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Kernel: Invoke heap constructors separately early on

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By having a separate list of constructors for the kernel heap
code, we can properly use constructors without re-running them
after the heap was already initialized. This solves some problems
where values were wiped out because they were overwritten by
running their constructors later in the initialization process.
This commit is contained in:
Tom 2020-08-10 09:44:35 -06:00 committed by Andreas Kling
parent de5e542930
commit 08ff25f4ef
4 changed files with 20 additions and 8 deletions
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12
Kernel/CMakeLists.txt
View file

@ -1,3 +1,8 @@
set(KERNEL_HEAP_SOURCES
Heap/SlabAllocator.cpp
Heap/kmalloc.cpp
)
set(KERNEL_SOURCES
ACPI/DynamicParser.cpp
ACPI/Initialize.cpp
@ -47,8 +52,6 @@ set(KERNEL_SOURCES
FileSystem/ProcFS.cpp
FileSystem/TmpFS.cpp
FileSystem/VirtualFileSystem.cpp
Heap/SlabAllocator.cpp
Heap/kmalloc.cpp
Interrupts/APIC.cpp
Interrupts/GenericInterruptHandler.cpp
Interrupts/IOAPIC.cpp
@ -244,6 +247,7 @@ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -nostdlib -nostdinc -nostdinc++")
add_link_options(LINKER:-T ${CMAKE_CURRENT_BINARY_DIR}/linker.ld -nostdlib)
add_library(boot OBJECT Arch/i386/Boot/boot.S)
add_library(kernel_heap STATIC ${KERNEL_HEAP_SOURCES})
file(GENERATE OUTPUT linker.ld INPUT linker.ld)
if (${CMAKE_HOST_SYSTEM_NAME} MATCHES SerenityOS)
@ -255,8 +259,8 @@ else()
endif()
add_executable(Kernel ${SOURCES})
target_link_libraries(Kernel gcc stdc++)
add_dependencies(Kernel boot)
target_link_libraries(Kernel kernel_heap gcc stdc++)
add_dependencies(Kernel boot kernel_heap)
install(TARGETS Kernel RUNTIME DESTINATION boot)
add_custom_command(

7
Kernel/Heap/SlabAllocator.cpp
View file

@ -100,12 +100,11 @@ private:
char padding[templated_slab_size - sizeof(FreeSlab*)];
};
// NOTE: These are not default-initialized to prevent an init-time constructor from overwriting them
FreeSlab* m_freelist;
FreeSlab* m_freelist { nullptr };
Atomic<size_t> m_num_allocated;
Atomic<size_t> m_num_free;
void* m_base;
void* m_end;
void* m_base { nullptr };
void* m_end { nullptr };
SpinLock<u32> m_lock;
static_assert(sizeof(FreeSlab) == templated_slab_size);

5
Kernel/init.cpp
View file

@ -76,6 +76,8 @@
// Defined in the linker script
typedef void (*ctor_func_t)();
extern ctor_func_t start_heap_ctors;
extern ctor_func_t end_heap_ctors;
extern ctor_func_t start_ctors;
extern ctor_func_t end_ctors;
@ -107,6 +109,9 @@ extern "C" [[noreturn]] void init()
s_bsp_processor.early_initialize(0);
// Invoke the constructors needed for the kernel heap
for (ctor_func_t* ctor = &start_heap_ctors; ctor < &end_heap_ctors; ctor++)
(*ctor)();
kmalloc_init();
slab_alloc_init();

4
Kernel/linker.ld
View file

@ -18,6 +18,10 @@ SECTIONS
.rodata ALIGN(4K) : AT (ADDR(.rodata) - 0xc0000000)
{
start_heap_ctors = .;
*libkernel_heap.a:*(.ctors)
end_heap_ctors = .;
start_ctors = .;
*(.ctors)
end_ctors = .;