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    Subject[PATCH 5.18 274/339] jump_label,noinstr: Avoid instrumentation for JUMP_LABEL=n builds
    Date
    From: Peter Zijlstra <peterz@infradead.org>

    [ Upstream commit 656d054e0a15ec327bd82801ccd58201e59f6896 ]

    When building x86_64 with JUMP_LABEL=n it's possible for
    instrumentation to sneak into noinstr:

    vmlinux.o: warning: objtool: exit_to_user_mode+0x14: call to static_key_count.constprop.0() leaves .noinstr.text section
    vmlinux.o: warning: objtool: syscall_exit_to_user_mode+0x2d: call to static_key_count.constprop.0() leaves .noinstr.text section
    vmlinux.o: warning: objtool: irqentry_exit_to_user_mode+0x1b: call to static_key_count.constprop.0() leaves .noinstr.text section

    Switch to arch_ prefixed atomic to avoid the explicit instrumentation.

    Reported-by: kernel test robot <lkp@intel.com>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    include/linux/jump_label.h | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
    index 107751cc047b..bf1eef337a07 100644
    --- a/include/linux/jump_label.h
    +++ b/include/linux/jump_label.h
    @@ -256,9 +256,9 @@ extern void static_key_disable_cpuslocked(struct static_key *key);
    #include <linux/atomic.h>
    #include <linux/bug.h>

    -static inline int static_key_count(struct static_key *key)
    +static __always_inline int static_key_count(struct static_key *key)
    {
    - return atomic_read(&key->enabled);
    + return arch_atomic_read(&key->enabled);
    }

    static __always_inline void jump_label_init(void)
    --
    2.35.1


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