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

[Ghannam, Yazen]

> -----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