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

acpi_physical_address get_rsdp_addr(void)
{
acpi_physical_address pa;
+ struct efi_setup_data *esd;

pa = get_acpi_rsdp();

if (!pa)
pa = boot_params->acpi_rsdp_addr;

+ esd = (struct efi_setup_data *) efi_get_kexec_setup_data_addr();
+ if (esd)
+ return kexec_get_rsdp_addr(esd);

if (!pa)
pa = efi_get_rsdp_addr();



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