[PATCH 2/2] powerpc/bpf: Reject atomic ops in ppc32 JIT
From: Naveen N. Rao <hidden>
Date: 2021-07-01 15:10:15
Also in:
bpf
Subsystem:
bpf jit for powerpc (32-bit and 64-bit), bpf [general] (safe dynamic programs and tools), linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Hari Bathini, Christophe Leroy, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Madhavan Srinivasan, Linus Torvalds
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 <redacted>
---
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