Messages in this thread | | | From | Andy Lutomirski <> | Date | Sat, 20 Jun 2020 08:59:57 -0700 | Subject | Linux FSGSBASE testing |
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Hi Stas-
FSGSBASE support is queued up for Linux 5.9. Since you're one of the more exotic users of segmentation on Linux, is there any chance you could test it? The code is here:
https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/log/?h=x86/fsgsbase
There are two interesting cases to test:
1. FSGSBASE on. This is the default if you boot this kernel on Ivy Bridge or newer hardware.
2. FSGSBASE off on a patched kernel. Boot the same kernel as in #1 but either pass nofsgsbase on the kernel command line or use pre-Ivy Bridge hardware. You will *
You can tell you have FSGSBASE enabled for test #1 by running tools/testing/selftests/x86/fsgsbase_64 -- the first line of output will be :FSGSBASE instructions are enabled". You can build it by cd-ing to tools/testing/selftests/x86 and running make.
If anything is broken for you, I'd like to know before this makes it into a released kernel!
Thanks, Andy
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