efi: print unrecognized CPER section

UEFI spec allows for non-standard section in Common Platform Error
Record. This is defined in section N.2.3 of UEFI version 2.5.

Currently if the CPER section's type (UUID) does not match with
one of the section types that the kernel knows how to parse, the
section is skipped. Therefore, user is not able to see
such CPER data, for instance, error record of non-standard section.

This change prints out the raw data in hex in the dmesg buffer so
that non-standard sections are reported to the user. Non-standard
section type errors should be reported to the user because these
can include errors which are vendor specific. The data length is
taken from Error Data length field of Generic Error Data Entry.

The following is a sample output from dmesg:
 Hardware error from APEI Generic Hardware Error Source: 2
 It has been corrected by h/w and requires no further action
 event severity: corrected
  time: precise 2017-03-15 20:37:35
  Error 0, type: corrected
   section type: unknown, d2e2621c-f936-468d-0d84-15a4ed015c8b
   section length: 0x238
   00000000: 4d415201 4d492031 453a4d45 435f4343  .RAM1 IMEM:ECC_C
   00000010: 53515f45 44525f42 00000000 00000000  E_QSB_RD........
   00000020: 00000000 00000000 00000000 00000000  ................
   00000030: 00000000 00000000 01010000 01010000  ................
   00000040: 00000000 00000000 00000005 00000000  ................
   00000050: 01010000 00000000 00000001 00dddd00  ................
...

The raw data from the error can then be decoded using vendor
specific tools.
Signed-off-by: Tyler Baicar <tbaicar@codeaurora.org>
CC: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

drivers/firmware/efi/cper.c

@@ -585,8 +585,15 @@ cper_estatus_print_section(const char *pfx, struct acpi_hest_generic_data *gdata
 		else
 			goto err_section_too_small;
 #endif
-	} else
-		printk("%s""section type: unknown, %pUl\n", newpfx, sec_type);
+	} else {
+		const void *err = acpi_hest_get_payload(gdata);
+
+		printk("%ssection type: unknown, %pUl\n", newpfx, sec_type);
+		printk("%ssection length: %#x\n", newpfx,
+		       gdata->error_data_length);
+		print_hex_dump(newpfx, "", DUMP_PREFIX_OFFSET, 16, 4, err,
+			       gdata->error_data_length, true);
+	}
 
 	return;