1. 03 Sep, 2014 1 commit
    • Marc Zyngier's avatar
      genirq: Add irq_domain-aware core IRQ handler · 76ba59f8
      Marc Zyngier authored
      Calling irq_find_mapping from outside a irq_{enter,exit} section is
      unsafe and produces ugly messages if CONFIG_PROVE_RCU is enabled:
      If coming from the idle state, the rcu_read_lock call in irq_find_mapping
      will generate an unpleasant warning:
      
      <quote>
      ===============================
      [ INFO: suspicious RCU usage. ]
      3.16.0-rc1+ #135 Not tainted
      -------------------------------
      include/linux/rcupdate.h:871 rcu_read_lock() used illegally while idle!
      
      other info that might help us debug this:
      
      RCU used illegally from idle CPU!
      rcu_scheduler_active = 1, debug_locks = 0
      RCU used illegally from extended quiescent state!
      1 lock held by swapper/0/0:
       #0:  (rcu_read_lock){......}, at: [<ffffffc00010206c>]
      irq_find_mapping+0x4c/0x198
      </quote>
      
      As this issue is fairly widespread and involves at least three
      different architectures, a possible solution is to add a new
      handle_domain_irq entry point into the generic IRQ code that
      the interrupt controller code can call.
      
      This new function takes an irq_domain, and calls into irq_find_domain
      inside the irq_{enter,exit} block. An additional "lookup" parameter is
      used to allow non-domain architecture code to be replaced by this as well.
      
      Interrupt controllers can then be updated to use the new mechanism.
      
      This code is sitting behind a new CONFIG_HANDLE_DOMAIN_IRQ, as not all
      architectures implement set_irq_regs (yes, mn10300, I'm looking at you...).
      Reported-by: default avatarVladimir Murzin <vladimir.murzin@arm.com>
      Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
      Link: https://lkml.kernel.org/r/1409047421-27649-2-git-send-email-marc.zyngier@arm.comSigned-off-by: default avatarJason Cooper <jason@lakedaemon.net>
      76ba59f8
  2. 16 Aug, 2014 39 commits