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-rw-r--r--arch/x86_64/CMakeLists.txt1
-rw-r--r--arch/x86_64/include/arch/memory/heap/global_heap_allocator.hpp7
-rw-r--r--arch/x86_64/include/arch/memory/heap/user_heap_allocator.hpp48
-rw-r--r--arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp2
-rw-r--r--arch/x86_64/src/kernel/main.cpp3
-rw-r--r--arch/x86_64/src/memory/heap/global_heap_allocator.cpp20
-rw-r--r--arch/x86_64/src/memory/heap/user_heap_allocator.cpp55
-rw-r--r--arch/x86_64/src/memory/main.cpp18
-rw-r--r--arch/x86_64/src/user/main.cpp4
9 files changed, 136 insertions, 22 deletions
diff --git a/arch/x86_64/CMakeLists.txt b/arch/x86_64/CMakeLists.txt
index 3d6d2c7..0a6ab9c 100644
--- a/arch/x86_64/CMakeLists.txt
+++ b/arch/x86_64/CMakeLists.txt
@@ -64,6 +64,7 @@ target_sources("_memory" PRIVATE
"src/memory/paging/active_page_table.cpp"
"src/memory/paging/inactive_page_table.cpp"
"src/memory/heap/bump_allocator.cpp"
+ "src/memory/heap/user_heap_allocator.cpp"
"src/memory/heap/memory_block.cpp"
"src/memory/heap/linked_list_allocator.cpp"
"src/memory/heap/global_heap_allocator.cpp"
diff --git a/arch/x86_64/include/arch/memory/heap/global_heap_allocator.hpp b/arch/x86_64/include/arch/memory/heap/global_heap_allocator.hpp
index bfc7b67..d0d1080 100644
--- a/arch/x86_64/include/arch/memory/heap/global_heap_allocator.hpp
+++ b/arch/x86_64/include/arch/memory/heap/global_heap_allocator.hpp
@@ -2,6 +2,7 @@
#define TEACHOS_ARCH_X86_64_MEMORY_HEAP_GLOBAL_HEAP_ALLOCATOR_HPP
#include "arch/memory/heap/heap_allocator.hpp"
+#include "arch/memory/heap/user_heap_allocator.hpp"
namespace teachos::arch::memory::heap
{
@@ -76,7 +77,8 @@ namespace teachos::arch::memory::heap
private:
static heap_allocator * kernel_allocator_instance; ///< Instance used to allocate and deallocate kernel heap memory
- static heap_allocator * user_allocator_instance; ///< Instance used to allocate and deallocate user heap memory
+ static user_heap_allocator *
+ user_allocator_instance; ///< Instance used to allocate and deallocate user heap memory
/**
* @brief Either returns the previously registered heap allocated or halts further execution
@@ -90,7 +92,8 @@ namespace teachos::arch::memory::heap
*
* @return Reference to the registered user heap allocation
*/
- static auto user() -> heap_allocator &;
+ [[gnu::section(".user_text")]]
+ static auto user() -> user_heap_allocator &;
};
} // namespace teachos::arch::memory::heap
diff --git a/arch/x86_64/include/arch/memory/heap/user_heap_allocator.hpp b/arch/x86_64/include/arch/memory/heap/user_heap_allocator.hpp
new file mode 100644
index 0000000..1dab047
--- /dev/null
+++ b/arch/x86_64/include/arch/memory/heap/user_heap_allocator.hpp
@@ -0,0 +1,48 @@
+#ifndef TEACHOS_ARCH_X86_64_MEMORY_HEAP_USER_HEAP_ALLOCATOR_HPP
+#define TEACHOS_ARCH_X86_64_MEMORY_HEAP_USER_HEAP_ALLOCATOR_HPP
+
+#include "arch/memory/heap/heap_allocator.hpp"
+
+#include <atomic>
+#include <cstdint>
+
+namespace teachos::arch::memory::heap
+{
+ /**
+ * @brief Simple heap allocator, which allocates linearly and leaks all allocated memory, because it does not really
+ * deallocate anything.
+ */
+ struct user_heap_allocator
+ {
+ /**
+ * @brief Constructor.
+ *
+ * @param heap_start Start of the allocatable heap area
+ * @param heap_end End of the allocatable heap area (Start + Size)
+ */
+ user_heap_allocator(std::size_t heap_start, std::size_t heap_end)
+ : heap_start{heap_start}
+ , heap_end{heap_end}
+ , next{heap_start}
+ {
+ // Nothing to do
+ }
+
+ auto allocate(std::size_t size) -> void *;
+
+ /**
+ * @copybrief heap_allocator::deallocate
+ *
+ * @note Simply does nothing, because this allocator leaks all memory
+ */
+ auto deallocate(void * pointer) noexcept -> void;
+
+ private:
+ std::size_t heap_start; ///< Start of the allocatable heap area
+ std::size_t heap_end; ///< End of the allocatable heap area
+ std::atomic_uint64_t next; ///< Current address, which is the start of still unused allocatable heap area
+ };
+
+} // namespace teachos::arch::memory::heap
+
+#endif // TEACHOS_ARCH_X86_64_MEMORY_HEAP_USER_HEAP_ALLOCATOR_HPP
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 ce74b98..6459107 100644
--- a/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
+++ b/arch/x86_64/include/arch/memory/paging/kernel_mapper.hpp
@@ -143,7 +143,7 @@ namespace teachos::arch::memory::paging
// statically allocated variables), .boot_rodata (Contains constant data stored in ROM)
// Not required: .text, .rodata, .ctors, .dtors, .bss, .data, .boot_data, .boot_text, .init
if (section.physical_address == 0x100000 || section.physical_address == 0x102000 ||
- section.physical_address == 0x216000)
+ section.physical_address == 0x217000)
{
entry.set_user_accesible();
}
diff --git a/arch/x86_64/src/kernel/main.cpp b/arch/x86_64/src/kernel/main.cpp
index 05c879e..43b5f90 100644
--- a/arch/x86_64/src/kernel/main.cpp
+++ b/arch/x86_64/src/kernel/main.cpp
@@ -63,6 +63,9 @@ namespace teachos::arch::kernel
memory::heap::global_heap_allocator::register_heap_allocator(memory::heap::heap_allocator_type::LINKED_LIST);
// heap_test();
+ auto address = memory::heap::global_heap_allocator::kmalloc(8U);
+ (void)address;
+
context_switching::switch_to_user_mode();
}
} // namespace teachos::arch::kernel
diff --git a/arch/x86_64/src/memory/heap/global_heap_allocator.cpp b/arch/x86_64/src/memory/heap/global_heap_allocator.cpp
index 51f6261..acba02d 100644
--- a/arch/x86_64/src/memory/heap/global_heap_allocator.cpp
+++ b/arch/x86_64/src/memory/heap/global_heap_allocator.cpp
@@ -3,11 +3,12 @@
#include "arch/exception_handling/assert.hpp"
#include "arch/memory/heap/bump_allocator.hpp"
#include "arch/memory/heap/linked_list_allocator.hpp"
+#include "arch/memory/heap/user_heap_allocator.hpp"
namespace teachos::arch::memory::heap
{
heap_allocator * global_heap_allocator::kernel_allocator_instance = nullptr;
- heap_allocator * global_heap_allocator::user_allocator_instance = nullptr;
+ user_heap_allocator * global_heap_allocator::user_allocator_instance = nullptr;
auto global_heap_allocator::kmalloc(std::size_t size) -> void * { return kernel().allocate(size); }
@@ -30,20 +31,17 @@ namespace teachos::arch::memory::heap
case heap_allocator_type::BUMP: {
static bump_allocator kernel_allocator{KERNEL_HEAP_START, KERNEL_HEAP_START + KERNEL_HEAP_SIZE};
kernel_allocator_instance = &kernel_allocator;
-
- static bump_allocator user_allocator{USER_HEAP_START, USER_HEAP_START + USER_HEAP_SIZE};
- user_allocator_instance = &user_allocator;
break;
}
case heap_allocator_type::LINKED_LIST: {
static linked_list_allocator kernel_allocator{KERNEL_HEAP_START, KERNEL_HEAP_START + KERNEL_HEAP_SIZE};
kernel_allocator_instance = &kernel_allocator;
-
- static linked_list_allocator user_allocator{USER_HEAP_START, USER_HEAP_START + USER_HEAP_SIZE};
- user_allocator_instance = &user_allocator;
break;
}
}
+
+ static user_heap_allocator user_allocator{USER_HEAP_START, USER_HEAP_START + USER_HEAP_SIZE};
+ user_allocator_instance = &user_allocator;
}
auto global_heap_allocator::kernel() -> heap_allocator &
@@ -55,11 +53,11 @@ namespace teachos::arch::memory::heap
return *kernel_allocator_instance;
}
- auto global_heap_allocator::user() -> heap_allocator &
+ auto global_heap_allocator::user() -> user_heap_allocator &
{
- exception_handling::assert(user_allocator_instance != nullptr,
- "Attempted to allocate or deallocate using the global_heap_allocator before "
- "register_heap_allocation_type was called.");
+ // exception_handling::assert(user_allocator_instance != nullptr,
+ // "Attempted to allocate or deallocate using the global_heap_allocator before "
+ // "register_heap_allocation_type was called.");
return *user_allocator_instance;
}
diff --git a/arch/x86_64/src/memory/heap/user_heap_allocator.cpp b/arch/x86_64/src/memory/heap/user_heap_allocator.cpp
new file mode 100644
index 0000000..f09811d
--- /dev/null
+++ b/arch/x86_64/src/memory/heap/user_heap_allocator.cpp
@@ -0,0 +1,55 @@
+#include "arch/memory/heap/user_heap_allocator.hpp"
+
+#include "arch/exception_handling/assert.hpp"
+
+#include <limits>
+#include <type_traits>
+
+namespace teachos::arch::memory::heap
+{
+ namespace
+ {
+ template<typename T>
+ [[gnu::section(".user_text")]]
+ auto saturating_add(T x, T y) -> T
+ requires std::is_unsigned_v<T>
+ {
+ if (x > std::numeric_limits<T>::max() - y)
+ {
+ return std::numeric_limits<T>::max();
+ }
+ T result = x + y;
+ return result;
+ }
+ } // namespace
+
+ auto user_heap_allocator::allocate(std::size_t size) -> void *
+ {
+ // Reading the value only has to be done once, because compare_exchange_weak updates the value as well if the
+ // exchange failed, becuase the value was not the expected one.
+ auto alloc_start = next.load(std::memory_order::relaxed);
+ // Repeat allocation until it succeeds, has to be done, because another allocator could overtake it at any time
+ // causing the value to differ and the calculation to have to be redone.
+ for (;;)
+ {
+ auto const alloc_end = saturating_add(alloc_start, size);
+ arch::exception_handling::assert(alloc_end <= heap_end, "[Heap Allocator] Out of memory");
+ // Check if the atomic value is still the one initally loaded, if it isn't we have been overtaken by another
+ // thread and need to redo the calculation. Spurious failure by weak can be ignored, because the whole allocation
+ // is wrapped in an infinite for loop so a failure that wasn't actually one will simply be retried until it works.
+ auto const updated = next.compare_exchange_weak(alloc_start, alloc_end, std::memory_order::relaxed);
+ if (updated)
+ {
+ return reinterpret_cast<void *>(alloc_start);
+ }
+ }
+ }
+
+ auto user_heap_allocator::deallocate(void * pointer) noexcept -> void
+ {
+ if (pointer)
+ {
+ }
+ }
+
+} // namespace teachos::arch::memory::heap
diff --git a/arch/x86_64/src/memory/main.cpp b/arch/x86_64/src/memory/main.cpp
index 558fbce..4cdfa80 100644
--- a/arch/x86_64/src/memory/main.cpp
+++ b/arch/x86_64/src/memory/main.cpp
@@ -20,18 +20,23 @@ namespace teachos::arch::memory
}
template<allocator::FrameAllocator T>
- auto remap_heap(T & allocator, paging::active_page_table & active_table) -> void
+ auto remap_heap(T & allocator, paging::active_page_table & active_table, bool is_user_heap = false) -> void
{
- auto const start_page = paging::virtual_page::containing_address(heap::KERNEL_HEAP_START);
- auto const end_page =
- ++(paging::virtual_page::containing_address(heap::KERNEL_HEAP_START + heap::KERNEL_HEAP_SIZE - 1));
+ auto const heap_start = is_user_heap ? heap::USER_HEAP_START : heap::KERNEL_HEAP_START;
+ auto const heap_size = is_user_heap ? heap::USER_HEAP_SIZE : heap::KERNEL_HEAP_SIZE;
+
+ auto const start_page = paging::virtual_page::containing_address(heap_start);
+ auto const end_page = ++(paging::virtual_page::containing_address(heap_start + heap_size - 1));
paging::page_container::iterator const begin{start_page};
paging::page_container::iterator const end{end_page};
paging::page_container const pages{begin, end};
+ constexpr auto base_flags = paging::entry::WRITABLE;
+ auto const flags = is_user_heap ? base_flags | paging::entry::USER_ACCESSIBLE : base_flags;
+
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, flags);
}
}
} // namespace
@@ -54,7 +59,8 @@ namespace teachos::arch::memory
video::vga::text::write("Kernel remapping successful", video::vga::text::common_attributes::green_on_black);
video::vga::text::newline();
- remap_heap(allocator, active_table);
+ remap_heap(allocator, active_table); // Remap kernel heap
+ remap_heap(allocator, active_table, true); // Remap user heap
video::vga::text::write("Heap remapping successful", video::vga::text::common_attributes::green_on_black);
video::vga::text::newline();
}
diff --git a/arch/x86_64/src/user/main.cpp b/arch/x86_64/src/user/main.cpp
index 4f6e688..59647f8 100644
--- a/arch/x86_64/src/user/main.cpp
+++ b/arch/x86_64/src/user/main.cpp
@@ -17,8 +17,8 @@ namespace teachos::arch::user
// kernel::cpu::clear_interrupt_flag(); // Causes crash Kernel Code (.text) is not mapped in User mMde
- auto test = memory::heap::global_heap_allocator::malloc(20U);
- (void)test;
+ auto address = memory::heap::global_heap_allocator::malloc(8U);
+ (void)address;
// auto test = new int{20}; // Causes crash Heap is not mapped in User Mode
// (void)test;
generated by cgit v1.2.3 (git 2.25.1) at 2026-04-19 10:46:23 +0000