CVSROOT: /cvs
Module name: src
Changes by: [email protected] 2026/05/13 19:39:38
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:
mitigate AMD Zen-2 operation cache corruption
On Zen 2, the operation cache can be used to change instructions
of a different privilege level.
https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7052.html
The mitigation is setting a chicken bit in an MSR. This is not documented
publicly, even in the security bulletin. The value comes from a patch
submitted to Linux by AMD employees.
ok deraadt@ brynet@
