RE: [PATCH v2 3/8] efi: Decode IA32/X64 Processor Error Info Structure

From: Ghannam, Yazen
Date: Tue Feb 27 2018 - 10:25:15 EST


> -----Original Message-----
> From: Borislav Petkov [mailto:bp@xxxxxxx]
> Sent: Tuesday, February 27, 2018 9:26 AM
> To: Ghannam, Yazen <Yazen.Ghannam@xxxxxxx>
> Cc: linux-efi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> ard.biesheuvel@xxxxxxxxxx; x86@xxxxxxxxxx
> Subject: Re: [PATCH v2 3/8] efi: Decode IA32/X64 Processor Error Info
> Structure
>
> On Mon, Feb 26, 2018 at 01:38:59PM -0600, Yazen Ghannam wrote:
> > From: Yazen Ghannam <yazen.ghannam@xxxxxxx>
> >
> > Print the fields in the IA32/X64 Processor Error Info Structure.
> >
> > Based on UEFI 2.7 Table 256. IA32/X64 Processor Error Information
> > Structure.
> >
> > Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
> > ---
> > Link:
> > https://lkml.kernel.org/r/20180223200333.6410-4-
> Yazen.Ghannam@xxxxxxx
> >
> > v1->v2:
> > * Add parantheses around "bits" expression in macro.
> > * Fix indentation on multi-line statements.
> >
> > drivers/firmware/efi/cper-x86.c | 53
> +++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 53 insertions(+)
> >
> > diff --git a/drivers/firmware/efi/cper-x86.c b/drivers/firmware/efi/cper-
> x86.c
> > index 9da0d981178f..417bd4e500a7 100644
> > --- a/drivers/firmware/efi/cper-x86.c
> > +++ b/drivers/firmware/efi/cper-x86.c
> > @@ -3,15 +3,28 @@
> >
> > #include <linux/cper.h>
> >
> > +#define INDENT_SP " "
>
> That's just silly.
>

This is the same as the other CPER code.

> > +
> > /*
> > * We don't need a "CPER_IA" prefix since these are all locally defined.
> > * This will save us a lot of line space.
> > */
> > #define VALID_LAPIC_ID BIT_ULL(0)
> > #define VALID_CPUID_INFO BIT_ULL(1)
> > +#define VALID_PROC_ERR_INFO_NUM(bits) (((bits) & GENMASK_ULL(7,
> 2)) >> 2)
> > +
> > +#define INFO_VALID_CHECK_INFO BIT_ULL(0)
> > +#define INFO_VALID_TARGET_ID BIT_ULL(1)
> > +#define INFO_VALID_REQUESTOR_ID BIT_ULL(2)
> > +#define INFO_VALID_RESPONDER_ID BIT_ULL(3)
> > +#define INFO_VALID_IP BIT_ULL(4)
> >
> > void cper_print_proc_ia(const char *pfx, const struct cper_sec_proc_ia
> *proc)
> > {
> > + int i;
> > + struct cper_ia_err_info *err_info;
> > + char newpfx[64];
> > +
> > printk("%sValidation Bits: 0x%016llx\n", pfx, proc->validation_bits);
> >
> > if (proc->validation_bits & VALID_LAPIC_ID)
> > @@ -22,4 +35,44 @@ void cper_print_proc_ia(const char *pfx, const struct
> cper_sec_proc_ia *proc)
> > print_hex_dump(pfx, "", DUMP_PREFIX_OFFSET, 16, 4, proc-
> >cpuid,
> > sizeof(proc->cpuid), 0);
> > }
> > +
> > + snprintf(newpfx, sizeof(newpfx), "%s%s", pfx, INDENT_SP);
> > +
> > + err_info = (struct cper_ia_err_info *)(proc + 1);
> > + for (i = 0; i < VALID_PROC_ERR_INFO_NUM(proc->validation_bits);
> i++) {
> > + printk("%sError Information Structure %d:\n", pfx, i);
> > +
> > + printk("%sError Structure Type: %pUl\n", newpfx,
> > + &err_info->err_type);
>
> That dumps a GUID - how do I find out what type that GUID refers to?
>

A later patch prints out the spec-defined type.

Also, the spec allows platform-defined GUIDs. So we should always print this
even if the GUID is not defined by the spec.

> > +
> > + printk("%sValidation Bits: 0x%016llx\n",
> > + newpfx, err_info->validation_bits);
>
> As before, no need for those.
>
> > +
> > + if (err_info->validation_bits & INFO_VALID_CHECK_INFO) {
> > + printk("%sCheck Information: 0x%016llx\n", newpfx,
> > + err_info->check_info);
> > + }
> > +
> > + if (err_info->validation_bits & INFO_VALID_TARGET_ID) {
> > + printk("%sTarget Identifier: 0x%016llx\n",
> > + newpfx, err_info->target_id);
> > + }
> > +
> > + if (err_info->validation_bits & INFO_VALID_REQUESTOR_ID) {
> > + printk("%sRequestor Identifier: 0x%016llx\n",
> > + newpfx, err_info->requestor_id);
> > + }
> > +
> > + if (err_info->validation_bits & INFO_VALID_RESPONDER_ID) {
> > + printk("%sResponder Identifier: 0x%016llx\n",
> > + newpfx, err_info->responder_id);
> > + }
>
> Those look like would need an additional decoding. Can we do that here
> too?
>

The Check Information will be decoded further in another patch.

I don't think there's much else to decode for the ID fields.

> > +
> > + if (err_info->validation_bits & INFO_VALID_IP) {
> > + printk("%sInstruction Pointer: 0x%016llx\n",
> > + newpfx, err_info->ip);
>
> The only thing that makes sense so far.
>
> > + }
> > +
> > + err_info++;
> > + }
>
> Also, it is worth checking how much duplication there is with
> drivers/firmware/efi/cper-arm.c and unifying the common pieces into
> functions in cper-common.c or so.
>

Other tables may have the same fields but the offsets are usually different.
So it may be more trouble than it's worth trying to unify the different tables.

Thanks,
Yazen