CVSROOT: /cvs
Module name: src
Changes by: [email protected] 2026/04/18 19:10:28
Modified files:
sys/arch/amd64/include: specialreg.h
sys/arch/amd64/amd64: cpu.c
sys/arch/i386/include: specialreg.h
sys/arch/i386/i386: machdep.c
Log message:
floating point state leakage can be observed on AMD Zen/Zen+ (Zen 1)
This was discovered by the Rootsec research group at the CISPA Helmholtz
Center for Information Security. Rootsec named the problem
Floating Point Divider State Sampling (FP-DSS).
Do AMD's suggested mitigation, setting a chicken bit in an MSR.
https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7053.html
https://roots.ec/blog/fpdss/
ok deraadt@ brynet@
