source: rtems-libbsd/libbsd.txt @ e6405ea

4.115-freebsd-12freebsd-9.3
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1RTEMS BSD Library Guide
2=======================
3:toc:
4:icons:
5:numbered:
6:website: http://www.rtems.org/
7
8RTEMS uses FreeBSD 9.2 as the source of its TCP/IP and USB stacks.
9This is a guide which captures information on the
10process of merging code from FreeBSD, building this library,
11RTEMS specific support files, and general guidelines on what
12modifications to the FreeBSD source are permitted.
13
14Goals of this effort are
15
16* update TCP/IP and provide USB in RTEMS,
17* ease updating to future FreeBSD versions,
18* ease tracking changes in FreeBSD code,
19* minimize manual changes in FreeBSD code, and
20* define stable kernel/device driver API which is implemented
21by both RTEMS and FreeBSD. This is the foundation of the port.
22
23We will work to push our changes upstream to the FreeBSD Project
24and minimize changes required at each update point.
25
26*******************************************************************************
27This is a work in progress and is very likely to be incomplete.
28Please help by adding to it.
29*******************************************************************************
30
31== Getting Started
32
33=== Tool Chain ===
34
35You need a tool chain for RTEMS based on at least
36
37* Binutils 2.24, and
38* Newlib 2.1.0.
39
40The Binutils version is required to ease the handling of linker command files.
41The Newlib version is required since some standard files like `<sys/types.h>`
42must be compatible enough for the files provided by the FreeBSD sources, e.g.
43`<sys/socket.h>`.
44
45=== Installation Overview ===
46
47. You must configure your BSP with the +--disable-networking+ option to disable
48the old network stack.  Make sure no header files of the old network stack are
49installed.
50. Clone the Git repository +git clone git://git.rtems.org/rtems-libbsd.git+.
51. Change into the RTEMS BSD library root directory.
52. Edit the `config.inc` Makefile configuration file and adjust it to your environment.
53. Run +make clean+.
54. Run +make install+.
55
56=== Board Support Package Requirements ===
57
58The RTEMS version must be at least 4.11.  The Board Support Package (BSP)
59should support the
60http://www.rtems.org/onlinedocs/doxygen/cpukit/html/group\__rtems\__interrupt__extension.html[Interrupt Manager Extension]
61// The first underscores have to be masked to stop asciidoc interpreting them
62to make use of generic FreeBSD based drivers.
63
64The linker command file of the BSP must contain the following section
65definitions:
66
67-------------------------------------------------------------------------------
68.rtemsroset : {
69        KEEP (*(SORT(.rtemsroset.*)))
70}
71
72.rtemsrwset : {
73        KEEP (*(SORT(.rtemsrwset.*)))
74}
75-------------------------------------------------------------------------------
76
77The first output section can be placed in read-only memory.  The second output
78section must be placed in read-write memory.  The output section name is not
79relevant.  The output sections may also contain other input sections.
80
81=== Board Support Package Configuration and Build ===
82
83You need to configure RTEMS for the desired BSP and install it.  The BSP should
84be configured with a disabled network stack.  The BSD library containing the
85new network stack is a separate package.  Using a BSP installation containing
86the old network stack may lead to confusion and unpredictable results.
87
88The following script is used to build the `arm/realview_pbx_a9_qemu` BSP for
89our internal testing purposes:
90
91-------------------------------------------------------------------------------
92#!/bin/sh
93
94cd ${HOME}/sandbox
95rm -rf b-realview_pbx_a9_qemu
96mkdir b-realview_pbx_a9_qemu
97cd b-realview_pbx_a9_qemu
98${HOME}/git-rtems/configure \
99        --prefix=${HOME}/sandbox/install \
100        --target=arm-rtems4.11 \
101        --enable-rtemsbsp=realview_pbx_a9_qemu \
102        --disable-networking && \
103        make && \
104        make install
105-------------------------------------------------------------------------------
106
107The `arm/realview_pbx_a9_qemu` BSP running on the Qemu simulator has some
108benefits for development and test of the BSD library
109
110* it offers a NULL pointer read and write protection,
111* Qemu is a fast simulator,
112* Qemu provides support for GDB watchpoints,
113* Qemu provides support for virtual Ethernet networks, e.g. TUN and bridge
114devices (you can run multiple test instances on one virtual network).
115
116=== BSD Library Configuration and Build ===
117
118In the BSD library source directory edit the file `config.inc`.  Continuing on
119the above, the `config.inc` used to match the above is:
120
121-------------------------------------------------------------------------------
122# Mandatory: Select your BSP and installation prefix
123TARGET = arm-rtems4.11
124BSP = realview_pbx_a9_qemu
125PREFIX = $(HOME)/sandbox/install
126
127# Optional: Separate installation base directory
128INSTALL_BASE = $(PREFIX)/$(TARGET)/$(BSP)
129
130# Optional: Network test configuration
131TEST_RUNNER = $(BSP)
132NET_CFG_SELF_IP = 10.0.0.2
133NET_CFG_NETMASK = 255.255.0.0
134NET_CFG_PEER_IP = 10.0.0.1
135NET_CFG_GATEWAY_IP = 10.0.0.1
136NET_TAP_INTERFACE = tap0
137-------------------------------------------------------------------------------
138
139Now you can build the BSD library and run the tests:
140
141-------------------------------------------------------------------------------
142make clean
143make
144make run_tests
145-------------------------------------------------------------------------------
146
147You can only run the tests directly in case a test runner is available.  The
148following tests run without an external network.  It is strongly advised to run
149them.
150
151* commands01
152* init01
153* loopback01
154* rwlock01
155* selectpollkqueue01
156* sleep01
157* swi01
158* syscalls01
159* thread01
160* timeout01
161* unix01
162
163To install the BSD library use this:
164
165-------------------------------------------------------------------------------
166make install
167-------------------------------------------------------------------------------
168
169=== BSD Library Initialization ===
170
171Use the following code to initialize the BSD library:
172
173-------------------------------------------------------------------------------
174#include <assert.h>
175#include <sysexits.h>
176
177#include <machine/rtems-bsd-commands.h>
178#include <rtems/bsd/bsd.h>
179
180static void
181network_ifconfig_lo0(void)
182{
183        int exit_code;
184        char *lo0[] = {
185                "ifconfig",
186                "lo0",
187                "inet",
188                "127.0.0.1",
189                "netmask",
190                "255.255.255.0",
191                NULL
192        };
193        char *lo0_inet6[] = {
194                "ifconfig",
195                "lo0",
196                "inet6",
197                "::1",
198                "prefixlen",
199                "128",
200                NULL
201        };
202
203        exit_code = rtems_bsd_command_ifconfig(RTEMS_BSD_ARGC(lo0), lo0);
204        assert(exit_code == EX_OK);
205
206        exit_code = rtems_bsd_command_ifconfig(RTEMS_BSD_ARGC(lo0_inet6), lo0_inet6);
207        assert(exit_code == EX_OK);
208}
209
210void
211network_init(void)
212{
213        rtems_status_code sc;
214
215        sc = rtems_bsd_initialize();
216        assert(sc == RTEMS_SUCCESSFUL);
217
218        network_ifconfig_lo0();
219}
220-------------------------------------------------------------------------------
221
222This performs the basic network stack initialization with a loopback interface.
223Further initialization must be done using the standard BSD network
224configuration commands
225http://www.freebsd.org/cgi/man.cgi?query=ifconfig&apropos=0&sektion=8&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[IFCONFIG(8)]
226using `rtems_bsd_command_ifconfig()` and
227http://www.freebsd.org/cgi/man.cgi?query=route&apropos=0&sektion=8&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[ROUTE(8)]
228using `rtems_bsd_command_route()`.  For an example please have a look at
229`testsuite/include/rtems/bsd/test/default-network-init.h`.
230
231== Network Stack Features
232
233http://roy.marples.name/projects/dhcpcd/index[DHCPCD(8)]:: DHCP client
234
235https://developer.apple.com/library/mac/documentation/Networking/Reference/DNSServiceDiscovery_CRef/Reference/reference.html[dns_sd.h]:: DNS Service Discovery
236
237http://www.opensource.apple.com/source/mDNSResponder/mDNSResponder-320.10/mDNSCore/mDNSEmbeddedAPI.h[mDNS]:: Multi-Cast DNS
238
239http://www.freebsd.org/cgi/man.cgi?query=unix&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[UNIX(4)]:: UNIX-domain protocol family
240
241http://www.freebsd.org/cgi/man.cgi?query=inet&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[INET(4)]:: Internet protocol family
242
243http://www.freebsd.org/cgi/man.cgi?query=inet6&apropos=0&sektion=4&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[INET6(4)]:: Internet protocol version 6 family
244
245http://www.freebsd.org/cgi/man.cgi?query=tcp&apropos=0&sektion=4&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[TCP(4)]:: Internet Transmission Control Protocol
246
247http://www.freebsd.org/cgi/man.cgi?query=udp&apropos=0&sektion=4&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[UDP(4)]:: Internet User Datagram Protocol
248
249http://www.freebsd.org/cgi/man.cgi?query=route&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[ROUTE(4)]:: Kernel packet forwarding database
250
251http://www.freebsd.org/cgi/man.cgi?query=bpf&apropos=0&sektion=4&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[BPF(4)]:: Berkeley Packet Filter
252
253http://www.freebsd.org/cgi/man.cgi?query=socket&apropos=0&sektion=2&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[SOCKET(2)]:: Create an endpoint for communication
254
255http://www.freebsd.org/cgi/man.cgi?query=kqueue&apropos=0&sektion=2&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[KQUEUE(2)]:: Kernel event notification mechanism
256
257http://www.freebsd.org/cgi/man.cgi?query=select&apropos=0&sektion=2&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[SELECT(2)]:: Synchronous I/O multiplexing
258
259http://www.freebsd.org/cgi/man.cgi?query=poll&apropos=0&sektion=2&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[POLL(2)]:: Synchronous I/O multiplexing
260
261http://www.freebsd.org/cgi/man.cgi?query=route&apropos=0&sektion=8&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[ROUTE(8)]:: Manually manipulate the routing tables
262
263http://www.freebsd.org/cgi/man.cgi?query=ifconfig&apropos=0&sektion=8&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[IFCONFIG(8)]:: Configure network interface parameters
264
265http://www.freebsd.org/cgi/man.cgi?query=netstat&apropos=0&sektion=1&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[NETSTAT(1)]:: Show network status
266
267http://www.freebsd.org/cgi/man.cgi?query=ping&apropos=0&sektion=8&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[PING(8)]:: Send ICMP ECHO_REQUEST packets to network hosts
268
269http://www.freebsd.org/cgi/man.cgi?query=ping6&apropos=0&sektion=8&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[PING6(8)]:: Send ICMPv6 ECHO_REQUEST packets to network hosts
270
271http://www.freebsd.org/cgi/man.cgi?query=sysctl&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[SYSCTL(3)]:: Get or set system information
272
273http://www.freebsd.org/cgi/man.cgi?query=resolver&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[RESOLVER(3)]:: Resolver routines
274
275http://www.freebsd.org/cgi/man.cgi?query=gethostbyname&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[GETHOSTBYNAME(3)]:: Get network host entry
276
277== Network Interface Drivers
278
279=== Link Up/Down Events
280
281You can notifiy the application space of link up/down events in your network
282interface driver via the if_link_state_change(LINK_STATE_UP/LINK_STATE_DOWN)
283function.  The DHCPCD(8) client is a consumer of these events for example.
284Make sure that the interface flag IFF_UP and the interface driver flag
285IFF_DRV_RUNNING is set in case the link is up, otherwise ether_output() will
286return the error status ENETDOWN.
287
288== Shell Commands
289
290=== HOSTNAME(1)
291
292In addition to the standard options the RTEMS version of the HOSTNAME(1)
293command supports the -m flag to set/get the multicast hostname of the
294mDNS resolver instance.  See also rtems_mdns_sethostname() and
295rtems_mdns_gethostname().
296
297== Issues and TODO
298
299* Per-CPU data should be enabled once the new stack is ready for SMP.
300
301* Per-CPU NETISR(9) should be enabled onece the new stack is ready for SMP.
302
303* Multiple routing tables are not supported.  Every FIB value is set to zero
304  (= BSD_DEFAULT_FIB).
305
306* Process identifiers are not supported.  Every PID value is set to zero
307  (= BSD_DEFAULT_PID).
308
309* User credentials are not supported.  The following functions allow the
310  operation for everyone
311  - prison_equal_ip4(),
312  - chgsbsize(),
313  - cr_cansee(),
314  - cr_canseesocket() and
315  - cr_canseeinpcb().
316
317* A basic USB functionality test that is known to work on Qemu is desirable.
318
319* Adapt generic IRQ PIC interface code to Simple Vectored Interrupt Model
320  so that those architectures can use new TCP/IP and USB code.
321
322* freebsd-userspace/rtems/include/sys/syslog.h is a copy from the old
323  RTEMS TCP/IP stack. For some reason, the __printflike markers do not
324  compile in this environment. We may want to use the FreeBSD syslog.h
325  and get this addressed.
326
327* in_cksum implementations for architectures not supported by FreeBSD.
328  This will require figuring out where to put implementations that do
329  not originate from FreeBSD and are populated via the script.
330
331* MAC support functions are not thread-safe ("freebsd/lib/libc/posix1e/mac.c").
332
333* IFCONFIG(8): IEEE80211 support is disabled.  This module depends on a XML
334  parser and mmap().
335
336* get_cyclecount(): The implementation is a security problem.
337
338* What to do with the priority parameter present in the FreeBSD synchronization
339  primitives and the thread creation functions?
340
341* TASKQUEUE(9): Support spin mutexes.
342
343* ZONE(9): Review allocator lock usage in rtems-bsd-chunk.c.
344
345* KQUEUE(2): Choose proper lock for global kqueue list.
346
347* TIMEOUT(9): Maybe use special task instead of timer server to call
348  callout_tick().
349
350* sysctl_handle_opaque(): Implement reliable snapshots.
351
352* PING6(8): What to do with SIGALARM?
353
354* <sys/param.h>: Update Newlib to use a MSIZE of 256.
355
356* BPF(4): Add support for zero-copy buffers.
357
358* UNIX(4): Fix race conditions in the area of socket object and file node
359  destruction.  Add support for file descriptor transmission via control
360  messages.
361
362* PRINTF(9): Add support for log(), the %D format specifier is missing in the
363  normal printf() family.
364
365* Why is the interrupt server used?  The BSD interrupt handlers can block on
366synchronization primitives like mutexes.  This is in contrast to RTEMS
367interrupt service routines.  The BSPs using the generic interrupt support must
368implement the `bsp_interrupt_vector_enable()` and
369`bsp_interrupt_vector_disable()` routines.  They normally enable/disable a
370particular interrupt source at the interrupt controller.  This can be used to
371implement the interrupt server.  The interrupt server is a task that wakes-up
372in case an associated interrupt happens.  The interrupt source is disabled in
373a generic interrupt handler that wakes-up the interrupt server task.   Once the
374postponed interrupt processing is performed in the interrupt server the
375interrupt source is enabled again.
376
377* Convert all BSP linkcmds to use a linkcmds.base so the sections are
378easier to insert.
379
380* NIC Device Drivers
381- Only common PCI NIC drivers have been included in the initial set. These
382do not include any system on chip or ISA drivers.
383- PCI configuration probe does not appear to happen to determine if a
384NIC is in I/O or memory space. We have worked around this by using a
385static hint to tell the fxp driver the correct mode. But this needs to
386be addressed.
387- The ISA drivers require more BSD infrastructure to be addressed. This was
388outside the scope of the initial porting effort.
389
390== FreeBSD Source
391
392You should be able to rely on FreebSD manual pages and documentation
393for details on the code itself.
394
395=== Automatically Generated FreeBSD Files
396
397Some source and header files are automatically generated during the FreeBSD
398build process.  The `Makefile.todo` file performs this manually.  The should be
399included in `freebsd-to-rtems.py` script some time in the future.  For details,
400see also
401http://www.freebsd.org/cgi/man.cgi?query=kobj&sektion=9&apropos=0&manpath=FreeBSD+9.2-RELEASE[KOBJ(9)].
402
403=== Rules for Modifying FreeBSD Source
404
405Only add lines.  Subtract code by added `#ifndef __rtems__`.  This makes
406merging easier in the future.  For example:
407
408-------------------------------------------------------------------------------
409/* Global variables for the kernel. */
410
411#ifndef __rtems__
412/* 1.1 */
413extern char kernelname[MAXPATHLEN];
414#endif /* __rtems__ */
415
416extern int tick;                        /* usec per tick (1000000 / hz) */
417-------------------------------------------------------------------------------
418
419-------------------------------------------------------------------------------
420#if defined(_KERNEL) || defined(_WANT_FILE)
421#ifdef __rtems__
422#include <rtems/libio_.h>
423#include <sys/fcntl.h>
424#endif /* __rtems__ */
425/*
426 * Kernel descriptor table.
427 * One entry for each open kernel vnode and socket.
428 *
429 * Below is the list of locks that protects members in struct file.
430 *
431 * (f) protected with mtx_lock(mtx_pool_find(fp))
432 * (d) cdevpriv_mtx
433 * none not locked
434 */
435-------------------------------------------------------------------------------
436
437-------------------------------------------------------------------------------
438extern int profprocs;                   /* number of process's profiling */
439#ifndef __rtems__
440extern volatile int ticks;
441#else /* __rtems__ */
442#include <rtems/score/watchdogimpl.h>
443#define ticks _Watchdog_Ticks_since_boot
444#endif /* __rtems__ */
445
446#endif /* _KERNEL */
447-------------------------------------------------------------------------------
448
449Add nothing (even blank lines) before or after the `__rtems__` guards.  Always
450include a `__rtems__` in the guards to make searches easy.
451
452== BSD Library Source
453
454=== What is in the Git Repository
455
456There is a self-contained kit with FreeBSD and RTEMS components pre-merged. The
457Makefile in this kit is automatically generated.
458
459Any changes to source in the `freebsd` directories will need to be merged
460upstream into our master FreeBSD checkout, the `freebsd-org` submodule.
461
462The repository contains two FreeBSD source trees.  In the `freebsd` directory
463are the so called 'managed' FreeBSD sources used to build the BSD library.  The
464FreeBSD source in `freebsd-org` is the 'master' version.  The
465`freebsd-to-rtems.py` script is used to transfer files between the two trees.
466In general terms, if you have modified managed FreeBSD sources, you will need
467to run the script in 'revert' or 'reverse' mode using the `-R` switch.  This
468will copy the source back to your local copy of the master FreeBSD source so
469you can run `git diff` against the upstream FreeBSD source.  If you want to
470transfer source files from the master FreeBSD source to the manged FreeBSD
471sources, then you must run the script in 'forward' mode (the default).
472
473=== Organization
474
475The top level directory contains a few directories and files. The following
476are important to understand
477
478* `freebsd-to-rtems.py` - script to convert to and free FreeBSD and RTEMS trees,
479* `Makefile` - automatically generated,
480* `freebsd/` - from FreeBSD by script,
481* `rtemsbsd/` - RTEMS specific implementations of FreeBSD kernel support routines,
482* `testsuite/` - RTEMS specific tests, and
483* `libbsd.txt` - documentation in Asciidoc.
484
485== Moving Code Between Managed and Master FreeBSD Source
486
487The script `freebsd-to-rtems.py` is used to copy code from FreeBSD to the
488rtems-libbsd tree and to reverse this process. This script attempts to
489automate this process as much as possible and performs some transformations
490on the FreeBSD code. Its command line arguments are shown below:
491
492----
493freebsd-to-rtems.py [args]
494  -?|-h|--help     print this and exit
495  -d|--dry-run     run program but no modifications
496  -D|--diff        provide diff of files between trees
497  -e|--early-exit  evaluate arguments, print results, and exit
498  -m|--makefile    just generate Makefile
499  -R|--reverse     default FreeBSD -> RTEMS, reverse that
500  -r|--rtems       RTEMS directory
501  -f|--freebsd     FreeBSD directory
502  -v|--verbose     enable verbose output mode
503----
504
505In its default mode of operation, freebsd-to-rtems.py is used to copy code
506from FreeBSD to the rtems-libbsd tree and perform transformations.  In forward
507mode, the script may be requested to just generate the Makefile.
508
509In "reverse mode", this script undoes those transformations and copies
510the source code back to the FreeBSD SVN tree. This allows us to do
511'svn diff', evaluate changes made by the RTEMS Project, and report changes
512back to FreeBSD upstream.
513
514In either mode, the script may be asked to perform a dry-run or be verbose.
515Also, in either mode, the script is also smart enough to avoid copying over
516files which have not changed. This means that the timestamps of files are
517not changed unless the contents change. The script will also report the
518number of files which changed. In verbose mode, the script will print
519the name of the files which are changed.
520
521The following is an example forward run with no changes.
522
523----
524$ ~/newbsd/git/libbsd-8.2/freebsd-to-rtems.py \
525    -r /home/joel/newbsd/git/libbsd-8.2 \
526    -f /home/joel/newbsd/libbsd/freebsd-8.2 -v
527Verbose:                yes
528Dry Run:                no
529Only Generate Makefile: no
530RTEMS Directory:        /home/joel/newbsd/git/libbsd-8.2
531FreeBSD Directory:      /home/joel/newbsd/libbsd/freebsd-8.2
532Direction:              forward
533Generating into /home/joel/newbsd/git/libbsd-8.2
5340 files were changed.
535----
536
537The script may also be used to generate a diff in either forward or reverse
538direction.
539
540== Initialization of the BSD Library
541
542The initialization of the BSD library is based on the FreeBSD SYSINIT(9)
543infrastructure.  The key to initializing a system is to ensure that the desired
544device drivers are explicitly pulled into the linked application.  This plus
545linking against the BSD library (`libbsd.a`) will pull in the necessary FreeBSD
546infrastructure.
547
548The FreeBSD kernel is not a library like the RTEMS kernel.  It is a bunch of
549object files linked together.  If we have a library, then creating the
550executable is simple.  We begin with a start symbol and recursively resolve all
551references.  With a bunch of object files linked together we need a different
552mechanism.  Most object files don't know each other.  Lets say we have a driver
553module.  The rest of the system has no references to this driver module.  The
554driver module needs a way to tell the rest of the system: Hey, kernel I am
555here, please use my services!
556
557This registration of independent components is performed by SYSINIT(9) and
558specializations:
559
560http://www.freebsd.org/cgi/man.cgi?query=SYSINIT
561
562The SYSINIT(9) uses some global data structures that are placed in a certain
563section.  In the linker command file we need this:
564
565-------------------------------------------------------------------------------
566.rtemsroset : {
567        KEEP (*(SORT(.rtemsroset.*)))
568}
569
570.rtemsrwset : {
571        KEEP (*(SORT(.rtemsrwset.*)))
572}
573-------------------------------------------------------------------------------
574
575This results for example in this executable layout:
576
577-------------------------------------------------------------------------------
578[...]
579 *(SORT(.rtemsroset.*))
580 .rtemsroset.bsd.modmetadata_set.begin
581                0x000000000025fe00        0x0 libbsd.a(rtems-bsd-init.o)
582                0x000000000025fe00                _bsd__start_set_modmetadata_set
583 .rtemsroset.bsd.modmetadata_set.content
584                0x000000000025fe00        0x8 libbsd.a(rtems-bsd-nexus.o)
585 .rtemsroset.bsd.modmetadata_set.content
586                0x000000000025fe08        0x4 libbsd.a(kern_module.o)
587[...]
588 .rtemsroset.bsd.modmetadata_set.content
589                0x000000000025fe68        0x4 libbsd.a(mii.o)
590 .rtemsroset.bsd.modmetadata_set.content
591                0x000000000025fe6c        0x4 libbsd.a(mii_bitbang.o)
592 .rtemsroset.bsd.modmetadata_set.end
593                0x000000000025fe70        0x0 libbsd.a(rtems-bsd-init.o)
594                0x000000000025fe70                _bsd__stop_set_modmetadata_set
595[...]
596.rtemsrwset     0x000000000030bad0      0x290
597 *(SORT(.rtemsrwset.*))
598 .rtemsrwset.bsd.sysinit_set.begin
599                0x000000000030bad0        0x0 libbsd.a(rtems-bsd-init.o)
600                0x000000000030bad0                _bsd__start_set_sysinit_set
601 .rtemsrwset.bsd.sysinit_set.content
602                0x000000000030bad0        0x4 libbsd.a(rtems-bsd-nexus.o)
603 .rtemsrwset.bsd.sysinit_set.content
604                0x000000000030bad4        0x8 libbsd.a(rtems-bsd-thread.o)
605 .rtemsrwset.bsd.sysinit_set.content
606                0x000000000030badc        0x4 libbsd.a(init_main.o)
607[...]
608 .rtemsrwset.bsd.sysinit_set.content
609                0x000000000030bd54        0x4 libbsd.a(frag6.o)
610 .rtemsrwset.bsd.sysinit_set.content
611                0x000000000030bd58        0x8 libbsd.a(uipc_accf.o)
612 .rtemsrwset.bsd.sysinit_set.end
613                0x000000000030bd60        0x0 libbsd.a(rtems-bsd-init.o)
614                0x000000000030bd60                _bsd__stop_set_sysinit_set
615[...]
616-------------------------------------------------------------------------------
617
618Here you can see, that some global data structures are collected into
619continuous memory areas.  This memory area can be identified by start and stop
620symbols.  This constructs a table of uniform items.
621
622The low level FreeBSD code calls at some time during the initialization the
623mi_startup() function (machine independent startup).  This function will sort
624the SYSINIT(9) set and call handler functions which perform further
625initialization.  The last step is the scheduler invocation.
626
627The SYSINIT(9) routines are run in mi_startup() which is called by
628rtems_bsd_initialize().
629
630This is also explained in "The Design and Implementation of the FreeBSD
631Operating System" section 14.3 "Kernel Initialization".
632
633In RTEMS we have a library and not a bunch of object files.  Thus we need a way
634to pull-in the desired services out of the libbsd.  Here the
635`rtems-bsd-sysinit.h` comes into play.  The SYSINIT(9) macros have been
636modified and extended for RTEMS in `<sys/kernel.h>`:
637
638-------------------------------------------------------------------------------
639#ifndef __rtems__
640#define C_SYSINIT(uniquifier, subsystem, order, func, ident)    \
641        static struct sysinit uniquifier ## _sys_init = {       \
642                subsystem,                                      \
643                order,                                          \
644                func,                                           \
645                (ident)                                         \
646        };                                                      \
647        DATA_SET(sysinit_set,uniquifier ## _sys_init)
648#else /* __rtems__ */
649#define SYSINIT_ENTRY_NAME(uniquifier)                          \
650        _bsd_ ## uniquifier ## _sys_init
651#define SYSINIT_REFERENCE_NAME(uniquifier)                      \
652        _bsd_ ## uniquifier ## _sys_init_ref
653#define C_SYSINIT(uniquifier, subsystem, order, func, ident)    \
654        struct sysinit SYSINIT_ENTRY_NAME(uniquifier) = {       \
655                subsystem,                                      \
656                order,                                          \
657                func,                                           \
658                (ident)                                         \
659        };                                                      \
660        RWDATA_SET(sysinit_set,SYSINIT_ENTRY_NAME(uniquifier))
661#define SYSINIT_REFERENCE(uniquifier)                           \
662        extern struct sysinit SYSINIT_ENTRY_NAME(uniquifier);   \
663        static struct sysinit const * const                     \
664        SYSINIT_REFERENCE_NAME(uniquifier) __used               \
665        = &SYSINIT_ENTRY_NAME(uniquifier)
666#define SYSINIT_MODULE_REFERENCE(mod)                           \
667        SYSINIT_REFERENCE(mod ## module)
668#define SYSINIT_DRIVER_REFERENCE(driver, bus)                   \
669        SYSINIT_MODULE_REFERENCE(driver ## _ ## bus)
670#define SYSINIT_DOMAIN_REFERENCE(dom)                           \
671        SYSINIT_REFERENCE(domain_add_ ## dom)
672#endif /* __rtems__ */
673-------------------------------------------------------------------------------
674
675Here you see that the SYSINIT(9) entries are no longer static.  The
676\*_REFERENCE() macros will create references to the corresponding modules which
677are later resolved by the linker.  The application has to provide an object
678file with references to all required FreeBSD modules.
679
680The FreeBSD device model is quite elaborated (with follow-ups):
681
682http://www.freebsd.org/cgi/man.cgi?query=driver
683
684The devices form a tree with the Nexus device at a high-level.  This Nexus
685device is architecture specific in FreeBSD.  In RTEMS we have our own Nexus
686device, see `rtemsbsd/bsp/bsp-bsd-nexus-devices.c`.
687
688=== SYSCTL_NODE Example
689
690During development, we had an undefined reference to
691_bsd_sysctl__net_children that we had trouble tracking down. Thanks to
692Chris Johns, we located it. He explained how to read SYSCTL_NODE
693definitions. This line from freebsd/netinet/in_proto.c is attempting
694to add the "inet" node to the parent node "_net".
695
696----
697SYSCTL_NODE(_net,      PF_INET,         inet,   CTLFLAG_RW, 0,
698        "Internet Family");
699----
700
701Our problem was that we could not find where _bsd_sysctl__net_children
702was defined. Chris suggested that when in doubt compile with -save-temps
703and look at the preprocessed .i files. But he did not need that. He
704explained that this the symbol name _bsd_sysctl__net_children was
705automatically generated by a SYSCTL_NODE as follows:
706
707* _bsd_ - added by RTEMS modifications to SYSCTL_NODE macro
708* sysctl_ - boilerplace added by SYSCTL_NODE macro
709* "" - empty string for parent node
710* net - name of SYSCTL_NODE
711* children - added by SYSCTL macros
712 
713This was all generated by a support macro declaring the node as this:
714
715----
716struct sysctl_oid_list SYSCTL_NODE_CHILDREN(parent, name);
717----
718
719Given this information, we located this SYSCTL_NODE declaration in
720kern/kern_mib.c
721
722----
723SYSCTL_NODE(, CTL_KERN,   kern,   CTLFLAG_RW, 0,
724        "High kernel, proc, limits &c");
725----
726
727== Core FreeBSD APIs and RTEMS Replacements ==
728
729=== SX(9) (Shared/exclusive locks) ===
730
731http://www.freebsd.org/cgi/man.cgi?query=sx
732
733Binary semaphores (this neglects the ability to allow shared access).
734
735=== MUTEX(9) (Mutual exclusion) ===
736
737http://www.freebsd.org/cgi/man.cgi?query=mutex
738
739Binary semaphores (not recursive mutexes are not supported this way).
740
741=== RWLOCK(9) (Reader/writer lock) ===
742
743http://www.freebsd.org/cgi/man.cgi?query=rwlock
744
745POSIX r/w lock.
746
747=== RMLOCK(9) (Reader/writer lock optimized for mostly read access patterns) ===
748
749Note:  This object was implemented as a wrapper for RWLOCK in the rm_lock header file.
750
751http://www.freebsd.org/cgi/man.cgi?query=rmlock
752
753POSIX r/w lock.
754
755=== CONDVAR(9) (Condition variables) ===
756
757http://www.freebsd.org/cgi/man.cgi?query=condvar
758
759POSIX condition variables with modifications (hack).
760
761=== CALLOUT(9) (Timer functions) ===
762
763http://www.freebsd.org/cgi/man.cgi?query=callout
764
765Timer server.
766
767=== TASKQUEUE(9) (Asynchronous task execution) ===
768
769http://www.freebsd.org/cgi/man.cgi?query=taskqueue
770
771TBD.
772
773=== KTHREAD(9), KPROC(9) (Tasks) ===
774
775http://www.freebsd.org/cgi/man.cgi?query=kthread
776
777http://www.freebsd.org/cgi/man.cgi?query=kproc
778
779Tasks.
780
781=== ZONE(9) (Zone allocator) ===
782
783http://www.freebsd.org/cgi/man.cgi?query=zone
784
785TBD.
786
787=== devfs (Device file system) ===
788
789Dummy, IMFS or new implementation (currently dummy).
790
791=== psignal (Signals) ===
792
793TBD.  Seems to be not needed.
794
795=== poll, select ===
796
797TBD.  Seems to be not needed.
798
799=== RMAN(9) (Resource management) ===
800
801http://www.freebsd.org/cgi/man.cgi?query=rman
802
803TBD.  Seems to be not needed.
804
805=== DEVCLASS(9), DEVICE(9), DRIVER(9), MAKE_DEV(9) (Device management) ===
806
807http://www.freebsd.org/cgi/man.cgi?query=devclass
808
809http://www.freebsd.org/cgi/man.cgi?query=device
810
811http://www.freebsd.org/cgi/man.cgi?query=driver
812
813http://www.freebsd.org/cgi/man.cgi?query=make_dev
814
815Use FreeBSD implementation as far as possible.  FreeBSD has a nice API for
816dynamic device handling.  It may be interesting for RTEMS to use this API
817internally in the future.
818
819=== BUS_SPACE(9), BUS_DMA(9) (Bus and DMA access) ===
820
821http://www.freebsd.org/cgi/man.cgi?query=bus_space
822
823http://www.freebsd.org/cgi/man.cgi?query=bus_dma
824
825Likely BSP dependent.  A default implementation for memory mapped linear access
826is easy to provide.  The current heap implementation supports all properties
827demanded by bus_dma (including the boundary constraint).
828
829== RTEMS Replacements by File Description ==
830
831Note:  Files with a status of USB are used by the USB test and have at least
832been partially tested.  If they contain both USB and Nic, then they are used
833by both and MAY contain methods that have not been tested yet.  Files that
834are only used by the Nic test are the most suspect.
835
836----
837rtems-libbsd File:      rtems-bsd-assert.c
838FreeBSD File:           rtems-bsd-config.h redefines BSD_ASSERT.
839Description:            This file contains the support method rtems_bsd_assert_func().
840Status:                 USB, Nic
841
842rtems-libbsd File:      rtems-bsd-autoconf.c
843FreeBSD File:           FreeBSD has BSP specific autoconf.c
844Description:            This file contains configuration methods that are used to setup the system.
845Status:                 USB
846
847rtems-libbsd File:      rtems-bsd-bus-dma.c
848FreeBSD File:           FreeBSD has BSP specific busdma_machdep.c
849Description:           
850Status:                 USB, Nic
851
852rtems-libbsd File:      rtems-bsd-bus-dma-mbuf.c       
853FreeBSD File:           FreeBSD has BSP specific busdma_machdep.c
854Description:           
855Status:                 Nic
856
857rtems-libbsd File:      rtems-bsd-callout.c             
858FreeBSD File:           kern/kern_timeout.c
859Description:           
860Status:                 USB, Nic
861
862rtems-libbsd File:      rtems-bsd-cam.c
863FreeBSD File:           cam/cam_sim.c
864Description:           
865Status:                 USB
866
867rtems-libbsd File:      rtems-bsd-condvar.c             
868FreeBSD File:           kern/kern_condvar.c
869Description:           
870Status:                 USB
871
872rtems-libbsd File:      rtems-bsd-copyinout.c
873FreeBSD File:           bsp specific copyinout.c )
874Description:            Note: The FreeBSD file is split with some methods being in rtems-bsd-support
875Status:                 Nic
876
877rtems-libbsd File:      rtems-bsd-delay.c
878FreeBSD File:           bsp specific file with multiple names
879Description:           
880Status:                 USB, Nic
881
882rtems-libbsd File:      rtems-bsd-descrip.c
883FreeBSD File:           kern/kern_descrip.c
884Description:           
885Status:                 Nic
886
887rtems-libbsd File:      rtems-bsd-generic.c             
888FreeBSD File:           kern/sys_generic.c
889Description:           
890Status:                 Nic
891
892rtems-libbsd File:      rtems-bsd-init.c
893FreeBSD File:           N/A
894Description:           
895Status:                 USB, Nic
896
897rtems-libbsd File:      rtems-bsd-init-with-irq.c
898FreeBSD File:           N/A
899Description:           
900Status:                 USB, Nic
901
902rtems-libbsd File:      rtems-bsd-jail.c
903FreeBSD File:           kern/kern_jail.c
904Description:           
905Status:                 USB, Nic
906
907rtems-libbsd File:      rtems-bsd-lock.c
908FreeBSD File:           kern/subr_lock.c
909Description:           
910Status:                 USB, Nic
911
912rtems-libbsd File:      rtems-bsd-log.c         
913FreeBSD File:           kern/subr_prf.c
914Description:           
915Status:                 Nic
916
917rtems-libbsd File:      rtems-bsd-malloc.c
918FreeBSD File:           kern/kern_malloc.c
919Description:           
920Status:                 USB, Nic
921
922rtems-libbsd File:      rtems-bsd-mutex.c
923FreeBSD File:           kern/kern_mutex.c
924Description:           
925Status:                 USB, Nic
926
927rtems-libbsd File:      rtems-bsd-newproc.c
928FreeBSD File:           N/A
929Description:           
930Status:                 Nic
931
932rtems-libbsd File:      rtems-bsd-nexus.c
933FreeBSD File:           bsp specific nexus.c
934Description:           
935Status:                 USB
936
937rtems-libbsd File:      rtems-bsd-panic.c               
938FreeBSD File:           boot/common/panic.c
939Description:           
940Status:                 USB, Nic
941
942rtems-libbsd File:      rtems-bsd-rwlock.c             
943FreeBSD File:           kern_rwlock.c
944Description:           
945Status:                 USB, Nic
946
947rtems-libbsd File:      rtems-bsd-shell.c               
948FreeBSD File:           N/A
949Description:           
950Status:                 USB
951
952rtems-libbsd File:      rtems-bsd-signal.c             
953FreeBSD File:           kern/kern_sig.c
954Description:           
955Status:                 Nic
956
957rtems-libbsd File:      rtems-bsd-smp.c                 
958FreeBSD File:           N/A
959Description:           
960Status:                 Nic
961
962rtems-libbsd File:      rtems-bsd-support.c             
963FreeBSD File:           bsp specific copyinout.c
964Description:            Note: the FreeBSD file is split with some methods being in rtems-bsd-copyinout.
965Status:                 USB, Nic
966
967rtems-libbsd File:      rtems-bsd-sx.c                 
968FreeBSD File:           kern/kern_sx.c
969Description:            Status: USB, Nic
970
971rtems-libbsd File:      rtems-bsd-synch.c               
972FreeBSD File:           kern/kern_synch.c
973Description:           
974Status:                 USB, Nic
975
976rtems-libbsd File:      rtems-bsd-syscalls.c           
977FreeBSD File:           User API for kern/uipc_syscalls.c
978Description:           
979Status:                 Nic
980
981rtems-libbsd File:      rtems-bsd-sysctlbyname.c       
982FreeBSD File:           User API for sysctlbyname(3)
983Description:           
984Status:
985
986rtems-libbsd File:      rtems-bsd-sysctl.c             
987FreeBSD File:           User API for sysctl(8)
988Description:           
989Status:
990
991rtems-libbsd File:      rtems-bsd-sysctlnametomib.c     
992FreeBSD File:           User API for sysctlnametomib
993Description:           
994Status:
995
996rtems-libbsd File:      rtems-bsd-taskqueue.c           
997FreeBSD File:           kern/subr_taskqueue.c
998Description:           
999Status:                 Nic
1000
1001rtems-libbsd File:      rtems-bsd-thread.c                     
1002FreeBSD File:           kern/kern_kthread.c
1003Description:           
1004Status:                 USB, Nic
1005
1006rtems-libbsd File:      rtems-bsd-timeout.c             
1007FreeBSD File:           kern/kern_timeout.c
1008Description:           
1009Status:                 Nic
1010
1011rtems-libbsd File:      rtems-bsd-timesupport.c         
1012FreeBSD File:           kern/kern_clock.c
1013Description:           
1014Status:                 Nic
1015
1016rtems-libbsd File:      rtems-bsd-vm_glue.c             
1017FreeBSD File:           vm/vm_glue.c
1018Description:           
1019Status:                 USB, Nic
1020----
1021
1022== Notes by File ==
1023
1024altq_subr.c - Arbitrary choices were made in this file that RTEMS would
1025not support tsc frequency change.  Additionally, the clock frequency
1026for machclk_freq is always measured for RTEMS.
1027
1028conf.h - In order to add make_dev and destroy_dev, variables in the cdev
1029structure that were not being used were conditionally compiled out. The
1030capability of supporting children did not appear to be needed and was
1031not implemented in the rtems version of these routines.
1032 
1033== NICs Status ==
1034
1035----
1036Driver                  Symbol                          Status
1037======                  ======                          ======
1038RealTek                 _bsd_re_pcimodule_sys_init      Links
1039EtherExpress            _bsd_fxp_pcimodule_sys_init     Links
1040DEC tulip               _bsd_dc_pcimodule_sys_init      Links
1041Broadcom BCM57xxx       _bsd_bce_pcimodule_sys_init     Links
1042Broadcom BCM4401        _bsd_bfe_pcimodule_sys_init     Links
1043Broadcom BCM570x        _bsd_bge_pcimodule_sys_init     Needs Symbols (A)
1044E1000 IGB               _bsd_igb_pcimodule_sys_init     Links
1045E1000 EM                _bsd_em_pcimodule_sys_init      Links
1046----
1047
1048
1049Symbols (A)
1050         pci_get_vpd_ident
1051 
1052== Problems to report to FreeBSD ==
1053
1054The MMAP_NOT_AVAILABLE define is inverted on its usage.  When it is
1055defined the mmap method is called. Additionally, it is not used
1056thoroughly. It is not used in the unmap portion of the source.
1057The file rec_open.c uses the define MMAP_NOT_AVAILABLE to wrap
1058the call to mmap and file rec_close.c uses the munmap method.
1059
1060
1061
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