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Switch page_manager to use frame_allocator.

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Removed the frame allocation logic from page_manager and replaced it
with using an instance of frame_allocator instead. This had several
major ripple effects:

- memory_initalize() had to change to support this new world
  - Where to map used blocks is now passed as a flag, since blocks don't
    track their virtual address anymore
  - Instead of the complicated "find N contiguous pages that can be
    mapped in with one page table", we now just have the bootloader give
    us some (currently 64) pages to use both for tables and scratch
    space.
  - frame_allocator initialization was split into two steps to allow
    mapping used blocks before std::move()ing them over
This commit is contained in:
Justin C. Miller
2019-02-26 22:56:14 -08:00
parent 626eec4a31
commit 8cdc39fdee
13 changed files with 286 additions and 784 deletions
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131
src/kernel/page_manager.h
View File

@@ -6,17 +6,14 @@
#include <stdint.h>
#include "kutil/enum_bitfields.h"
#include "kutil/frame_allocator.h"
#include "kutil/linked_list.h"
#include "kutil/slab_allocator.h"
struct page_block;
struct page_table;
struct free_page_header;
using page_block_list = kutil::linked_list<page_block>;
using page_block_slab = kutil::slab_allocator<page_block>;
/// Manager for allocation of physical pages.
/// Manager for allocation and mapping of pages
class page_manager
{
public:
@@ -35,7 +32,7 @@ public:
/// Initial process thread's stack size, in pages
static const unsigned initial_stack_pages = 1;
page_manager();
page_manager(kutil::frame_allocator &frames);
/// Helper to get the number of pages needed for a given number of bytes.
/// \arg bytes The number of bytes desired
@@ -78,13 +75,6 @@ public:
/// \returns A pointer to the start of the mapped region
void * map_pages(uintptr_t address, size_t count, bool user = false, page_table *pml4 = nullptr);
/// Allocate and map contiguous pages into virtual memory, with
/// a constant offset from their physical address.
/// \arg count The number of pages to map
/// \returns A pointer to the start of the mapped region, or
/// nullptr if no region could be found to fit the request.
void * map_offset_pages(size_t count);
/// Unmap existing pages from memory.
/// \arg address The virtual address of the memory to unmap
/// \arg count The number of pages to unmap
@@ -111,10 +101,6 @@ public:
return kutil::offset_pointer(reinterpret_cast<void *>(a), page_offset);
}
/// Log the current free/used block lists.
/// \arg used_only If true, skip printing free list. Default false.
void dump_blocks(bool used_only = false);
/// Dump the given or current PML4 to the console
/// \arg pml4 The page table to use, null for the current one
/// \arg max_index The max index of pml4 to print
@@ -125,20 +111,6 @@ public:
static page_manager * get();
private:
/// Set up the memory manager from bootstraped memory
void init(
page_block_list free,
page_block_list used,
page_block_list cache);
/// Create a `page_block` struct or pull one from the cache.
/// \returns An empty `page_block` struct
page_block * get_block();
/// Return a list of `page_block` structs to the cache.
/// \arg block A list of `page_block` structs
void free_blocks(page_block *block);
/// Allocate a page for a page table, or pull one from the cache
/// \returns An empty page mapped in page space
page_table * get_table_page();
@@ -148,10 +120,6 @@ private:
/// \arg count Number of pages in the range
void free_table_pages(void *pages, size_t count);
/// Consolidate the free and used block lists. Return freed blocks
/// to the cache.
void consolidate_blocks();
/// Helper function to allocate a new page table. If table entry `i` in
/// table `base` is empty, allocate a new page table and point `base[i]` at
/// it.
@@ -182,23 +150,11 @@ private:
uintptr_t virt_addr,
size_t count);
/// Get free pages from the free list. Only pages from the first free block
/// are returned, so the number may be less than requested, but they will
/// be contiguous. Pages will not be mapped into virtual memory.
/// \arg count The maximum number of pages to get
/// \arg address [out] The address of the first page
/// \returns The number of pages retrieved
size_t pop_pages(size_t count, uintptr_t *address);
page_table *m_kernel_pml4; ///< The PML4 of just kernel pages
page_block_list m_free; ///< Free pages list
page_block_list m_used; ///< In-use pages list
page_block_slab m_block_slab; ///< page_block slab allocator
free_page_header *m_page_cache; ///< Cache of free pages to use for tables
kutil::frame_allocator &m_frames;
friend void memory_initialize(const void *, size_t, size_t);
friend void memory_initialize(uint16_t, const void *, size_t, size_t);
page_manager(const page_manager &) = delete;
};
@@ -207,67 +163,6 @@ extern page_manager g_page_manager;
inline page_manager * page_manager::get() { return &g_page_manager; }
/// Flags used by `page_block`.
enum class page_block_flags : uint32_t
{
free = 0x00000000, ///< Not a flag, value for free memory
used = 0x00000001, ///< Memory is in use
mapped = 0x00000002, ///< Memory is mapped to virtual address
mmio = 0x00000010, ///< Memory is a MMIO region
nonvolatile = 0x00000020, ///< Memory is non-volatile storage
pending_free = 0x10000000, ///< Memory should be freed
acpi_wait = 0x40000000, ///< Memory should be freed after ACPI init
permanent = 0x80000000, ///< Memory is permanently unusable
max_flags
};
IS_BITFIELD(page_block_flags);
/// A block of contiguous pages. Each `page_block` represents contiguous
/// physical pages with the same attributes. A `page_block *` is also a
/// linked list of such structures.
struct page_block
{
uintptr_t physical_address;
uintptr_t virtual_address;
uint32_t count;
page_block_flags flags;
inline bool has_flag(page_block_flags f) const { return bitfield_has(flags, f); }
inline uintptr_t physical_end() const { return physical_address + (count * page_manager::page_size); }
inline uintptr_t virtual_end() const { return virtual_address + (count * page_manager::page_size); }
inline bool contains(uintptr_t vaddr) const { return vaddr >= virtual_address && vaddr < virtual_end(); }
inline bool contains_physical(uintptr_t addr) const { return addr >= physical_address && addr < physical_end(); }
/// Helper to zero out a block and optionally set the next pointer.
void zero();
/// Helper to copy a bock from another block
/// \arg other The block to copy from
void copy(page_block *other);
/// Compare two blocks by address.
/// \arg rhs The right-hand comparator
/// \returns <0 if this is sorts earlier, >0 if this sorts later, 0 for equal
int compare(const page_block *rhs) const;
/// Traverse the list, joining adjacent blocks where possible.
/// \arg list The list to consolidate
/// \returns A linked list of freed page_block structures.
static page_block_list consolidate(page_block_list &list);
/// Traverse the list, printing debug info on this list.
/// \arg list The list to print
/// \arg name [optional] String to print as the name of this list
/// \arg show_permanent [optional] If false, hide unmapped blocks
static void dump(const page_block_list &list, const char *name = nullptr, bool show_unmapped = false);
};
/// Struct to allow easy accessing of a memory page being used as a page table.
struct page_table
@@ -293,19 +188,19 @@ struct page_table
/// Helper struct for computing page table indices of a given address.
struct page_table_indices
{
page_table_indices(uint64_t v = 0) :
index{
(v >> 39) & 0x1ff,
(v >> 30) & 0x1ff,
(v >> 21) & 0x1ff,
(v >> 12) & 0x1ff }
{}
page_table_indices(uint64_t v = 0);
uintptr_t addr() const;
inline operator uintptr_t() const { return addr(); }
/// Get the index for a given level of page table.
uint64_t & operator[](size_t i) { return index[i]; }
uint64_t operator[](size_t i) const { return index[i]; }
uint64_t index[4]; ///< Indices for each level of tables.
};
bool operator==(const page_table_indices &l, const page_table_indices &r);
/// Calculate a page-aligned address.
/// \arg p The address to align.
@@ -336,4 +231,4 @@ inline size_t page_count(size_t n) { return ((n - 1) / page_manager::page_size)
/// Bootstrap the memory managers.
void memory_initialize(const void *memory_map, size_t map_length, size_t desc_length);
void memory_initialize(uint16_t scratch_pages, const void *memory_map, size_t map_length, size_t desc_length);