On Mon, Aug 22, 2016 at 6:23 PM, H. Peter Anvin <[email protected]> wrote: > On August 22, 2016 2:48:46 PM PDT, Andi Kleen <[email protected]> wrote: >>Josh Poimboeuf <[email protected]> writes: >> >>> This zeroed word has no apparent purpose, so remove it. >>> >>> Brian Gerst says: >>> >>> "FYI the word used to be the SS segment selector for the LSS >>> instruction, which isn't needed in 64-bit mode." >>> >> >>Seems dangerous. It wouldn't surprise me if some CPUs or x86 emulations >>load it anyways and trigger page faults if there is really nothing >>there. >> >>-Andi > > Yes, seems pointlessly risky.
It was added in commit 9cf4f298e29abba25c16679fe7be70898223167e, copied from 32-bit but never used. It doesn't look like we ever used LSS on 64-bit. -- Brian Gerst
