Hi Michael, On Tue, Jul 05, 2016 at 03:40:40PM +1000, Michael Ellerman wrote: > On Wed, 2016-06-04 at 07:00:12 UTC, Simon Guo wrote: > > These 2 fields track whether user process has used Altivec/VSX > > registers or not. They are used by kernel to setup signal frame > > on user stack correctly regarding vector part. > > > > CRIU(Checkpoint and Restore In User space) builds signal frame > > for restored process. It will need this export information to > > setup signal frame correctly. And CRIU will need to restore these > > 2 fields for the restored process. > > > > Signed-off-by: Simon Guo <wei.guo.si...@gmail.com> > > Reviewed-by: Laurent Dufour <lduf...@linux.vnet.ibm.com> > > @@ -176,6 +176,17 @@ struct pt_regs { > > #define PTRACE_GETREGS64 0x16 > > #define PTRACE_SETREGS64 0x17 > > > > +/* > > + * Get or set some register used bit. > > + * The flags will be saved in a 32 bit data. > > + * Currently it is only used for VR/VSR usage. > > + */ > > +#define PTRACE_GET_REGS_USAGE 0x1e > > +#define PTRACE_SET_REGS_USAGE 0x1f > > + > > +#define PTRACE_REGS_USAGE_VR_BIT 0x00000001 > > +#define PTRACE_REGS_USAGE_VSR_BIT 0x00000002 > > > It looks like you just made up this new ptrace ABI ? > > Or is it used on other arches ? (no AFAICS) > > How do other arches handle this ? > > I'm a bit wary of adding new ptrace ABIs. > > If we do want to do this, I'd at least think the mask should be u64, to give > us > more capacity to add new registers. > > cheers
It is only used on PowerPc currently. I had better rename it to: #define PPC_PTRACE_GET_REGS_USAGE 0x96 #define PPC_PTRACE_SET_REGS_USAGE 0x97 I will change the mask into u64. Thanks, - Simon _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev