Memory Management

Memory management functions and structures. More...

Collaboration diagram for Memory Management:

Topics
	Paging
	A platform-independent interface to map/unmap virtual memory to physical memory.
	Physical Memory Manager
	Allocate/free the physical memory, in the form of physical frames.

Classes
struct	pagefault_t
struct	vmap_t

Macros
#define	pfn_va(pfn)
#define	va_pfn(va)
#define	va_phyframe(va)
#define	phyframe_va(frame)
#define	pa_va(pa)
#define	mm_free_page(frame)
#define	mm_free_pages(frame, npages)

Typedefs
typedef vmfault_result_t(*	vmfault_handler_t) (vmap_t *vmap, ptr_t fault_addr, pagefault_t *info)

Enumerations
enum	vmap_content_t {   VMAP_UNKNOWN = 0 , VMAP_STACK , VMAP_FILE , VMAP_MMAP ,   VMAP_DMA }
enum	vmap_type_t { VMAP_TYPE_PRIVATE = MMAP_PRIVATE , VMAP_TYPE_SHARED = MMAP_SHARED }
enum	vmfault_result_t {   VMFAULT_COMPLETE , VMFAULT_MAP_BACKING_PAGE_RO , VMFAULT_MAP_BACKING_PAGE , VMFAULT_COPY_BACKING_PAGE ,   VMFAULT_CANNOT_HANDLE = 0xff }

Functions
phyframe_t *	mm_get_free_page (void)
phyframe_t *	mm_get_free_page_raw (void)
phyframe_t *	mm_get_free_pages (size_t npages)
MMContext *	mm_create_context (void)
	Create a user-mode platform-dependent page table.
void	mm_destroy_context (MMContext *table)
	Destroy a user-mode platform-dependent page table.
void	mm_lock_context_pair (MMContext *ctx1, MMContext *ctx2=nullptr)
	Lock and unlock a pair of MMContext objects.
void	mm_unlock_context_pair (MMContext *ctx1, MMContext *ctx2=nullptr)
__nodiscard MMContext *	mm_switch_context (MMContext *new_ctx)
vmap_t *	vmap_create (MMContext *mmctx, ptr_t vaddr, size_t npages)
	Create a vmap object and insert it into the address space.
void	vmap_destroy (vmap_t *vmap)
	Destroy a vmap object, and unmmap the region.
vmap_t *	vmap_obtain (MMContext *mmctx, ptr_t vaddr, size_t *out_offset=nullptr)
	Get the vmap object for a virtual address.
vmap_t *	vmap_split (vmap_t *vmap, size_t split)
	Split a vmap object into two, at the specified offset.
vmap_t *	vmap_split_for_range (vmap_t *vmap, size_t rstart_pgoff, size_t rend_pgoff)
	Split a vmap to get a vmap object for a range of pages.
void	vmap_finalise_init (vmap_t *vmap, vmap_content_t content, vmap_type_t type)
	Finalize the initialization of a vmap object.
vmfault_result_t	mm_resolve_cow_fault (vmap_t *vmap, ptr_t fault_addr, pagefault_t *info)
	Helper function to resolve a copy-on-write fault.
void	mm_handle_fault (ptr_t fault_addr, pagefault_t *info)
	Handle a page fault.

Detailed Description

Memory management functions and structures.

Macro Definition Documentation

pfn_va

#define pfn_va

(

pfn

)

Value:

((ptr_t) (platform_info->direct_map_base + (pfn) * (MOS_PAGE_SIZE)))

Definition at line 83 of file mm.hpp.

Referenced by dmabuf_share(), dmabuf_unshare(), initrd_read(), platform_pml2e_get_pml1(), platform_pml3e_get_pml2(), platform_pml4e_get_pml3(), platform_startup_setup_kernel_mm(), pmm_init(), and x86_setup_direct_map().

va_pfn

#define va_pfn

(

va

)

Value:

((((ptr_t) (va)) - platform_info->direct_map_base) / MOS_PAGE_SIZE)

Definition at line 84 of file mm.hpp.

Referenced by limine_entry(), pml2_traverse(), and pml2e_get_or_create_pml1().

va_phyframe

#define va_phyframe

(

va

)

Value:

(&phyframes[va_pfn(va)])

Definition at line 85 of file mm.hpp.

Referenced by __destroy_page_table(), pipe_close_one_end(), slab_impl_free_page(), and thread_destroy().

phyframe_va

#define phyframe_va

(

frame

)

Value:

((ptr_t) pfn_va(phyframe_pfn(frame)))

Definition at line 86 of file mm.hpp.

Referenced by __create_page_table(), cpio_fill_cache(), dmabuf_do_allocate(), mm_copy_page(), mm_get_free_page(), pipe_create(), process_do_fork(), register_sysfs_acpi_node(), register_sysfs_acpi_rsdp(), slab_impl_new_page(), sysfs_expand_buffer(), sysfs_fops_read(), sysfs_printf(), sysfs_put_data(), thread_new(), userfs_inode_cache_fill_cache(), userfs_inode_cache_flush_page(), vfs_read_pagecache(), vfs_write_pagecache(), and zero_page().

pa_va

#define pa_va

(

pa

)

Value:

((ptr_t) (pa) + platform_info->direct_map_base)

Definition at line 87 of file mm.hpp.

Referenced by do_handle_sdt_header(), do_iterate_sdts(), ioapic_init(), lapic_memory_setup(), platform_get_unix_timestamp(), platform_shutdown(), and platform_startup_late().

mm_free_page

#define mm_free_page

(

frame

)

Value:

pmm_free_frames(frame, 1)

Definition at line 93 of file mm.hpp.

Referenced by __destroy_page_table().

mm_free_pages

#define mm_free_pages	(		frame,
			npages )

Value:

pmm_free_frames(frame, npages)

Definition at line 94 of file mm.hpp.

Referenced by pipe_close_one_end(), slab_impl_free_page(), sysfs_expand_buffer(), sysfs_fops_release(), and thread_destroy().

Typedef Documentation

vmfault_handler_t

typedef vmfault_result_t(* vmfault_handler_t) (vmap_t *vmap, ptr_t fault_addr, pagefault_t *info)

Definition at line 57 of file mm.hpp.

Enumeration Type Documentation

vmap_content_t

enum vmap_content_t

Enumerator
VMAP_UNKNOWN
VMAP_STACK
VMAP_FILE
VMAP_MMAP
VMAP_DMA

Definition at line 22 of file mm.hpp.

vmap_type_t

enum vmap_type_t

Enumerator
VMAP_TYPE_PRIVATE
VMAP_TYPE_SHARED

Definition at line 31 of file mm.hpp.

vmfault_result_t

enum vmfault_result_t

Enumerator
VMFAULT_COMPLETE	no further action is needed, the page is correctly mapped now
VMFAULT_MAP_BACKING_PAGE_RO	the caller should map the backing page into the faulting address, and mark it non-writable
VMFAULT_MAP_BACKING_PAGE	the caller should map the backing page into the faulting address
VMFAULT_COPY_BACKING_PAGE	the caller should copy the backing page into the faulting address
VMFAULT_CANNOT_HANDLE	the handler cannot handle this fault

Definition at line 46 of file mm.hpp.

Function Documentation

mm_get_free_page()

phyframe_t * mm_get_free_page

(

void

)

Definition at line 38 of file mm.cpp.

Referenced by __create_page_table(), cow_zod_fault_handler(), cpio_fill_cache(), mm_handle_fault(), mm_resolve_cow_fault(), tmpfs_fill_cache(), userfs_inode_cache_fill_cache(), and zero_page().

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mm_get_free_page_raw()

phyframe_t * mm_get_free_page_raw

(

void

)

Definition at line 26 of file mm.cpp.

Referenced by mm_get_free_page().

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mm_get_free_pages()

phyframe_t * mm_get_free_pages

(

size_t

npages

)

Definition at line 47 of file mm.cpp.

Referenced by pipe_create(), process_do_fork(), register_sysfs_acpi_node(), register_sysfs_acpi_rsdp(), slab_impl_new_page(), sysfs_expand_buffer(), and thread_new().

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mm_create_context()

MMContext * mm_create_context

(

void

)

Create a user-mode platform-dependent page table.

Returns

MMContext The created page table.

Note

A platform-independent page-map is also created.

Definition at line 59 of file mm.cpp.

Referenced by Process::Process().

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mm_destroy_context()

void mm_destroy_context

(

MMContext *

table

)

Destroy a user-mode platform-dependent page table.

Parameters

table

The page table to destroy.

Note

The platform-independent page-map is also destroyed.

Definition at line 75 of file mm.cpp.

Referenced by process_destroy().

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mm_lock_context_pair()

void mm_lock_context_pair	(	MMContext *	ctx1,
		MMContext *	ctx2 = nullptr )

Lock and unlock a pair of MMContext objects.

Parameters

ctx1	The first context
ctx2	The second context

Definition at line 87 of file mm.cpp.

Referenced by mm_handle_fault(), mmap_file(), process_do_fork(), and thread_new().

mm_unlock_context_pair()

void mm_unlock_context_pair	(	MMContext *	ctx1,
		MMContext *	ctx2 = nullptr )

Definition at line 105 of file mm.cpp.

Referenced by mm_handle_fault(), mmap_file(), process_do_fork(), and thread_new().

mm_switch_context()

__nodiscard MMContext * mm_switch_context

(

MMContext *

new_ctx

)

Definition at line 124 of file mm.cpp.

Referenced by elf_do_fill_process(), and reschedule().

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vmap_create()

vmap_t * vmap_create	(	MMContext *	mmctx,
		ptr_t	vaddr,
		size_t	npages )

Create a vmap object and insert it into the address space.

Parameters

mmctx	The address space
vaddr	Starting virtual address of the region
npages	Number of pages in the region

Returns

vmap_t* The created vmap object, with its lock held for further initialization.

Definition at line 156 of file mm.cpp.

Referenced by mm_get_free_vaddr_locked().

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vmap_destroy()

void vmap_destroy

(

vmap_t *

vmap

)

Destroy a vmap object, and unmmap the region.

Parameters

vmap	The vmap object

Note

The vmap object will be freed.

Definition at line 168 of file mm.cpp.

Referenced by dmabuf_free(), mmap_file(), munmap(), process_destroy(), process_do_execveat(), and thread_destroy().

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vmap_obtain()

vmap_t * vmap_obtain	(	MMContext *	mmctx,
		ptr_t	vaddr,
		size_t *	out_offset = nullptr )

Get the vmap object for a virtual address.

Parameters

mmctx	The address space to search
vaddr	The virtual address
out_offset	An optional pointer to receive the offset of the address in the vmap

Returns

vmap_t* The vmap object, or NULL if not found, with its lock held.

Definition at line 189 of file mm.cpp.

Referenced by dmabuf_free(), mm_handle_fault(), munmap(), thread_destroy(), thread_new(), vm_protect(), and x86_dump_stack_at().

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vmap_split()

vmap_t * vmap_split	(	vmap_t *	vmap,
		size_t	split )

Split a vmap object into two, at the specified offset.

Parameters

vmap	The vmap object
split	The number of pages in the first vmap object

Returns

vmap_t* The second vmap object, with its lock held.

Definition at line 209 of file mm.cpp.

Referenced by thread_new(), vm_protect(), and vmap_split_for_range().

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vmap_split_for_range()

vmap_t * vmap_split_for_range	(	vmap_t *	vmap,
		size_t	rstart_pgoff,
		size_t	rend_pgoff )

Split a vmap to get a vmap object for a range of pages.

Parameters

vmap	The vmap object to split
rstart_pgoff	The starting page offset
rend_pgoff	The ending page offset

Returns

vmap_t* The vmap object for the range, with its lock held.

|----—|----—|----—| |begin |rstart |rend |end |----—|----—|----—|

Definition at line 231 of file mm.cpp.

Referenced by munmap().

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vmap_finalise_init()

void vmap_finalise_init	(	vmap_t *	vmap,
		vmap_content_t	content,
		vmap_type_t	type )

Finalize the initialization of a vmap object.

Parameters

vmap	The vmap object
content	The content type of the region,

See also

vmap_content_t

Parameters

type	The fork behavior of the region,

See also

vmap_type_t

Note

The vmap object must be locked, and will be unlocked after this function returns.

Definition at line 254 of file mm.cpp.

Referenced by mm_map_user_pages(), mmap_anonymous(), mmap_file(), process_do_execveat(), process_do_fork(), and thread_new().

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mm_resolve_cow_fault()

vmfault_result_t mm_resolve_cow_fault ( vmap_t * vmap, ptr_t fault_addr, pagefault_t * info )

nodiscard

Helper function to resolve a copy-on-write fault.

Parameters

vmap	The vmap object
fault_addr	The fault address
info	The page fault info

Returns

vmfault_result_t always VMFAULT_COMPLETE

Definition at line 270 of file mm.cpp.

Referenced by cow_zod_fault_handler(), and vfs_fault_handler().

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mm_handle_fault()

void mm_handle_fault	(	ptr_t	fault_addr,
		pagefault_t *	info )

Handle a page fault.

Parameters

fault_addr	The fault address
info	The page fault info

Definition at line 363 of file mm.cpp.

Referenced by riscv64_trap_handler(), and x86_handle_exception().

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