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    Subject[PATCH RFC V3 0/8] jump-label: allow early jump_label_enable()
    From: Jeremy Fitzhardinge <>

    [ Change from V2: add arch_jump_label_transform_static() for use on
    code which can't possibly be currently executing (ie, a freshly
    loaded module), which can avoid heavyweight things like
    stop_machine. The default implementation is simply
    arch_jump_label_transform(), so only architectures which would
    particularly benefit need implement it (x86 and s390 in this
    series). ]

    While trying to use the jump-label stuff for my PV ticketlock changes,
    I had some problems using jump labels early in the kernel's lifetime

    The basic problem is that even if I enable a jump_label_key, the
    jump_label_init() initializer ends up nopping out all the code sites.

    This series enables early use of jump labels by making
    jump_label_init() respect already-enabled keys.

    To do this, I've dropped arch_jump_label_poke_text_early() and
    replaced it with arch_jump_label_transform(), allowing it to either
    insert an optimal nop, or leave the jump in place.

    Part of this series makes sure that stop_machine() is safe to call
    in an early pre-SMP environment, by making it just call the function
    with interrupts disabled.

    git:// upstream/jump-label-noearly

    Jeremy Fitzhardinge (8):
    jump_label: use proper atomic_t initializer
    stop_machine: make stop_machine safe and efficient to call early
    jump_label: if a key has already been initialized, don't nop it out
    x86/jump_label: drop arch_jump_label_text_poke_early()
    sparc/jump_label: drop arch_jump_label_text_poke_early()
    jump_label: add arch_jump_label_transform_static() to optimise
    non-live code updates
    s390/jump-label: add arch_jump_label_transform_static()
    x86/jump_label: add arch_jump_label_transform_static()

    arch/s390/kernel/jump_label.c | 51 ++++++++++++++++++++++++---------------
    arch/sparc/kernel/jump_label.c | 8 ------
    arch/x86/kernel/jump_label.c | 20 +++++++++++----
    include/linux/jump_label.h | 9 ++++---
    kernel/jump_label.c | 32 +++++++++++++++---------
    kernel/stop_machine.c | 22 +++++++++++++++++
    6 files changed, 92 insertions(+), 50 deletions(-)


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