> If user code programs fs != 0 and fsbase != whatever is implied by fs > and the GDT/LDT, what happens?
We load the value from the LDT/GDT. > There's already a minor buglet in that > area without wrfsbase, but fixing it would be a big performance hit > because we don't have rdfsbase and rdgsbase to read the state > efficiently. (Specifically, if we have gs == 0, gsbase == 0, but > *saved* gsbase != 0, then we corrupt gsbase on context switch.) > > But, with the new instructions, we can do it simply, efficiently, and > correctly in all cases. Let's do so. We would need an instruction to write the index without changing the base. That's not what the new instructions do. -Andi -- a...@linux.intel.com -- Speaking for myself only -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
