---
- branch: MAIN
  date: Sat Oct 24 07:14:30 UTC 2020
  files:
  - new: '1.42'
    old: '1.41'
    path: src/sys/arch/x86/include/cpufunc.h
    pathrev: src/sys/arch/x86/include/cpufunc.h@1.42
    type: modified
  - new: '1.23'
    old: '1.22'
    path: src/sys/arch/x86/include/fpu.h
    pathrev: src/sys/arch/x86/include/fpu.h@1.23
    type: modified
  - new: '1.76'
    old: '1.75'
    path: src/sys/arch/x86/x86/fpu.c
    pathrev: src/sys/arch/x86/x86/fpu.c@1.76
    type: modified
  - new: '1.82'
    old: '1.81'
    path: src/sys/dev/nvmm/x86/nvmm_x86_svm.c
    pathrev: src/sys/dev/nvmm/x86/nvmm_x86_svm.c@1.82
    type: modified
  - new: '1.81'
    old: '1.80'
    path: src/sys/dev/nvmm/x86/nvmm_x86_vmx.c
    pathrev: src/sys/dev/nvmm/x86/nvmm_x86_vmx.c@1.81
    type: modified
  - new: '1.30'
    old: '1.29'
    path: src/tests/lib/libc/sys/t_ptrace_x86_wait.h
    pathrev: src/tests/lib/libc/sys/t_ptrace_x86_wait.h@1.30
    type: modified
  id: 20201024T071430Z.b41257964584dcc9e129d9852bd067483b9e886d
  log: |
    Issue 64-bit versions of *XSAVE* for 64-bit amd64 programs

    When calling FXSAVE, XSAVE, FXRSTOR, ... for 64-bit programs on amd64
    use the 64-suffixed variant in order to include the complete FIP/FDP
    registers in the x87 area.

    The difference between the two variants is that the FXSAVE64 (new)
    variant represents FIP/FDP as 64-bit fields (union fp_addr.fa_64),
    while the legacy FXSAVE variant uses split fields: 32-bit offset,
    16-bit segment and 16-bit reserved field (union fp_addr.fa_32).
    The latter implies that the actual addresses are truncated to 32 bits
    which is insufficient in modern programs.

    The change is applied only to 64-bit programs on amd64.  Plain i386
    and compat32 continue using plain FXSAVE.  Similarly, NVMM is not
    changed as I am not familiar with that code.

    This is a potentially breaking change.  However, I don't think it likely
    to actually break anything because the data provided by the old variant
    were not meaningful (because of the truncated pointer).
  module: src
  subject: 'CVS commit: src'
  unixtime: '1603523670'
  user: mgorny