1# Extending `cper-parse` With OEM Sections 2 3Section definitions within `cper-parse` are entirely modular, and can be easily 4modified at compile time to include custom OEM section extensions. This document 5will detail how these extensions can be added in from a stock version of the 6project. 7 8## Creating a Section Parser 9 10First, we need to create a parser to actually handle the conversion of the 11section from CPER -> CPER-JSON and CPER-JSON -> CPER. For the purposes of 12example here, we will create a fake CPER section, "myVendorSection", in 13`cper-section-myvendor.h` and `cper-section-myvendor.c`. 14 15_sections/cper-section-myvendor.h_: 16 17```c 18#ifndef CPER_SECTION_MYVENDOR 19#define CPER_SECTION_MYVENDOR 20 21#include <json.h> 22#include "../edk/Cper.h" 23 24json_object* cper_section_myvendor_to_ir(void* section, EFI_ERROR_SECTION_DESCRIPTOR* descriptor); 25void ir_section_myvendor_to_cper(json_object* section, FILE* out); 26 27#endif 28``` 29 30_sections/cper-section-myvendor.c_: 31 32```c 33/** 34 * Describes functions for converting MyVendor sections from binary and JSON format 35 * into an intermediate format. 36 * 37 * Author: author@example.com 38 **/ 39#include <stdio.h> 40#include <json.h> 41#include "../edk/Cper.h" 42#include "cper-section-ccix-per.h" 43 44json_object* cper_section_myvendor_to_ir(void* section, EFI_ERROR_SECTION_DESCRIPTOR* descriptor) 45{ 46 //Define a method here that converts the bytes starting from "section" into JSON IR. 47 //The length of the bytes is described in descriptor->Length. 48 //... 49} 50 51void ir_section_myvendor_to_cper(json_object* section, FILE* out) 52{ 53 //Define a method here that converts the given JSON IR object into CPER binary, 54 //writing the output to the provided stream. 55 //... 56} 57``` 58 59Once this is done, we can add our section to the parser. 60 61## Adding a Section GUID 62 63To identify our section for parsing, we must define a section GUID within 64`edk/Cper.h` and `edk/Cper.c` respectively. They are defined here for shared use 65in both `cper-parse` and also `cper-generator` if you wish to write a generation 66method for your section. 67 68_edk/Cper.h_: 69 70```c 71... 72extern EFI_GUID gEfiCxlVirtualSwitchErrorSectionGuid; 73extern EFI_GUID gEfiCxlMldPortErrorSectionGuid; 74extern EFI_GUID gMyVendorSectionGuid; 75``` 76 77_edk/Cper.c_: 78 79```c 80... 81EFI_GUID gEfiCxlVirtualSwitchErrorSectionGuid = { 0x40d26425, 0x3396, 0x4c4d, { 0xa5, 0xda, 0x3d, 0x47, 0x26, 0x3a, 0xf4, 0x25 }}; 82EFI_GUID gEfiCxlMldPortErrorSectionGuid = { 0x8dc44363, 0x0c96, 0x4710, { 0xb7, 0xbf, 0x04, 0xbb, 0x99, 0x53, 0x4c, 0x3f }}; 83EFI_GUID gMyVendorSectionGuid = { 0x40d26425, 0x3396, 0x4c4d, { 0xa5, 0xda, 0x3d, 0x47, 0x26, 0x3a, 0xf4, 0x25 }}; 84``` 85 86## Adding a Section Definition 87 88Finally, we need to add a section definition for our section, matching the GUID 89to the name and conversion methods. Open `sections/cper-section.c` and add your 90definition to the `section_definitions` array, like so: 91 92_sections/cper-section.c_: 93 94```c 95/** 96 * Describes available sections to the CPER parser. 97 * 98 * Author: Lawrence.Tang@arm.com 99 **/ 100#include "../edk/Cper.h" 101#include "cper-section.h" 102... 103#include "cper-section-myvendor.h" 104 105//Definitions of all sections available to the CPER parser. 106CPER_SECTION_DEFINITION section_definitions[] = { 107 ... 108 {&gMyVendorSectionGuid, "MyVendor Error", cper_section_myvendor_to_ir, ir_section_myvendor_to_cper}, 109}; 110``` 111 112Now you're done! After a further `cmake .` and `make`, `cper-convert` and all 113other conversion libraries included should successfully convert your OEM CPER 114section between CPER-JSON and CPER binary. 115