• Kyle Huey's avatar
    x86/arch_prctl: Add ARCH_[GET|SET]_CPUID · e9ea1e7f
    Kyle Huey authored
    Intel supports faulting on the CPUID instruction beginning with Ivy Bridge.
    When enabled, the processor will fault on attempts to execute the CPUID
    instruction with CPL>0. Exposing this feature to userspace will allow a
    ptracer to trap and emulate the CPUID instruction.
    When supported, this feature is controlled by toggling bit 0 of
    MSR_MISC_FEATURES_ENABLES. It is documented in detail in Section 2.3.2 of
    Implement a new pair of arch_prctls, available on both x86-32 and x86-64.
    ARCH_GET_CPUID: Returns the current CPUID state, either 0 if CPUID faulting
        is enabled (and thus the CPUID instruction is not available) or 1 if
        CPUID faulting is not enabled.
    ARCH_SET_CPUID: Set the CPUID state to the second argument. If
        cpuid_enabled is 0 CPUID faulting will be activated, otherwise it will
        be deactivated. Returns ENODEV if CPUID faulting is not supported on
        this system.
    The state of the CPUID faulting flag is propagated across forks, but reset
    upon exec.
    Signed-off-by: default avatarKyle Huey <khuey@kylehuey.com>
    Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
    Cc: kvm@vger.kernel.org
    Cc: Radim Krčmář <rkrcmar@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Dave Hansen <dave.hansen@linux.intel.com>
    Cc: Andi Kleen <andi@firstfloor.org>
    Cc: linux-kselftest@vger.kernel.org
    Cc: Nadav Amit <nadav.amit@gmail.com>
    Cc: Robert O'Callahan <robert@ocallahan.org>
    Cc: Richard Weinberger <richard@nod.at>
    Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
    Cc: Borislav Petkov <bp@suse.de>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Len Brown <len.brown@intel.com>
    Cc: Shuah Khan <shuah@kernel.org>
    Cc: user-mode-linux-devel@lists.sourceforge.net
    Cc: Jeff Dike <jdike@addtoit.com>
    Cc: Alexander Viro <viro@zeniv.linux.org.uk>
    Cc: user-mode-linux-user@lists.sourceforge.net
    Cc: David Matlack <dmatlack@google.com>
    Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
    Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
    Cc: linux-fsdevel@vger.kernel.org
    Cc: Paolo Bonzini <pbonzini@redhat.com>
    Link: http://lkml.kernel.org/r/20170320081628.18952-9-khuey@kylehuey.comSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
exec.c 44.5 KB