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| author | Alexei Starovoitov <ast@kernel.org> | 2025-05-14 17:48:57 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-05-14 17:50:37 -0700 |
| commit | 9325d53fe9adff354b6a93fda5f38c165947da0f (patch) | |
| tree | e521f17306c7cb77eba2977fee7dce7f654e2deb | |
| parent | 5f55f2168432298f5a55294831ab6a76a10cb3c3 (diff) | |
| parent | 8e57cf09c84cac99eb31354a3cc70f8b8981bfc2 (diff) | |
Merge branch 's390-bpf-remove-the-orig_call-null-check'
Ilya Leoshkevich says:
====================
I've been looking at fixing the tailcall_bpf2bpf_hierarchy failures on
s390. One of the challenges is that when a BPF trampoline calls a BPF
prog A, the prologue of A sets the tail call count to 0. Therefore it
would be useful to know whether the trampoline is attached to some
other BPF prog B, in which case A should be called using an offset
equal to tail_call_start, bypassing the tail call count initialization.
The trampoline attachment point is passed to trampoline functions via
the orig_call variable. Unfortunately in the case of calculating the
size of a struct_ops trampoline it's NULL, and I could not think of a
good reason to have it this way. This series makes it always non-NULL.
====================
Link: https://patch.msgid.link/20250512221911.61314-1-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | arch/s390/net/bpf_jit_comp.c | 5 | ||||
| -rw-r--r-- | kernel/bpf/bpf_struct_ops.c | 2 |
2 files changed, 3 insertions, 4 deletions
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 945106b5562d..6f22b5199c20 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -2583,9 +2583,8 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, if (nr_stack_args > MAX_NR_STACK_ARGS) return -ENOTSUPP; - /* Return to %r14, since func_addr and %r0 are not available. */ - if ((!func_addr && !(flags & BPF_TRAMP_F_ORIG_STACK)) || - (flags & BPF_TRAMP_F_INDIRECT)) + /* Return to %r14 in the struct_ops case. */ + if (flags & BPF_TRAMP_F_INDIRECT) flags |= BPF_TRAMP_F_SKIP_FRAME; /* diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index db13ee70d94d..96113633e391 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -601,7 +601,7 @@ int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks, if (model->ret_size > 0) flags |= BPF_TRAMP_F_RET_FENTRY_RET; - size = arch_bpf_trampoline_size(model, flags, tlinks, NULL); + size = arch_bpf_trampoline_size(model, flags, tlinks, stub_func); if (size <= 0) return size ? : -EFAULT; |