S32k3 APP_BL length

[vikmonti7804]

Hi ,

 I am using the HSE example code S32K344_Hse_SHE_SecureBoot_Example, which is using the S32K344_SecureBoot_AppBL as application code to be varified. But i checked the linked file for the both the project and found that the length of the App_BL if given .codeLength = (uint32_t)(0x91F40),  or  APP_0 (RX) : ORIGIN = 0x004420C0, LENGTH = 0x91F40 /*APPLICATION*/

but i checked the size of binary file for S32K344_SecureBoot_AppBL if 4 kb, can you please clear why linker file has this big length given but real size is 4kb.

kindly explain

Thank you

[Julián_AragónM]

Hi @vikmonti7804,

The HSE Example Codes utilize the files from the "S32K344_DemoAppTemplate" folder in order to create the managed linker script that is autogenerated into the Debug/Release subdirectory of your project. It is possible to tweak this template for project specific requirements.

You can find the linker file for the demo app under:

"C:\NXP\S32K3_HSE_DemoExamples_1_0_0\S32K3_HSE_DemoExamples\Template\S32K344_DemoAppTemplate\src\target\m7\GHS\ld\standard"

I hope you find this helpful.

Best regards,
Julián.

[vikmonti7804]

i have seen the project carefully so i found that the project is using its own linker file where it is importing the application code App_Bl so i am not able to find any relation between the example code with template project.

Kindly explain in detail or please review the example code.

[Julián_AragónM]

Hi @vikmonti7804,

I apologize for the misunderstanding.

The examples are made from a linker template which does not reflect the final application size.

Best regards,
Julián 

[vikmonti7804]

Hi,

   Then how CMAC is generated with the different size allocation in IVT compare to original binary size because CMAC generation uses the binary to generate the CMAC tag.

What will happen if i change the size in IVT with 4K?

[Julián_AragónM]

Hi @vikmonti7804,

Under the S32K3 Reference Manual, you can find the structure definition of image vector table:

You can make modifications to the size with precautions to not go over the address or app size. The IVT start address is calculated by adding an offset to the device base address that depends on the
location of IVT.

There is information from the HSE firmware Reference Manual (Which is only available through DocStore:
https://www.docstore.nxp.com/products?path=/content/docstore/product-hierarchy/AMP) that describes the IVT structure in more detail, including offset, byte size, category, description and value, as well as the AppBL structure.

Please help me revising the secure document for additional information.

Best regards,
Julián.