Hello,

I am trying to build real time Linux kernel (not the PREEMPT_RT but the RTLinux which is not in active development currently).

Questions:
1) I have explored very much for the RTLinux patch but could not get that. If anyone can provide the patch, it would be great.(Kernel version is not a problem, I need a patch for any version)

2) I could get the RTLinux kernel source on github at (Latest commit on 3.x kernel)
https://github.com/clrkwllms/rt-linux.git

I got error related to libsas (related to scsi) and disabled some scsi options in kernel config and rebuilt successfully but boot fails, dropping to initramfs shell, where it shows /proc/devices not found error. I doubt if this is due to disabling some scsi options in config file.

3) Great if anyone can share their experiences reg this and inputs on how to proceed with the RTLinux kernel source build. I need RTLinux in particular and not any alternatives or similar ones like RTAI.

Thanks and regards,

All roads seem to lead to WindRiver. Might ask them for download access.

Might search out people who may still have information. https://www.cs.fsu.edu/~baker/realti...s/rtlinux.html I assume the guy still works there.

1 members found this post helpful.

Dear jefro,

Yes any links from blogs etc which were earlier pointing to FSMlabs or other are redirected to windriver website, but not to any particular page of windriver that can provide relevant information.I think that's not good, not sure of what happened to GPL licensing terms (probably, the license validity period is over and the GPL license is revoked; am not an expert of open source licenses, so not sure) when windriver has taken over FSM Labs.

I have already mailed to an existing fsmlabs support mail id and valid one and got acknowledgement mail, but no further response.

That apart, trying to contact Mr. Ted Baker, the author of the post you had sent the link.

Thank you very much for your time,

Might look at QNX too. It has been around a long time and may be able to be purchased for use. I think you can download QNX 6 still. There was an openqnx but doubt that ever took off.

MenuetOS I think is supposed to be real time.

1 members found this post helpful.

Thank you for the valuable information jefro.
Your inputs are very helpful.

I have got patch with kernel source for. 2.4.20 at the link (by Mr Ted Baker) you mentioned above and working on that. It is taking time ( as the source looks unstable or interim sort of and for particular architecture, or apt for 32 bit, or compatibility issues with older gcc and gcc5 that am using...) for me to build kernel making corrections as the build errors are shooting up one after the another.

I am currently stuck at below error.I believe it is related to architecture (32/64) but do not know how to resolve, checking that:
(Last lines of the kernel build log )

/usr/src/rtlinux-3.2-pre2/linux-2.4.20/include/asm/apic.h:81:20: warning: ‘nmi_watchdog_tick’ declared ‘static’ but never defined [-Wunused-function]
static inline void nmi_watchdog_tick (struct pt_regs * regs);
^
process.c: Assembler messages:
process.c:461: Error: unsupported instruction `mov'
process.c:462: Error: unsupported instruction `mov'
process.c:463: Error: unsupported instruction `mov'
process.c:464: Error: unsupported instruction `mov'
process.c:513: Error: unsupported instruction `mov'
process.c:517: Error: unsupported instruction `mov'
process.c:519: Error: operand type mismatch for `pop'
process.c:523: Error: operand type mismatch for `pop'
/usr/src/rtlinux-3.2-pre2/linux-2.4.20/Rules.make:60: recipe for target 'process.o' failed
make[1]: *** [process.o] Error 1
make[1]: Leaving directory '/usr/src/rtlinux-3.2-pre2/linux-2.4.20/arch/x86_64/kernel'
Makefile:320: recipe for target '_dir_arch/x86_64/kernel' failed
make: *** [_dir_arch/x86_64/kernel] Error 2

My machine is :Intel(R) Core(TM)2 Duo CPU P9600 @ 2.66GHz
OS : x86_64 x86_64 GNU/Linux

NOTE: I tried giving option -m32 in the highest level makefile which is caught by make bzImage, but it din help.


Thanks and regards,

Error output when added -m32 when trying to resolve Unsupported instruction mov error, and doing make bzImage:

brt@brt:/usr/src/rtlinux/linux$ sudo make bzImage
make -C arch/x86_64/tools /usr/src/rtlinux-3.2-pre2/linux-2.4.20/include/asm-x86_64/offset.h
make[1]: Entering directory '/usr/src/rtlinux-3.2-pre2/linux-2.4.20/arch/x86_64/tools'
gcc -D__KERNEL__ -I/usr/src/rtlinux-3.2-pre2/linux-2.4.20/include -Wall -Wstrict-prototypes -Wno-trigraphs -O2 -fno-strict-aliasing -fno-common -m32 -fomit-frame-pointer -mno-red-zone -mcmodel=kernel -pipe -fno-reorder-blocks -finline-limit=2000 -fno-strength-reduce -S -o offset.tmp offset.c
offset.c:1:0: error: code model ‘kernel’ not supported in the 32 bit mode
/* Written 2000 by Andi Kleen */
^
Makefile:18: recipe for target 'offset.h' failed
make[1]: *** [offset.h] Error 1
make[1]: Leaving directory '/usr/src/rtlinux-3.2-pre2/linux-2.4.20/arch/x86_64/tools'
arch/x86_64/Makefile:92: recipe for target 'checkoffset' failed
make: *** [checkoffset] Error 2


NOTE: Got above error, when I added -m32 option to wither HOSTCFLAGS or CFLAGS or both. Kindly help