• Thomas Gleixner's avatar
    genirq: x86: Ensure that dynamic irq allocation does not conflict · 62a08ae2
    Thomas Gleixner authored
    On x86 the allocation of irq descriptors may allocate interrupts which
    are in the range of the GSI interrupts. That's wrong as those
    interrupts are hardwired and we don't have the irq domain translation
    like PPC. So one of these interrupts can be hooked up later to one of
    the devices which are hard wired to it and the io_apic init code for
    that particular interrupt line happily reuses that descriptor with a
    completely different configuration so hell breaks lose.
    Inside x86 we allocate dynamic interrupts from above nr_gsi_irqs,
    except for a few usage sites which have not yet blown up in our face
    for whatever reason. But for drivers which need an irq range, like the
    GPIO drivers, we have no limit in place and we don't want to expose
    such a detail to a driver.
    To cure this introduce a function which an architecture can implement
    to impose a lower bound on the dynamic interrupt allocations.
    Implement it for x86 and set the lower bound to nr_gsi_irqs, which is
    the end of the hardwired interrupt space, so all dynamic allocations
    happen above.
    That not only allows the GPIO driver to work sanely, it also protects
    the bogus callsites of create_irq_nr() in hpet, uv, irq_remapping and
    htirq code. They need to be cleaned up as well, but that's a separate
    Reported-by: default avatarJin Yao <yao.jin@linux.intel.com>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Tested-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
    Cc: Mathias Nyman <mathias.nyman@linux.intel.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Grant Likely <grant.likely@linaro.org>
    Cc: H. Peter Anvin <hpa@linux.intel.com>
    Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
    Cc: Krogerus Heikki <heikki.krogerus@intel.com>
    Cc: Linus Walleij <linus.walleij@linaro.org>
    Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1404241617360.28206@ionos.tec.linutronix.deSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
softirq.c 18.8 KB