[PATCH v4] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel

Junichi Nomura j-nomura at ce.jp.nec.com
Thu Apr 11 02:32:59 PDT 2019


On 4/11/19 6:21 PM, Boris Petkov wrote:
> On April 11, 2019 11:13:03 AM GMT+02:00, Junichi Nomura <j-nomura at ce.jp.nec.com> wrote:
>> On 4/11/19 5:37 PM, Borislav Petkov wrote:
>>> On Thu, Apr 11, 2019 at 08:16:45AM +0000, Junichi Nomura wrote:
>>>> kexec_get_rsdp_addr() might fail on kexec-booted kernel, e.g. if the
>>>> setup_data was invalid. In such a case, falling back to
>> efi_get_rsdp_addr()
>>>> will hit the problem of accessing invalid table pointer again.
>>>
>>> Then you need to do this:
>>>
>>> 	if (kexeced kernel) {
>>> 		addr = kexec_get_rsdp_addr();
>>> 		if (!addr) {
>>> 			/* cannot get address */
>>> 			return -1;
>>> 		}
>>>
>>> 		return addr;
>>> 	}
>>>
>>> and the calling function get_rsdp_addr() must check the return value
>> and
>>> if it is not 0, return immediately.
>>
>> Do you mean making get_rsdp_addr() like this?
> 
> Does that look like what I've typed above?

No. But that's why I asked the question. Do you mean putting
the above code in efi_get_rsdp_addr()?

-- 
Jun'ichi Nomura, NEC Corporation / NEC Solution Innovators, Ltd.


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