Re: [PATCH] powerpc/xive: Fix bogus error code returned by OPAL

[Greg KH]

On Mon, Sep 23, 2019 at 08:29:40AM +0200, 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
> in the field.
> 
> Internally convert 0xffffffff to OPAL_RESOURCE which is the usual error
> returned upon resource exhaustion.
> 
> Cc: stable@xxxxxxxxxxxxxxx # v4.12+
> Signed-off-by: Greg Kurz <groug@xxxxxxxx>
> Reviewed-by: Cédric Le Goater <clg@xxxxxxxx>
> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Link: https://lore.kernel.org/r/156821713818.1985334.14123187368108582810.stgit@xxxxxxxxx
> (cherry picked from commit 6ccb4ac2bf8a35c694ead92f8ac5530a16e8f2c8,
>  groug: fix arch/powerpc/platforms/powernv/opal-wrappers.S instead of
>         non-existing arch/powerpc/platforms/powernv/opal-call.c)
> Signed-off-by: Greg Kurz <groug@xxxxxxxx>
> ---
> 
> This is for 4.14 and 4.19.

Thanks for the backport, now queued up.

greg k-h