On 10/09/2019 15:53, Greg Kurz wrote: > There's a bug in skiboot that causes the OPAL_XIVE_ALLOCATE_IRQ call > to return the 32-bit value 0xffffffff when OPAL has run out of IRQs. > Unfortunatelty, OPAL return values are signed 64-bit entities and > errors are supposed to be negative. If that happens, the linux code > confusingly treats 0xffffffff as a valid IRQ number and panics at some > point. > > A fix was recently merged in skiboot: > > e97391ae2bb5 ("xive: fix return value of opal_xive_allocate_irq()") > > but we need a workaround anyway to support older skiboots already > on the field. > > Internally convert 0xffffffff to OPAL_RESOURCE which is the usual error > returned upon resource exhaustion. > > Signed-off-by: Greg Kurz <gr...@kaod.org>
Reviewed-by: Cédric Le Goater <c...@kaod.org> Thanks, C. > --- > arch/powerpc/sysdev/xive/native.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/sysdev/xive/native.c > b/arch/powerpc/sysdev/xive/native.c > index 37987c815913..c35583f84f9f 100644 > --- a/arch/powerpc/sysdev/xive/native.c > +++ b/arch/powerpc/sysdev/xive/native.c > @@ -231,6 +231,15 @@ static bool xive_native_match(struct device_node *node) > return of_device_is_compatible(node, "ibm,opal-xive-vc"); > } > > +static int64_t opal_xive_allocate_irq_fixup(uint32_t chip_id) > +{ > + s64 irq = opal_xive_allocate_irq(chip_id); > + > +#define XIVE_ALLOC_NO_SPACE 0xffffffff /* No possible space */ > + return > + irq == XIVE_ALLOC_NO_SPACE ? OPAL_RESOURCE : irq; > +} > + > #ifdef CONFIG_SMP > static int xive_native_get_ipi(unsigned int cpu, struct xive_cpu *xc) > { > @@ -238,7 +247,7 @@ static int xive_native_get_ipi(unsigned int cpu, struct > xive_cpu *xc) > > /* Allocate an IPI and populate info about it */ > for (;;) { > - irq = opal_xive_allocate_irq(xc->chip_id); > + irq = opal_xive_allocate_irq_fixup(xc->chip_id); > if (irq == OPAL_BUSY) { > msleep(OPAL_BUSY_DELAY_MS); > continue; > @@ -259,7 +268,7 @@ u32 xive_native_alloc_irq(void) > s64 rc; > > for (;;) { > - rc = opal_xive_allocate_irq(OPAL_XIVE_ANY_CHIP); > + rc = opal_xive_allocate_irq_fixup(OPAL_XIVE_ANY_CHIP); > if (rc != OPAL_BUSY) > break; > msleep(OPAL_BUSY_DELAY_MS); >