topic Re: Keep same header structure in SRK Table and Record in i.MX Processors

Keep same header structure in SRK Table and Record

csoapy — Fri, 11 Sep 2020 10:30:55 GMT

I'm writing code to parse container file. And found that there are 3 similar struct headers used to indicate data block's TAG, SIZE and VERSION:

A: { VERSION, LENGTH_L, LENGHT_H, TAG}

Used in Container, SignatureBlock, Signature, Certificate, Block(DEK)'s header.

B: {TAG, LENGTH_L/H, LENGHT_H/L, VERSION}

Used in SRK Table's header.

C: {Tag, LENGTH_L/H, LENGHT_H/L}

Used in SRK Record's header

P.S. I use `L/H` because there are labled as `Variable` in a fixed length of 2 bytes in i.MX8 RM Rev.0

This two make me confused:

Why not use same structures?
Why not place TAG to the first byte of a structure?

Re: Keep same header structure in SRK Table and Record

igorpadykov — Sat, 12 Sep 2020 06:41:40 GMT

Hi csoapy

one can refer to tutorial for creating i.MX8 image

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/i-MX8-Boot-process-and-creating-a-bootable-image/ta-p/1101253

AHAB documentation

https://source.codeaurora.org/external/imx/uboot-imx/tree/doc/imx/ahab?h=imx_v2020.04_5.4.24_2.1.0

Secure Boot on i.MX 8 and i.MX 8X Families using AHAB

Best regards
igor

Re: Keep same header structure in SRK Table and Record

csoapy — Sat, 12 Sep 2020 01:35:56 GMT

@igorpadykov Can you delete your reply? It's not an answer to the question.

Re: Keep same header structure in SRK Table and Record

igorpadykov — Sat, 12 Sep 2020 07:03:35 GMT

answer to the questions:

Why not use same structures?
Why not place TAG to the first byte of a structure?

A: it is defined in i.MX8 ROM.

Best regards
igor

Re: Keep same header structure in SRK Table and Record

csoapy — Mon, 14 Sep 2020 01:46:55 GMT

@igorpadykov I mean, it's a bad definition, a bad design in another word.

Re: Keep same header structure in SRK Table and Record

igorpadykov — Mon, 14 Sep 2020 05:16:30 GMT

>I mean, it's a bad definition, a bad design in another word.

sorry processor ROM structures and definitions are hardcoded at chip design level,

they can not be changed later.

Best regards
igor

Re: Keep same header structure in SRK Table and Record

csoapy — Thu, 17 Sep 2020 12:59:46 GMT

Another weird order in Signature Block:

Offset: {Certi, SRK Table, Sign, Blob}

Content: {SRK Table, Sign, Certi, Blob}

Re: Keep same header structure in SRK Table and Record

igorpadykov — Thu, 17 Sep 2020 14:42:00 GMT

processor ROM structures and definitions are hardcoded at chip design level,

they can not be changed later.

Best regards
igor

Re: Keep same header structure in SRK Table and Record

csoapy — Fri, 18 Sep 2020 01:12:54 GMT

processor ROM structures and definitions are hardcoded at chip design level,

they can not be changed later.

Since it's hardcoded, then hardcode them again.

I don't think they can not be changed later.

There're i.MX8 B0 and C0 release. So why can't fix them in D0?

It's about how much works need to be done.

It's not about CAN or CAN NOT.

BAD is BAD. and need to be fixed.