• Guenter Roeck's avatar
    hwmon: Remove amd_energy driver · 9049572f
    Guenter Roeck authored
    Commit 60268b0e ("hwmon: (amd_energy) modify the visibility of
    the counters") restricted visibility of AMD energy counters to work
    around a side-channel attack using energy data to determine which
    instructions are executed. The attack is described in 'PLATYPUS:
    Software-based Power Side-Channel Attacks on x86'. It relies on quick
    and accurate energy readings.
    
    This change made the counters provided by the amd_energy driver
    effectively unusable for non-provileged users. However, unprivileged
    read access is the whole point of hardware monitoring attributes.
    
    An attempt to remedy the situation by limiting and randomizing access
    to chip registers was rejected by AMD. Since the driver is for all
    practical purposes unusable, remove it.
    
    Cc: Naveen Krishna Chatradhi <nchatrad@amd.com>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
    9049572f
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