On Tue, Apr 18, 2017 at 3:48 PM, Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, 05 Apr, at 10:23:17AM, Ard Biesheuvel wrote:
>> The firmware for Quark X102x prepends a security header to the capsule
>> which is needed to support the mandatory secure boot on this processor.
>> The header can be detected by checking for the "_CSH" signature and -
>> to avoid any GUID conflict - validating its size field to contain the
>> expected value. Then we need to look for the EFI header right after the
>> security header and pass the real header to __efi_capsule_setup_info.
>>
>> To be minimally invasive and maximally safe, the quirk version of
>> efi_capsule_identify_image is only effective on Quark processors.
>> +#ifdef CONFIG_EFI_CAPSULE_QUIRK_QUARK_CSH
>> +
>> +static const struct x86_cpu_id quark_ids[] = {
>> + { X86_VENDOR_INTEL, 5, 9 }, /* Intel Quark X1000 */
>> + { }
>> +};
>> +
>> +int efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
>> + size_t hdr_bytes)
>> +{
>> + struct quark_security_header *csh = kbuff;
>> +
>> + cap_info->total_size = 0;
>> +
>> + if (!x86_match_cpu(quark_ids))
>> + goto fallback;
>> +
>
> I'd prefer to see the quark quirk pulled out into its own function and
> referenced from the __weak efi_capsule_setup_info() function, which
> makes it easier to people to read the EFI capsule code flow if they're
> not interested in the Quark quick.
>
> Something like this,
>
> int efi_capsule_setup_info(...)
> {
> ...
>
> if (x86_match_cpu(quark_ids))
> return efi_capsule_quark_setup_quirk(cap_info, kbuff, hdr_bytes);
Previously I had proposed to use driver_data field
Something like
struct _info {
int(*setup)(...);
}; <<< this is optional, might be useful in the future, otherwise just
simple typedef.
int efi_capsule_quark_setup_quirk(...)
{
}
struct _info efi_capsule_quark_info = {
.setup = ..._setup_quirk,
};
#define ICPU(family, model, ddata) ...
static const struct x86_cpu_id quark_ids[] = {
ICPU(5, 9, efi_capsule_quark_info),
{}
};
Though didn't hear back on it.
--
With Best Regards,
Andy Shevchenko
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