On Fri, 2024-12-13 at 19:44 -0700, Daniel Xu wrote:
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/* First handle precisely tracked STACK_ZERO, up to BPF_REG_SIZE */stype = state->stack[spi].slot_type;for (i = 0; i < BPF_REG_SIZE && stype[i] == STACK_ZERO; i++)it's Friday and I'm lazy, but please double-check that this works for both big-endian and little-endian :)
Any tips? Are the existing tests running thru s390x hosts in CI sufficient or should I add some tests writen in C (and not BPF assembler)? I can never think about endianness correctly...
I think that if test operates on a key like:
valid key 15 v 0000000f <-- written to stack as a single u64 value ^^^^^^^ stack zero marks
and is executed (e.g. using __retval annotation), then CI passing for s390 should be enough.
There is a guide on how to gen a s390 environment locally: https://docs.kernel.org/bpf/s390.html I used it recently to build a vmlinux for s390 with no or minimal issues. Used it to boot long time ago, but don't remember if there were any surprises.
with Eduard's suggestion this also becomes interesting when you have 000mmm mix (as one example), because that gives you a small range, and all values might be valid keys for arrays
Can you define what "small range" means? What range is there with 0's? Any pointers would be helpful.
I think Andrii means that each 'm' adds 8 bits of range. E.g. range for 0000_000m is 0-255, range for 0000_00mm is 0-65535, etc.
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