Re: sysmips syscall

[Ralf Baechle <ralf@oss.sgi.com>]

On Fri, Nov 17, 2000 at 07:28:50PM -0600, rajesh.palani@philips.com wrote:

>    The following lines appear in the linuxthreads/sysdeps/mips/pt-machine.h file in version
> LinuxThreads 2.1.2:
> 
> TODO: This version makes use of MIPS ISA 2 features.  It won't
>    work on ISA 1.  These machines will have to take the overhead of
>    a sysmips(MIPS_ATOMIC_SET, ...) syscall which isn't implemented
>    yet correctly.  There is however a better solution for R3000
>    uniprocessor machines possible.
> 
> My questions are:
> 1.  Is the sysmips syscall implemented correctly yet?

Yes.

> 2.  What is the better solution for R3000 uniprocessor machines?

You can base a spinlock implementation on the fact that the register k0
will be left at a value != zero after any exception, also including context
switches.

Problem: this solution breaks silently on multiproessor systems.

> 3.  Does anyone have a patch for LinuxThreads that supports MIPS ISA 1?

glibc 2.2's pthread will do that out of the box.

  Ralf