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From: Song Liu <song@kernel.org>
To: <bpf@vger.kernel.org>
Cc: <ast@kernel.org>, <daniel@iogearbox.net>, <andrii@kernel.org>,
	<martin.lau@kernel.org>, <kernel-team@meta.com>,
	<iii@linux.ibm.com>, <bjorn@kernel.org>,
	Song Liu <song@kernel.org>
Subject: [PATCH v3 bpf-next 1/8] s390/bpf: Let arch_prepare_bpf_trampoline return program size
Date: Tue, 26 Sep 2023 12:00:13 -0700	[thread overview]
Message-ID: <20230926190020.1111575-2-song@kernel.org> (raw)
In-Reply-To: <20230926190020.1111575-1-song@kernel.org>

arch_prepare_bpf_trampoline() for s390 currently returns 0 on success. This
is not a problem for regular trampoline. However, struct_ops relies on the
return value to advance "image" pointer:

bpf_struct_ops_map_update_elem() {
    ...
    for_each_member(i, t, member) {
        ...
        err = bpf_struct_ops_prepare_trampoline();
        ...
        image += err;
    }
}

When arch_prepare_bpf_trampoline returns 0 on success, all members of the
struct_ops will point to the same trampoline (the last one).

Fix this by returning the program size in arch_prepare_bpf_trampoline (on
success). This is the same behavior as other architectures.

Signed-off-by: Song Liu <song@kernel.org>
Fixes: 528eb2cb87bc ("s390/bpf: Implement arch_prepare_bpf_trampoline()")
Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230919060258.3237176-2-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 arch/s390/net/bpf_jit_comp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 9ed0a13865ca..fd1936a63878 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -2652,7 +2652,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image,
 			return -E2BIG;
 	}
 
-	return ret;
+	return tjit.common.prg;
 }
 
 bool bpf_jit_supports_subprog_tailcalls(void)
-- 
2.34.1


  reply	other threads:[~2023-09-26 19:00 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-26 19:00 [PATCH v3 bpf-next 0/8] Allocate bpf trampoline on bpf_prog_pack Song Liu
2023-09-26 19:00 ` Song Liu [this message]
2023-09-26 19:00 ` [PATCH v3 bpf-next 2/8] bpf: Let bpf_prog_pack_free handle any pointer Song Liu
2023-09-27 18:29   ` Björn Töpel
2023-09-26 19:00 ` [PATCH v3 bpf-next 3/8] bpf: Adjust argument names of arch_prepare_bpf_trampoline() Song Liu
2023-09-26 19:00 ` [PATCH v3 bpf-next 4/8] bpf: Add helpers for trampoline image management Song Liu
2023-09-26 19:00 ` [PATCH v3 bpf-next 5/8] bpf, x86: Adjust arch_prepare_bpf_trampoline return value Song Liu
2023-09-26 19:00 ` [PATCH v3 bpf-next 6/8] bpf: Add arch_bpf_trampoline_size() Song Liu
2023-09-26 19:00 ` [PATCH v3 bpf-next 7/8] bpf: Use arch_bpf_trampoline_size Song Liu
2023-09-26 19:00 ` [PATCH v3 bpf-next 8/8] x86, bpf: Use bpf_prog_pack for bpf trampoline Song Liu
2023-09-27 13:16   ` Jiri Olsa
2023-09-27 15:47     ` Song Liu
2023-10-04 15:40 ` [PATCH v3 bpf-next 0/8] Allocate bpf trampoline on bpf_prog_pack patchwork-bot+netdevbpf
2023-10-04 15:50   ` Alexei Starovoitov

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