Hi Friedrich,

On Thu, 7 Nov 2024 at 14:53, Friedrich Doku friedrichdoku2030@u.northwestern.edu wrote:

Hi,

I hope this email finds you well. I am currently working on a project involving U-Boot, and I have a question regarding memory management. Specifically, I would like to understand the best approach to zero all memory that is not currently in use.

I am considering using memset to achieve this, but I am unsure about the most efficient and safe way to determine which regions of memory are not in use and can be safely zeroed out. Could you please provide guidance on:

1. Identifying unused memory regions in U-Boot during runtime.
2. Using memset or any other recommended method to zero these regions

without interfering with critical data structures or operational stability. 3. Any potential risks or best practices I should be aware of when performing such operations in U-Boot.

I would greatly appreciate any insights, examples, or documentation you could share on this topic. Thank you for your time and for all the incredible work you do to maintain and enhance U-Boot.

Looking forward to your response.

After relocation, before images are loaded, you can zero from the start of memory to the bottom of the U-Boot stack. The 'meminfo' command[1] shows this mapping.

Unfortunately a recent change has make the EFI_LOADER use memory outside the U-Boot region. I am still hoping we can correct this design error before it causes too many problems. For now you can disable CONFIG_EFI_LOADER to avoid this, so long as you don't need to load/run EFI apps.

Regards, Simon

[1] https://docs.u-boot.org/en/latest/usage/cmd/meminfo.html