• James Morse's avatar
    arm64: hibernate: Refuse to hibernate if the boot cpu is offline · 1fe492ce
    James Morse authored
    Hibernation represents a system state save/restore through
    a system reboot; this implies that the logical cpus carrying
    out hibernation/thawing must be the same, so that the context
    saved in the snapshot image on hibernation is consistent with
    the state of the system on resume. If resume from hibernation
    is driven through kernel command line parameter, the cpu responsible
    for thawing the system will be whatever CPU firmware boots the system
    on upon cold-boot (ie logical cpu 0); this means that in order to
    keep system context consistent between the hibernate snapshot image
    and system state on kernel resume from hibernate, logical cpu 0 must
    be online on hibernation and must be the logical cpu that creates
    the snapshot image.
    
    This patch adds a PM notifier that enforces logical cpu 0 is online
    when the hibernation is started (and prevents hibernation if it is
    not), which is sufficient to guarantee it will be the one creating
    the snapshot image therefore providing the resume cpu a consistent
    snapshot of the system to resume to.
    Signed-off-by: default avatarJames Morse <james.morse@arm.com>
    Acked-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
    Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
    1fe492ce
hibernate.c 12.2 KB