Re: [PATCH -mm] i386 syscall opcode reordering (pipelining)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Followup to:  <[email protected]>
By author:    Arjan van de Ven <[email protected]>
In newsgroup: linux.dev.kernel
>
> Andreas Mohr wrote:
> > Hi all,
> > 
> > I'd guess that this version features improved pipeline parallelism,
> > since we isolate competing %ebx accesses (_syscall4()) and
> > stack push operations (_syscall5()), right?
> 
> is anybody actually EVER using those???
> I would think not....

Probably not.  The _syscallN() macros are broken for the general case
on any 32-bit architecture, since they can't handle multiregister
arguments.

Similarly, a general syscall() function is broken (in the sense that
one would have to have syscall-specific code to mangle the arguments)
on *some*, but not all, 32-bit architectures, since some architectures
have alignment constraints on multiregister arguments, and the syscall
number argument throws off that alignment.

	-hpa

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux