Re: [PATCH 00/15] x86: Enable FSGSBASE instructions

[Bae, Chang Seok]

> Summary please.

These deltas I found as comparing with your old codes [4]
* Paranoid entry changes to avoid vulnerability 
* Ptrace changes to support the legacy behavior (conditionally)
* Dropped [1] to be aligned with what is concluded in [3]
* Dropped [2] since save_fsgs() doesnât copy base when index is zero; now open code with FSGSBASE instructions.
* Re-wrote assembly macros and dropped (redundant) SWAPGS intrinsic
* Revised helper functions -- dropped unused helpers and factor out write_task_fs/gsbase
* Introducing all of helper functions at the beginning of patch series
* Factor out load_fsgs()
* One of the test cases will be included later (as published 15 patches already)

[1] Refresh FS and GS when modify_ldt changes an entry
https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/commit/?h=x86/fsgsbase&id=fbe2c2a0ba5b879f8229ca7dfc0d434dbe31a805
[2] When copying a thread, safe FS and GS for real
https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/commit/?h=x86/fsgsbase&id=e51eceeefbd587b514ca357b745b46e8e2746d34 
[3] FSGSBASE ABI discussion
https://marc.info/?l=linux-kernel&m=150212735223392&w=2 
[4] https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/log/?h=x86/fsgsbase