[PATCH v3 0/9] x86/xsaves: Fix XSAVES known issues

[Yu-cheng Yu]

XSAVES is a kernel-mode instruction. It offers a compacted format and
memory-write optimization. These patches fix known issues in the first
implementation. They are intended for discussion and getting feedback
before actually getting applied.

Version 3 adds a WARN_ONCE() in patch 9 to make it clear XSAVES supervisor
states are not yet supported.

Version 2 fixes a mistake in handling supervisor states of ptrace function
copyin_to_xsaves() and some coding style/naming issues in the first version.
It also limits XSAVES only to 64-bit kernel in patch 9.

Patch 1, 2, and 4 are for converting between kernel-mode xstate area and
signal frames.

Patch 3 fixes optimization issues introduced by XSAVES to the buffer
init_fpstate.

Patch 5 and 6 are related to xstate component offsets.

Patch 7 is for converting between kernel-mode xstate area and ptrace
frames.

Patch 8 fixes xstate area print out.

Patch 9 re-enables XSAVES.

Yu-cheng Yu (9):
  x86/xsaves: Define and use user_xstate_size for xstate size in signal
    context
  x86/xsaves: Rename xstate_size to kernel_xstate_size to explicitly
    distinguish xstate size in kernel from user space
  x86/xsaves: Keep init_fpstate.xsave.header.xfeatures as zero for init
    optimization
  x86/xsaves: Introduce a new check that allows correct xstates copy
    from kernel to user directly
  x86/xsaves: Align xstate components according to CPUID
  x86/xsaves: Supervisor state component offset
  x86/xsaves: Fix PTRACE frames for XSAVES
  x86/xsaves: Fix XSTATE component offset print out
  x86/xsaves: Re-enable XSAVES

 arch/x86/include/asm/fpu/types.h  |   2 +
 arch/x86/include/asm/fpu/xstate.h |   8 +-
 arch/x86/include/asm/processor.h  |   3 +-
 arch/x86/kernel/fpu/core.c        |   6 +-
 arch/x86/kernel/fpu/init.c        |  35 ++--
 arch/x86/kernel/fpu/regset.c      |  56 ++++--
 arch/x86/kernel/fpu/signal.c      |  69 ++++++-
 arch/x86/kernel/fpu/xstate.c      | 400 +++++++++++++++++++++++++++++---------
 8 files changed, 443 insertions(+), 136 deletions(-)

-- 
1.9.1