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

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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
parent bb5bad6a78
commit 1c5bc60f95
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1 changed files with 20 additions and 0 deletions
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tools/testing/selftests/bpf/progs/arena_kfunc_jit.c
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@ -32,6 +32,10 @@ __jited(" movl %edi, %edi")
__jited(" addq %r12, %rdi")
__jited("...")
__jited(" callq {{.*}}")
__arch_arm64
__jited("...")
__jited(" add x0, x28, w0, uxtw")
__jited(" {{(bl|mov) .*}}")
__success
int arena_arg_jit_rebase(void *ctx)
{
@ -48,6 +52,12 @@ __jited(" testl %edi, %edi")
__jited(" je L0")
__jited(" addq %r12, %rdi")
__jited("L0: callq {{.*}}")
__arch_arm64
__jited("...")
__jited(" mov w0, w0")
__jited(" cbz w0, L0")
__jited(" add x0, x28, w0, uxtw")
__jited("L0: {{.*}}")
__success
int arena_arg_jit_nullable(void *ctx)
{
@ -72,6 +82,16 @@ __jited(" testl %r8d, %r8d")
__jited(" je L0")
__jited(" addq %r12, %r8")
__jited("L0: callq {{.*}}")
__arch_arm64
__jited("...")
__jited(" add x0, x28, w0, uxtw")
__jited(" add x1, x28, w1, uxtw")
__jited(" add x2, x28, w2, uxtw")
__jited(" add x3, x28, w3, uxtw")
__jited(" mov w4, w4")
__jited(" cbz w4, L0")
__jited(" add x4, x28, w4, uxtw")
__jited("L0: {{.*}}")
__success
int arena_arg_jit_args5(void *ctx)
{