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SubjectRe: [PATCH] powerpc/xive: Fix bogus error code returned by OPAL
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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 <groug@kaod.org>



Reviewed-by: Cédric Le Goater <clg@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);
>

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