Go to file
jhb 7cfc736e89 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
2018-08-24 15:00:02 +02:00
config
etc
include
libgloss Add BSP and semihosting library for nios2-generic-nommu QEMU emulation. 2018-08-08 10:53:03 +02:00
newlib Add a new file operations hook for mmap 2018-08-24 15:00:02 +02:00
texinfo
winsup Add __nl_item to <sys/_types.h> and use it 2018-08-24 15:00:01 +02:00
.drone.yml
.gitattributes
.gitignore
COPYING
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB Change license to FreeBSD License for RISC-V 2017-08-21 11:08:54 +02:00
COPYING3
COPYING3.LIB
ChangeLog
MAINTAINERS
Makefile.def Sync with upstream gcc. 2016-06-23 15:54:55 -04:00
Makefile.in Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
Makefile.tpl Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
README 19990502 sourceware import 1999-05-03 07:29:06 +00:00
README-maintainer-mode
compile Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
config-ml.in
config.guess Update config.guess and config.sub 2018-07-06 10:46:43 +02:00
config.rpath
config.sub Update config.guess and config.sub 2018-07-06 10:46:43 +02:00
configure Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
configure.ac Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
depcomp Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
djunpack.bat
install-sh
libtool.m4
ltgcc.m4 * libtool.m4: Update to libtool 2.2.6. 2008-09-29 15:28:14 +00:00
ltmain.sh
ltoptions.m4 Sync Libtool from GCC. 2010-01-09 21:11:32 +00:00
ltsugar.m4
ltversion.m4 Sync Libtool from GCC. 2010-01-09 21:11:32 +00:00
lt~obsolete.m4
makefile.vms 19990502 sourceware import 1999-05-03 07:29:06 +00:00
missing
mkdep
mkinstalldirs
move-if-change
setup.com
src-release
symlink-tree
ylwrap

README

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.