frame.c File Reference

#include <stdbool.h>
#include <stddef.h>
#include <string.h>
#include "mm/kalloc.h"
#include "kernel/limine_responses.h"
#include "kernel/panic.h"
#include "mm/frame.h"

Data Structures
struct	frame
	Metadata for a physical frame. More...

Functions
static bool	limine_entry_type_maybe_usable (uint64_t type)
	Check if a Limine memmap entry type is either usable (now) or reclaimable.
size_t	pfn_to_phys (size_t pfn)
	Converts a PFN to a physical address.
struct frame *	alloc_frame (const char *identifier)
	Allocates a frame and returns a pointer to it. The allocated frame will be zeroed out.
void	free_frame (struct frame *frame)
	Frees a frame.
size_t	frame_to_pfn (struct frame *frame)
	Returns the PFN of a frame.
static void	memmap_count_init (const struct limine_memmap_response *memmap_response)
	Counting the number of usable frames in the Limine memory map response to initialize memmap_count
static void	find_memmap_base (const struct limine_memmap_response *memmap_response)
	Finds a suitable place in memory to place our own memmap, and initializes memmap, memmap_start_phys, and memmap_end_phys.
void	memmap_init (const struct limine_memmap_response *memmap_response)
	Initializes the array of memmap entries and the free frame linked list based on the Limine memory map response.
void	frame_init ()
	Initializes the frame allocator and memory map.

Variables
static struct frame *	memmap
	Array of physical frame metadata, indexed by PFN.
static size_t	memmap_count
	Number of frames in memmap.
static size_t	memmap_start_phys = 0
	Physical address start of memmap, inclusive. Page aligned.
static size_t	memmap_end_phys = 0
	Physical address end of memmap, exclusive. Page aligned.
static struct frame *	free_frame_list
	Pointer to the head of the free frame linked list.
static const char *const	limine_memmap_entry_type_to_string []
	String representations of Limine memmap entry types for debugging purposes.

Function Documentation

alloc_frame()

struct frame * alloc_frame

(

const char *

identifier

)

Allocates a frame and returns a pointer to it. The allocated frame will be zeroed out.

Parameters

identifier

A string identifier for the frame (for debugging purposes).

Returns

A pointer to the allocated frame.

find_memmap_base()

static void find_memmap_base ( const struct limine_memmap_response *  memmap_response )

static

Finds a suitable place in memory to place our own memmap, and initializes memmap, memmap_start_phys, and memmap_end_phys.

frame_init()

void frame_init

(

)

Initializes the frame allocator and memory map.

frame_to_pfn()

size_t frame_to_pfn

(

struct frame *

frame

)

Returns the PFN of a frame.

Parameters

frame

A pointer to the frame.

Returns

The PFN of the frame.

free_frame()

void free_frame

(

struct frame *

frame

)

Frees a frame.

Parameters

frame

A pointer to the frame to free.

Note

The frame will only be truly freed if its reference count drops to 0.

limine_entry_type_maybe_usable()

static bool limine_entry_type_maybe_usable ( uint64_t  type )

static

Check if a Limine memmap entry type is either usable (now) or reclaimable.

Parameters

type	The Limine memmap entry type to check.

Returns

true if the entry type is maybe usable, false otherwise.

memmap_count_init()

static void memmap_count_init ( const struct limine_memmap_response *  memmap_response )

static

Counting the number of usable frames in the Limine memory map response to initialize memmap_count

memmap_init()

void memmap_init

(

const struct limine_memmap_response *

memmap_response

)

Initializes the array of memmap entries and the free frame linked list based on the Limine memory map response.

pfn_to_phys()

size_t pfn_to_phys

(

size_t

pfn

)

Converts a PFN to a physical address.

Parameters

pfn	The PFN to convert.

Returns

The physical address.

Variable Documentation

free_frame_list

struct frame* free_frame_list

static

Pointer to the head of the free frame linked list.

limine_memmap_entry_type_to_string

const char* const limine_memmap_entry_type_to_string[]

static

Initial value:

= {
        [LIMINE_MEMMAP_USABLE] = "usable",
        [LIMINE_MEMMAP_RESERVED] = "reserved",
        [LIMINE_MEMMAP_ACPI_RECLAIMABLE] = "acpi reclaimable",
        [LIMINE_MEMMAP_ACPI_NVS] = "acpi nvs",
        [LIMINE_MEMMAP_BAD_MEMORY] = "bad memory",
        [LIMINE_MEMMAP_BOOTLOADER_RECLAIMABLE] = "bootloader reclaimable",
        [LIMINE_MEMMAP_EXECUTABLE_AND_MODULES] = "executable and modules",
        [LIMINE_MEMMAP_FRAMEBUFFER] = "framebuffer",
        [LIMINE_MEMMAP_ACPI_TABLES] = "acpi tables",
}

String representations of Limine memmap entry types for debugging purposes.

memmap

struct frame* memmap

static

Array of physical frame metadata, indexed by PFN.

memmap_count

size_t memmap_count

static

Number of frames in memmap.

memmap_end_phys

size_t memmap_end_phys = 0

static

Physical address end of memmap, exclusive. Page aligned.

memmap_start_phys

size_t memmap_start_phys = 0

static

Physical address start of memmap, inclusive. Page aligned.