Hi Bjorn,
On 14/08/15 15:57, Bjorn Helgaas wrote:
> Hi Marc,
>
> On Fri, Aug 14, 2015 at 03:41:07PM +0100, Marc Zyngier wrote:
>> When find_and_init_phbs() looks for the probe-only property, it seems
>> to trust the firmware to be correctly written, and assumes that there
>> is a parameter to the property.
>>
>> It is conceivable that the firmware could not be that perfect, and it
>> could expose this property naked (at least one arm64 platform seems to
>> exhibit this exact behaviour). The setup code the ends up making
>> a decision based on whatever the property pointer points to, which
>> is likely to be junk.
>>
>> Instead, let's check for the validity of the property, and ignore
>> it if the firmware couldn't make up its mind.
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
>> ---
>> arch/powerpc/platforms/pseries/setup.c | 15 ++++++++++-----
>> 1 file changed, 10 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
>> index df6a704..6bdc1f9 100644
>> --- a/arch/powerpc/platforms/pseries/setup.c
>> +++ b/arch/powerpc/platforms/pseries/setup.c
>> @@ -490,14 +490,19 @@ static void __init find_and_init_phbs(void)
>> */
>> if (of_chosen) {
>> const int *prop;
>> + int len;
>>
>> prop = of_get_property(of_chosen,
>> - "linux,pci-probe-only", NULL);
>> + "linux,pci-probe-only", &len);
>> if (prop) {
>> - if (*prop)
>> - pci_add_flags(PCI_PROBE_ONLY);
>> - else
>> - pci_clear_flags(PCI_PROBE_ONLY);
>> + if (len) {
>> + if (be32_to_cpup(prop))
>> + pci_add_flags(PCI_PROBE_ONLY);
>> + else
>> + pci_clear_flags(PCI_PROBE_ONLY);
>> + } else {
>> + pr_warn("linux,pci-probe-only set without value, ignoring\n");
>> + }
>
> This seems essentially identical to the pci-host-generic version.
> Is there a way we can factor it out so there's only one copy?
Probably. drivers/of/of_pci.c seems like a good landing place for it.
I'll hack something and repost it.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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