source: rtems-libbsd/libbsd.txt @ 43dc972

4.115-freebsd-12freebsd-9.3
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doc: Add network interface link up/down hint

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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== Issues and TODO
289
290* Per-CPU data should be enabled once the new stack is ready for SMP.
291
292* Per-CPU NETISR(9) should be enabled onece the new stack is ready for SMP.
293
294* Multiple routing tables are not supported.  Every FIB value is set to zero
295  (= BSD_DEFAULT_FIB).
296
297* Process identifiers are not supported.  Every PID value is set to zero
298  (= BSD_DEFAULT_PID).
299
300* User credentials are not supported.  The following functions allow the
301  operation for everyone
302  - prison_equal_ip4(),
303  - chgsbsize(),
304  - cr_cansee(),
305  - cr_canseesocket() and
306  - cr_canseeinpcb().
307
308* A basic USB functionality test that is known to work on Qemu is desirable.
309
310* Adapt generic IRQ PIC interface code to Simple Vectored Interrupt Model
311  so that those architectures can use new TCP/IP and USB code.
312
313* freebsd-userspace/rtems/include/sys/syslog.h is a copy from the old
314  RTEMS TCP/IP stack. For some reason, the __printflike markers do not
315  compile in this environment. We may want to use the FreeBSD syslog.h
316  and get this addressed.
317
318* in_cksum implementations for architectures not supported by FreeBSD.
319  This will require figuring out where to put implementations that do
320  not originate from FreeBSD and are populated via the script.
321
322* MAC support functions are not thread-safe ("freebsd/lib/libc/posix1e/mac.c").
323
324* IFCONFIG(8): IEEE80211 support is disabled.  This module depends on a XML
325  parser and mmap().
326
327* get_cyclecount(): The implementation is a security problem.
328
329* What to do with the priority parameter present in the FreeBSD synchronization
330  primitives and the thread creation functions?
331
332* TASKQUEUE(9): Support spin mutexes.
333
334* ZONE(9): Review allocator lock usage in rtems-bsd-chunk.c.
335
336* KQUEUE(2): Choose proper lock for global kqueue list.
337
338* TIMEOUT(9): Maybe use special task instead of timer server to call
339  callout_tick().
340
341* sysctl_handle_opaque(): Implement reliable snapshots.
342
343* PING6(8): What to do with SIGALARM?
344
345* <sys/param.h>: Update Newlib to use a MSIZE of 256.
346
347* BPF(4): Add support for zero-copy buffers.
348
349* UNIX(4): Fix race conditions in the area of socket object and file node
350  destruction.  Add support for file descriptor transmission via control
351  messages.
352
353* PRINTF(9): Add support for log(), the %D format specifier is missing in the
354  normal printf() family.
355
356* Why is the interrupt server used?  The BSD interrupt handlers can block on
357synchronization primitives like mutexes.  This is in contrast to RTEMS
358interrupt service routines.  The BSPs using the generic interrupt support must
359implement the `bsp_interrupt_vector_enable()` and
360`bsp_interrupt_vector_disable()` routines.  They normally enable/disable a
361particular interrupt source at the interrupt controller.  This can be used to
362implement the interrupt server.  The interrupt server is a task that wakes-up
363in case an associated interrupt happens.  The interrupt source is disabled in
364a generic interrupt handler that wakes-up the interrupt server task.   Once the
365postponed interrupt processing is performed in the interrupt server the
366interrupt source is enabled again.
367
368* Convert all BSP linkcmds to use a linkcmds.base so the sections are
369easier to insert.
370
371* NIC Device Drivers
372- Only common PCI NIC drivers have been included in the initial set. These
373do not include any system on chip or ISA drivers.
374- PCI configuration probe does not appear to happen to determine if a
375NIC is in I/O or memory space. We have worked around this by using a
376static hint to tell the fxp driver the correct mode. But this needs to
377be addressed.
378- The ISA drivers require more BSD infrastructure to be addressed. This was
379outside the scope of the initial porting effort.
380
381== FreeBSD Source
382
383You should be able to rely on FreebSD manual pages and documentation
384for details on the code itself.
385
386=== Automatically Generated FreeBSD Files
387
388Some source and header files are automatically generated during the FreeBSD
389build process.  The `Makefile.todo` file performs this manually.  The should be
390included in `freebsd-to-rtems.py` script some time in the future.  For details,
391see also
392http://www.freebsd.org/cgi/man.cgi?query=kobj&sektion=9&apropos=0&manpath=FreeBSD+9.2-RELEASE[KOBJ(9)].
393
394=== Rules for Modifying FreeBSD Source
395
396Only add lines.  Subtract code by added `#ifndef __rtems__`.  This makes
397merging easier in the future.  For example:
398
399-------------------------------------------------------------------------------
400/* Global variables for the kernel. */
401
402#ifndef __rtems__
403/* 1.1 */
404extern char kernelname[MAXPATHLEN];
405#endif /* __rtems__ */
406
407extern int tick;                        /* usec per tick (1000000 / hz) */
408-------------------------------------------------------------------------------
409
410-------------------------------------------------------------------------------
411#if defined(_KERNEL) || defined(_WANT_FILE)
412#ifdef __rtems__
413#include <rtems/libio_.h>
414#include <sys/fcntl.h>
415#endif /* __rtems__ */
416/*
417 * Kernel descriptor table.
418 * One entry for each open kernel vnode and socket.
419 *
420 * Below is the list of locks that protects members in struct file.
421 *
422 * (f) protected with mtx_lock(mtx_pool_find(fp))
423 * (d) cdevpriv_mtx
424 * none not locked
425 */
426-------------------------------------------------------------------------------
427
428-------------------------------------------------------------------------------
429extern int profprocs;                   /* number of process's profiling */
430#ifndef __rtems__
431extern volatile int ticks;
432#else /* __rtems__ */
433#include <rtems/score/watchdogimpl.h>
434#define ticks _Watchdog_Ticks_since_boot
435#endif /* __rtems__ */
436
437#endif /* _KERNEL */
438-------------------------------------------------------------------------------
439
440Add nothing (even blank lines) before or after the `__rtems__` guards.  Always
441include a `__rtems__` in the guards to make searches easy.
442
443== BSD Library Source
444
445=== What is in the Git Repository
446
447There is a self-contained kit with FreeBSD and RTEMS components pre-merged. The
448Makefile in this kit is automatically generated.
449
450Any changes to source in the `freebsd` directories will need to be merged
451upstream into our master FreeBSD checkout, the `freebsd-org` submodule.
452
453The repository contains two FreeBSD source trees.  In the `freebsd` directory
454are the so called 'managed' FreeBSD sources used to build the BSD library.  The
455FreeBSD source in `freebsd-org` is the 'master' version.  The
456`freebsd-to-rtems.py` script is used to transfer files between the two trees.
457In general terms, if you have modified managed FreeBSD sources, you will need
458to run the script in 'revert' or 'reverse' mode using the `-R` switch.  This
459will copy the source back to your local copy of the master FreeBSD source so
460you can run `git diff` against the upstream FreeBSD source.  If you want to
461transfer source files from the master FreeBSD source to the manged FreeBSD
462sources, then you must run the script in 'forward' mode (the default).
463
464=== Organization
465
466The top level directory contains a few directories and files. The following
467are important to understand
468
469* `freebsd-to-rtems.py` - script to convert to and free FreeBSD and RTEMS trees,
470* `Makefile` - automatically generated,
471* `freebsd/` - from FreeBSD by script,
472* `rtemsbsd/` - RTEMS specific implementations of FreeBSD kernel support routines,
473* `testsuite/` - RTEMS specific tests, and
474* `libbsd.txt` - documentation in Asciidoc.
475
476== Moving Code Between Managed and Master FreeBSD Source
477
478The script `freebsd-to-rtems.py` is used to copy code from FreeBSD to the
479rtems-libbsd tree and to reverse this process. This script attempts to
480automate this process as much as possible and performs some transformations
481on the FreeBSD code. Its command line arguments are shown below:
482
483----
484freebsd-to-rtems.py [args]
485  -?|-h|--help     print this and exit
486  -d|--dry-run     run program but no modifications
487  -D|--diff        provide diff of files between trees
488  -e|--early-exit  evaluate arguments, print results, and exit
489  -m|--makefile    just generate Makefile
490  -R|--reverse     default FreeBSD -> RTEMS, reverse that
491  -r|--rtems       RTEMS directory
492  -f|--freebsd     FreeBSD directory
493  -v|--verbose     enable verbose output mode
494----
495
496In its default mode of operation, freebsd-to-rtems.py is used to copy code
497from FreeBSD to the rtems-libbsd tree and perform transformations.  In forward
498mode, the script may be requested to just generate the Makefile.
499
500In "reverse mode", this script undoes those transformations and copies
501the source code back to the FreeBSD SVN tree. This allows us to do
502'svn diff', evaluate changes made by the RTEMS Project, and report changes
503back to FreeBSD upstream.
504
505In either mode, the script may be asked to perform a dry-run or be verbose.
506Also, in either mode, the script is also smart enough to avoid copying over
507files which have not changed. This means that the timestamps of files are
508not changed unless the contents change. The script will also report the
509number of files which changed. In verbose mode, the script will print
510the name of the files which are changed.
511
512The following is an example forward run with no changes.
513
514----
515$ ~/newbsd/git/libbsd-8.2/freebsd-to-rtems.py \
516    -r /home/joel/newbsd/git/libbsd-8.2 \
517    -f /home/joel/newbsd/libbsd/freebsd-8.2 -v
518Verbose:                yes
519Dry Run:                no
520Only Generate Makefile: no
521RTEMS Directory:        /home/joel/newbsd/git/libbsd-8.2
522FreeBSD Directory:      /home/joel/newbsd/libbsd/freebsd-8.2
523Direction:              forward
524Generating into /home/joel/newbsd/git/libbsd-8.2
5250 files were changed.
526----
527
528The script may also be used to generate a diff in either forward or reverse
529direction.
530
531== Initialization of the BSD Library
532
533The initialization of the BSD library is based on the FreeBSD SYSINIT(9)
534infrastructure.  The key to initializing a system is to ensure that the desired
535device drivers are explicitly pulled into the linked application.  This plus
536linking against the BSD library (`libbsd.a`) will pull in the necessary FreeBSD
537infrastructure.
538
539The FreeBSD kernel is not a library like the RTEMS kernel.  It is a bunch of
540object files linked together.  If we have a library, then creating the
541executable is simple.  We begin with a start symbol and recursively resolve all
542references.  With a bunch of object files linked together we need a different
543mechanism.  Most object files don't know each other.  Lets say we have a driver
544module.  The rest of the system has no references to this driver module.  The
545driver module needs a way to tell the rest of the system: Hey, kernel I am
546here, please use my services!
547
548This registration of independent components is performed by SYSINIT(9) and
549specializations:
550
551http://www.freebsd.org/cgi/man.cgi?query=SYSINIT
552
553The SYSINIT(9) uses some global data structures that are placed in a certain
554section.  In the linker command file we need this:
555
556-------------------------------------------------------------------------------
557.rtemsroset : {
558        KEEP (*(SORT(.rtemsroset.*)))
559}
560
561.rtemsrwset : {
562        KEEP (*(SORT(.rtemsrwset.*)))
563}
564-------------------------------------------------------------------------------
565
566This results for example in this executable layout:
567
568-------------------------------------------------------------------------------
569[...]
570 *(SORT(.rtemsroset.*))
571 .rtemsroset.bsd.modmetadata_set.begin
572                0x000000000025fe00        0x0 libbsd.a(rtems-bsd-init.o)
573                0x000000000025fe00                _bsd__start_set_modmetadata_set
574 .rtemsroset.bsd.modmetadata_set.content
575                0x000000000025fe00        0x8 libbsd.a(rtems-bsd-nexus.o)
576 .rtemsroset.bsd.modmetadata_set.content
577                0x000000000025fe08        0x4 libbsd.a(kern_module.o)
578[...]
579 .rtemsroset.bsd.modmetadata_set.content
580                0x000000000025fe68        0x4 libbsd.a(mii.o)
581 .rtemsroset.bsd.modmetadata_set.content
582                0x000000000025fe6c        0x4 libbsd.a(mii_bitbang.o)
583 .rtemsroset.bsd.modmetadata_set.end
584                0x000000000025fe70        0x0 libbsd.a(rtems-bsd-init.o)
585                0x000000000025fe70                _bsd__stop_set_modmetadata_set
586[...]
587.rtemsrwset     0x000000000030bad0      0x290
588 *(SORT(.rtemsrwset.*))
589 .rtemsrwset.bsd.sysinit_set.begin
590                0x000000000030bad0        0x0 libbsd.a(rtems-bsd-init.o)
591                0x000000000030bad0                _bsd__start_set_sysinit_set
592 .rtemsrwset.bsd.sysinit_set.content
593                0x000000000030bad0        0x4 libbsd.a(rtems-bsd-nexus.o)
594 .rtemsrwset.bsd.sysinit_set.content
595                0x000000000030bad4        0x8 libbsd.a(rtems-bsd-thread.o)
596 .rtemsrwset.bsd.sysinit_set.content
597                0x000000000030badc        0x4 libbsd.a(init_main.o)
598[...]
599 .rtemsrwset.bsd.sysinit_set.content
600                0x000000000030bd54        0x4 libbsd.a(frag6.o)
601 .rtemsrwset.bsd.sysinit_set.content
602                0x000000000030bd58        0x8 libbsd.a(uipc_accf.o)
603 .rtemsrwset.bsd.sysinit_set.end
604                0x000000000030bd60        0x0 libbsd.a(rtems-bsd-init.o)
605                0x000000000030bd60                _bsd__stop_set_sysinit_set
606[...]
607-------------------------------------------------------------------------------
608
609Here you can see, that some global data structures are collected into
610continuous memory areas.  This memory area can be identified by start and stop
611symbols.  This constructs a table of uniform items.
612
613The low level FreeBSD code calls at some time during the initialization the
614mi_startup() function (machine independent startup).  This function will sort
615the SYSINIT(9) set and call handler functions which perform further
616initialization.  The last step is the scheduler invocation.
617
618The SYSINIT(9) routines are run in mi_startup() which is called by
619rtems_bsd_initialize().
620
621This is also explained in "The Design and Implementation of the FreeBSD
622Operating System" section 14.3 "Kernel Initialization".
623
624In RTEMS we have a library and not a bunch of object files.  Thus we need a way
625to pull-in the desired services out of the libbsd.  Here the
626`rtems-bsd-sysinit.h` comes into play.  The SYSINIT(9) macros have been
627modified and extended for RTEMS in `<sys/kernel.h>`:
628
629-------------------------------------------------------------------------------
630#ifndef __rtems__
631#define C_SYSINIT(uniquifier, subsystem, order, func, ident)    \
632        static struct sysinit uniquifier ## _sys_init = {       \
633                subsystem,                                      \
634                order,                                          \
635                func,                                           \
636                (ident)                                         \
637        };                                                      \
638        DATA_SET(sysinit_set,uniquifier ## _sys_init)
639#else /* __rtems__ */
640#define SYSINIT_ENTRY_NAME(uniquifier)                          \
641        _bsd_ ## uniquifier ## _sys_init
642#define SYSINIT_REFERENCE_NAME(uniquifier)                      \
643        _bsd_ ## uniquifier ## _sys_init_ref
644#define C_SYSINIT(uniquifier, subsystem, order, func, ident)    \
645        struct sysinit SYSINIT_ENTRY_NAME(uniquifier) = {       \
646                subsystem,                                      \
647                order,                                          \
648                func,                                           \
649                (ident)                                         \
650        };                                                      \
651        RWDATA_SET(sysinit_set,SYSINIT_ENTRY_NAME(uniquifier))
652#define SYSINIT_REFERENCE(uniquifier)                           \
653        extern struct sysinit SYSINIT_ENTRY_NAME(uniquifier);   \
654        static struct sysinit const * const                     \
655        SYSINIT_REFERENCE_NAME(uniquifier) __used               \
656        = &SYSINIT_ENTRY_NAME(uniquifier)
657#define SYSINIT_MODULE_REFERENCE(mod)                           \
658        SYSINIT_REFERENCE(mod ## module)
659#define SYSINIT_DRIVER_REFERENCE(driver, bus)                   \
660        SYSINIT_MODULE_REFERENCE(driver ## _ ## bus)
661#define SYSINIT_DOMAIN_REFERENCE(dom)                           \
662        SYSINIT_REFERENCE(domain_add_ ## dom)
663#endif /* __rtems__ */
664-------------------------------------------------------------------------------
665
666Here you see that the SYSINIT(9) entries are no longer static.  The
667\*_REFERENCE() macros will create references to the corresponding modules which
668are later resolved by the linker.  The application has to provide an object
669file with references to all required FreeBSD modules.
670
671The FreeBSD device model is quite elaborated (with follow-ups):
672
673http://www.freebsd.org/cgi/man.cgi?query=driver
674
675The devices form a tree with the Nexus device at a high-level.  This Nexus
676device is architecture specific in FreeBSD.  In RTEMS we have our own Nexus
677device, see `rtemsbsd/bsp/bsp-bsd-nexus-devices.c`.
678
679=== SYSCTL_NODE Example
680
681During development, we had an undefined reference to
682_bsd_sysctl__net_children that we had trouble tracking down. Thanks to
683Chris Johns, we located it. He explained how to read SYSCTL_NODE
684definitions. This line from freebsd/netinet/in_proto.c is attempting
685to add the "inet" node to the parent node "_net".
686
687----
688SYSCTL_NODE(_net,      PF_INET,         inet,   CTLFLAG_RW, 0,
689        "Internet Family");
690----
691
692Our problem was that we could not find where _bsd_sysctl__net_children
693was defined. Chris suggested that when in doubt compile with -save-temps
694and look at the preprocessed .i files. But he did not need that. He
695explained that this the symbol name _bsd_sysctl__net_children was
696automatically generated by a SYSCTL_NODE as follows:
697
698* _bsd_ - added by RTEMS modifications to SYSCTL_NODE macro
699* sysctl_ - boilerplace added by SYSCTL_NODE macro
700* "" - empty string for parent node
701* net - name of SYSCTL_NODE
702* children - added by SYSCTL macros
703 
704This was all generated by a support macro declaring the node as this:
705
706----
707struct sysctl_oid_list SYSCTL_NODE_CHILDREN(parent, name);
708----
709
710Given this information, we located this SYSCTL_NODE declaration in
711kern/kern_mib.c
712
713----
714SYSCTL_NODE(, CTL_KERN,   kern,   CTLFLAG_RW, 0,
715        "High kernel, proc, limits &c");
716----
717
718== Core FreeBSD APIs and RTEMS Replacements ==
719
720=== SX(9) (Shared/exclusive locks) ===
721
722http://www.freebsd.org/cgi/man.cgi?query=sx
723
724Binary semaphores (this neglects the ability to allow shared access).
725
726=== MUTEX(9) (Mutual exclusion) ===
727
728http://www.freebsd.org/cgi/man.cgi?query=mutex
729
730Binary semaphores (not recursive mutexes are not supported this way).
731
732=== RWLOCK(9) (Reader/writer lock) ===
733
734http://www.freebsd.org/cgi/man.cgi?query=rwlock
735
736POSIX r/w lock.
737
738=== RMLOCK(9) (Reader/writer lock optimized for mostly read access patterns) ===
739
740Note:  This object was implemented as a wrapper for RWLOCK in the rm_lock header file.
741
742http://www.freebsd.org/cgi/man.cgi?query=rmlock
743
744POSIX r/w lock.
745
746=== CONDVAR(9) (Condition variables) ===
747
748http://www.freebsd.org/cgi/man.cgi?query=condvar
749
750POSIX condition variables with modifications (hack).
751
752=== CALLOUT(9) (Timer functions) ===
753
754http://www.freebsd.org/cgi/man.cgi?query=callout
755
756Timer server.
757
758=== TASKQUEUE(9) (Asynchronous task execution) ===
759
760http://www.freebsd.org/cgi/man.cgi?query=taskqueue
761
762TBD.
763
764=== KTHREAD(9), KPROC(9) (Tasks) ===
765
766http://www.freebsd.org/cgi/man.cgi?query=kthread
767
768http://www.freebsd.org/cgi/man.cgi?query=kproc
769
770Tasks.
771
772=== ZONE(9) (Zone allocator) ===
773
774http://www.freebsd.org/cgi/man.cgi?query=zone
775
776TBD.
777
778=== devfs (Device file system) ===
779
780Dummy, IMFS or new implementation (currently dummy).
781
782=== psignal (Signals) ===
783
784TBD.  Seems to be not needed.
785
786=== poll, select ===
787
788TBD.  Seems to be not needed.
789
790=== RMAN(9) (Resource management) ===
791
792http://www.freebsd.org/cgi/man.cgi?query=rman
793
794TBD.  Seems to be not needed.
795
796=== DEVCLASS(9), DEVICE(9), DRIVER(9), MAKE_DEV(9) (Device management) ===
797
798http://www.freebsd.org/cgi/man.cgi?query=devclass
799
800http://www.freebsd.org/cgi/man.cgi?query=device
801
802http://www.freebsd.org/cgi/man.cgi?query=driver
803
804http://www.freebsd.org/cgi/man.cgi?query=make_dev
805
806Use FreeBSD implementation as far as possible.  FreeBSD has a nice API for
807dynamic device handling.  It may be interesting for RTEMS to use this API
808internally in the future.
809
810=== BUS_SPACE(9), BUS_DMA(9) (Bus and DMA access) ===
811
812http://www.freebsd.org/cgi/man.cgi?query=bus_space
813
814http://www.freebsd.org/cgi/man.cgi?query=bus_dma
815
816Likely BSP dependent.  A default implementation for memory mapped linear access
817is easy to provide.  The current heap implementation supports all properties
818demanded by bus_dma (including the boundary constraint).
819
820== RTEMS Replacements by File Description ==
821
822Note:  Files with a status of USB are used by the USB test and have at least
823been partially tested.  If they contain both USB and Nic, then they are used
824by both and MAY contain methods that have not been tested yet.  Files that
825are only used by the Nic test are the most suspect.
826
827----
828rtems-libbsd File:      rtems-bsd-assert.c
829FreeBSD File:           rtems-bsd-config.h redefines BSD_ASSERT.
830Description:            This file contains the support method rtems_bsd_assert_func().
831Status:                 USB, Nic
832
833rtems-libbsd File:      rtems-bsd-autoconf.c
834FreeBSD File:           FreeBSD has BSP specific autoconf.c
835Description:            This file contains configuration methods that are used to setup the system.
836Status:                 USB
837
838rtems-libbsd File:      rtems-bsd-bus-dma.c
839FreeBSD File:           FreeBSD has BSP specific busdma_machdep.c
840Description:           
841Status:                 USB, Nic
842
843rtems-libbsd File:      rtems-bsd-bus-dma-mbuf.c       
844FreeBSD File:           FreeBSD has BSP specific busdma_machdep.c
845Description:           
846Status:                 Nic
847
848rtems-libbsd File:      rtems-bsd-callout.c             
849FreeBSD File:           kern/kern_timeout.c
850Description:           
851Status:                 USB, Nic
852
853rtems-libbsd File:      rtems-bsd-cam.c
854FreeBSD File:           cam/cam_sim.c
855Description:           
856Status:                 USB
857
858rtems-libbsd File:      rtems-bsd-condvar.c             
859FreeBSD File:           kern/kern_condvar.c
860Description:           
861Status:                 USB
862
863rtems-libbsd File:      rtems-bsd-copyinout.c
864FreeBSD File:           bsp specific copyinout.c )
865Description:            Note: The FreeBSD file is split with some methods being in rtems-bsd-support
866Status:                 Nic
867
868rtems-libbsd File:      rtems-bsd-delay.c
869FreeBSD File:           bsp specific file with multiple names
870Description:           
871Status:                 USB, Nic
872
873rtems-libbsd File:      rtems-bsd-descrip.c
874FreeBSD File:           kern/kern_descrip.c
875Description:           
876Status:                 Nic
877
878rtems-libbsd File:      rtems-bsd-generic.c             
879FreeBSD File:           kern/sys_generic.c
880Description:           
881Status:                 Nic
882
883rtems-libbsd File:      rtems-bsd-init.c
884FreeBSD File:           N/A
885Description:           
886Status:                 USB, Nic
887
888rtems-libbsd File:      rtems-bsd-init-with-irq.c
889FreeBSD File:           N/A
890Description:           
891Status:                 USB, Nic
892
893rtems-libbsd File:      rtems-bsd-jail.c
894FreeBSD File:           kern/kern_jail.c
895Description:           
896Status:                 USB, Nic
897
898rtems-libbsd File:      rtems-bsd-lock.c
899FreeBSD File:           kern/subr_lock.c
900Description:           
901Status:                 USB, Nic
902
903rtems-libbsd File:      rtems-bsd-log.c         
904FreeBSD File:           kern/subr_prf.c
905Description:           
906Status:                 Nic
907
908rtems-libbsd File:      rtems-bsd-malloc.c
909FreeBSD File:           kern/kern_malloc.c
910Description:           
911Status:                 USB, Nic
912
913rtems-libbsd File:      rtems-bsd-mutex.c
914FreeBSD File:           kern/kern_mutex.c
915Description:           
916Status:                 USB, Nic
917
918rtems-libbsd File:      rtems-bsd-newproc.c
919FreeBSD File:           N/A
920Description:           
921Status:                 Nic
922
923rtems-libbsd File:      rtems-bsd-nexus.c
924FreeBSD File:           bsp specific nexus.c
925Description:           
926Status:                 USB
927
928rtems-libbsd File:      rtems-bsd-panic.c               
929FreeBSD File:           boot/common/panic.c
930Description:           
931Status:                 USB, Nic
932
933rtems-libbsd File:      rtems-bsd-rwlock.c             
934FreeBSD File:           kern_rwlock.c
935Description:           
936Status:                 USB, Nic
937
938rtems-libbsd File:      rtems-bsd-shell.c               
939FreeBSD File:           N/A
940Description:           
941Status:                 USB
942
943rtems-libbsd File:      rtems-bsd-signal.c             
944FreeBSD File:           kern/kern_sig.c
945Description:           
946Status:                 Nic
947
948rtems-libbsd File:      rtems-bsd-smp.c                 
949FreeBSD File:           N/A
950Description:           
951Status:                 Nic
952
953rtems-libbsd File:      rtems-bsd-support.c             
954FreeBSD File:           bsp specific copyinout.c
955Description:            Note: the FreeBSD file is split with some methods being in rtems-bsd-copyinout.
956Status:                 USB, Nic
957
958rtems-libbsd File:      rtems-bsd-sx.c                 
959FreeBSD File:           kern/kern_sx.c
960Description:            Status: USB, Nic
961
962rtems-libbsd File:      rtems-bsd-synch.c               
963FreeBSD File:           kern/kern_synch.c
964Description:           
965Status:                 USB, Nic
966
967rtems-libbsd File:      rtems-bsd-syscalls.c           
968FreeBSD File:           User API for kern/uipc_syscalls.c
969Description:           
970Status:                 Nic
971
972rtems-libbsd File:      rtems-bsd-sysctlbyname.c       
973FreeBSD File:           User API for sysctlbyname(3)
974Description:           
975Status:
976
977rtems-libbsd File:      rtems-bsd-sysctl.c             
978FreeBSD File:           User API for sysctl(8)
979Description:           
980Status:
981
982rtems-libbsd File:      rtems-bsd-sysctlnametomib.c     
983FreeBSD File:           User API for sysctlnametomib
984Description:           
985Status:
986
987rtems-libbsd File:      rtems-bsd-taskqueue.c           
988FreeBSD File:           kern/subr_taskqueue.c
989Description:           
990Status:                 Nic
991
992rtems-libbsd File:      rtems-bsd-thread.c                     
993FreeBSD File:           kern/kern_kthread.c
994Description:           
995Status:                 USB, Nic
996
997rtems-libbsd File:      rtems-bsd-timeout.c             
998FreeBSD File:           kern/kern_timeout.c
999Description:           
1000Status:                 Nic
1001
1002rtems-libbsd File:      rtems-bsd-timesupport.c         
1003FreeBSD File:           kern/kern_clock.c
1004Description:           
1005Status:                 Nic
1006
1007rtems-libbsd File:      rtems-bsd-vm_glue.c             
1008FreeBSD File:           vm/vm_glue.c
1009Description:           
1010Status:                 USB, Nic
1011----
1012
1013== Notes by File ==
1014
1015altq_subr.c - Arbitrary choices were made in this file that RTEMS would
1016not support tsc frequency change.  Additionally, the clock frequency
1017for machclk_freq is always measured for RTEMS.
1018
1019conf.h - In order to add make_dev and destroy_dev, variables in the cdev
1020structure that were not being used were conditionally compiled out. The
1021capability of supporting children did not appear to be needed and was
1022not implemented in the rtems version of these routines.
1023 
1024== NICs Status ==
1025
1026----
1027Driver                  Symbol                          Status
1028======                  ======                          ======
1029RealTek                 _bsd_re_pcimodule_sys_init      Links
1030EtherExpress            _bsd_fxp_pcimodule_sys_init     Links
1031DEC tulip               _bsd_dc_pcimodule_sys_init      Links
1032Broadcom BCM57xxx       _bsd_bce_pcimodule_sys_init     Links
1033Broadcom BCM4401        _bsd_bfe_pcimodule_sys_init     Links
1034Broadcom BCM570x        _bsd_bge_pcimodule_sys_init     Needs Symbols (A)
1035E1000 IGB               _bsd_igb_pcimodule_sys_init     Links
1036E1000 EM                _bsd_em_pcimodule_sys_init      Links
1037----
1038
1039
1040Symbols (A)
1041         pci_get_vpd_ident
1042 
1043== Problems to report to FreeBSD ==
1044
1045The MMAP_NOT_AVAILABLE define is inverted on its usage.  When it is
1046defined the mmap method is called. Additionally, it is not used
1047thoroughly. It is not used in the unmap portion of the source.
1048The file rec_open.c uses the define MMAP_NOT_AVAILABLE to wrap
1049the call to mmap and file rec_close.c uses the munmap method.
1050
1051
1052
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