[uClibc]Re: ftruncate64 on arm

Miles Bader miles at lsi.nec.co.jp
Mon Apr 1 04:15:29 UTC 2002


Erik Andersen <andersen at codepoet.org> writes:
> Mostly, I just poked at the kernel source and saw that for x86
> and arm, in linux/arch/arm/kernel/calls.S it directly calls
> sys_ftruncate64 suggesting that it should just work... 

On the v850 at least the problem with passing 64-bit arguments directly
is the use of `asm' magic in the user syscall inlines.  The kernel-side
doesn't have to do anything special, because syscalls basically use the
same calling conventions as functions for 64-bit args.

The same seems to be true of the other ports I looked at (but this is
merely by inspection, I haven't done any testing :-)

[BTW, it's possible that things will `work' by accident, if the upper
32 bits of the offset arg happen to be in the right register (because
the function and syscall calling-conventions are the same), but I think
it would be very poor practice to rely on this.]

-Miles
-- 
Ich bin ein Virus. Mach' mit und kopiere mich in Deine .signature.



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