On Wed, Feb 8, 2012 at 8:29 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: > On 02/08/2012 08:20 PM, Indan Zupancic wrote: >> >> CS is already available to user space, but any other value than 0x23 or 0x33 >> will confuse user space, as that is all they know about. Apparently Xen uses >> different values, but if those are static then user space can check for them >> separately. But if the values change dynamically then some other way may be >> needed. >> >> But does it make much sense to pass the CPU mode of user space if that mode >> can be changed at any moment? I don't think it really does. Can you give an >> example of how that info can be used by a ptracer? >> > > Uh... you could make THAT argument about ANY register state! > > I believe H.J. can fill you in about the usage. > GDB uses CS value to tell ia32 process from x86-64 process. At minimum, we need a bit in CS for GDB. But any changes will break old GDB. H.J. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
