source: rtems-libbsd/libbsd.txt @ 5383ed4

4.115-freebsd-12freebsd-9.3
Last change on this file since 5383ed4 was 5383ed4, checked in by Sebastian Huber <sebastian.huber@…>, on Feb 13, 2015 at 9:31:27 AM

Add and use rtems_bsd_get_allocator_domain_size()

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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=== Task Priorities and Stack Size ===
232
233The default task priority is 96 for the interrupt server task (name "IRQS"), 98
234for the timer server task (name "TIME") and 100 for all other tasks.  The
235application may provide their own implementation of the
236`rtems_bsd_get_task_priority()` function (for example in the module which calls
237`rtems_bsd_initialize()`) if different values are desired.
238
239The task stack size is determined by the `rtems_bsd_get_task_stack_size()`
240function which may be provided by the application in case the default is not
241appropriate.
242
243=== Size for Allocator Domains ===
244
245The size for an allocator domain can be specified via the
246`rtems_bsd_get_allocator_domain_size()` function.  The application may provide
247their own implementation of the `rtems_bsd_get_allocator_domain_size()`
248function (for example in the module which calls `rtems_bsd_initialize()`) if
249different values are desired.  The default size is 8MiB for all domains.
250
251== Network Stack Features
252
253http://roy.marples.name/projects/dhcpcd/index[DHCPCD(8)]:: DHCP client
254
255https://developer.apple.com/library/mac/documentation/Networking/Reference/DNSServiceDiscovery_CRef/Reference/reference.html[dns_sd.h]:: DNS Service Discovery
256
257http://www.opensource.apple.com/source/mDNSResponder/mDNSResponder-320.10/mDNSCore/mDNSEmbeddedAPI.h[mDNS]:: Multi-Cast DNS
258
259http://www.freebsd.org/cgi/man.cgi?query=unix&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[UNIX(4)]:: UNIX-domain protocol family
260
261http://www.freebsd.org/cgi/man.cgi?query=inet&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[INET(4)]:: Internet protocol family
262
263http://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
264
265http://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
266
267http://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
268
269http://www.freebsd.org/cgi/man.cgi?query=route&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[ROUTE(4)]:: Kernel packet forwarding database
270
271http://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
272
273http://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
274
275http://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
276
277http://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
278
279http://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
280
281http://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
282
283http://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
284
285http://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
286
287http://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
288
289http://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
290
291http://www.freebsd.org/cgi/man.cgi?query=sysctl&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[SYSCTL(3)]:: Get or set system information
292
293http://www.freebsd.org/cgi/man.cgi?query=resolver&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[RESOLVER(3)]:: Resolver routines
294
295http://www.freebsd.org/cgi/man.cgi?query=gethostbyname&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[GETHOSTBYNAME(3)]:: Get network host entry
296
297== Network Interface Drivers
298
299=== Link Up/Down Events
300
301You can notifiy the application space of link up/down events in your network
302interface driver via the if_link_state_change(LINK_STATE_UP/LINK_STATE_DOWN)
303function.  The DHCPCD(8) client is a consumer of these events for example.
304Make sure that the interface flag IFF_UP and the interface driver flag
305IFF_DRV_RUNNING is set in case the link is up, otherwise ether_output() will
306return the error status ENETDOWN.
307
308== Shell Commands
309
310=== HOSTNAME(1)
311
312In addition to the standard options the RTEMS version of the HOSTNAME(1)
313command supports the -m flag to set/get the multicast hostname of the
314mDNS resolver instance.  See also rtems_mdns_sethostname() and
315rtems_mdns_gethostname().
316
317== Issues and TODO
318
319* Per-CPU data should be enabled once the new stack is ready for SMP.
320
321* Per-CPU NETISR(9) should be enabled onece the new stack is ready for SMP.
322
323* Multiple routing tables are not supported.  Every FIB value is set to zero
324  (= BSD_DEFAULT_FIB).
325
326* Process identifiers are not supported.  Every PID value is set to zero
327  (= BSD_DEFAULT_PID).
328
329* User credentials are not supported.  The following functions allow the
330  operation for everyone
331  - prison_equal_ip4(),
332  - chgsbsize(),
333  - cr_cansee(),
334  - cr_canseesocket() and
335  - cr_canseeinpcb().
336
337* A basic USB functionality test that is known to work on Qemu is desirable.
338
339* Adapt generic IRQ PIC interface code to Simple Vectored Interrupt Model
340  so that those architectures can use new TCP/IP and USB code.
341
342* freebsd-userspace/rtems/include/sys/syslog.h is a copy from the old
343  RTEMS TCP/IP stack. For some reason, the __printflike markers do not
344  compile in this environment. We may want to use the FreeBSD syslog.h
345  and get this addressed.
346
347* in_cksum implementations for architectures not supported by FreeBSD.
348  This will require figuring out where to put implementations that do
349  not originate from FreeBSD and are populated via the script.
350
351* MAC support functions are not thread-safe ("freebsd/lib/libc/posix1e/mac.c").
352
353* IFCONFIG(8): IEEE80211 support is disabled.  This module depends on a XML
354  parser and mmap().
355
356* get_cyclecount(): The implementation is a security problem.
357
358* What to do with the priority parameter present in the FreeBSD synchronization
359  primitives and the thread creation functions?
360
361* TASKQUEUE(9): Support spin mutexes.
362
363* ZONE(9): Review allocator lock usage in rtems-bsd-chunk.c.
364
365* KQUEUE(2): Choose proper lock for global kqueue list.
366
367* TIMEOUT(9): Maybe use special task instead of timer server to call
368  callout_tick().
369
370* sysctl_handle_opaque(): Implement reliable snapshots.
371
372* PING6(8): What to do with SIGALARM?
373
374* <sys/param.h>: Update Newlib to use a MSIZE of 256.
375
376* BPF(4): Add support for zero-copy buffers.
377
378* UNIX(4): Fix race conditions in the area of socket object and file node
379  destruction.  Add support for file descriptor transmission via control
380  messages.
381
382* PRINTF(9): Add support for log(), the %D format specifier is missing in the
383  normal printf() family.
384
385* Why is the interrupt server used?  The BSD interrupt handlers can block on
386synchronization primitives like mutexes.  This is in contrast to RTEMS
387interrupt service routines.  The BSPs using the generic interrupt support must
388implement the `bsp_interrupt_vector_enable()` and
389`bsp_interrupt_vector_disable()` routines.  They normally enable/disable a
390particular interrupt source at the interrupt controller.  This can be used to
391implement the interrupt server.  The interrupt server is a task that wakes-up
392in case an associated interrupt happens.  The interrupt source is disabled in
393a generic interrupt handler that wakes-up the interrupt server task.   Once the
394postponed interrupt processing is performed in the interrupt server the
395interrupt source is enabled again.
396
397* Convert all BSP linkcmds to use a linkcmds.base so the sections are
398easier to insert.
399
400* NIC Device Drivers
401- Only common PCI NIC drivers have been included in the initial set. These
402do not include any system on chip or ISA drivers.
403- PCI configuration probe does not appear to happen to determine if a
404NIC is in I/O or memory space. We have worked around this by using a
405static hint to tell the fxp driver the correct mode. But this needs to
406be addressed.
407- The ISA drivers require more BSD infrastructure to be addressed. This was
408outside the scope of the initial porting effort.
409
410== FreeBSD Source
411
412You should be able to rely on FreebSD manual pages and documentation
413for details on the code itself.
414
415=== Automatically Generated FreeBSD Files
416
417Some source and header files are automatically generated during the FreeBSD
418build process.  The `Makefile.todo` file performs this manually.  The should be
419included in `freebsd-to-rtems.py` script some time in the future.  For details,
420see also
421http://www.freebsd.org/cgi/man.cgi?query=kobj&sektion=9&apropos=0&manpath=FreeBSD+9.2-RELEASE[KOBJ(9)].
422
423=== Rules for Modifying FreeBSD Source
424
425Only add lines.  Subtract code by added `#ifndef __rtems__`.  This makes
426merging easier in the future.  For example:
427
428-------------------------------------------------------------------------------
429/* Global variables for the kernel. */
430
431#ifndef __rtems__
432/* 1.1 */
433extern char kernelname[MAXPATHLEN];
434#endif /* __rtems__ */
435
436extern int tick;                        /* usec per tick (1000000 / hz) */
437-------------------------------------------------------------------------------
438
439-------------------------------------------------------------------------------
440#if defined(_KERNEL) || defined(_WANT_FILE)
441#ifdef __rtems__
442#include <rtems/libio_.h>
443#include <sys/fcntl.h>
444#endif /* __rtems__ */
445/*
446 * Kernel descriptor table.
447 * One entry for each open kernel vnode and socket.
448 *
449 * Below is the list of locks that protects members in struct file.
450 *
451 * (f) protected with mtx_lock(mtx_pool_find(fp))
452 * (d) cdevpriv_mtx
453 * none not locked
454 */
455-------------------------------------------------------------------------------
456
457-------------------------------------------------------------------------------
458extern int profprocs;                   /* number of process's profiling */
459#ifndef __rtems__
460extern volatile int ticks;
461#else /* __rtems__ */
462#include <rtems/score/watchdogimpl.h>
463#define ticks _Watchdog_Ticks_since_boot
464#endif /* __rtems__ */
465
466#endif /* _KERNEL */
467-------------------------------------------------------------------------------
468
469Add nothing (even blank lines) before or after the `__rtems__` guards.  Always
470include a `__rtems__` in the guards to make searches easy.
471
472== BSD Library Source
473
474=== What is in the Git Repository
475
476There is a self-contained kit with FreeBSD and RTEMS components pre-merged. The
477Makefile in this kit is automatically generated.
478
479Any changes to source in the `freebsd` directories will need to be merged
480upstream into our master FreeBSD checkout, the `freebsd-org` submodule.
481
482The repository contains two FreeBSD source trees.  In the `freebsd` directory
483are the so called 'managed' FreeBSD sources used to build the BSD library.  The
484FreeBSD source in `freebsd-org` is the 'master' version.  The
485`freebsd-to-rtems.py` script is used to transfer files between the two trees.
486In general terms, if you have modified managed FreeBSD sources, you will need
487to run the script in 'revert' or 'reverse' mode using the `-R` switch.  This
488will copy the source back to your local copy of the master FreeBSD source so
489you can run `git diff` against the upstream FreeBSD source.  If you want to
490transfer source files from the master FreeBSD source to the manged FreeBSD
491sources, then you must run the script in 'forward' mode (the default).
492
493=== Organization
494
495The top level directory contains a few directories and files. The following
496are important to understand
497
498* `freebsd-to-rtems.py` - script to convert to and free FreeBSD and RTEMS trees,
499* `Makefile` - automatically generated,
500* `freebsd/` - from FreeBSD by script,
501* `rtemsbsd/` - RTEMS specific implementations of FreeBSD kernel support routines,
502* `testsuite/` - RTEMS specific tests, and
503* `libbsd.txt` - documentation in Asciidoc.
504
505== Moving Code Between Managed and Master FreeBSD Source
506
507The script `freebsd-to-rtems.py` is used to copy code from FreeBSD to the
508rtems-libbsd tree and to reverse this process. This script attempts to
509automate this process as much as possible and performs some transformations
510on the FreeBSD code. Its command line arguments are shown below:
511
512----
513freebsd-to-rtems.py [args]
514  -?|-h|--help     print this and exit
515  -d|--dry-run     run program but no modifications
516  -D|--diff        provide diff of files between trees
517  -e|--early-exit  evaluate arguments, print results, and exit
518  -m|--makefile    just generate Makefile
519  -R|--reverse     default FreeBSD -> RTEMS, reverse that
520  -r|--rtems       RTEMS directory
521  -f|--freebsd     FreeBSD directory
522  -v|--verbose     enable verbose output mode
523----
524
525In its default mode of operation, freebsd-to-rtems.py is used to copy code
526from FreeBSD to the rtems-libbsd tree and perform transformations.  In forward
527mode, the script may be requested to just generate the Makefile.
528
529In "reverse mode", this script undoes those transformations and copies
530the source code back to the FreeBSD SVN tree. This allows us to do
531'svn diff', evaluate changes made by the RTEMS Project, and report changes
532back to FreeBSD upstream.
533
534In either mode, the script may be asked to perform a dry-run or be verbose.
535Also, in either mode, the script is also smart enough to avoid copying over
536files which have not changed. This means that the timestamps of files are
537not changed unless the contents change. The script will also report the
538number of files which changed. In verbose mode, the script will print
539the name of the files which are changed.
540
541The following is an example forward run with no changes.
542
543----
544$ ~/newbsd/git/libbsd-8.2/freebsd-to-rtems.py \
545    -r /home/joel/newbsd/git/libbsd-8.2 \
546    -f /home/joel/newbsd/libbsd/freebsd-8.2 -v
547Verbose:                yes
548Dry Run:                no
549Only Generate Makefile: no
550RTEMS Directory:        /home/joel/newbsd/git/libbsd-8.2
551FreeBSD Directory:      /home/joel/newbsd/libbsd/freebsd-8.2
552Direction:              forward
553Generating into /home/joel/newbsd/git/libbsd-8.2
5540 files were changed.
555----
556
557The script may also be used to generate a diff in either forward or reverse
558direction.
559
560== Initialization of the BSD Library
561
562The initialization of the BSD library is based on the FreeBSD SYSINIT(9)
563infrastructure.  The key to initializing a system is to ensure that the desired
564device drivers are explicitly pulled into the linked application.  This plus
565linking against the BSD library (`libbsd.a`) will pull in the necessary FreeBSD
566infrastructure.
567
568The FreeBSD kernel is not a library like the RTEMS kernel.  It is a bunch of
569object files linked together.  If we have a library, then creating the
570executable is simple.  We begin with a start symbol and recursively resolve all
571references.  With a bunch of object files linked together we need a different
572mechanism.  Most object files don't know each other.  Lets say we have a driver
573module.  The rest of the system has no references to this driver module.  The
574driver module needs a way to tell the rest of the system: Hey, kernel I am
575here, please use my services!
576
577This registration of independent components is performed by SYSINIT(9) and
578specializations:
579
580http://www.freebsd.org/cgi/man.cgi?query=SYSINIT
581
582The SYSINIT(9) uses some global data structures that are placed in a certain
583section.  In the linker command file we need this:
584
585-------------------------------------------------------------------------------
586.rtemsroset : {
587        KEEP (*(SORT(.rtemsroset.*)))
588}
589
590.rtemsrwset : {
591        KEEP (*(SORT(.rtemsrwset.*)))
592}
593-------------------------------------------------------------------------------
594
595This results for example in this executable layout:
596
597-------------------------------------------------------------------------------
598[...]
599 *(SORT(.rtemsroset.*))
600 .rtemsroset.bsd.modmetadata_set.begin
601                0x000000000025fe00        0x0 libbsd.a(rtems-bsd-init.o)
602                0x000000000025fe00                _bsd__start_set_modmetadata_set
603 .rtemsroset.bsd.modmetadata_set.content
604                0x000000000025fe00        0x8 libbsd.a(rtems-bsd-nexus.o)
605 .rtemsroset.bsd.modmetadata_set.content
606                0x000000000025fe08        0x4 libbsd.a(kern_module.o)
607[...]
608 .rtemsroset.bsd.modmetadata_set.content
609                0x000000000025fe68        0x4 libbsd.a(mii.o)
610 .rtemsroset.bsd.modmetadata_set.content
611                0x000000000025fe6c        0x4 libbsd.a(mii_bitbang.o)
612 .rtemsroset.bsd.modmetadata_set.end
613                0x000000000025fe70        0x0 libbsd.a(rtems-bsd-init.o)
614                0x000000000025fe70                _bsd__stop_set_modmetadata_set
615[...]
616.rtemsrwset     0x000000000030bad0      0x290
617 *(SORT(.rtemsrwset.*))
618 .rtemsrwset.bsd.sysinit_set.begin
619                0x000000000030bad0        0x0 libbsd.a(rtems-bsd-init.o)
620                0x000000000030bad0                _bsd__start_set_sysinit_set
621 .rtemsrwset.bsd.sysinit_set.content
622                0x000000000030bad0        0x4 libbsd.a(rtems-bsd-nexus.o)
623 .rtemsrwset.bsd.sysinit_set.content
624                0x000000000030bad4        0x8 libbsd.a(rtems-bsd-thread.o)
625 .rtemsrwset.bsd.sysinit_set.content
626                0x000000000030badc        0x4 libbsd.a(init_main.o)
627[...]
628 .rtemsrwset.bsd.sysinit_set.content
629                0x000000000030bd54        0x4 libbsd.a(frag6.o)
630 .rtemsrwset.bsd.sysinit_set.content
631                0x000000000030bd58        0x8 libbsd.a(uipc_accf.o)
632 .rtemsrwset.bsd.sysinit_set.end
633                0x000000000030bd60        0x0 libbsd.a(rtems-bsd-init.o)
634                0x000000000030bd60                _bsd__stop_set_sysinit_set
635[...]
636-------------------------------------------------------------------------------
637
638Here you can see, that some global data structures are collected into
639continuous memory areas.  This memory area can be identified by start and stop
640symbols.  This constructs a table of uniform items.
641
642The low level FreeBSD code calls at some time during the initialization the
643mi_startup() function (machine independent startup).  This function will sort
644the SYSINIT(9) set and call handler functions which perform further
645initialization.  The last step is the scheduler invocation.
646
647The SYSINIT(9) routines are run in mi_startup() which is called by
648rtems_bsd_initialize().
649
650This is also explained in "The Design and Implementation of the FreeBSD
651Operating System" section 14.3 "Kernel Initialization".
652
653In RTEMS we have a library and not a bunch of object files.  Thus we need a way
654to pull-in the desired services out of the libbsd.  Here the
655`rtems-bsd-sysinit.h` comes into play.  The SYSINIT(9) macros have been
656modified and extended for RTEMS in `<sys/kernel.h>`:
657
658-------------------------------------------------------------------------------
659#ifndef __rtems__
660#define C_SYSINIT(uniquifier, subsystem, order, func, ident)    \
661        static struct sysinit uniquifier ## _sys_init = {       \
662                subsystem,                                      \
663                order,                                          \
664                func,                                           \
665                (ident)                                         \
666        };                                                      \
667        DATA_SET(sysinit_set,uniquifier ## _sys_init)
668#else /* __rtems__ */
669#define SYSINIT_ENTRY_NAME(uniquifier)                          \
670        _bsd_ ## uniquifier ## _sys_init
671#define SYSINIT_REFERENCE_NAME(uniquifier)                      \
672        _bsd_ ## uniquifier ## _sys_init_ref
673#define C_SYSINIT(uniquifier, subsystem, order, func, ident)    \
674        struct sysinit SYSINIT_ENTRY_NAME(uniquifier) = {       \
675                subsystem,                                      \
676                order,                                          \
677                func,                                           \
678                (ident)                                         \
679        };                                                      \
680        RWDATA_SET(sysinit_set,SYSINIT_ENTRY_NAME(uniquifier))
681#define SYSINIT_REFERENCE(uniquifier)                           \
682        extern struct sysinit SYSINIT_ENTRY_NAME(uniquifier);   \
683        static struct sysinit const * const                     \
684        SYSINIT_REFERENCE_NAME(uniquifier) __used               \
685        = &SYSINIT_ENTRY_NAME(uniquifier)
686#define SYSINIT_MODULE_REFERENCE(mod)                           \
687        SYSINIT_REFERENCE(mod ## module)
688#define SYSINIT_DRIVER_REFERENCE(driver, bus)                   \
689        SYSINIT_MODULE_REFERENCE(driver ## _ ## bus)
690#define SYSINIT_DOMAIN_REFERENCE(dom)                           \
691        SYSINIT_REFERENCE(domain_add_ ## dom)
692#endif /* __rtems__ */
693-------------------------------------------------------------------------------
694
695Here you see that the SYSINIT(9) entries are no longer static.  The
696\*_REFERENCE() macros will create references to the corresponding modules which
697are later resolved by the linker.  The application has to provide an object
698file with references to all required FreeBSD modules.
699
700The FreeBSD device model is quite elaborated (with follow-ups):
701
702http://www.freebsd.org/cgi/man.cgi?query=driver
703
704The devices form a tree with the Nexus device at a high-level.  This Nexus
705device is architecture specific in FreeBSD.  In RTEMS we have our own Nexus
706device, see `rtemsbsd/bsp/bsp-bsd-nexus-devices.c`.
707
708=== SYSCTL_NODE Example
709
710During development, we had an undefined reference to
711_bsd_sysctl__net_children that we had trouble tracking down. Thanks to
712Chris Johns, we located it. He explained how to read SYSCTL_NODE
713definitions. This line from freebsd/netinet/in_proto.c is attempting
714to add the "inet" node to the parent node "_net".
715
716----
717SYSCTL_NODE(_net,      PF_INET,         inet,   CTLFLAG_RW, 0,
718        "Internet Family");
719----
720
721Our problem was that we could not find where _bsd_sysctl__net_children
722was defined. Chris suggested that when in doubt compile with -save-temps
723and look at the preprocessed .i files. But he did not need that. He
724explained that this the symbol name _bsd_sysctl__net_children was
725automatically generated by a SYSCTL_NODE as follows:
726
727* _bsd_ - added by RTEMS modifications to SYSCTL_NODE macro
728* sysctl_ - boilerplace added by SYSCTL_NODE macro
729* "" - empty string for parent node
730* net - name of SYSCTL_NODE
731* children - added by SYSCTL macros
732 
733This was all generated by a support macro declaring the node as this:
734
735----
736struct sysctl_oid_list SYSCTL_NODE_CHILDREN(parent, name);
737----
738
739Given this information, we located this SYSCTL_NODE declaration in
740kern/kern_mib.c
741
742----
743SYSCTL_NODE(, CTL_KERN,   kern,   CTLFLAG_RW, 0,
744        "High kernel, proc, limits &c");
745----
746
747== Core FreeBSD APIs and RTEMS Replacements ==
748
749=== SX(9) (Shared/exclusive locks) ===
750
751http://www.freebsd.org/cgi/man.cgi?query=sx
752
753Binary semaphores (this neglects the ability to allow shared access).
754
755=== MUTEX(9) (Mutual exclusion) ===
756
757http://www.freebsd.org/cgi/man.cgi?query=mutex
758
759Binary semaphores (not recursive mutexes are not supported this way).
760
761=== RWLOCK(9) (Reader/writer lock) ===
762
763http://www.freebsd.org/cgi/man.cgi?query=rwlock
764
765POSIX r/w lock.
766
767=== RMLOCK(9) (Reader/writer lock optimized for mostly read access patterns) ===
768
769Note:  This object was implemented as a wrapper for RWLOCK in the rm_lock header file.
770
771http://www.freebsd.org/cgi/man.cgi?query=rmlock
772
773POSIX r/w lock.
774
775=== CONDVAR(9) (Condition variables) ===
776
777http://www.freebsd.org/cgi/man.cgi?query=condvar
778
779POSIX condition variables with modifications (hack).
780
781=== CALLOUT(9) (Timer functions) ===
782
783http://www.freebsd.org/cgi/man.cgi?query=callout
784
785Timer server.
786
787=== TASKQUEUE(9) (Asynchronous task execution) ===
788
789http://www.freebsd.org/cgi/man.cgi?query=taskqueue
790
791TBD.
792
793=== KTHREAD(9), KPROC(9) (Tasks) ===
794
795http://www.freebsd.org/cgi/man.cgi?query=kthread
796
797http://www.freebsd.org/cgi/man.cgi?query=kproc
798
799Tasks.
800
801=== ZONE(9) (Zone allocator) ===
802
803http://www.freebsd.org/cgi/man.cgi?query=zone
804
805TBD.
806
807=== devfs (Device file system) ===
808
809Dummy, IMFS or new implementation (currently dummy).
810
811=== psignal (Signals) ===
812
813TBD.  Seems to be not needed.
814
815=== poll, select ===
816
817TBD.  Seems to be not needed.
818
819=== RMAN(9) (Resource management) ===
820
821http://www.freebsd.org/cgi/man.cgi?query=rman
822
823TBD.  Seems to be not needed.
824
825=== DEVCLASS(9), DEVICE(9), DRIVER(9), MAKE_DEV(9) (Device management) ===
826
827http://www.freebsd.org/cgi/man.cgi?query=devclass
828
829http://www.freebsd.org/cgi/man.cgi?query=device
830
831http://www.freebsd.org/cgi/man.cgi?query=driver
832
833http://www.freebsd.org/cgi/man.cgi?query=make_dev
834
835Use FreeBSD implementation as far as possible.  FreeBSD has a nice API for
836dynamic device handling.  It may be interesting for RTEMS to use this API
837internally in the future.
838
839=== BUS_SPACE(9), BUS_DMA(9) (Bus and DMA access) ===
840
841http://www.freebsd.org/cgi/man.cgi?query=bus_space
842
843http://www.freebsd.org/cgi/man.cgi?query=bus_dma
844
845Likely BSP dependent.  A default implementation for memory mapped linear access
846is easy to provide.  The current heap implementation supports all properties
847demanded by bus_dma (including the boundary constraint).
848
849== RTEMS Replacements by File Description ==
850
851Note:  Files with a status of USB are used by the USB test and have at least
852been partially tested.  If they contain both USB and Nic, then they are used
853by both and MAY contain methods that have not been tested yet.  Files that
854are only used by the Nic test are the most suspect.
855
856----
857rtems-libbsd File:      rtems-bsd-assert.c
858FreeBSD File:           rtems-bsd-config.h redefines BSD_ASSERT.
859Description:            This file contains the support method rtems_bsd_assert_func().
860Status:                 USB, Nic
861
862rtems-libbsd File:      rtems-bsd-autoconf.c
863FreeBSD File:           FreeBSD has BSP specific autoconf.c
864Description:            This file contains configuration methods that are used to setup the system.
865Status:                 USB
866
867rtems-libbsd File:      rtems-bsd-bus-dma.c
868FreeBSD File:           FreeBSD has BSP specific busdma_machdep.c
869Description:           
870Status:                 USB, Nic
871
872rtems-libbsd File:      rtems-bsd-bus-dma-mbuf.c       
873FreeBSD File:           FreeBSD has BSP specific busdma_machdep.c
874Description:           
875Status:                 Nic
876
877rtems-libbsd File:      rtems-bsd-callout.c             
878FreeBSD File:           kern/kern_timeout.c
879Description:           
880Status:                 USB, Nic
881
882rtems-libbsd File:      rtems-bsd-cam.c
883FreeBSD File:           cam/cam_sim.c
884Description:           
885Status:                 USB
886
887rtems-libbsd File:      rtems-bsd-condvar.c             
888FreeBSD File:           kern/kern_condvar.c
889Description:           
890Status:                 USB
891
892rtems-libbsd File:      rtems-bsd-copyinout.c
893FreeBSD File:           bsp specific copyinout.c )
894Description:            Note: The FreeBSD file is split with some methods being in rtems-bsd-support
895Status:                 Nic
896
897rtems-libbsd File:      rtems-bsd-delay.c
898FreeBSD File:           bsp specific file with multiple names
899Description:           
900Status:                 USB, Nic
901
902rtems-libbsd File:      rtems-bsd-descrip.c
903FreeBSD File:           kern/kern_descrip.c
904Description:           
905Status:                 Nic
906
907rtems-libbsd File:      rtems-bsd-generic.c             
908FreeBSD File:           kern/sys_generic.c
909Description:           
910Status:                 Nic
911
912rtems-libbsd File:      rtems-bsd-init.c
913FreeBSD File:           N/A
914Description:           
915Status:                 USB, Nic
916
917rtems-libbsd File:      rtems-bsd-init-with-irq.c
918FreeBSD File:           N/A
919Description:           
920Status:                 USB, Nic
921
922rtems-libbsd File:      rtems-bsd-jail.c
923FreeBSD File:           kern/kern_jail.c
924Description:           
925Status:                 USB, Nic
926
927rtems-libbsd File:      rtems-bsd-lock.c
928FreeBSD File:           kern/subr_lock.c
929Description:           
930Status:                 USB, Nic
931
932rtems-libbsd File:      rtems-bsd-log.c         
933FreeBSD File:           kern/subr_prf.c
934Description:           
935Status:                 Nic
936
937rtems-libbsd File:      rtems-bsd-malloc.c
938FreeBSD File:           kern/kern_malloc.c
939Description:           
940Status:                 USB, Nic
941
942rtems-libbsd File:      rtems-bsd-mutex.c
943FreeBSD File:           kern/kern_mutex.c
944Description:           
945Status:                 USB, Nic
946
947rtems-libbsd File:      rtems-bsd-newproc.c
948FreeBSD File:           N/A
949Description:           
950Status:                 Nic
951
952rtems-libbsd File:      rtems-bsd-nexus.c
953FreeBSD File:           bsp specific nexus.c
954Description:           
955Status:                 USB
956
957rtems-libbsd File:      rtems-bsd-panic.c               
958FreeBSD File:           boot/common/panic.c
959Description:           
960Status:                 USB, Nic
961
962rtems-libbsd File:      rtems-bsd-rwlock.c             
963FreeBSD File:           kern_rwlock.c
964Description:           
965Status:                 USB, Nic
966
967rtems-libbsd File:      rtems-bsd-shell.c               
968FreeBSD File:           N/A
969Description:           
970Status:                 USB
971
972rtems-libbsd File:      rtems-bsd-signal.c             
973FreeBSD File:           kern/kern_sig.c
974Description:           
975Status:                 Nic
976
977rtems-libbsd File:      rtems-bsd-smp.c                 
978FreeBSD File:           N/A
979Description:           
980Status:                 Nic
981
982rtems-libbsd File:      rtems-bsd-support.c             
983FreeBSD File:           bsp specific copyinout.c
984Description:            Note: the FreeBSD file is split with some methods being in rtems-bsd-copyinout.
985Status:                 USB, Nic
986
987rtems-libbsd File:      rtems-bsd-sx.c                 
988FreeBSD File:           kern/kern_sx.c
989Description:            Status: USB, Nic
990
991rtems-libbsd File:      rtems-bsd-synch.c               
992FreeBSD File:           kern/kern_synch.c
993Description:           
994Status:                 USB, Nic
995
996rtems-libbsd File:      rtems-bsd-syscalls.c           
997FreeBSD File:           User API for kern/uipc_syscalls.c
998Description:           
999Status:                 Nic
1000
1001rtems-libbsd File:      rtems-bsd-sysctlbyname.c       
1002FreeBSD File:           User API for sysctlbyname(3)
1003Description:           
1004Status:
1005
1006rtems-libbsd File:      rtems-bsd-sysctl.c             
1007FreeBSD File:           User API for sysctl(8)
1008Description:           
1009Status:
1010
1011rtems-libbsd File:      rtems-bsd-sysctlnametomib.c     
1012FreeBSD File:           User API for sysctlnametomib
1013Description:           
1014Status:
1015
1016rtems-libbsd File:      rtems-bsd-taskqueue.c           
1017FreeBSD File:           kern/subr_taskqueue.c
1018Description:           
1019Status:                 Nic
1020
1021rtems-libbsd File:      rtems-bsd-thread.c                     
1022FreeBSD File:           kern/kern_kthread.c
1023Description:           
1024Status:                 USB, Nic
1025
1026rtems-libbsd File:      rtems-bsd-timeout.c             
1027FreeBSD File:           kern/kern_timeout.c
1028Description:           
1029Status:                 Nic
1030
1031rtems-libbsd File:      rtems-bsd-timesupport.c         
1032FreeBSD File:           kern/kern_clock.c
1033Description:           
1034Status:                 Nic
1035
1036rtems-libbsd File:      rtems-bsd-vm_glue.c             
1037FreeBSD File:           vm/vm_glue.c
1038Description:           
1039Status:                 USB, Nic
1040----
1041
1042== Notes by File ==
1043
1044altq_subr.c - Arbitrary choices were made in this file that RTEMS would
1045not support tsc frequency change.  Additionally, the clock frequency
1046for machclk_freq is always measured for RTEMS.
1047
1048conf.h - In order to add make_dev and destroy_dev, variables in the cdev
1049structure that were not being used were conditionally compiled out. The
1050capability of supporting children did not appear to be needed and was
1051not implemented in the rtems version of these routines.
1052 
1053== NICs Status ==
1054
1055----
1056Driver                  Symbol                          Status
1057======                  ======                          ======
1058RealTek                 _bsd_re_pcimodule_sys_init      Links
1059EtherExpress            _bsd_fxp_pcimodule_sys_init     Links
1060DEC tulip               _bsd_dc_pcimodule_sys_init      Links
1061Broadcom BCM57xxx       _bsd_bce_pcimodule_sys_init     Links
1062Broadcom BCM4401        _bsd_bfe_pcimodule_sys_init     Links
1063Broadcom BCM570x        _bsd_bge_pcimodule_sys_init     Needs Symbols (A)
1064E1000 IGB               _bsd_igb_pcimodule_sys_init     Links
1065E1000 EM                _bsd_em_pcimodule_sys_init      Links
1066----
1067
1068
1069Symbols (A)
1070         pci_get_vpd_ident
1071 
1072== Problems to report to FreeBSD ==
1073
1074The MMAP_NOT_AVAILABLE define is inverted on its usage.  When it is
1075defined the mmap method is called. Additionally, it is not used
1076thoroughly. It is not used in the unmap portion of the source.
1077The file rec_open.c uses the define MMAP_NOT_AVAILABLE to wrap
1078the call to mmap and file rec_close.c uses the munmap method.
1079
1080
1081
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