Messages in this thread | | | Date | Fri, 11 Sep 2009 13:00:56 +0200 | From | Louis Rilling <> | Subject | Re: [RFC][v6][PATCH 8/9]: Define clone_with_pids() syscall |
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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
-- Dr Louis Rilling Kerlabs Skype: louis.rilling Batiment Germanium Phone: (+33|0) 6 80 89 08 23 80 avenue des Buttes de Coesmes http://www.kerlabs.com/ 35700 Rennes [unhandled content-type:application/pgp-signature] | |