From aea7ef8a82c0ea13ff20b65ff2edf8a38a17eda8 Mon Sep 17 00:00:00 2001 From: Hari Bathini Date: Fri, 10 Jun 2022 21:25:51 +0530 Subject: [PATCH] powerpc/bpf/32: add support for BPF_ATOMIC bitwise operations Adding instructions for ppc32 for atomic_and atomic_or atomic_xor atomic_fetch_add atomic_fetch_and atomic_fetch_or atomic_fetch_xor Signed-off-by: Hari Bathini Tested-by: Naveen N. Rao (ppc64le) Reviewed-by: Naveen N. Rao Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220610155552.25892-5-hbathini@linux.ibm.com --- arch/powerpc/net/bpf_jit_comp32.c | 53 ++++++++++++++++++++++++++++++--------- 1 file changed, 41 insertions(+), 12 deletions(-) diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c index e46ed1e..28dc6a1a8 100644 --- a/arch/powerpc/net/bpf_jit_comp32.c +++ b/arch/powerpc/net/bpf_jit_comp32.c @@ -294,6 +294,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * u32 dst_reg_h = dst_reg - 1; u32 src_reg = bpf_to_ppc(insn[i].src_reg); u32 src_reg_h = src_reg - 1; + u32 ax_reg = bpf_to_ppc(BPF_REG_AX); u32 tmp_reg = bpf_to_ppc(TMP_REG); u32 size = BPF_SIZE(code); s16 off = insn[i].off; @@ -798,25 +799,53 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * * BPF_STX ATOMIC (atomic ops) */ 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); + bpf_set_seen_register(ctx, ax_reg); + /* Get offset into TMP_REG */ EMIT(PPC_RAW_LI(tmp_reg, off)); + tmp_idx = ctx->idx * 4; /* load value from memory into r0 */ EMIT(PPC_RAW_LWARX(_R0, tmp_reg, dst_reg, 0)); - /* add value from src_reg into this */ - EMIT(PPC_RAW_ADD(_R0, _R0, src_reg)); - /* store result back */ + + /* Save old value in BPF_REG_AX */ + if (imm & BPF_FETCH) + EMIT(PPC_RAW_MR(ax_reg, _R0)); + + switch (imm) { + case BPF_ADD: + case BPF_ADD | BPF_FETCH: + EMIT(PPC_RAW_ADD(_R0, _R0, src_reg)); + break; + case BPF_AND: + case BPF_AND | BPF_FETCH: + EMIT(PPC_RAW_AND(_R0, _R0, src_reg)); + break; + case BPF_OR: + case BPF_OR | BPF_FETCH: + EMIT(PPC_RAW_OR(_R0, _R0, src_reg)); + break; + case BPF_XOR: + case BPF_XOR | BPF_FETCH: + EMIT(PPC_RAW_XOR(_R0, _R0, src_reg)); + break; + default: + pr_err_ratelimited("eBPF filter atomic op code %02x (@%d) unsupported\n", + code, i); + return -EOPNOTSUPP; + } + + /* store new value */ EMIT(PPC_RAW_STWCX(_R0, tmp_reg, dst_reg)); /* we're done if this succeeded */ - PPC_BCC_SHORT(COND_NE, (ctx->idx - 3) * 4); + PPC_BCC_SHORT(COND_NE, tmp_idx); + + /* For the BPF_FETCH variant, get old data into src_reg */ + if (imm & BPF_FETCH) { + EMIT(PPC_RAW_MR(src_reg, ax_reg)); + if (!fp->aux->verifier_zext) + EMIT(PPC_RAW_LI(src_reg_h, 0)); + } break; case BPF_STX | BPF_ATOMIC | BPF_DW: /* *(u64 *)(dst + off) += src */ -- 2.7.4