == 0U; }
 
   auto entry::set_unused() -> void { flags = 0U; }
 
+  auto entry::set_user_accesible() -> void { flags |= entry::USER_ACCESSIBLE; }
+
   auto entry::calculate_pointed_to_frame() const -> std::optional<allocator::physical_frame>
   {
     if (contains_flags(PRESENT))
@@ -57,8 +56,7 @@ namespace teachos::arch::memory::paging
     exception_handling::assert((frame.start_address() & ~PHYSICAL_ADDRESS_MASK) == 0,
                                "[Paging Entry] Start address is not aligned with page");
 
-    // TODO: Temporarily make all entries user accessible
-    flags = frame.start_address() | additional_flags.to_ulong() | entry::USER_ACCESSIBLE;
+    flags = frame.start_address() | additional_flags.to_ulong();
   }
 
   auto entry::get_flags() const -> std::bitset<64U> { return flags.to_ulong() & ~PHYSICAL_ADDRESS_MASK; }
diff --git a/arch/x86_64/src/memory/paging/temporary_page.cpp b/arch/x86_64/src/memory/paging/temporary_page.cpp
index 152241d..9946f36 100644
--- a/arch/x86_64/src/memory/paging/temporary_page.cpp
+++ b/arch/x86_64/src/memory/paging/temporary_page.cpp
@@ -4,21 +4,21 @@
 
 namespace teachos::arch::memory::paging
 {
-  auto temporary_page::map_table_frame(allocator::physical_frame frame,
-                                       active_page_table & active_table) -> page_table_handle
+  auto temporary_page::map_table_frame(allocator::physical_frame frame, active_page_table & active_table)
+      -> page_table_handle
   {
     page_table_handle handle{reinterpret_cast<page_table *>(map_to_frame(frame, active_table)),
                              page_table_handle::LEVEL1};
     return handle;
   }
 
-  auto temporary_page::map_to_frame(allocator::physical_frame frame,
-                                    active_page_table & active_table) -> virtual_address
+  auto temporary_page::map_to_frame(allocator::physical_frame frame, active_page_table & active_table)
+      -> virtual_address
   {
     exception_handling::assert(!active_table.translate_page(page).has_value(),
                                "[Temporary page] Page is already mapped");
 
-    active_table.map_page_to_frame(allocator, page, frame, entry::WRITABLE);
+    active_table.map_page_to_frame(allocator, page, frame, entry::WRITABLE | entry::USER_ACCESSIBLE);
     return page.start_address();
   }
 
diff --git a/arch/x86_64/src/user/main.cpp b/arch/x86_64/src/user/main.cpp
index 1d56d2e..3ddcb32 100644
--- a/arch/x86_64/src/user/main.cpp
+++ b/arch/x86_64/src/user/main.cpp
@@ -10,18 +10,6 @@ namespace teachos::arch::user
   [[gnu::section(".user_text")]]
   auto main() -> void
   {
-    // TODO: Remove or replace this wall of text
-    // RFLAGS is saved into R11, RIP of the next instruction into RCX
-    // Required for SYSRETURN to know where to return too.
-    // Additional state needs to be saved by calling convention:
-
-    // Syscall Number: RAX, Return Value: RAX (0 indicating no error, and -1 indicating an error, use as a boolean)
-    // Argument in this order (max 6. no argument on stack): RDI, RSI, RDX, R10, R8, R9
-    // Not used registers: RBX, RSP, R12, R13, R14
-
-    // Actual Source: https://man7.org/linux/man-pages/man2/syscall.2.html More cleare documentation:
-    // https://sys.readthedocs.io/en/latest/doc/05_calling_system_calls.html
-
     char constexpr syscall_message[] = "Successfully entered user mode and wrote to VGA buffer via syscall!";
     auto const error = context_switching::syscall::syscall(context_switching::syscall::type::WRITE,
                                                            {reinterpret_cast<uint64_t>(&syscall_message)});
diff --git a/elf_sections.txt b/elf_sections.txt
deleted file mode 100644
index b46a55f..0000000
--- a/elf_sections.txt
+++ /dev/null
@@ -1,57 +0,0 @@
-There are 26 section headers, starting at offset 0x133308:
-
-Section Headers:
-  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
-  [ 0]                   NULL            0000000000000000 000000 000000 00      0   0  0
-  [ 1] .boot_rodata      PROGBITS        0000000000100000 001000 0000f7 00   A  0   0  8
-  [ 2] .boot_text        PROGBITS        0000000000101000 002000 0001ae 00  AX  0   0 16
-  [ 3] .boot_bss         NOBITS          0000000000102000 0021ae 104000 00  WA  0   0 4096
-  [ 4] .boot_data        PROGBITS        0000000000206000 003000 000004 00  WA  0   0  1
-  [ 5] .init             PROGBITS        0000000000207000 004000 000010 00  AX  0   0  1
-  [ 6] .fini             PROGBITS        0000000000208000 005000 00000b 00  AX  0   0  1
-  [ 7] .text             PROGBITS        0000000000209000 006000 00ced0 00  AX  0   0 32
-  [ 8] .user_text        PROGBITS        0000000000216000 013000 00016c 00  AX  0   0  1
-  [ 9] .rodata           PROGBITS        0000000000217000 014000 000bc3 00   A  0   0 16
-  [10] .ctors            PROGBITS        0000000000218000 015000 000010 00  WA  0   0  8
-  [11] .dtors            PROGBITS        0000000000219000 016000 000010 00  WA  0   0  8
-  [12] .bss              NOBITS          000000000021a000 016010 0004a0 00  WA  0   0 32
-  [13] .data             PROGBITS        000000000021b000 018000 000010 00  WA  0   0  8
-  [14] .debug_line       PROGBITS        0000000000000000 018010 00e784 00      0   0  1
-  [15] .debug_line_str   PROGBITS        0000000000000000 026794 00256f 01  MS  0   0  1
-  [16] .debug_info       PROGBITS        0000000000000000 028d03 063564 00      0   0  1
-  [17] .debug_abbrev     PROGBITS        0000000000000000 08c267 00f2ae 00      0   0  1
-  [18] .debug_aranges    PROGBITS        0000000000000000 09b520 0031b0 00      0   0 16
-  [19] .debug_str        PROGBITS        0000000000000000 09e6d0 0441b3 01  MS  0   0  1
-  [20] .debug_rnglists   PROGBITS        0000000000000000 0e2883 001f06 00      0   0  1
-  [21] .debug_macro      PROGBITS        0000000000000000 0e4789 03471b 00      0   0  1
-  [22] .debug_loclists   PROGBITS        0000000000000000 118ea4 00030f 00      0   0  1
-  [23] .symtab           SYMTAB          0000000000000000 1191b8 005448 18     24 816  8
-  [24] .strtab           STRTAB          0000000000000000 11e600 014c03 00      0   0  1
-  [25] .shstrtab         STRTAB          0000000000000000 133203 000103 00      0   0  1
-Key to Flags:
-  W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
-  L (link order), O (extra OS processing required), G (group), T (TLS),
-  C (compressed), x (unknown), o (OS specific), E (exclude),
-  D (mbind), l (large), p (processor specific)
-
-Elf file type is EXEC (Executable file)
-Entry point 0x101061
-There are 6 program headers, starting at offset 64
-
-Program Headers:
-  Type           Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align
-  LOAD           0x001000 0x0000000000100000 0x0000000000100000 0x0000f7 0x0000f7 R   0x1000
-  LOAD           0x002000 0x0000000000101000 0x0000000000101000 0x0001ae 0x105000 R E 0x1000
-  LOAD           0x003000 0x0000000000206000 0x0000000000206000 0x000004 0x000004 RW  0x1000
-  LOAD           0x004000 0x0000000000207000 0x0000000000207000 0x00f16c 0x00f16c R E 0x1000
-  LOAD           0x015000 0x0000000000218000 0x0000000000218000 0x003010 0x003010 RW  0x1000
-  LOAD           0x014000 0x0000000000217000 0x0000000000217000 0x000bc3 0x000bc3 R   0x1000
-
- Section to Segment mapping:
-  Segment Sections...
-   00     .boot_rodata 
-   01     .boot_text .boot_bss 
-   02     .boot_data 
-   03     .init .fini .text .user_text 
-   04     .ctors .dtors .bss .data 
-   05     .rodata