source: rtems-libbsd/libbsd.txt @ 33a15c3

4.115-freebsd-12freebsd-9.3
Last change on this file since 33a15c3 was 33a15c3, checked in by Sebastian Huber <sebastian.huber@…>, on Jan 20, 2015 at 7:57:36 AM

Add and use rtems_bsd_get_task_stack_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== Network Stack Features
244
245http://roy.marples.name/projects/dhcpcd/index[DHCPCD(8)]:: DHCP client
246
247https://developer.apple.com/library/mac/documentation/Networking/Reference/DNSServiceDiscovery_CRef/Reference/reference.html[dns_sd.h]:: DNS Service Discovery
248
249http://www.opensource.apple.com/source/mDNSResponder/mDNSResponder-320.10/mDNSCore/mDNSEmbeddedAPI.h[mDNS]:: Multi-Cast DNS
250
251http://www.freebsd.org/cgi/man.cgi?query=unix&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[UNIX(4)]:: UNIX-domain protocol family
252
253http://www.freebsd.org/cgi/man.cgi?query=inet&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[INET(4)]:: Internet protocol family
254
255http://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
256
257http://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
258
259http://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
260
261http://www.freebsd.org/cgi/man.cgi?query=route&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[ROUTE(4)]:: Kernel packet forwarding database
262
263http://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
264
265http://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
266
267http://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
268
269http://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
270
271http://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
272
273http://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
274
275http://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
276
277http://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
278
279http://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
280
281http://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
282
283http://www.freebsd.org/cgi/man.cgi?query=sysctl&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[SYSCTL(3)]:: Get or set system information
284
285http://www.freebsd.org/cgi/man.cgi?query=resolver&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[RESOLVER(3)]:: Resolver routines
286
287http://www.freebsd.org/cgi/man.cgi?query=gethostbyname&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[GETHOSTBYNAME(3)]:: Get network host entry
288
289== Network Interface Drivers
290
291=== Link Up/Down Events
292
293You can notifiy the application space of link up/down events in your network
294interface driver via the if_link_state_change(LINK_STATE_UP/LINK_STATE_DOWN)
295function.  The DHCPCD(8) client is a consumer of these events for example.
296Make sure that the interface flag IFF_UP and the interface driver flag
297IFF_DRV_RUNNING is set in case the link is up, otherwise ether_output() will
298return the error status ENETDOWN.
299
300== Shell Commands
301
302=== HOSTNAME(1)
303
304In addition to the standard options the RTEMS version of the HOSTNAME(1)
305command supports the -m flag to set/get the multicast hostname of the
306mDNS resolver instance.  See also rtems_mdns_sethostname() and
307rtems_mdns_gethostname().
308
309== Issues and TODO
310
311* Per-CPU data should be enabled once the new stack is ready for SMP.
312
313* Per-CPU NETISR(9) should be enabled onece the new stack is ready for SMP.
314
315* Multiple routing tables are not supported.  Every FIB value is set to zero
316  (= BSD_DEFAULT_FIB).
317
318* Process identifiers are not supported.  Every PID value is set to zero
319  (= BSD_DEFAULT_PID).
320
321* User credentials are not supported.  The following functions allow the
322  operation for everyone
323  - prison_equal_ip4(),
324  - chgsbsize(),
325  - cr_cansee(),
326  - cr_canseesocket() and
327  - cr_canseeinpcb().
328
329* A basic USB functionality test that is known to work on Qemu is desirable.
330
331* Adapt generic IRQ PIC interface code to Simple Vectored Interrupt Model
332  so that those architectures can use new TCP/IP and USB code.
333
334* freebsd-userspace/rtems/include/sys/syslog.h is a copy from the old
335  RTEMS TCP/IP stack. For some reason, the __printflike markers do not
336  compile in this environment. We may want to use the FreeBSD syslog.h
337  and get this addressed.
338
339* in_cksum implementations for architectures not supported by FreeBSD.
340  This will require figuring out where to put implementations that do
341  not originate from FreeBSD and are populated via the script.
342
343* MAC support functions are not thread-safe ("freebsd/lib/libc/posix1e/mac.c").
344
345* IFCONFIG(8): IEEE80211 support is disabled.  This module depends on a XML
346  parser and mmap().
347
348* get_cyclecount(): The implementation is a security problem.
349
350* What to do with the priority parameter present in the FreeBSD synchronization
351  primitives and the thread creation functions?
352
353* TASKQUEUE(9): Support spin mutexes.
354
355* ZONE(9): Review allocator lock usage in rtems-bsd-chunk.c.
356
357* KQUEUE(2): Choose proper lock for global kqueue list.
358
359* TIMEOUT(9): Maybe use special task instead of timer server to call
360  callout_tick().
361
362* sysctl_handle_opaque(): Implement reliable snapshots.
363
364* PING6(8): What to do with SIGALARM?
365
366* <sys/param.h>: Update Newlib to use a MSIZE of 256.
367
368* BPF(4): Add support for zero-copy buffers.
369
370* UNIX(4): Fix race conditions in the area of socket object and file node
371  destruction.  Add support for file descriptor transmission via control
372  messages.
373
374* PRINTF(9): Add support for log(), the %D format specifier is missing in the
375  normal printf() family.
376
377* Why is the interrupt server used?  The BSD interrupt handlers can block on
378synchronization primitives like mutexes.  This is in contrast to RTEMS
379interrupt service routines.  The BSPs using the generic interrupt support must
380implement the `bsp_interrupt_vector_enable()` and
381`bsp_interrupt_vector_disable()` routines.  They normally enable/disable a
382particular interrupt source at the interrupt controller.  This can be used to
383implement the interrupt server.  The interrupt server is a task that wakes-up
384in case an associated interrupt happens.  The interrupt source is disabled in
385a generic interrupt handler that wakes-up the interrupt server task.   Once the
386postponed interrupt processing is performed in the interrupt server the
387interrupt source is enabled again.
388
389* Convert all BSP linkcmds to use a linkcmds.base so the sections are
390easier to insert.
391
392* NIC Device Drivers
393- Only common PCI NIC drivers have been included in the initial set. These
394do not include any system on chip or ISA drivers.
395- PCI configuration probe does not appear to happen to determine if a
396NIC is in I/O or memory space. We have worked around this by using a
397static hint to tell the fxp driver the correct mode. But this needs to
398be addressed.
399- The ISA drivers require more BSD infrastructure to be addressed. This was
400outside the scope of the initial porting effort.
401
402== FreeBSD Source
403
404You should be able to rely on FreebSD manual pages and documentation
405for details on the code itself.
406
407=== Automatically Generated FreeBSD Files
408
409Some source and header files are automatically generated during the FreeBSD
410build process.  The `Makefile.todo` file performs this manually.  The should be
411included in `freebsd-to-rtems.py` script some time in the future.  For details,
412see also
413http://www.freebsd.org/cgi/man.cgi?query=kobj&sektion=9&apropos=0&manpath=FreeBSD+9.2-RELEASE[KOBJ(9)].
414
415=== Rules for Modifying FreeBSD Source
416
417Only add lines.  Subtract code by added `#ifndef __rtems__`.  This makes
418merging easier in the future.  For example:
419
420-------------------------------------------------------------------------------
421/* Global variables for the kernel. */
422
423#ifndef __rtems__
424/* 1.1 */
425extern char kernelname[MAXPATHLEN];
426#endif /* __rtems__ */
427
428extern int tick;                        /* usec per tick (1000000 / hz) */
429-------------------------------------------------------------------------------
430
431-------------------------------------------------------------------------------
432#if defined(_KERNEL) || defined(_WANT_FILE)
433#ifdef __rtems__
434#include <rtems/libio_.h>
435#include <sys/fcntl.h>
436#endif /* __rtems__ */
437/*
438 * Kernel descriptor table.
439 * One entry for each open kernel vnode and socket.
440 *
441 * Below is the list of locks that protects members in struct file.
442 *
443 * (f) protected with mtx_lock(mtx_pool_find(fp))
444 * (d) cdevpriv_mtx
445 * none not locked
446 */
447-------------------------------------------------------------------------------
448
449-------------------------------------------------------------------------------
450extern int profprocs;                   /* number of process's profiling */
451#ifndef __rtems__
452extern volatile int ticks;
453#else /* __rtems__ */
454#include <rtems/score/watchdogimpl.h>
455#define ticks _Watchdog_Ticks_since_boot
456#endif /* __rtems__ */
457
458#endif /* _KERNEL */
459-------------------------------------------------------------------------------
460
461Add nothing (even blank lines) before or after the `__rtems__` guards.  Always
462include a `__rtems__` in the guards to make searches easy.
463
464== BSD Library Source
465
466=== What is in the Git Repository
467
468There is a self-contained kit with FreeBSD and RTEMS components pre-merged. The
469Makefile in this kit is automatically generated.
470
471Any changes to source in the `freebsd` directories will need to be merged
472upstream into our master FreeBSD checkout, the `freebsd-org` submodule.
473
474The repository contains two FreeBSD source trees.  In the `freebsd` directory
475are the so called 'managed' FreeBSD sources used to build the BSD library.  The
476FreeBSD source in `freebsd-org` is the 'master' version.  The
477`freebsd-to-rtems.py` script is used to transfer files between the two trees.
478In general terms, if you have modified managed FreeBSD sources, you will need
479to run the script in 'revert' or 'reverse' mode using the `-R` switch.  This
480will copy the source back to your local copy of the master FreeBSD source so
481you can run `git diff` against the upstream FreeBSD source.  If you want to
482transfer source files from the master FreeBSD source to the manged FreeBSD
483sources, then you must run the script in 'forward' mode (the default).
484
485=== Organization
486
487The top level directory contains a few directories and files. The following
488are important to understand
489
490* `freebsd-to-rtems.py` - script to convert to and free FreeBSD and RTEMS trees,
491* `Makefile` - automatically generated,
492* `freebsd/` - from FreeBSD by script,
493* `rtemsbsd/` - RTEMS specific implementations of FreeBSD kernel support routines,
494* `testsuite/` - RTEMS specific tests, and
495* `libbsd.txt` - documentation in Asciidoc.
496
497== Moving Code Between Managed and Master FreeBSD Source
498
499The script `freebsd-to-rtems.py` is used to copy code from FreeBSD to the
500rtems-libbsd tree and to reverse this process. This script attempts to
501automate this process as much as possible and performs some transformations
502on the FreeBSD code. Its command line arguments are shown below:
503
504----
505freebsd-to-rtems.py [args]
506  -?|-h|--help     print this and exit
507  -d|--dry-run     run program but no modifications
508  -D|--diff        provide diff of files between trees
509  -e|--early-exit  evaluate arguments, print results, and exit
510  -m|--makefile    just generate Makefile
511  -R|--reverse     default FreeBSD -> RTEMS, reverse that
512  -r|--rtems       RTEMS directory
513  -f|--freebsd     FreeBSD directory
514  -v|--verbose     enable verbose output mode
515----
516
517In its default mode of operation, freebsd-to-rtems.py is used to copy code
518from FreeBSD to the rtems-libbsd tree and perform transformations.  In forward
519mode, the script may be requested to just generate the Makefile.
520
521In "reverse mode", this script undoes those transformations and copies
522the source code back to the FreeBSD SVN tree. This allows us to do
523'svn diff', evaluate changes made by the RTEMS Project, and report changes
524back to FreeBSD upstream.
525
526In either mode, the script may be asked to perform a dry-run or be verbose.
527Also, in either mode, the script is also smart enough to avoid copying over
528files which have not changed. This means that the timestamps of files are
529not changed unless the contents change. The script will also report the
530number of files which changed. In verbose mode, the script will print
531the name of the files which are changed.
532
533The following is an example forward run with no changes.
534
535----
536$ ~/newbsd/git/libbsd-8.2/freebsd-to-rtems.py \
537    -r /home/joel/newbsd/git/libbsd-8.2 \
538    -f /home/joel/newbsd/libbsd/freebsd-8.2 -v
539Verbose:                yes
540Dry Run:                no
541Only Generate Makefile: no
542RTEMS Directory:        /home/joel/newbsd/git/libbsd-8.2
543FreeBSD Directory:      /home/joel/newbsd/libbsd/freebsd-8.2
544Direction:              forward
545Generating into /home/joel/newbsd/git/libbsd-8.2
5460 files were changed.
547----
548
549The script may also be used to generate a diff in either forward or reverse
550direction.
551
552== Initialization of the BSD Library
553
554The initialization of the BSD library is based on the FreeBSD SYSINIT(9)
555infrastructure.  The key to initializing a system is to ensure that the desired
556device drivers are explicitly pulled into the linked application.  This plus
557linking against the BSD library (`libbsd.a`) will pull in the necessary FreeBSD
558infrastructure.
559
560The FreeBSD kernel is not a library like the RTEMS kernel.  It is a bunch of
561object files linked together.  If we have a library, then creating the
562executable is simple.  We begin with a start symbol and recursively resolve all
563references.  With a bunch of object files linked together we need a different
564mechanism.  Most object files don't know each other.  Lets say we have a driver
565module.  The rest of the system has no references to this driver module.  The
566driver module needs a way to tell the rest of the system: Hey, kernel I am
567here, please use my services!
568
569This registration of independent components is performed by SYSINIT(9) and
570specializations:
571
572http://www.freebsd.org/cgi/man.cgi?query=SYSINIT
573
574The SYSINIT(9) uses some global data structures that are placed in a certain
575section.  In the linker command file we need this:
576
577-------------------------------------------------------------------------------
578.rtemsroset : {
579        KEEP (*(SORT(.rtemsroset.*)))
580}
581
582.rtemsrwset : {
583        KEEP (*(SORT(.rtemsrwset.*)))
584}
585-------------------------------------------------------------------------------
586
587This results for example in this executable layout:
588
589-------------------------------------------------------------------------------
590[...]
591 *(SORT(.rtemsroset.*))
592 .rtemsroset.bsd.modmetadata_set.begin
593                0x000000000025fe00        0x0 libbsd.a(rtems-bsd-init.o)
594                0x000000000025fe00                _bsd__start_set_modmetadata_set
595 .rtemsroset.bsd.modmetadata_set.content
596                0x000000000025fe00        0x8 libbsd.a(rtems-bsd-nexus.o)
597 .rtemsroset.bsd.modmetadata_set.content
598                0x000000000025fe08        0x4 libbsd.a(kern_module.o)
599[...]
600 .rtemsroset.bsd.modmetadata_set.content
601                0x000000000025fe68        0x4 libbsd.a(mii.o)
602 .rtemsroset.bsd.modmetadata_set.content
603                0x000000000025fe6c        0x4 libbsd.a(mii_bitbang.o)
604 .rtemsroset.bsd.modmetadata_set.end
605                0x000000000025fe70        0x0 libbsd.a(rtems-bsd-init.o)
606                0x000000000025fe70                _bsd__stop_set_modmetadata_set
607[...]
608.rtemsrwset     0x000000000030bad0      0x290
609 *(SORT(.rtemsrwset.*))
610 .rtemsrwset.bsd.sysinit_set.begin
611                0x000000000030bad0        0x0 libbsd.a(rtems-bsd-init.o)
612                0x000000000030bad0                _bsd__start_set_sysinit_set
613 .rtemsrwset.bsd.sysinit_set.content
614                0x000000000030bad0        0x4 libbsd.a(rtems-bsd-nexus.o)
615 .rtemsrwset.bsd.sysinit_set.content
616                0x000000000030bad4        0x8 libbsd.a(rtems-bsd-thread.o)
617 .rtemsrwset.bsd.sysinit_set.content
618                0x000000000030badc        0x4 libbsd.a(init_main.o)
619[...]
620 .rtemsrwset.bsd.sysinit_set.content
621                0x000000000030bd54        0x4 libbsd.a(frag6.o)
622 .rtemsrwset.bsd.sysinit_set.content
623                0x000000000030bd58        0x8 libbsd.a(uipc_accf.o)
624 .rtemsrwset.bsd.sysinit_set.end
625                0x000000000030bd60        0x0 libbsd.a(rtems-bsd-init.o)
626                0x000000000030bd60                _bsd__stop_set_sysinit_set
627[...]
628-------------------------------------------------------------------------------
629
630Here you can see, that some global data structures are collected into
631continuous memory areas.  This memory area can be identified by start and stop
632symbols.  This constructs a table of uniform items.
633
634The low level FreeBSD code calls at some time during the initialization the
635mi_startup() function (machine independent startup).  This function will sort
636the SYSINIT(9) set and call handler functions which perform further
637initialization.  The last step is the scheduler invocation.
638
639The SYSINIT(9) routines are run in mi_startup() which is called by
640rtems_bsd_initialize().
641
642This is also explained in "The Design and Implementation of the FreeBSD
643Operating System" section 14.3 "Kernel Initialization".
644
645In RTEMS we have a library and not a bunch of object files.  Thus we need a way
646to pull-in the desired services out of the libbsd.  Here the
647`rtems-bsd-sysinit.h` comes into play.  The SYSINIT(9) macros have been
648modified and extended for RTEMS in `<sys/kernel.h>`:
649
650-------------------------------------------------------------------------------
651#ifndef __rtems__
652#define C_SYSINIT(uniquifier, subsystem, order, func, ident)    \
653        static struct sysinit uniquifier ## _sys_init = {       \
654                subsystem,                                      \
655                order,                                          \
656                func,                                           \
657                (ident)                                         \
658        };                                                      \
659        DATA_SET(sysinit_set,uniquifier ## _sys_init)
660#else /* __rtems__ */
661#define SYSINIT_ENTRY_NAME(uniquifier)                          \
662        _bsd_ ## uniquifier ## _sys_init
663#define SYSINIT_REFERENCE_NAME(uniquifier)                      \
664        _bsd_ ## uniquifier ## _sys_init_ref
665#define C_SYSINIT(uniquifier, subsystem, order, func, ident)    \
666        struct sysinit SYSINIT_ENTRY_NAME(uniquifier) = {       \
667                subsystem,                                      \
668                order,                                          \
669                func,                                           \
670                (ident)                                         \
671        };                                                      \
672        RWDATA_SET(sysinit_set,SYSINIT_ENTRY_NAME(uniquifier))
673#define SYSINIT_REFERENCE(uniquifier)                           \
674        extern struct sysinit SYSINIT_ENTRY_NAME(uniquifier);   \
675        static struct sysinit const * const                     \
676        SYSINIT_REFERENCE_NAME(uniquifier) __used               \
677        = &SYSINIT_ENTRY_NAME(uniquifier)
678#define SYSINIT_MODULE_REFERENCE(mod)                           \
679        SYSINIT_REFERENCE(mod ## module)
680#define SYSINIT_DRIVER_REFERENCE(driver, bus)                   \
681        SYSINIT_MODULE_REFERENCE(driver ## _ ## bus)
682#define SYSINIT_DOMAIN_REFERENCE(dom)                           \
683        SYSINIT_REFERENCE(domain_add_ ## dom)
684#endif /* __rtems__ */
685-------------------------------------------------------------------------------
686
687Here you see that the SYSINIT(9) entries are no longer static.  The
688\*_REFERENCE() macros will create references to the corresponding modules which
689are later resolved by the linker.  The application has to provide an object
690file with references to all required FreeBSD modules.
691
692The FreeBSD device model is quite elaborated (with follow-ups):
693
694http://www.freebsd.org/cgi/man.cgi?query=driver
695
696The devices form a tree with the Nexus device at a high-level.  This Nexus
697device is architecture specific in FreeBSD.  In RTEMS we have our own Nexus
698device, see `rtemsbsd/bsp/bsp-bsd-nexus-devices.c`.
699
700=== SYSCTL_NODE Example
701
702During development, we had an undefined reference to
703_bsd_sysctl__net_children that we had trouble tracking down. Thanks to
704Chris Johns, we located it. He explained how to read SYSCTL_NODE
705definitions. This line from freebsd/netinet/in_proto.c is attempting
706to add the "inet" node to the parent node "_net".
707
708----
709SYSCTL_NODE(_net,      PF_INET,         inet,   CTLFLAG_RW, 0,
710        "Internet Family");
711----
712
713Our problem was that we could not find where _bsd_sysctl__net_children
714was defined. Chris suggested that when in doubt compile with -save-temps
715and look at the preprocessed .i files. But he did not need that. He
716explained that this the symbol name _bsd_sysctl__net_children was
717automatically generated by a SYSCTL_NODE as follows:
718
719* _bsd_ - added by RTEMS modifications to SYSCTL_NODE macro
720* sysctl_ - boilerplace added by SYSCTL_NODE macro
721* "" - empty string for parent node
722* net - name of SYSCTL_NODE
723* children - added by SYSCTL macros
724 
725This was all generated by a support macro declaring the node as this:
726
727----
728struct sysctl_oid_list SYSCTL_NODE_CHILDREN(parent, name);
729----
730
731Given this information, we located this SYSCTL_NODE declaration in
732kern/kern_mib.c
733
734----
735SYSCTL_NODE(, CTL_KERN,   kern,   CTLFLAG_RW, 0,
736        "High kernel, proc, limits &c");
737----
738
739== Core FreeBSD APIs and RTEMS Replacements ==
740
741=== SX(9) (Shared/exclusive locks) ===
742
743http://www.freebsd.org/cgi/man.cgi?query=sx
744
745Binary semaphores (this neglects the ability to allow shared access).
746
747=== MUTEX(9) (Mutual exclusion) ===
748
749http://www.freebsd.org/cgi/man.cgi?query=mutex
750
751Binary semaphores (not recursive mutexes are not supported this way).
752
753=== RWLOCK(9) (Reader/writer lock) ===
754
755http://www.freebsd.org/cgi/man.cgi?query=rwlock
756
757POSIX r/w lock.
758
759=== RMLOCK(9) (Reader/writer lock optimized for mostly read access patterns) ===
760
761Note:  This object was implemented as a wrapper for RWLOCK in the rm_lock header file.
762
763http://www.freebsd.org/cgi/man.cgi?query=rmlock
764
765POSIX r/w lock.
766
767=== CONDVAR(9) (Condition variables) ===
768
769http://www.freebsd.org/cgi/man.cgi?query=condvar
770
771POSIX condition variables with modifications (hack).
772
773=== CALLOUT(9) (Timer functions) ===
774
775http://www.freebsd.org/cgi/man.cgi?query=callout
776
777Timer server.
778
779=== TASKQUEUE(9) (Asynchronous task execution) ===
780
781http://www.freebsd.org/cgi/man.cgi?query=taskqueue
782
783TBD.
784
785=== KTHREAD(9), KPROC(9) (Tasks) ===
786
787http://www.freebsd.org/cgi/man.cgi?query=kthread
788
789http://www.freebsd.org/cgi/man.cgi?query=kproc
790
791Tasks.
792
793=== ZONE(9) (Zone allocator) ===
794
795http://www.freebsd.org/cgi/man.cgi?query=zone
796
797TBD.
798
799=== devfs (Device file system) ===
800
801Dummy, IMFS or new implementation (currently dummy).
802
803=== psignal (Signals) ===
804
805TBD.  Seems to be not needed.
806
807=== poll, select ===
808
809TBD.  Seems to be not needed.
810
811=== RMAN(9) (Resource management) ===
812
813http://www.freebsd.org/cgi/man.cgi?query=rman
814
815TBD.  Seems to be not needed.
816
817=== DEVCLASS(9), DEVICE(9), DRIVER(9), MAKE_DEV(9) (Device management) ===
818
819http://www.freebsd.org/cgi/man.cgi?query=devclass
820
821http://www.freebsd.org/cgi/man.cgi?query=device
822
823http://www.freebsd.org/cgi/man.cgi?query=driver
824
825http://www.freebsd.org/cgi/man.cgi?query=make_dev
826
827Use FreeBSD implementation as far as possible.  FreeBSD has a nice API for
828dynamic device handling.  It may be interesting for RTEMS to use this API
829internally in the future.
830
831=== BUS_SPACE(9), BUS_DMA(9) (Bus and DMA access) ===
832
833http://www.freebsd.org/cgi/man.cgi?query=bus_space
834
835http://www.freebsd.org/cgi/man.cgi?query=bus_dma
836
837Likely BSP dependent.  A default implementation for memory mapped linear access
838is easy to provide.  The current heap implementation supports all properties
839demanded by bus_dma (including the boundary constraint).
840
841== RTEMS Replacements by File Description ==
842
843Note:  Files with a status of USB are used by the USB test and have at least
844been partially tested.  If they contain both USB and Nic, then they are used
845by both and MAY contain methods that have not been tested yet.  Files that
846are only used by the Nic test are the most suspect.
847
848----
849rtems-libbsd File:      rtems-bsd-assert.c
850FreeBSD File:           rtems-bsd-config.h redefines BSD_ASSERT.
851Description:            This file contains the support method rtems_bsd_assert_func().
852Status:                 USB, Nic
853
854rtems-libbsd File:      rtems-bsd-autoconf.c
855FreeBSD File:           FreeBSD has BSP specific autoconf.c
856Description:            This file contains configuration methods that are used to setup the system.
857Status:                 USB
858
859rtems-libbsd File:      rtems-bsd-bus-dma.c
860FreeBSD File:           FreeBSD has BSP specific busdma_machdep.c
861Description:           
862Status:                 USB, Nic
863
864rtems-libbsd File:      rtems-bsd-bus-dma-mbuf.c       
865FreeBSD File:           FreeBSD has BSP specific busdma_machdep.c
866Description:           
867Status:                 Nic
868
869rtems-libbsd File:      rtems-bsd-callout.c             
870FreeBSD File:           kern/kern_timeout.c
871Description:           
872Status:                 USB, Nic
873
874rtems-libbsd File:      rtems-bsd-cam.c
875FreeBSD File:           cam/cam_sim.c
876Description:           
877Status:                 USB
878
879rtems-libbsd File:      rtems-bsd-condvar.c             
880FreeBSD File:           kern/kern_condvar.c
881Description:           
882Status:                 USB
883
884rtems-libbsd File:      rtems-bsd-copyinout.c
885FreeBSD File:           bsp specific copyinout.c )
886Description:            Note: The FreeBSD file is split with some methods being in rtems-bsd-support
887Status:                 Nic
888
889rtems-libbsd File:      rtems-bsd-delay.c
890FreeBSD File:           bsp specific file with multiple names
891Description:           
892Status:                 USB, Nic
893
894rtems-libbsd File:      rtems-bsd-descrip.c
895FreeBSD File:           kern/kern_descrip.c
896Description:           
897Status:                 Nic
898
899rtems-libbsd File:      rtems-bsd-generic.c             
900FreeBSD File:           kern/sys_generic.c
901Description:           
902Status:                 Nic
903
904rtems-libbsd File:      rtems-bsd-init.c
905FreeBSD File:           N/A
906Description:           
907Status:                 USB, Nic
908
909rtems-libbsd File:      rtems-bsd-init-with-irq.c
910FreeBSD File:           N/A
911Description:           
912Status:                 USB, Nic
913
914rtems-libbsd File:      rtems-bsd-jail.c
915FreeBSD File:           kern/kern_jail.c
916Description:           
917Status:                 USB, Nic
918
919rtems-libbsd File:      rtems-bsd-lock.c
920FreeBSD File:           kern/subr_lock.c
921Description:           
922Status:                 USB, Nic
923
924rtems-libbsd File:      rtems-bsd-log.c         
925FreeBSD File:           kern/subr_prf.c
926Description:           
927Status:                 Nic
928
929rtems-libbsd File:      rtems-bsd-malloc.c
930FreeBSD File:           kern/kern_malloc.c
931Description:           
932Status:                 USB, Nic
933
934rtems-libbsd File:      rtems-bsd-mutex.c
935FreeBSD File:           kern/kern_mutex.c
936Description:           
937Status:                 USB, Nic
938
939rtems-libbsd File:      rtems-bsd-newproc.c
940FreeBSD File:           N/A
941Description:           
942Status:                 Nic
943
944rtems-libbsd File:      rtems-bsd-nexus.c
945FreeBSD File:           bsp specific nexus.c
946Description:           
947Status:                 USB
948
949rtems-libbsd File:      rtems-bsd-panic.c               
950FreeBSD File:           boot/common/panic.c
951Description:           
952Status:                 USB, Nic
953
954rtems-libbsd File:      rtems-bsd-rwlock.c             
955FreeBSD File:           kern_rwlock.c
956Description:           
957Status:                 USB, Nic
958
959rtems-libbsd File:      rtems-bsd-shell.c               
960FreeBSD File:           N/A
961Description:           
962Status:                 USB
963
964rtems-libbsd File:      rtems-bsd-signal.c             
965FreeBSD File:           kern/kern_sig.c
966Description:           
967Status:                 Nic
968
969rtems-libbsd File:      rtems-bsd-smp.c                 
970FreeBSD File:           N/A
971Description:           
972Status:                 Nic
973
974rtems-libbsd File:      rtems-bsd-support.c             
975FreeBSD File:           bsp specific copyinout.c
976Description:            Note: the FreeBSD file is split with some methods being in rtems-bsd-copyinout.
977Status:                 USB, Nic
978
979rtems-libbsd File:      rtems-bsd-sx.c                 
980FreeBSD File:           kern/kern_sx.c
981Description:            Status: USB, Nic
982
983rtems-libbsd File:      rtems-bsd-synch.c               
984FreeBSD File:           kern/kern_synch.c
985Description:           
986Status:                 USB, Nic
987
988rtems-libbsd File:      rtems-bsd-syscalls.c           
989FreeBSD File:           User API for kern/uipc_syscalls.c
990Description:           
991Status:                 Nic
992
993rtems-libbsd File:      rtems-bsd-sysctlbyname.c       
994FreeBSD File:           User API for sysctlbyname(3)
995Description:           
996Status:
997
998rtems-libbsd File:      rtems-bsd-sysctl.c             
999FreeBSD File:           User API for sysctl(8)
1000Description:           
1001Status:
1002
1003rtems-libbsd File:      rtems-bsd-sysctlnametomib.c     
1004FreeBSD File:           User API for sysctlnametomib
1005Description:           
1006Status:
1007
1008rtems-libbsd File:      rtems-bsd-taskqueue.c           
1009FreeBSD File:           kern/subr_taskqueue.c
1010Description:           
1011Status:                 Nic
1012
1013rtems-libbsd File:      rtems-bsd-thread.c                     
1014FreeBSD File:           kern/kern_kthread.c
1015Description:           
1016Status:                 USB, Nic
1017
1018rtems-libbsd File:      rtems-bsd-timeout.c             
1019FreeBSD File:           kern/kern_timeout.c
1020Description:           
1021Status:                 Nic
1022
1023rtems-libbsd File:      rtems-bsd-timesupport.c         
1024FreeBSD File:           kern/kern_clock.c
1025Description:           
1026Status:                 Nic
1027
1028rtems-libbsd File:      rtems-bsd-vm_glue.c             
1029FreeBSD File:           vm/vm_glue.c
1030Description:           
1031Status:                 USB, Nic
1032----
1033
1034== Notes by File ==
1035
1036altq_subr.c - Arbitrary choices were made in this file that RTEMS would
1037not support tsc frequency change.  Additionally, the clock frequency
1038for machclk_freq is always measured for RTEMS.
1039
1040conf.h - In order to add make_dev and destroy_dev, variables in the cdev
1041structure that were not being used were conditionally compiled out. The
1042capability of supporting children did not appear to be needed and was
1043not implemented in the rtems version of these routines.
1044 
1045== NICs Status ==
1046
1047----
1048Driver                  Symbol                          Status
1049======                  ======                          ======
1050RealTek                 _bsd_re_pcimodule_sys_init      Links
1051EtherExpress            _bsd_fxp_pcimodule_sys_init     Links
1052DEC tulip               _bsd_dc_pcimodule_sys_init      Links
1053Broadcom BCM57xxx       _bsd_bce_pcimodule_sys_init     Links
1054Broadcom BCM4401        _bsd_bfe_pcimodule_sys_init     Links
1055Broadcom BCM570x        _bsd_bge_pcimodule_sys_init     Needs Symbols (A)
1056E1000 IGB               _bsd_igb_pcimodule_sys_init     Links
1057E1000 EM                _bsd_em_pcimodule_sys_init      Links
1058----
1059
1060
1061Symbols (A)
1062         pci_get_vpd_ident
1063 
1064== Problems to report to FreeBSD ==
1065
1066The MMAP_NOT_AVAILABLE define is inverted on its usage.  When it is
1067defined the mmap method is called. Additionally, it is not used
1068thoroughly. It is not used in the unmap portion of the source.
1069The file rec_open.c uses the define MMAP_NOT_AVAILABLE to wrap
1070the call to mmap and file rec_close.c uses the munmap method.
1071
1072
1073
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