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    Subject[RFC PATCH 2/6] jump_label: Add the jump_label_can_update_check() helper
    Date
    Move the check of if a jump_entry is valid to a function.

    Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
    Cc: Masami Hiramatsu <mhiramat@kernel.org>
    Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
    Cc: Zhou Chengming <zhouchengming1@huawei.com>
    Cc: Jiri Kosina <jkosina@suse.cz>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
    Cc: Chris von Recklinghausen <crecklin@redhat.com>
    Cc: Jason Baron <jbaron@akamai.com>
    Cc: Scott Wood <swood@redhat.com>
    Cc: Marcelo Tosatti <mtosatti@redhat.com>
    Cc: Clark Williams <williams@redhat.com>
    Cc: x86@kernel.org
    Cc: linux-kernel@vger.kernel.org
    ---
    kernel/jump_label.c | 29 ++++++++++++++++++-----------
    1 file changed, 18 insertions(+), 11 deletions(-)

    diff --git a/kernel/jump_label.c b/kernel/jump_label.c
    index e853916a3b46..940ba7819c87 100644
    --- a/kernel/jump_label.c
    +++ b/kernel/jump_label.c
    @@ -361,22 +361,29 @@ static enum jump_label_type jump_label_type(struct jump_entry *entry)
    return enabled ^ branch;
    }

    +bool jump_label_can_update_check(struct jump_entry *entry)
    +{
    + /*
    + * An entry->code of 0 indicates an entry which has been
    + * disabled because it was in an init text area.
    + */
    + if (entry->code) {
    + if (kernel_text_address(entry->code))
    + return 1;
    + else
    + WARN_ONCE(1, "can't patch jump_label at %pS",
    + (void *)(unsigned long)entry->code);
    + }
    + return 0;
    +}
    +
    static void __jump_label_update(struct static_key *key,
    struct jump_entry *entry,
    struct jump_entry *stop)
    {
    for_each_label_entry(key, entry, stop) {
    - /*
    - * An entry->code of 0 indicates an entry which has been
    - * disabled because it was in an init text area.
    - */
    - if (entry->code) {
    - if (kernel_text_address(entry->code))
    - arch_jump_label_transform(entry, jump_label_type(entry));
    - else
    - WARN_ONCE(1, "can't patch jump_label at %pS",
    - (void *)(unsigned long)entry->code);
    - }
    + if (jump_label_can_update_check(entry))
    + arch_jump_label_transform(entry, jump_label_type(entry));
    }
    }

    --
    2.17.1
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