Hi Bohdan,

I don’t know about IAR.

For Armclang, I think __main does copy codes and data:

https://developer.arm.com/documentation/100748/0618/Embedded-Software-Development/Application-startup

“__main performs code and data copying, decompression, and zero initialization of the ZI data.”

I had a quick look, so probably I’m wrong.

I don’t see any codes or data put into ER_RAM_VECTORS?
They copying code in startup does not copy ER_RAM_VECTORS either?

Best Regards,

Kevin

From: Bohdan.Hunko--- via TF-M <tf-m@lists.trustedfirmware.org>
Sent: Monday, June 27, 2022 10:02 PM
To: tf-m@lists.trustedfirmware.org
Subject: [TF-M] Re: Automatically copy RAM_VECTORS when using ARMClang and IAR

Hi,

I would highly appreciate any help on this one.

Thanks!

Regards,

Bohdan Hunko

Cypress Semiconductor Ukraine

Engineer

CSUKR CSS ICW SW FW

Mobile: +38099 50 19 714
Bohdan.Hunko@infineon.com

From: Bohdan.Hunko--- via TF-M <tf-m@lists.trustedfirmware.org>
Sent: Wednesday, 13 April 2022 21:46
To: tf-m@lists.trustedfirmware.org
Subject: [TF-M] Automatically copy RAM_VECTORS when using ARMClang and IAR

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Hi,

When poking around some startup files I have found interesting place related to RAM_VECTORS support

CMSIS have __PROGRAM_START macro which is different for each compiler.

For GCC it uses __cmsis_start, for ARMClang - __main and for IAR - __iar_program_start

Basically each of the functions should copy several sections (.TFM_DATA for example) from FLASH to RAM and zero out some parts of RAM (for .TFM_BSS for example)

In current implementation GCC __cmsis_start function also copies the vector table from FLASH to SRAM (if RAM_VECTORS are enabled)

But ARMClang and IAR equivalents of that function (__main, __iar_program_start) does not seem to take care of copying vector table, so platforms startup should do that

I wonder if there is a way to change linker script in a way which will make copying of vector table automatic (by compiler dependent function).

This will make platform startups a bit cleaner and will allow platform to just use __PROGRAM_START macro without any additional code to copy vector table.

From what I see IAR has “initialize by copy” syntaxis so I think it may be used to tell IAR to automatically copy vector table.

It is a bit more tricky with ARMClang as I have not found a way to do that there.