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Date:   Mon, 23 Sep 2019 09:31:29 +0200
From:   Greg KH <greg@kroah.com>
To:     Greg Kurz <groug@kaod.org>
Cc:     Sasha Levin <sashal@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>, stable@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc/xive: Fix bogus error code returned by OPAL
Message-ID: <20190923073129.GA2749134@kroah.com>
References: <156922009207.910857.10785273696571088534.stgit@bahia.lan>
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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@vger.kernel.org # v4.12+
> Signed-off-by: Greg Kurz <groug@kaod.org>
> Reviewed-by: C?dric Le Goater <clg@kaod.org>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> Link: https://lore.kernel.org/r/156821713818.1985334.14123187368108582810.stgit@bahia.lan
> (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@kaod.org>
> ---
> 
> This is for 4.14 and 4.19.

Thanks for the backport, now queued up.

greg k-h