coreboot

What about rmodule_clear_bss() ? I'm confused here. Is this a theoretical issue or a do you have a rmodule where things aren't cleared?

payload_size is the on-disk usage while rmodule_memory_size is the full program (including bss).

This is from rmodule_load():

-------/*
------- * In order to load the module at a given address, the following steps
------- * take place:
------- * 1. Copy payload to base address.
------- * 2. Adjust relocations within the module to new base address.
------- * 3. Clear the bss segment last since the relocations live where
------- * the bss is. If an rmodule is being loaded from its load
------- * address the relocations need to be processed before the bss.
------- */
-------module->location = base;
-------rmodule_copy_payload(module);
-------if (rmodule_relocate(module))
------->-------return -1;
-------rmodule_clear_bss(module);

You want to verify the contents of the on-disk piece? I'm confused when/where you are trying to do measurements. It seems like you are doing it at the wrong place. There's not much information to go on here w.r.t. the original report.

I'm not sure about module_clear_bss() and will need to look into it. Right now I'm doing the measurement in cbfs_load_and_decompress().

The one module that shows the problem is the SMM code. However, I note that cbfs_prog_stage_load() appears to memset() the extra memory, so perhaps I need to relocate my measurement.

You are making your measurement at the wrong place for the rmodules. You need to hook into the full loading path for each type of thing loaded. prog_segment_loaded(..., SEG_FINAL) are the final contents including memory location and size. You could certainly hook into that in some form. That would give you a better view of the contents of memory.