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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


WARNING: multiple messages have this Message-ID (diff)
From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: <bpf@vger.kernel.org>, <linuxppc-dev@lists.ozlabs.org>
Cc: Brendan Jackman <jackmanb@google.com>,
	Jiri Olsa <jolsa@redhat.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


  parent reply	other threads:[~2021-07-01 15:10 UTC|newest]

Thread overview: 19+ 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 ` Naveen N. Rao
2021-07-01 15:08 ` [PATCH 1/2] powerpc/bpf: Fix detecting BPF atomic instructions Naveen N. Rao
2021-07-01 15:08   ` Naveen N. Rao
2021-07-01 16:03   ` Alexei Starovoitov
2021-07-01 16:03     ` Alexei Starovoitov
2021-07-01 19:32     ` Naveen N. Rao
2021-07-01 19:32       ` Naveen N. Rao
2021-07-01 19:33       ` Alexei Starovoitov
2021-07-01 19:33         ` Alexei Starovoitov
2021-07-02 10:26   ` Jiri Olsa
2021-07-02 10:26     ` Jiri Olsa
2021-07-01 15:08 ` Naveen N. Rao [this message]
2021-07-01 15:08   ` [PATCH 2/2] powerpc/bpf: Reject atomic ops in ppc32 JIT Naveen N. Rao
2021-07-01 16:36   ` Christophe Leroy
2021-07-01 19:36     ` Naveen N. Rao
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
2021-07-06 10:52   ` Michael Ellerman

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