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[bpf,1/2] s390/bpf: Let arch_prepare_bpf_trampoline return program size

Message ID 20230919060258.3237176-2-song@kernel.org (mailing list archive)
State Accepted
Commit cf094baa3e0f19f1f80ceaf205c80402b024386c
Delegated to: BPF
Headers show
Series s390/bpf: Fix arch_prepare_bpf_trampoline | expand

Checks

Context Check Description
bpf/vmtest-bpf-VM_Test-25 success Logs for test_verifier on s390x with gcc
bpf/vmtest-bpf-VM_Test-11 success Logs for test_progs on s390x with gcc
bpf/vmtest-bpf-PR fail PR summary
bpf/vmtest-bpf-VM_Test-7 success Logs for test_maps on s390x with gcc
bpf/vmtest-bpf-VM_Test-0 success Logs for ShellCheck
bpf/vmtest-bpf-VM_Test-3 success Logs for build for x86_64 with gcc
bpf/vmtest-bpf-VM_Test-5 success Logs for set-matrix
bpf/vmtest-bpf-VM_Test-1 success Logs for build for aarch64 with gcc
bpf/vmtest-bpf-VM_Test-4 success Logs for build for x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-2 success Logs for build for s390x with gcc
bpf/vmtest-bpf-VM_Test-6 success Logs for test_maps on aarch64 with gcc
bpf/vmtest-bpf-VM_Test-14 success Logs for test_progs_no_alu32 on aarch64 with gcc
bpf/vmtest-bpf-VM_Test-18 success Logs for test_progs_no_alu32_parallel on aarch64 with gcc
bpf/vmtest-bpf-VM_Test-21 success Logs for test_progs_parallel on aarch64 with gcc
bpf/vmtest-bpf-VM_Test-26 success Logs for test_verifier on x86_64 with gcc
bpf/vmtest-bpf-VM_Test-24 success Logs for test_verifier on aarch64 with gcc
bpf/vmtest-bpf-VM_Test-28 success Logs for veristat
bpf/vmtest-bpf-VM_Test-8 success Logs for test_maps on x86_64 with gcc
bpf/vmtest-bpf-VM_Test-9 success Logs for test_maps on x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-10 fail Logs for test_progs on aarch64 with gcc
bpf/vmtest-bpf-VM_Test-12 success Logs for test_progs on x86_64 with gcc
bpf/vmtest-bpf-VM_Test-13 success Logs for test_progs on x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-16 success Logs for test_progs_no_alu32 on x86_64 with gcc
bpf/vmtest-bpf-VM_Test-17 success Logs for test_progs_no_alu32 on x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-19 success Logs for test_progs_no_alu32_parallel on x86_64 with gcc
bpf/vmtest-bpf-VM_Test-22 success Logs for test_progs_parallel on x86_64 with gcc
bpf/vmtest-bpf-VM_Test-20 success Logs for test_progs_no_alu32_parallel on x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-27 success Logs for test_verifier on x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-23 success Logs for test_progs_parallel on x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-15 fail Logs for test_progs_no_alu32 on s390x with gcc
netdev/tree_selection success Clearly marked for bpf
netdev/apply success Patch already applied to bpf

Commit Message

Song Liu Sept. 19, 2023, 6:02 a.m. UTC 
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>
---
 arch/s390/net/bpf_jit_comp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Ilya Leoshkevich Sept. 19, 2023, 9:04 a.m. UTC | #1 
On Mon, 2023-09-18 at 23:02 -0700, Song Liu wrote:
> 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>
> ---
>  arch/s390/net/bpf_jit_comp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Thanks!

Fixes: 528eb2cb87bc ("s390/bpf: Implement
arch_prepare_bpf_trampoline()")
Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
diff mbox series

Patch

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index de2fb12120d2..2861e3360aff 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -2513,7 +2513,7 @@  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)