Re: [RFC][v6][PATCH 8/9]: Define clone_with_pids() syscall

[Louis Rilling]

On 11/09/09 12:31 +0200, Arnd Bergmann wrote:
> On Thursday 10 September 2009, Sukadev Bhattiprolu wrote:
> > Since this is a variant of clone() and clone is listed as a PTREGSCALL(),
> > I pass in the pt_regs.
> > 
> > arch/x86/kernel/entry_32.S lists clone() under this comment:
> > 
> > /*
> >  * System calls that need a pt_regs pointer.
> >  */
> > 
> > Is there a guideline on what system calls use/need pt_regs ?
> 
> You need pt_regs if you access any registers from the user task
> other than the argument registers. In case of clone(), this is
> the user stack pointer.

AFAICS clone() actually needs _all_ registers (see x86 copy_thread() for
instance). Any variant of clone() will have this requirement.

Louis

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