From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: <bpf@vger.kernel.org>, <linuxppc-dev@lists.ozlabs.org>
Cc: Jiri Olsa <jolsa@redhat.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Brendan Jackman <jackmanb@google.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Daniel Borkmann <daniel@iogearbox.net>
Subject: [PATCH 2/2] powerpc/bpf: Reject atomic ops in ppc32 JIT
Date: Thu, 1 Jul 2021 20:38:59 +0530 [thread overview]
Message-ID: <426699046d89fe50f66ecf74bd31c01eda976ba5.1625145429.git.naveen.n.rao@linux.vnet.ibm.com> (raw)
In-Reply-To: <cover.1625145429.git.naveen.n.rao@linux.vnet.ibm.com>
Commit 91c960b0056672 ("bpf: Rename BPF_XADD and prepare to encode other
atomics in .imm") converted BPF_XADD to BPF_ATOMIC and updated all JIT
implementations to reject JIT'ing instructions with an immediate value
different from BPF_ADD. However, ppc32 BPF JIT was implemented around
the same time and didn't include the same change. Update the ppc32 JIT
accordingly.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
arch/powerpc/net/bpf_jit_comp32.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c
index cbe5b399ed869d..91c990335a16c9 100644
--- a/arch/powerpc/net/bpf_jit_comp32.c
+++ b/arch/powerpc/net/bpf_jit_comp32.c
@@ -773,9 +773,17 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
break;
/*
- * BPF_STX XADD (atomic_add)
+ * BPF_STX ATOMIC (atomic ops)
*/
- case BPF_STX | BPF_XADD | BPF_W: /* *(u32 *)(dst + off) += src */
+ case BPF_STX | BPF_ATOMIC | BPF_W:
+ if (imm != BPF_ADD) {
+ pr_err_ratelimited(
+ "eBPF filter atomic op code %02x (@%d) unsupported\n", code, i);
+ return -ENOTSUPP;
+ }
+
+ /* *(u32 *)(dst + off) += src */
+
bpf_set_seen_register(ctx, tmp_reg);
/* Get offset into TMP_REG */
EMIT(PPC_RAW_LI(tmp_reg, off));
@@ -789,7 +797,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
PPC_BCC_SHORT(COND_NE, (ctx->idx - 3) * 4);
break;
- case BPF_STX | BPF_XADD | BPF_DW: /* *(u64 *)(dst + off) += src */
+ case BPF_STX | BPF_ATOMIC | BPF_DW: /* *(u64 *)(dst + off) += src */
return -EOPNOTSUPP;
/*
--
2.31.1
next prev parent reply other threads:[~2021-07-01 15:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-01 15:08 [PATCH 0/2] powerpc/bpf: Fix issue with atomic ops Naveen N. Rao
2021-07-01 15:08 ` [PATCH 1/2] powerpc/bpf: Fix detecting BPF atomic instructions Naveen N. Rao
2021-07-01 16:03 ` Alexei Starovoitov
2021-07-01 19:32 ` Naveen N. Rao
2021-07-01 19:33 ` Alexei Starovoitov
2021-07-02 10:26 ` Jiri Olsa
2021-07-01 15:08 ` Naveen N. Rao [this message]
2021-07-01 16:36 ` [PATCH 2/2] powerpc/bpf: Reject atomic ops in ppc32 JIT Christophe Leroy
2021-07-01 19:36 ` Naveen N. Rao
2021-07-06 10:52 ` [PATCH 0/2] powerpc/bpf: Fix issue with atomic ops Michael Ellerman
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