banan-os/kernel/include/kernel/Memory/PageTable.h

126 lines
3.0 KiB
C++

#pragma once
#include <BAN/Errors.h>
#include <BAN/Traits.h>
#include <kernel/CriticalScope.h>
#include <kernel/Memory/Types.h>
#include <kernel/SpinLock.h>
namespace Kernel
{
template<typename F>
concept with_fast_page_callback = requires(F func)
{
requires BAN::is_same_v<decltype(func()), void>;
};
class PageTable
{
public:
using flags_t = uint16_t;
enum Flags : flags_t
{
Present = (1 << 0),
ReadWrite = (1 << 1),
UserSupervisor = (1 << 2),
CacheDisable = (1 << 4),
Reserved = (1 << 9),
Execute = (1 << 15),
Used = Present | Reserved,
};
public:
static void initialize();
static PageTable& kernel();
static PageTable& current();
static void map_fast_page(paddr_t);
static void unmap_fast_page();
static constexpr vaddr_t fast_page() { return KERNEL_OFFSET; }
template<with_fast_page_callback F>
static void with_fast_page(paddr_t paddr, F callback)
{
CriticalScope _;
map_fast_page(paddr);
callback();
unmap_fast_page();
}
// FIXME: implement sized checks, return span, etc
static void* fast_page_as_ptr(size_t offset = 0)
{
ASSERT(offset <= PAGE_SIZE);
return reinterpret_cast<void*>(fast_page() + offset);
}
template<typename T>
static T& fast_page_as(size_t offset = 0)
{
ASSERT(offset + sizeof(T) <= PAGE_SIZE);
return *reinterpret_cast<T*>(fast_page() + offset);
}
// Retrieves index'th element from fast_page
template<typename T>
static T& fast_page_as_sized(size_t index)
{
ASSERT((index + 1) * sizeof(T) <= PAGE_SIZE);
return *reinterpret_cast<T*>(fast_page() + index * sizeof(T));
}
static bool is_valid_pointer(uintptr_t);
static BAN::ErrorOr<PageTable*> create_userspace();
~PageTable();
void unmap_page(vaddr_t);
void unmap_range(vaddr_t, size_t bytes);
void map_range_at(paddr_t, vaddr_t, size_t bytes, flags_t);
void map_page_at(paddr_t, vaddr_t, flags_t);
paddr_t physical_address_of(vaddr_t) const;
flags_t get_page_flags(vaddr_t) const;
bool is_page_free(vaddr_t) const;
bool is_range_free(vaddr_t, size_t bytes) const;
bool reserve_page(vaddr_t, bool only_free = true);
bool reserve_range(vaddr_t, size_t bytes, bool only_free = true);
vaddr_t reserve_free_page(vaddr_t first_address, vaddr_t last_address = UINTPTR_MAX);
vaddr_t reserve_free_contiguous_pages(size_t page_count, vaddr_t first_address, vaddr_t last_address = UINTPTR_MAX);
void load();
void lock() const { m_lock.lock(); }
void unlock() const { m_lock.unlock(); }
void debug_dump();
private:
PageTable() = default;
uint64_t get_page_data(vaddr_t) const;
void initialize_kernel();
void map_kernel_memory();
void prepare_fast_page();
static void invalidate(vaddr_t);
private:
paddr_t m_highest_paging_struct { 0 };
mutable RecursiveSpinLock m_lock;
};
static constexpr size_t range_page_count(vaddr_t start, size_t bytes)
{
size_t first_page = start / PAGE_SIZE;
size_t last_page = BAN::Math::div_round_up<size_t>(start + bytes, PAGE_SIZE);
return last_page - first_page;
}
}