Hi all,

In GCC linker scripts ands of sections are aligned using following syntax:

. = ALIGN(TFM_LINKER_XXX_ALIGNMENT);

But in ARMClang TFM does not use similar approach, instead it creates Position tags sections like following:

TFM_APP_CODE_START +0 ALIGN TFM_LINKER_APP_ROT_LINKER_CODE_ALIGNMENT EMPTY 0x0 {

    }

    TFM_APP_ROT_LINKER +0 ALIGN TFM_LINKER_APP_ROT_LINKER_CODE_ALIGNMENT {

        *tfm_app_rot_partition* (+RO-CODE, +RO-DATA)

        *libplatform_s* (TFM_*_APP-ROT_ATTR_FN)

        *.o (TFM_*_APP-ROT_ATTR_FN)

    }

    /*

     * This empty, zero long execution region is here to mark the end address

     * of APP RoT code.

     */

    TFM_APP_CODE_END +0 ALIGN TFM_LINKER_APP_ROT_LINKER_CODE_ALIGNMENT EMPTY 0x0 {

    }

I believe this is done because clang does not have syntaxes for aligning end of the section (please correct me if I am wrong).

This approach results in bug in TFM_UNPRIV_CODE section protections,  because TFM_UNPRIV_CODE Base and Limit are used directly and Limit is not aligned.

For now this problem stayed undetected because present platforms does not validate region_limit when applying protections.

I have created this patch  , which adds validation of region_limit and ran Ci on it and I can see that CI failed in tests for Clang builds

So I guess this is the problem that have to be fixed. I see following possible solutions:

1. Align and of TFM_UNPRIV_CODE section (but I guess clang does not support that)
2. Add position tags for _START and END

Solution 1 will simpler as it will not require changed in platform code, but I guess clang syntaxes is limiting us here.

So my question would be whether there is a plan to fix this issue ?

Regards,

Bohdan Hunko

Cypress Semiconductor Ukraine

Engineer

CSUKR CSS ICW SW FW

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