• Schspa Shi's avatar
    gpio: use raw spinlock for gpio chip shadowed data · 3c938cc5
    Schspa Shi authored
    In case of PREEMPT_RT, there is a raw_spinlock -> spinlock dependency
    as the lockdep report shows.
    
    __irq_set_handler
      irq_get_desc_buslock
        __irq_get_desc_lock
          raw_spin_lock_irqsave(&desc->lock, *flags);  // raw spinlock get here
      __irq_do_set_handler
        mask_ack_irq
          dwapb_irq_ack
            spin_lock_irqsave(&gc->bgpio_lock, flags); // sleep able spinlock
      irq_put_desc_busunlock
    
    Replace with a raw lock to avoid BUGs. This lock is only used to access
    registers, and It's safe to replace with the raw lock without bad
    influence.
    
    [   15.090359][    T1] =============================
    [   15.090365][    T1] [ BUG: Invalid wait context ]
    [   15.090373][    T1] 5.10.59-rt52-00983-g186a6841c682-dirty #3 Not tainted
    [   15.090386][    T1] -----------------------------
    [   15.090392][    T1] swapper/0/1 is trying to lock:
    [   15.090402][    T1] 70ff00018507c188 (&gc->bgpio_lock){....}-{3:3}, at: _raw_spin_lock_irqsave+0x1c/0x28
    [   15.090470][    T1] other info that might help us debug this:
    [   15.090477][    T1] context-{5:5}
    [   15.090485][    T1] 3 locks held by swapper/0/1:
    [   15.090497][    T1]  #0: c2ff0001816de1a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock+0x98/0x104
    [   15.090553][    T1]  #1: ffff90001485b4b8 (irq_domain_mutex){+.+.}-{4:4}, at: irq_domain_associate+0xbc/0x6d4
    [   15.090606][    T1]  #2: 4bff000185d7a8e0 (lock_class){....}-{2:2}, at: _raw_spin_lock_irqsave+0x1c/0x28
    [   15.090654][    T1] stack backtrace:
    [   15.090661][    T1] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.10.59-rt52-00983-g186a6841c682-dirty #3
    [   15.090682][    T1] Hardware name: Horizon Robotics Journey 5 DVB (DT)
    [   15.090692][    T1] Call trace:
    ......
    [   15.090811][    T1]  _raw_spin_lock_irqsave+0x1c/0x28
    [   15.090828][    T1]  dwapb_irq_ack+0xb4/0x300
    [   15.090846][    T1]  __irq_do_set_handler+0x494/0xb2c
    [   15.090864][    T1]  __irq_set_handler+0x74/0x114
    [   15.090881][    T1]  irq_set_chip_and_handler_name+0x44/0x58
    [   15.090900][    T1]  gpiochip_irq_map+0x210/0x644
    Signed-off-by: default avatarSchspa Shi <schspa@gmail.com>
    Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
    Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
    Acked-by: default avatarDoug Berger <opendmb@gmail.com>
    Acked-by: default avatarSerge Semin <fancer.lancer@gmail.com>
    Signed-off-by: default avatarBartosz Golaszewski <brgl@bgdev.pl>
    3c938cc5
gpio-sifive.c 7.53 KB