selftests/bpf: Add arm64 JIT-sequence tests for __arena kfunc arguments

Pin the arm64 counterparts of the x86-64 rebase sequences: the single
extended-register add for an unconditional argument, the nullable
truncate-test-and-skip variant, and all five argument registers in one
call. The nullable cases use a local label so the branch is pinned to
the instruction right after the add, and the label line does not spell
out the call because arm64 emits either a direct bl or a materialize-
and-blr pair depending on the distance to the kfunc.

Note that on arm64 an unconditional argument is one instruction with
nothing to anchor it against, so arena_arg_jit_rebase alone cannot tell
the two forms apart; it only requires that nothing is emitted between
the rebase and the call. The args5 test is what pins the distinction,
since its four consecutive adds leave no room for a nullable
truncate-and-branch pair between them.

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/bpf/20260813190356.335181-6-puranjay@kernel.org
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
This commit is contained in:
Puranjay Mohan 2026-08-13 12:03:52 -07:00 • committed by Kumar Kartikeya Dwivedi
commit 1c5bc60f95
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