freebsd-skq/sys/vm/vm_extern.h
John Baldwin 7077c42623 Add a new file operations hook for mmap operations. File type-specific
logic is now placed in the mmap hook implementation rather than requiring
it to be placed in sys/vm/vm_mmap.c.  This hook allows new file types to
support mmap() as well as potentially allowing mmap() for existing file
types that do not currently support any mapping.

The vm_mmap() function is now split up into two functions.  A new
vm_mmap_object() function handles the "back half" of vm_mmap() and accepts
a referenced VM object to map rather than a (handle, handle_type) tuple.
vm_mmap() is now reduced to converting a (handle, handle_type) tuple to a
a VM object and then calling vm_mmap_object() to handle the actual mapping.
The vm_mmap() function remains for use by other parts of the kernel
(e.g. device drivers and exec) but now only supports mapping vnodes,
character devices, and anonymous memory.

The mmap() system call invokes vm_mmap_object() directly with a NULL object
for anonymous mappings.  For mappings using a file descriptor, the
descriptors fo_mmap() hook is invoked instead.  The fo_mmap() hook is
responsible for performing type-specific checks and adjustments to
arguments as well as possibly modifying mapping parameters such as flags
or the object offset.  The fo_mmap() hook routines then call
vm_mmap_object() to handle the actual mapping.

The fo_mmap() hook is optional.  If it is not set, then fo_mmap() will
fail with ENODEV.  A fo_mmap() hook is implemented for regular files,
character devices, and shared memory objects (created via shm_open()).

While here, consistently use the VM_PROT_* constants for the vm_prot_t
type for the 'prot' variable passed to vm_mmap() and vm_mmap_object()
as well as the vm_mmap_vnode() and vm_mmap_cdev() helper routines.
Previously some places were using the mmap()-specific PROT_* constants
instead.  While this happens to work because PROT_xx == VM_PROT_xx,
using VM_PROT_* is more correct.

Differential Revision:	https://reviews.freebsd.org/D2658
Reviewed by:	alc (glanced over), kib
MFC after:	1 month
Sponsored by:	Chelsio
2015-06-04 19:41:15 +00:00

119 lines
5.1 KiB
C

/*-
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vm_extern.h 8.2 (Berkeley) 1/12/94
* $FreeBSD$
*/
#ifndef _VM_EXTERN_H_
#define _VM_EXTERN_H_
struct pmap;
struct proc;
struct vmspace;
struct vnode;
struct vmem;
#ifdef _KERNEL
struct cdev;
struct cdevsw;
/* These operate on kernel virtual addresses only. */
vm_offset_t kva_alloc(vm_size_t);
void kva_free(vm_offset_t, vm_size_t);
/* These operate on pageable virtual addresses. */
vm_offset_t kmap_alloc_wait(vm_map_t, vm_size_t);
void kmap_free_wakeup(vm_map_t, vm_offset_t, vm_size_t);
/* These operate on virtual addresses backed by memory. */
vm_offset_t kmem_alloc_attr(struct vmem *, vm_size_t size, int flags,
vm_paddr_t low, vm_paddr_t high, vm_memattr_t memattr);
vm_offset_t kmem_alloc_contig(struct vmem *, vm_size_t size, int flags,
vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary,
vm_memattr_t memattr);
vm_offset_t kmem_malloc(struct vmem *, vm_size_t size, int flags);
void kmem_free(struct vmem *, vm_offset_t, vm_size_t);
/* This provides memory for previously allocated address space. */
int kmem_back(vm_object_t, vm_offset_t, vm_size_t, int);
void kmem_unback(vm_object_t, vm_offset_t, vm_size_t);
/* Bootstrapping. */
vm_map_t kmem_suballoc(vm_map_t, vm_offset_t *, vm_offset_t *, vm_size_t,
boolean_t);
void kmem_init(vm_offset_t, vm_offset_t);
void kmem_init_zero_region(void);
void kmeminit(void);
void swapout_procs(int);
int kernacc(void *, int, int);
int useracc(void *, int, int);
int vm_fault(vm_map_t, vm_offset_t, vm_prot_t, int);
void vm_fault_copy_entry(vm_map_t, vm_map_t, vm_map_entry_t, vm_map_entry_t,
vm_ooffset_t *);
int vm_fault_disable_pagefaults(void);
void vm_fault_enable_pagefaults(int save);
int vm_fault_hold(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
int fault_flags, vm_page_t *m_hold);
int vm_fault_quick_hold_pages(vm_map_t map, vm_offset_t addr, vm_size_t len,
vm_prot_t prot, vm_page_t *ma, int max_count);
int vm_forkproc(struct thread *, struct proc *, struct thread *,
struct vmspace *, int);
void vm_waitproc(struct proc *);
int vm_mmap(vm_map_t, vm_offset_t *, vm_size_t, vm_prot_t, vm_prot_t, int,
objtype_t, void *, vm_ooffset_t);
int vm_mmap_object(vm_map_t, vm_offset_t *, vm_size_t, vm_prot_t,
vm_prot_t, int, vm_object_t, vm_ooffset_t, boolean_t, struct thread *);
int vm_mmap_to_errno(int rv);
int vm_mmap_cdev(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *,
int *, struct cdev *, struct cdevsw *, vm_ooffset_t *, vm_object_t *);
int vm_mmap_vnode(struct thread *, vm_size_t, vm_prot_t, vm_prot_t *, int *,
struct vnode *, vm_ooffset_t *, vm_object_t *, boolean_t *);
void vm_set_page_size(void);
void vm_sync_icache(vm_map_t, vm_offset_t, vm_size_t);
typedef int (*pmap_pinit_t)(struct pmap *pmap);
struct vmspace *vmspace_alloc(vm_offset_t, vm_offset_t, pmap_pinit_t);
struct vmspace *vmspace_fork(struct vmspace *, vm_ooffset_t *);
int vmspace_exec(struct proc *, vm_offset_t, vm_offset_t);
int vmspace_unshare(struct proc *);
void vmspace_exit(struct thread *);
struct vmspace *vmspace_acquire_ref(struct proc *);
void vmspace_free(struct vmspace *);
void vmspace_exitfree(struct proc *);
void vnode_pager_setsize(struct vnode *, vm_ooffset_t);
int vslock(void *, size_t);
void vsunlock(void *, size_t);
struct sf_buf *vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset);
void vm_imgact_unmap_page(struct sf_buf *sf);
void vm_thread_dispose(struct thread *td);
int vm_thread_new(struct thread *td, int pages);
int vm_mlock(struct proc *, struct ucred *, const void *, size_t);
#endif /* _KERNEL */
#endif /* !_VM_EXTERN_H_ */