core: kernel: use XOR for transfer list checksum

[harrisonmutai-arm]

Change checksum logic from sum to XOR in C implementation, matching the specification. Update transfer_list_update_checksum and verification functions accordingly.

[jenswi-linaro]

Please fix the style issue reported by checkpatch. Tip: you can check locally using:

./scripts/checkpatch.sh github/master..

Depending on your base branch, and that you have checkpatch.pl in your $PATH.

[harrisonmutai-arm]

Thanks @jenswi-linaro, one thing I'm a bit unsure of is this line:

WARNING: line length of 82 exceeds 80 columns
#53: FILE: core/kernel/transfer_list.c:320:
+        * Zeroing the checksum is necessary because  `calc_byte_xor` works on the

total: 0 errors, 1 warnings, 0 checks, 49 lines checked

My editor indicates the line is 76 chars, does the script convert tabs to spaces?

[jenswi-linaro]

My editor indicates the line is 76 chars, does the script convert tabs to spaces?

I guess it counts a tab as 8 spaces.

[etienne-lms]

LGTM. Would you mind updating the commit message header line?

-core: kernel: use XOR for checksum
+core: kernel: use XOR for transfer list checksum

Reviewed-by: Etienne Carriere <[email protected]> once addressed.

[harrisonmutai-arm]

@etienne-lms did you want me to apply the reviewed line once I'd addressed your comment?

[jenswi-linaro]

Acked-by: Jens Wiklander <[email protected]>

[etienne-lms]

LGTM. Could you rebase your P-R?

[harrisonmutai-arm]

@etienne-lms, @jenswi-linaro I think we need to hold this off, there's a bit of an integration problem as U-Boot and TF-A still use the old scheme. Updating here will almost certainly break any configurations with those projects. Will get back to you once I have some clarification from this discussion [1].

[1] FirmwareHandoff/firmware_handoff#78

[github-actions]

This pull request has been marked as a stale pull request because it has been open (more than) 30 days with no activity. Remove the stale label or add a comment, otherwise this pull request will automatically be closed in 5 days. Note, that you can always re-open a closed issue at any time.