[0/4] x86: decode Xen/KVM emulate prefixes

Message

Maximilian Heyne May 10, 2022, 1:30 p.m. UTC

This is a backport of a patch series for 5.4.x.

The patch series allows the x86 decoder to decode the Xen and KVM emulate
prefixes.

In particular this solves the following issue that appeared when commit
db6c6a0df840 ("objtool: Fix noreturn detection for ignored functions") was
backported to 5.4.69:

  arch/x86/xen/enlighten_pv.o: warning: objtool: xen_cpuid()+0x25: can't find jump dest instruction at .text+0x9c

Also now that this decoding is possible, also backport the commit which prevents
kprobes on probing such prefixed instructions. This was also part of the
original series.

The series applied mostly cleanly on 5.4.192 except for a contextual problem in
the 3rd patch ("x86: xen: insn: Decode Xen and KVM emulate-prefix signature").

Masami Hiramatsu (4):
  x86/asm: Allow to pass macros to __ASM_FORM()
  x86: xen: kvm: Gather the definition of emulate prefixes
  x86: xen: insn: Decode Xen and KVM emulate-prefix signature
  x86: kprobes: Prohibit probing on instruction which has emulate prefix

 arch/x86/include/asm/asm.h                  |  8 +++--
 arch/x86/include/asm/emulate_prefix.h       | 14 +++++++++
 arch/x86/include/asm/insn.h                 |  6 ++++
 arch/x86/include/asm/xen/interface.h        | 11 +++----
 arch/x86/kernel/kprobes/core.c              |  4 +++
 arch/x86/kvm/x86.c                          |  4 ++-
 arch/x86/lib/insn.c                         | 34 +++++++++++++++++++++
 tools/arch/x86/include/asm/emulate_prefix.h | 14 +++++++++
 tools/arch/x86/include/asm/insn.h           |  6 ++++
 tools/arch/x86/lib/insn.c                   | 34 +++++++++++++++++++++
 tools/objtool/sync-check.sh                 |  3 +-
 tools/perf/check-headers.sh                 |  3 +-
 12 files changed, 128 insertions(+), 13 deletions(-)
 create mode 100644 arch/x86/include/asm/emulate_prefix.h
 create mode 100644 tools/arch/x86/include/asm/emulate_prefix.h


base-commit: 1d72b776f6dc973211f5d153453cf8955fb3d70a