• Manoj N. Kumar's avatar
    cxlflash: Fix regression issue with re-ordering patch · 9526f360
    Manoj N. Kumar authored
    While running 'sg_reset -H' back to back the following exception was seen:
    
    [  735.115695] Faulting instruction address: 0xd0000000098c0864
    cpu 0x0: Vector: 300 (Data Access) at [c000000ffffafa80]
        pc: d0000000098c0864: cxlflash_async_err_irq+0x84/0x5c0 [cxlflash]
        lr: c00000000013aed0: handle_irq_event_percpu+0xa0/0x310
        sp: c000000ffffafd00
       msr: 9000000000009033
       dar: 2010000
     dsisr: 40000000
      current = 0xc000000001510880
      paca    = 0xc00000000fb80000   softe: 0        irq_happened: 0x01
        pid   = 0, comm = swapper/0
    
    Linux version 4.5.0-491-26f710d+
    
    enter ? for help
    [c000000ffffafe10] c00000000013aed0 handle_irq_event_percpu+0xa0/0x310
    [c000000ffffafed0] c00000000013b1a8 handle_irq_event+0x68/0xc0
    [c000000ffffaff00] c0000000001404ec handle_fasteoi_irq+0xec/0x2a0
    [c000000ffffaff30] c00000000013a084 generic_handle_irq+0x54/0x80
    [c000000ffffaff60] c000000000011130 __do_irq+0x80/0x1d0
    [c000000ffffaff90] c000000000024d40 call_do_irq+0x14/0x24
    [c000000001573a20] c000000000011318 do_IRQ+0x98/0x140
    [c000000001573a70] c000000000002594 hardware_interrupt_common+0x114/0x180
    
    This exception is being hit because the async_err interrupt path performs
    an MMIO to read the interrupt status register. The MMIO region in this
    case is not available.
    
    Commit 6ded8b3c ("cxlflash: Unmap problem state area before detaching
    master context") re-ordered the sequence in which term_mc() and stop_afu()
    are called. This introduces a window for interrupts to come in with the
    problem space area unmapped, that did not exist previously.
    
    The fix is to separate the disabling of all AFU interrupts to a distinct
    function, term_intr() so that it is the first thing that is done in the
    tear down process.
    
    To keep the initialization process symmetric, separate the AFU interrupt
    setup also to a distinct function: init_intr().
    
    Fixes: 6ded8b3c ("cxlflash: Unmap problem state area before detaching master context")
    Signed-off-by: default avatarManoj N. Kumar <manoj@linux.vnet.ibm.com>
    Acked-by: default avatarMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
    Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
    Signed-off-by: default avatarUma Krishnan <ukrishn@linux.vnet.ibm.com>
    Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
    9526f360
main.h 2.57 KB