The Linux 6.15 core has received a significant set of updates for the X86 architecture, marking one of the largest updates in recent years. These updates bring many new features for both AMD processors and Intel, focusing on performance optimization, safety enhancements, and support for new processor generations.
For AMD processors, the core now includes support for InvLPB instructions found in Zen 3, which aids in broadcasting TLB disability and improves performance. Additionally, improvements have been made to the AMD Node driver and the System Management Network (SMN).
On the Intel side, preparations are being made to transition to new processor families (Family 18 and 19) from the traditional Family 6. The core now features enhancements to the CPU identification system, support for Linear Address Masking (LAM), and the new FinEIBT-BHI protection. A significant update also allows for selective application of vulnerability measures to specific cores (p or e) rather than all cores simultaneously.
New parameters, such as setcpuid loading parameters = and Clearcpuid =, have been added to allow manual enabling or disabling of specific CPU functions for testing or forced protection activation. The execmem_rox function has been modified to support large pages for reading and execution, after being previously rejected due to issues.
Other notable changes include a reduction in entropy in the Kaslr system to avoid conflicts with PCI BAR exceeding 10 Tib when assembling a nucleus with config_pci_p2pdma included. The minimum compiler version requirements have also been updated to GCC 8.1 or Clang 15.0 for Linux 6.15 assembly.
Support for 32-bit cores on X86_64 processors has seen changes, with Config_highmem64g and support for more than 4 GB of RAM for 32-bit systems removed. Furthermore, Bigsmp support has been excluded. Improvements have been made in performance through the use of ASM_inline () for atomic lock instructions, accompanied by minor improvements and corrections.
These updates constitute only a portion of the changes to the X86 subsystem in Linux 6.15. Additional improvements for Intel and AMD CPUs, such as crypto and CRC acceleration, are included in other pull requests. The merging of these changes is expected to continue until the end of the week.
Source: Pull requests for Linux 6.15