source: rtems-libbsd/libbsd.txt @ 97c5024a

5-freebsd-12freebsd-9.3
Last change on this file since 97c5024a was 97c5024a, checked in by Chris Johns <chrisj@…>, on Apr 18, 2016 at 12:53:20 AM

Add RTEMS version support, update all python to 2 and 3.

Add support to force the RTEMS version. This remove the need for using
the --rtems-version command line option if the automatic detection fails.

Update all python code to support python 2 and 3.

Update rtems_waf to the latest version to support the RTEMS version,
check environment variables and to display the CC version.

Sort all tests. I think the unsorted list is dependent on the version
of python and so would result in repo noise as if it regenerted.

  • Property mode set to 100644
File size: 39.3 KB
Line 
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 RSB 4.12 April 2016 or later.
36=== Installation Overview ===
37
38. You must configure your BSP with the +--disable-networking+ option to disable
39the old network stack.  Make sure no header files of the old network stack are
40installed.
41
42. Clone the Git repository +git clone git://git.rtems.org/rtems-libbsd.git+.
43. Change into the RTEMS BSD library root directory.
44. Edit the `config.inc` configuration file and adjust it to your environment.
45. Run +waf configure ...+.
46. Run +waf+.
47. Run +waf install+.
48
49Refer to the README.waf for Waf building instructions.
50
51Make sure the submodules have been initialised and are updated. If a 'git
52status' says `rtems_waf` need updating run the submodule update command:
53
54 $ git submodule rtems_waf update
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
118The build system based on the Waf build system. To build with Waf please refer
119to the README.waf file.
120
121===== Example Configuration =====
122
123In the BSD library source directory edit the file `config.inc`.  Continuing on
124the above, the `config.inc` used to match the above is:
125
126-------------------------------------------------------------------------------
127# Mandatory: Select your BSP and installation prefix
128TARGET = arm-rtems4.11
129BSP = realview_pbx_a9_qemu
130PREFIX = $(HOME)/sandbox/install
131
132# Optional: Separate installation base directory
133INSTALL_BASE = $(PREFIX)/$(TARGET)/$(BSP)
134
135# Optional: Network test configuration
136TEST_RUNNER = $(BSP)
137NET_CFG_SELF_IP = 10.0.0.2
138NET_CFG_NETMASK = 255.255.0.0
139NET_CFG_PEER_IP = 10.0.0.1
140NET_CFG_GATEWAY_IP = 10.0.0.1
141NET_TAP_INTERFACE = tap0
142-------------------------------------------------------------------------------
143
144=== BSD Library Initialization ===
145
146Use the following code to initialize the BSD library:
147
148-------------------------------------------------------------------------------
149#include <assert.h>
150#include <sysexits.h>
151
152#include <machine/rtems-bsd-commands.h>
153#include <rtems/bsd/bsd.h>
154
155static void
156network_ifconfig_lo0(void)
157{
158        int exit_code;
159        char *lo0[] = {
160                "ifconfig",
161                "lo0",
162                "inet",
163                "127.0.0.1",
164                "netmask",
165                "255.255.255.0",
166                NULL
167        };
168        char *lo0_inet6[] = {
169                "ifconfig",
170                "lo0",
171                "inet6",
172                "::1",
173                "prefixlen",
174                "128",
175                NULL
176        };
177
178        exit_code = rtems_bsd_command_ifconfig(RTEMS_BSD_ARGC(lo0), lo0);
179        assert(exit_code == EX_OK);
180
181        exit_code = rtems_bsd_command_ifconfig(RTEMS_BSD_ARGC(lo0_inet6), lo0_inet6);
182        assert(exit_code == EX_OK);
183}
184
185void
186network_init(void)
187{
188        rtems_status_code sc;
189
190        sc = rtems_bsd_initialize();
191        assert(sc == RTEMS_SUCCESSFUL);
192
193        network_ifconfig_lo0();
194}
195-------------------------------------------------------------------------------
196
197This performs the basic network stack initialization with a loopback interface.
198Further initialization must be done using the standard BSD network
199configuration commands
200http://www.freebsd.org/cgi/man.cgi?query=ifconfig&apropos=0&sektion=8&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[IFCONFIG(8)]
201using `rtems_bsd_command_ifconfig()` and
202http://www.freebsd.org/cgi/man.cgi?query=route&apropos=0&sektion=8&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[ROUTE(8)]
203using `rtems_bsd_command_route()`.  For an example please have a look at
204`testsuite/include/rtems/bsd/test/default-network-init.h`.
205
206=== Task Priorities and Stack Size ===
207
208The default task priority is 96 for the interrupt server task (name "IRQS"), 98
209for the timer server task (name "TIME") and 100 for all other tasks.  The
210application may provide their own implementation of the
211`rtems_bsd_get_task_priority()` function (for example in the module which calls
212`rtems_bsd_initialize()`) if different values are desired.
213
214The task stack size is determined by the `rtems_bsd_get_task_stack_size()`
215function which may be provided by the application in case the default is not
216appropriate.
217
218=== Size for Allocator Domains ===
219
220The size for an allocator domain can be specified via the
221`rtems_bsd_get_allocator_domain_size()` function.  The application may provide
222their own implementation of the `rtems_bsd_get_allocator_domain_size()`
223function (for example in the module which calls `rtems_bsd_initialize()`) if
224different values are desired.  The default size is 8MiB for all domains.
225
226== Network Stack Features
227
228http://roy.marples.name/projects/dhcpcd/index[DHCPCD(8)]:: DHCP client
229
230https://developer.apple.com/library/mac/documentation/Networking/Reference/DNSServiceDiscovery_CRef/Reference/reference.html[dns_sd.h]:: DNS Service Discovery
231
232http://www.opensource.apple.com/source/mDNSResponder/mDNSResponder-320.10/mDNSCore/mDNSEmbeddedAPI.h[mDNS]:: Multi-Cast DNS
233
234http://www.freebsd.org/cgi/man.cgi?query=unix&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[UNIX(4)]:: UNIX-domain protocol family
235
236http://www.freebsd.org/cgi/man.cgi?query=inet&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[INET(4)]:: Internet protocol family
237
238http://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
239
240http://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
241
242http://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
243
244http://www.freebsd.org/cgi/man.cgi?query=route&sektion=4&apropos=0&manpath=FreeBSD+9.2-RELEASE[ROUTE(4)]:: Kernel packet forwarding database
245
246http://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
247
248http://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
249
250http://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
251
252http://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
253
254http://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
255
256http://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
257
258http://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
259
260http://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
261
262http://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
263
264http://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
265
266http://www.freebsd.org/cgi/man.cgi?query=sysctl&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[SYSCTL(3)]:: Get or set system information
267
268http://www.freebsd.org/cgi/man.cgi?query=resolver&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[RESOLVER(3)]:: Resolver routines
269
270http://www.freebsd.org/cgi/man.cgi?query=gethostbyname&sektion=3&apropos=0&manpath=FreeBSD+9.2-RELEASE[GETHOSTBYNAME(3)]:: Get network host entry
271
272== Network Interface Drivers
273
274=== Link Up/Down Events
275
276You can notifiy the application space of link up/down events in your network
277interface driver via the if_link_state_change(LINK_STATE_UP/LINK_STATE_DOWN)
278function.  The DHCPCD(8) client is a consumer of these events for example.
279Make sure that the interface flag IFF_UP and the interface driver flag
280IFF_DRV_RUNNING is set in case the link is up, otherwise ether_output() will
281return the error status ENETDOWN.
282
283== Shell Commands
284
285=== HOSTNAME(1)
286
287In addition to the standard options the RTEMS version of the HOSTNAME(1)
288command supports the -m flag to set/get the multicast hostname of the
289mDNS resolver instance.  See also rtems_mdns_sethostname() and
290rtems_mdns_gethostname().
291
292== Qemu
293
294Use the following script to set up a virtual network with three tap devices
295connected via one bridge device.
296
297-------------------------------------------------------------------------------
298#!/bin/sh -x
299
300user=`whoami`
301interfaces=(1 2 3)
302
303tap=qtap
304bri=qbri
305
306case $1 in
307        up)
308                sudo -i brctl addbr $bri
309                for i in ${interfaces[@]} ; do
310                        sudo -i tunctl -t $tap$i -u $user ;
311                        sudo -i ifconfig $tap$i up ;
312                        sudo -i brctl addif $bri $tap$i ;
313                done
314                sudo -i ifconfig $bri up
315                ;;
316        down)
317                for i in ${interfaces[@]} ; do
318                        sudo -i ifconfig $tap$i down ;
319                        sudo -i tunctl -d $tap$i ;
320                done
321                sudo -i ifconfig $bri down
322                sudo -i brctl delbr $bri
323                ;;
324esac
325-------------------------------------------------------------------------------
326
327Connect your Qemu instance to one of the tap devices, e.g.
328
329-------------------------------------------------------------------------------
330qemu-system-i386 -m 512 -boot a -cpu pentium3 \
331        -drive file=$HOME/qemu/pc386_fda,index=0,if=floppy,format=raw \
332        -drive file=fat:$HOME/qemu/hd,format=raw \
333        -net nic,model=e1000,macaddr=0e:b0:ba:5e:ba:11 \
334        -net tap,ifname=qtap1,script=no,downscript=no \
335        -nodefaults -nographic -serial stdio
336-------------------------------------------------------------------------------
337
338Make sure that each Qemu instance uses its own MAC address to avoid an address
339conflict (or otherwise use it as a test).
340
341To connect the Qemu instances with your local network use the following
342(replace 'eth0' with the network interface of your host).
343
344-------------------------------------------------------------------------------
345ifconfig eth0 0.0.0.0
346brctl addif qbri eth0
347dhclient qbri
348-------------------------------------------------------------------------------
349
350== Issues and TODO
351
352* PCI support on x86 uses a quick and dirty hack, see pci_reserve_map().
353
354* Priority queues are broken with clustered scheduling.
355
356* Per-CPU data should be enabled once the new stack is ready for SMP.
357
358* Per-CPU NETISR(9) should be enabled onece the new stack is ready for SMP.
359
360* Multiple routing tables are not supported.  Every FIB value is set to zero
361  (= BSD_DEFAULT_FIB).
362
363* Process identifiers are not supported.  Every PID value is set to zero
364  (= BSD_DEFAULT_PID).
365
366* User credentials are not supported.  The following functions allow the
367  operation for everyone
368  - prison_equal_ip4(),
369  - chgsbsize(),
370  - cr_cansee(),
371  - cr_canseesocket() and
372  - cr_canseeinpcb().
373
374* A basic USB functionality test that is known to work on Qemu is desirable.
375
376* Adapt generic IRQ PIC interface code to Simple Vectored Interrupt Model
377  so that those architectures can use new TCP/IP and USB code.
378
379* freebsd-userspace/rtems/include/sys/syslog.h is a copy from the old
380  RTEMS TCP/IP stack. For some reason, the __printflike markers do not
381  compile in this environment. We may want to use the FreeBSD syslog.h
382  and get this addressed.
383
384* in_cksum implementations for architectures not supported by FreeBSD.
385  This will require figuring out where to put implementations that do
386  not originate from FreeBSD and are populated via the script.
387
388* MAC support functions are not thread-safe ("freebsd/lib/libc/posix1e/mac.c").
389
390* IFCONFIG(8): IEEE80211 support is disabled.  This module depends on a XML
391  parser and mmap().
392
393* get_cyclecount(): The implementation is a security problem.
394
395* What to do with the priority parameter present in the FreeBSD synchronization
396  primitives and the thread creation functions?
397
398* TASKQUEUE(9): Support spin mutexes.
399
400* ZONE(9): Review allocator lock usage in rtems-bsd-chunk.c.
401
402* KQUEUE(2): Choose proper lock for global kqueue list.
403
404* TIMEOUT(9): Maybe use special task instead of timer server to call
405  callout_tick().
406
407* sysctl_handle_opaque(): Implement reliable snapshots.
408
409* PING6(8): What to do with SIGALARM?
410
411* <sys/param.h>: Update Newlib to use a MSIZE of 256.
412
413* BPF(4): Add support for zero-copy buffers.
414
415* UNIX(4): Fix race conditions in the area of socket object and file node
416  destruction.  Add support for file descriptor transmission via control
417  messages.
418
419* PRINTF(9): Add support for log(), the %D format specifier is missing in the
420  normal printf() family.
421
422* Why is the interrupt server used?  The BSD interrupt handlers can block on
423synchronization primitives like mutexes.  This is in contrast to RTEMS
424interrupt service routines.  The BSPs using the generic interrupt support must
425implement the `bsp_interrupt_vector_enable()` and
426`bsp_interrupt_vector_disable()` routines.  They normally enable/disable a
427particular interrupt source at the interrupt controller.  This can be used to
428implement the interrupt server.  The interrupt server is a task that wakes-up
429in case an associated interrupt happens.  The interrupt source is disabled in
430a generic interrupt handler that wakes-up the interrupt server task.   Once the
431postponed interrupt processing is performed in the interrupt server the
432interrupt source is enabled again.
433
434* Convert all BSP linkcmds to use a linkcmds.base so the sections are
435easier to insert.
436
437* NIC Device Drivers
438- Only common PCI NIC drivers have been included in the initial set. These
439do not include any system on chip or ISA drivers.
440- PCI configuration probe does not appear to happen to determine if a
441NIC is in I/O or memory space. We have worked around this by using a
442static hint to tell the fxp driver the correct mode. But this needs to
443be addressed.
444- The ISA drivers require more BSD infrastructure to be addressed. This was
445outside the scope of the initial porting effort.
446
447== FreeBSD Source
448
449You should be able to rely on FreebSD manual pages and documentation
450for details on the code itself.
451
452=== Automatically Generated FreeBSD Files
453
454Some source and header files are automatically generated during the FreeBSD
455build process.  The `Makefile.todo` file performs this manually.  The should be
456included in `freebsd-to-rtems.py` script some time in the future.  For details,
457see also
458http://www.freebsd.org/cgi/man.cgi?query=kobj&sektion=9&apropos=0&manpath=FreeBSD+9.2-RELEASE[KOBJ(9)].
459
460=== Rules for Modifying FreeBSD Source
461
462Only add lines.  If your patch contains lines starting with a '-', then this is
463wrong.  Subtract code by added `#ifndef __rtems__`.  This makes merging easier
464in the future.  For example:
465
466-------------------------------------------------------------------------------
467/* Global variables for the kernel. */
468
469#ifndef __rtems__
470/* 1.1 */
471extern char kernelname[MAXPATHLEN];
472#endif /* __rtems__ */
473
474extern int tick;                        /* usec per tick (1000000 / hz) */
475-------------------------------------------------------------------------------
476
477-------------------------------------------------------------------------------
478#if defined(_KERNEL) || defined(_WANT_FILE)
479#ifdef __rtems__
480#include <rtems/libio_.h>
481#include <sys/fcntl.h>
482#endif /* __rtems__ */
483/*
484 * Kernel descriptor table.
485 * One entry for each open kernel vnode and socket.
486 *
487 * Below is the list of locks that protects members in struct file.
488 *
489 * (f) protected with mtx_lock(mtx_pool_find(fp))
490 * (d) cdevpriv_mtx
491 * none not locked
492 */
493-------------------------------------------------------------------------------
494
495-------------------------------------------------------------------------------
496extern int profprocs;                   /* number of process's profiling */
497#ifndef __rtems__
498extern volatile int ticks;
499#else /* __rtems__ */
500#include <rtems/score/watchdogimpl.h>
501#define ticks _Watchdog_Ticks_since_boot
502#endif /* __rtems__ */
503
504#endif /* _KERNEL */
505-------------------------------------------------------------------------------
506
507Add nothing (even blank lines) before or after the `__rtems__` guards.  Always
508include a `__rtems__` in the guards to make searches easy, so use
509
510* `#ifndef __rtems__`,
511* `#ifdef __rtems__`,
512* `#else /* __rtems__ */`, and
513* `#endif /* __rtems__ */`.
514
515For new code use
516http://www.freebsd.org/cgi/man.cgi?query=style&apropos=0&sektion=9&manpath=FreeBSD+9.2-RELEASE&arch=default&format=html[STYLE(9)].
517Do not format original FreeBSD code.
518
519== BSD Library Source
520
521=== What is in the Git Repository
522
523There is a self-contained kit with FreeBSD and RTEMS components pre-merged. The
524Waf wscript in this kit is automatically generated.
525
526Any changes to source in the `freebsd` directories will need to be merged
527upstream into our master FreeBSD checkout, the `freebsd-org` submodule.
528
529The repository contains two FreeBSD source trees.  In the `freebsd` directory
530are the so called 'managed' FreeBSD sources used to build the BSD library.  The
531FreeBSD source in `freebsd-org` is the 'master' version.  The
532`freebsd-to-rtems.py` script is used to transfer files between the two trees.
533In general terms, if you have modified managed FreeBSD sources, you will need
534to run the script in 'revert' or 'reverse' mode using the `-R` switch.  This
535will copy the source back to your local copy of the master FreeBSD source so
536you can run `git diff` against the upstream FreeBSD source.  If you want to
537transfer source files from the master FreeBSD source to the manged FreeBSD
538sources, then you must run the script in 'forward' mode (the default).
539
540=== Organization
541
542The top level directory contains a few directories and files. The following
543are important to understand
544
545* `freebsd-to-rtems.py` - script to convert to and free FreeBSD and RTEMS trees,
546* `wscript` - automatically generated,
547* `freebsd/` - from FreeBSD by script,
548* `rtemsbsd/` - RTEMS specific implementations of FreeBSD kernel support routines,
549* `testsuite/` - RTEMS specific tests, and
550* `libbsd.txt` - documentation in Asciidoc.
551
552== Moving Code Between Managed and Master FreeBSD Source
553
554The script `freebsd-to-rtems.py` is used to copy code from FreeBSD to the
555rtems-libbsd tree and to reverse this process. This script attempts to
556automate this process as much as possible and performs some transformations
557on the FreeBSD code. Its command line arguments are shown below:
558
559----
560freebsd-to-rtems.py [args]
561  -?|-h|--help      print this and exit
562  -d|--dry-run      run program but no modifications
563  -D|--diff         provide diff of files between trees
564  -e|--early-exit   evaluate arguments, print results, and exit
565  -m|--makefile     Warning: depreciated and will be removed
566  -b|--buildscripts just generate the build scripts
567  -R|--reverse      default FreeBSD -> RTEMS, reverse that
568  -r|--rtems        RTEMS directory
569  -f|--freebsd      FreeBSD directory
570  -v|--verbose      enable verbose output mode
571----
572
573In its default mode of operation, freebsd-to-rtems.py is used to copy code
574from FreeBSD to the rtems-libbsd tree and perform transformations.  In forward
575mode, the script may be requested to just generate the Waf script.
576
577In "reverse mode", this script undoes those transformations and copies
578the source code back to the FreeBSD SVN tree. This allows us to do
579'svn diff', evaluate changes made by the RTEMS Project, and report changes
580back to FreeBSD upstream.
581
582In either mode, the script may be asked to perform a dry-run or be verbose.
583Also, in either mode, the script is also smart enough to avoid copying over
584files which have not changed. This means that the timestamps of files are
585not changed unless the contents change. The script will also report the
586number of files which changed. In verbose mode, the script will print
587the name of the files which are changed.
588
589The following is an example forward run with no changes.
590
591----
592$ ~/newbsd/git/libbsd-8.2/freebsd-to-rtems.py \
593    -r /home/joel/newbsd/git/libbsd-8.2 \
594    -f /home/joel/newbsd/libbsd/freebsd-8.2 -v
595Verbose:                yes
596Dry Run:                no
597Only Generate Makefile: no
598RTEMS Directory:        /home/joel/newbsd/git/libbsd-8.2
599FreeBSD Directory:      /home/joel/newbsd/libbsd/freebsd-8.2
600Direction:              forward
601Generating into /home/joel/newbsd/git/libbsd-8.2
6020 files were changed.
603----
604
605The script may also be used to generate a diff in either forward or reverse
606direction.
607
608== Initialization of the BSD Library
609
610The initialization of the BSD library is based on the FreeBSD SYSINIT(9)
611infrastructure.  The key to initializing a system is to ensure that the desired
612device drivers are explicitly pulled into the linked application.  This plus
613linking against the BSD library (`libbsd.a`) will pull in the necessary FreeBSD
614infrastructure.
615
616The FreeBSD kernel is not a library like the RTEMS kernel.  It is a bunch of
617object files linked together.  If we have a library, then creating the
618executable is simple.  We begin with a start symbol and recursively resolve all
619references.  With a bunch of object files linked together we need a different
620mechanism.  Most object files don't know each other.  Lets say we have a driver
621module.  The rest of the system has no references to this driver module.  The
622driver module needs a way to tell the rest of the system: Hey, kernel I am
623here, please use my services!
624
625This registration of independent components is performed by SYSINIT(9) and
626specializations:
627
628http://www.freebsd.org/cgi/man.cgi?query=SYSINIT
629
630The SYSINIT(9) uses some global data structures that are placed in a certain
631section.  In the linker command file we need this:
632
633-------------------------------------------------------------------------------
634.rtemsroset : {
635        KEEP (*(SORT(.rtemsroset.*)))
636}
637
638.rtemsrwset : {
639        KEEP (*(SORT(.rtemsrwset.*)))
640}
641-------------------------------------------------------------------------------
642
643This results for example in this executable layout:
644
645-------------------------------------------------------------------------------
646[...]
647 *(SORT(.rtemsroset.*))
648 .rtemsroset.bsd.modmetadata_set.begin
649                0x000000000025fe00        0x0 libbsd.a(rtems-bsd-init.o)
650                0x000000000025fe00                _bsd__start_set_modmetadata_set
651 .rtemsroset.bsd.modmetadata_set.content
652                0x000000000025fe00        0x8 libbsd.a(rtems-bsd-nexus.o)
653 .rtemsroset.bsd.modmetadata_set.content
654                0x000000000025fe08        0x4 libbsd.a(kern_module.o)
655[...]
656 .rtemsroset.bsd.modmetadata_set.content
657                0x000000000025fe68        0x4 libbsd.a(mii.o)
658 .rtemsroset.bsd.modmetadata_set.content
659                0x000000000025fe6c        0x4 libbsd.a(mii_bitbang.o)
660 .rtemsroset.bsd.modmetadata_set.end
661                0x000000000025fe70        0x0 libbsd.a(rtems-bsd-init.o)
662                0x000000000025fe70                _bsd__stop_set_modmetadata_set
663[...]
664.rtemsrwset     0x000000000030bad0      0x290
665 *(SORT(.rtemsrwset.*))
666 .rtemsrwset.bsd.sysinit_set.begin
667                0x000000000030bad0        0x0 libbsd.a(rtems-bsd-init.o)
668                0x000000000030bad0                _bsd__start_set_sysinit_set
669 .rtemsrwset.bsd.sysinit_set.content
670                0x000000000030bad0        0x4 libbsd.a(rtems-bsd-nexus.o)
671 .rtemsrwset.bsd.sysinit_set.content
672                0x000000000030bad4        0x8 libbsd.a(rtems-bsd-thread.o)
673 .rtemsrwset.bsd.sysinit_set.content
674                0x000000000030badc        0x4 libbsd.a(init_main.o)
675[...]
676 .rtemsrwset.bsd.sysinit_set.content
677                0x000000000030bd54        0x4 libbsd.a(frag6.o)
678 .rtemsrwset.bsd.sysinit_set.content
679                0x000000000030bd58        0x8 libbsd.a(uipc_accf.o)
680 .rtemsrwset.bsd.sysinit_set.end
681                0x000000000030bd60        0x0 libbsd.a(rtems-bsd-init.o)
682                0x000000000030bd60                _bsd__stop_set_sysinit_set
683[...]
684-------------------------------------------------------------------------------
685
686Here you can see, that some global data structures are collected into
687continuous memory areas.  This memory area can be identified by start and stop
688symbols.  This constructs a table of uniform items.
689
690The low level FreeBSD code calls at some time during the initialization the
691mi_startup() function (machine independent startup).  This function will sort
692the SYSINIT(9) set and call handler functions which perform further
693initialization.  The last step is the scheduler invocation.
694
695The SYSINIT(9) routines are run in mi_startup() which is called by
696rtems_bsd_initialize().
697
698This is also explained in "The Design and Implementation of the FreeBSD
699Operating System" section 14.3 "Kernel Initialization".
700
701In RTEMS we have a library and not a bunch of object files.  Thus we need a way
702to pull-in the desired services out of the libbsd.  Here the
703`rtems-bsd-sysinit.h` comes into play.  The SYSINIT(9) macros have been
704modified and extended for RTEMS in `<sys/kernel.h>`:
705
706-------------------------------------------------------------------------------
707#ifndef __rtems__
708#define C_SYSINIT(uniquifier, subsystem, order, func, ident)    \
709        static struct sysinit uniquifier ## _sys_init = {       \
710                subsystem,                                      \
711                order,                                          \
712                func,                                           \
713                (ident)                                         \
714        };                                                      \
715        DATA_SET(sysinit_set,uniquifier ## _sys_init)
716#else /* __rtems__ */
717#define SYSINIT_ENTRY_NAME(uniquifier)                          \
718        _bsd_ ## uniquifier ## _sys_init
719#define SYSINIT_REFERENCE_NAME(uniquifier)                      \
720        _bsd_ ## uniquifier ## _sys_init_ref
721#define C_SYSINIT(uniquifier, subsystem, order, func, ident)    \
722        struct sysinit SYSINIT_ENTRY_NAME(uniquifier) = {       \
723                subsystem,                                      \
724                order,                                          \
725                func,                                           \
726                (ident)                                         \
727        };                                                      \
728        RWDATA_SET(sysinit_set,SYSINIT_ENTRY_NAME(uniquifier))
729#define SYSINIT_REFERENCE(uniquifier)                           \
730        extern struct sysinit SYSINIT_ENTRY_NAME(uniquifier);   \
731        static struct sysinit const * const                     \
732        SYSINIT_REFERENCE_NAME(uniquifier) __used               \
733        = &SYSINIT_ENTRY_NAME(uniquifier)
734#define SYSINIT_MODULE_REFERENCE(mod)                           \
735        SYSINIT_REFERENCE(mod ## module)
736#define SYSINIT_DRIVER_REFERENCE(driver, bus)                   \
737        SYSINIT_MODULE_REFERENCE(driver ## _ ## bus)
738#define SYSINIT_DOMAIN_REFERENCE(dom)                           \
739        SYSINIT_REFERENCE(domain_add_ ## dom)
740#endif /* __rtems__ */
741-------------------------------------------------------------------------------
742
743Here you see that the SYSINIT(9) entries are no longer static.  The
744\*_REFERENCE() macros will create references to the corresponding modules which
745are later resolved by the linker.  The application has to provide an object
746file with references to all required FreeBSD modules.
747
748The FreeBSD device model is quite elaborated (with follow-ups):
749
750http://www.freebsd.org/cgi/man.cgi?query=driver
751
752The devices form a tree with the Nexus device at a high-level.  This Nexus
753device is architecture specific in FreeBSD.  In RTEMS we have our own Nexus
754device, see `rtemsbsd/bsp/bsp-bsd-nexus-devices.c`.
755
756=== SYSCTL_NODE Example
757
758During development, we had an undefined reference to
759_bsd_sysctl__net_children that we had trouble tracking down. Thanks to
760Chris Johns, we located it. He explained how to read SYSCTL_NODE
761definitions. This line from freebsd/netinet/in_proto.c is attempting
762to add the "inet" node to the parent node "_net".
763
764----
765SYSCTL_NODE(_net,      PF_INET,         inet,   CTLFLAG_RW, 0,
766        "Internet Family");
767----
768
769Our problem was that we could not find where _bsd_sysctl__net_children
770was defined. Chris suggested that when in doubt compile with -save-temps
771and look at the preprocessed .i files. But he did not need that. He
772explained that this the symbol name _bsd_sysctl__net_children was
773automatically generated by a SYSCTL_NODE as follows:
774
775* _bsd_ - added by RTEMS modifications to SYSCTL_NODE macro
776* sysctl_ - boilerplace added by SYSCTL_NODE macro
777* "" - empty string for parent node
778* net - name of SYSCTL_NODE
779* children - added by SYSCTL macros
780
781This was all generated by a support macro declaring the node as this:
782
783----
784struct sysctl_oid_list SYSCTL_NODE_CHILDREN(parent, name);
785----
786
787Given this information, we located this SYSCTL_NODE declaration in
788kern/kern_mib.c
789
790----
791SYSCTL_NODE(, CTL_KERN,   kern,   CTLFLAG_RW, 0,
792        "High kernel, proc, limits &c");
793----
794
795== Core FreeBSD APIs and RTEMS Replacements ==
796
797=== SX(9) (Shared/exclusive locks) ===
798
799http://www.freebsd.org/cgi/man.cgi?query=sx
800
801Binary semaphores (this neglects the ability to allow shared access).
802
803=== MUTEX(9) (Mutual exclusion) ===
804
805http://www.freebsd.org/cgi/man.cgi?query=mutex
806
807Binary semaphores (not recursive mutexes are not supported this way).
808
809=== RWLOCK(9) (Reader/writer lock) ===
810
811http://www.freebsd.org/cgi/man.cgi?query=rwlock
812
813POSIX r/w lock.
814
815=== RMLOCK(9) (Reader/writer lock optimized for mostly read access patterns) ===
816
817Note:  This object was implemented as a wrapper for RWLOCK in the rm_lock header file.
818
819http://www.freebsd.org/cgi/man.cgi?query=rmlock
820
821POSIX r/w lock.
822
823=== CONDVAR(9) (Condition variables) ===
824
825http://www.freebsd.org/cgi/man.cgi?query=condvar
826
827POSIX condition variables with modifications (hack).
828
829=== CALLOUT(9) (Timer functions) ===
830
831http://www.freebsd.org/cgi/man.cgi?query=callout
832
833Timer server.
834
835=== TASKQUEUE(9) (Asynchronous task execution) ===
836
837http://www.freebsd.org/cgi/man.cgi?query=taskqueue
838
839TBD.
840
841=== KTHREAD(9), KPROC(9) (Tasks) ===
842
843http://www.freebsd.org/cgi/man.cgi?query=kthread
844
845http://www.freebsd.org/cgi/man.cgi?query=kproc
846
847Tasks.
848
849=== ZONE(9) (Zone allocator) ===
850
851http://www.freebsd.org/cgi/man.cgi?query=zone
852
853TBD.
854
855=== devfs (Device file system) ===
856
857Dummy, IMFS or new implementation (currently dummy).
858
859=== psignal (Signals) ===
860
861TBD.  Seems to be not needed.
862
863=== poll, select ===
864
865TBD.  Seems to be not needed.
866
867=== RMAN(9) (Resource management) ===
868
869http://www.freebsd.org/cgi/man.cgi?query=rman
870
871TBD.  Seems to be not needed.
872
873=== DEVCLASS(9), DEVICE(9), DRIVER(9), MAKE_DEV(9) (Device management) ===
874
875http://www.freebsd.org/cgi/man.cgi?query=devclass
876
877http://www.freebsd.org/cgi/man.cgi?query=device
878
879http://www.freebsd.org/cgi/man.cgi?query=driver
880
881http://www.freebsd.org/cgi/man.cgi?query=make_dev
882
883Use FreeBSD implementation as far as possible.  FreeBSD has a nice API for
884dynamic device handling.  It may be interesting for RTEMS to use this API
885internally in the future.
886
887=== BUS_SPACE(9), BUS_DMA(9) (Bus and DMA access) ===
888
889http://www.freebsd.org/cgi/man.cgi?query=bus_space
890
891http://www.freebsd.org/cgi/man.cgi?query=bus_dma
892
893Likely BSP dependent.  A default implementation for memory mapped linear access
894is easy to provide.  The current heap implementation supports all properties
895demanded by bus_dma (including the boundary constraint).
896
897== RTEMS Replacements by File Description ==
898
899Note:  Files with a status of USB are used by the USB test and have at least
900been partially tested.  If they contain both USB and Nic, then they are used
901by both and MAY contain methods that have not been tested yet.  Files that
902are only used by the Nic test are the most suspect.
903
904----
905rtems-libbsd File:      rtems-bsd-assert.c
906FreeBSD File:           rtems-bsd-config.h redefines BSD_ASSERT.
907Description:            This file contains the support method rtems_bsd_assert_func().
908Status:                 USB, Nic
909
910rtems-libbsd File:      rtems-bsd-autoconf.c
911FreeBSD File:           FreeBSD has BSP specific autoconf.c
912Description:            This file contains configuration methods that are used to setup the system.
913Status:                 USB
914
915rtems-libbsd File:      rtems-bsd-bus-dma.c
916FreeBSD File:           FreeBSD has BSP specific busdma_machdep.c
917Description:
918Status:                 USB, Nic
919
920rtems-libbsd File:      rtems-bsd-bus-dma-mbuf.c
921FreeBSD File:           FreeBSD has BSP specific busdma_machdep.c
922Description:
923Status:                 Nic
924
925rtems-libbsd File:      rtems-bsd-callout.c
926FreeBSD File:           kern/kern_timeout.c
927Description:
928Status:                 USB, Nic
929
930rtems-libbsd File:      rtems-bsd-cam.c
931FreeBSD File:           cam/cam_sim.c
932Description:
933Status:                 USB
934
935rtems-libbsd File:      rtems-bsd-condvar.c
936FreeBSD File:           kern/kern_condvar.c
937Description:
938Status:                 USB
939
940rtems-libbsd File:      rtems-bsd-copyinout.c
941FreeBSD File:           bsp specific copyinout.c )
942Description:            Note: The FreeBSD file is split with some methods being in rtems-bsd-support
943Status:                 Nic
944
945rtems-libbsd File:      rtems-bsd-delay.c
946FreeBSD File:           bsp specific file with multiple names
947Description:
948Status:                 USB, Nic
949
950rtems-libbsd File:      rtems-bsd-descrip.c
951FreeBSD File:           kern/kern_descrip.c
952Description:
953Status:                 Nic
954
955rtems-libbsd File:      rtems-bsd-generic.c
956FreeBSD File:           kern/sys_generic.c
957Description:
958Status:                 Nic
959
960rtems-libbsd File:      rtems-bsd-init.c
961FreeBSD File:           N/A
962Description:
963Status:                 USB, Nic
964
965rtems-libbsd File:      rtems-bsd-init-with-irq.c
966FreeBSD File:           N/A
967Description:
968Status:                 USB, Nic
969
970rtems-libbsd File:      rtems-bsd-jail.c
971FreeBSD File:           kern/kern_jail.c
972Description:
973Status:                 USB, Nic
974
975rtems-libbsd File:      rtems-bsd-lock.c
976FreeBSD File:           kern/subr_lock.c
977Description:
978Status:                 USB, Nic
979
980rtems-libbsd File:      rtems-bsd-log.c
981FreeBSD File:           kern/subr_prf.c
982Description:
983Status:                 Nic
984
985rtems-libbsd File:      rtems-bsd-malloc.c
986FreeBSD File:           kern/kern_malloc.c
987Description:
988Status:                 USB, Nic
989
990rtems-libbsd File:      rtems-bsd-mutex.c
991FreeBSD File:           kern/kern_mutex.c
992Description:
993Status:                 USB, Nic
994
995rtems-libbsd File:      rtems-bsd-newproc.c
996FreeBSD File:           N/A
997Description:
998Status:                 Nic
999
1000rtems-libbsd File:      rtems-bsd-nexus.c
1001FreeBSD File:           bsp specific nexus.c
1002Description:
1003Status:                 USB
1004
1005rtems-libbsd File:      rtems-bsd-panic.c
1006FreeBSD File:           boot/common/panic.c
1007Description:
1008Status:                 USB, Nic
1009
1010rtems-libbsd File:      rtems-bsd-rwlock.c
1011FreeBSD File:           kern_rwlock.c
1012Description:
1013Status:                 USB, Nic
1014
1015rtems-libbsd File:      rtems-bsd-shell.c
1016FreeBSD File:           N/A
1017Description:
1018Status:                 USB
1019
1020rtems-libbsd File:      rtems-bsd-signal.c
1021FreeBSD File:           kern/kern_sig.c
1022Description:
1023Status:                 Nic
1024
1025rtems-libbsd File:      rtems-bsd-smp.c
1026FreeBSD File:           N/A
1027Description:
1028Status:                 Nic
1029
1030rtems-libbsd File:      rtems-bsd-support.c
1031FreeBSD File:           bsp specific copyinout.c
1032Description:            Note: the FreeBSD file is split with some methods being in rtems-bsd-copyinout.
1033Status:                 USB, Nic
1034
1035rtems-libbsd File:      rtems-bsd-sx.c
1036FreeBSD File:           kern/kern_sx.c
1037Description:            Status: USB, Nic
1038
1039rtems-libbsd File:      rtems-bsd-synch.c
1040FreeBSD File:           kern/kern_synch.c
1041Description:
1042Status:                 USB, Nic
1043
1044rtems-libbsd File:      rtems-bsd-syscalls.c
1045FreeBSD File:           User API for kern/uipc_syscalls.c
1046Description:
1047Status:                 Nic
1048
1049rtems-libbsd File:      rtems-bsd-sysctlbyname.c
1050FreeBSD File:           User API for sysctlbyname(3)
1051Description:
1052Status:
1053
1054rtems-libbsd File:      rtems-bsd-sysctl.c
1055FreeBSD File:           User API for sysctl(8)
1056Description:
1057Status:
1058
1059rtems-libbsd File:      rtems-bsd-sysctlnametomib.c
1060FreeBSD File:           User API for sysctlnametomib
1061Description:
1062Status:
1063
1064rtems-libbsd File:      rtems-bsd-taskqueue.c
1065FreeBSD File:           kern/subr_taskqueue.c
1066Description:
1067Status:                 Nic
1068
1069rtems-libbsd File:      rtems-bsd-thread.c
1070FreeBSD File:           kern/kern_kthread.c
1071Description:
1072Status:                 USB, Nic
1073
1074rtems-libbsd File:      rtems-bsd-timeout.c
1075FreeBSD File:           kern/kern_timeout.c
1076Description:
1077Status:                 Nic
1078
1079rtems-libbsd File:      rtems-bsd-timesupport.c
1080FreeBSD File:           kern/kern_clock.c
1081Description:
1082Status:                 Nic
1083
1084rtems-libbsd File:      rtems-bsd-vm_glue.c
1085FreeBSD File:           vm/vm_glue.c
1086Description:
1087Status:                 USB, Nic
1088----
1089
1090== Notes by File ==
1091
1092altq_subr.c - Arbitrary choices were made in this file that RTEMS would
1093not support tsc frequency change.  Additionally, the clock frequency
1094for machclk_freq is always measured for RTEMS.
1095
1096conf.h - In order to add make_dev and destroy_dev, variables in the cdev
1097structure that were not being used were conditionally compiled out. The
1098capability of supporting children did not appear to be needed and was
1099not implemented in the rtems version of these routines.
1100
1101== NICs Status ==
1102
1103----
1104Driver                  Symbol                          Status
1105======                  ======                          ======
1106RealTek                 _bsd_re_pcimodule_sys_init      Links
1107EtherExpress            _bsd_fxp_pcimodule_sys_init     Links
1108DEC tulip               _bsd_dc_pcimodule_sys_init      Links
1109Broadcom BCM57xxx       _bsd_bce_pcimodule_sys_init     Links
1110Broadcom BCM4401        _bsd_bfe_pcimodule_sys_init     Links
1111Broadcom BCM570x        _bsd_bge_pcimodule_sys_init     Needs Symbols (A)
1112E1000 IGB               _bsd_igb_pcimodule_sys_init     Links
1113E1000 EM                _bsd_em_pcimodule_sys_init      Links
1114Cadence                 ?                               Links, works.
1115----
1116
1117Symbols (A)
1118         pci_get_vpd_ident
1119
1120=== Cadence ===
1121
1122The cadence driver works on the Xilinx Zynq platform. The hardware checksum
1123support works on real hardware but does not seem to be supported on qemu
1124therefore the default state is to disable TXCSUM and RXCSUM and this can be
1125enabled from the shell with:
1126
1127  # ifconfig cgem0 rxcsum txcsum
1128
1129or with an ioctl call to the network interface driver with SIOCSIFCAP and the
1130mask IFCAP_TXCSUM and IFCAP_RXCSUM set.
1131
1132== Problems to report to FreeBSD ==
1133
1134The MMAP_NOT_AVAILABLE define is inverted on its usage.  When it is
1135defined the mmap method is called. Additionally, it is not used
1136thoroughly. It is not used in the unmap portion of the source.
1137The file rec_open.c uses the define MMAP_NOT_AVAILABLE to wrap
1138the call to mmap and file rec_close.c uses the munmap method.
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