netdev - [PATH bpf-next 03/13] bpf: JIT blinds support JMP32

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Message-Id: <1545259460-13376-4-git-send-email-jiong.wang@netronome.com>
Date:   Wed, 19 Dec 2018 17:44:10 -0500
From:   Jiong Wang <jiong.wang@...ronome.com>
To:     ast@...nel.org, daniel@...earbox.net
Cc:     netdev@...r.kernel.org, oss-drivers@...ronome.com,
        Jiong Wang <jiong.wang@...ronome.com>
Subject: [PATH bpf-next 03/13] bpf: JIT blinds support JMP32

JIT blinds is building eBPF JMP insn directly, and is transforming BPF_K
into BPF_X.

Update the code to be aware of JMP32

Signed-off-by: Jiong Wang <jiong.wang@...ronome.com>
---
 kernel/bpf/core.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 33609f3..0252e28 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -902,7 +902,13 @@ static int bpf_jit_blind_insn(const struct bpf_insn *from,
 			off -= 2;
 		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
-		*to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
+		*to = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
+		if (from->src_reg)
+			/* NOTE: BPF_K has been transformed into BPF_X,
+			 * mark imm instead of src_reg
+			 */
+			to->imm |= BPF_JMP_SUBOP_32BIT;
+		to++;
 		break;
 
 	case BPF_LD | BPF_IMM | BPF_DW:
-- 
2.7.4