[Skiboot] [PATCH skiboot] phb3: Deprecate reading the PHB status

[Andrew Donnellan]

On 10/1/19 11:50 am, Alexey Kardashevskiy wrote:
> The OPAL_PCI_EEH_FREEZE_STATUS call takes a bunch of parameters, one of
> them is @phb_status. It is defined as __be64* and always NULL in
> the current Linux upstream but if anyone ever decides to read that status,
> then the PHB3's handler will assume it is struct OpalIoPhb3ErrorData*
> (which is a lot bigger than 8 bytes) and zero it causing the stack
> corruption.
> 
> This makes @phb_status deprecated by copying the error message from PHB4.
> 
> Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>

Looks like p7ioc does the same thing. If the API is obviously wrong 
here, should we move the deprecation warning to core/pci-opal.c and just 
get rid of phb_status from the internal API?

> ---
>   hw/phb3.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/hw/phb3.c b/hw/phb3.c
> index 771ccfc..38b8f46 100644
> --- a/hw/phb3.c
> +++ b/hw/phb3.c
> @@ -2772,8 +2772,7 @@ static int64_t phb3_eeh_freeze_status(struct phb *phb, uint64_t pe_number,
>   
>   bail:
>   	if (phb_status)
> -		phb3_read_phb_status(p,
> -			(struct OpalIoPhb3ErrorData *)phb_status);
> +		PHBERR(p, "%s: deprecated PHB status\n", __func__);
>   
>   	return OPAL_SUCCESS;
>   }
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited