ERROR: ROM size exceeds 48KiB during system level simulation

[diswd]

Hi all,
I am trying to run system level simulation of Caliptra. During simulating some functions such as hmac,ecc,dma,sha256 and so on, the error "ROM size exceeds 48KiB" which is set in "caliptra-rtl-main/src/integration/test_suites/libs/riscv_hw_if/link.ld" will occur. But some functions such as sha512 and sha_accel will not occur this error and can be simulated normally. Could you please tell me how to solve this error? Thank you very much.

[pranjal3060]

Either you can increase the ROM size or you can try to optimize the code.

[diswd]

Either you can increase the ROM size or you can try to optimize the code.

Thanks for your reply. Do you know how to increase the ROM size in Caliptra?

[calebofearth]

This linker script is used to compile Caliptra unit tests/smoke tests - it is not used for the actual production ROM, which is maintained over at caliptra-sw.

The linker script throws an error when the firmware being compiled exceeds the available ROM memory in Caliptra. Smoke tests that are known to work are listed in the L0 regression (which is run for every new Pull Request to main).

Increasing ROM size is not permitted by integrators, as this violates the Caliptra Trademark policy that requires integrators to consume Caliptra RTL as-is, without modification.
(We are increasing memory sizes as part of the Caliptra 2.0 release - see #681. But this change will be part of the official release and should not be modified afterwards).

If you've written your own test and are trying to compile it with our Makefile, you can do a few things:

• split your test into many smaller tests
• put large data variables into a DCCM section that is directly loaded into DCCM at simulation start (like shown here) so they don't consume memory in the ROM
• use a custom linker script specific to your new test case (for example, see smoke_test_mldsa)