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From: Tiezhu Yang <yangtiezhu@loongson.cn>
To: Huacai Chen <chenhuacai@kernel.org>, Hengqi Chen <hengqi.chen@gmail.com>
Cc: loongarch@lists.linux.dev, bpf@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v3 2/5] LoongArch: BPF: Add the default case in emit_atomic() and rename it
Date: Mon, 13 Apr 2026 12:05:03 +0800	[thread overview]
Message-ID: <20260413040506.26640-3-yangtiezhu@loongson.cn> (raw)
In-Reply-To: <20260413040506.26640-1-yangtiezhu@loongson.cn>

Like the other archs such as x86 and riscv, add the default case
in emit_atomic() to print an error message for the invalid opcode
and return -EINVAL , then make its return type as int.

While at it, given that all of the instructions in emit_atomic()
are only read-modify-write instructions, rename emit_atomic() to
emit_atomic_rmw() to make it clear, because there will be a new
function emit_atomic_ld_st() for load-acquire and store-release
instructions in the later patch.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 arch/loongarch/net/bpf_jit.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
index 9cb796e16379..fefda4050a20 100644
--- a/arch/loongarch/net/bpf_jit.c
+++ b/arch/loongarch/net/bpf_jit.c
@@ -344,7 +344,7 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int insn)
 #undef jmp_offset
 }
 
-static void emit_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
+static int emit_atomic_rmw(const struct bpf_insn *insn, struct jit_ctx *ctx)
 {
 	const u8 t1 = LOONGARCH_GPR_T1;
 	const u8 t2 = LOONGARCH_GPR_T2;
@@ -448,7 +448,12 @@ static void emit_atomic(const struct bpf_insn *insn, struct jit_ctx *ctx)
 			emit_zext_32(ctx, r0, true);
 		}
 		break;
+	default:
+		pr_err_once("bpf-jit: invalid atomic read-modify-write opcode %02x\n", imm);
+		return -EINVAL;
 	}
+
+	return 0;
 }
 
 static bool is_signed_bpf_cond(u8 cond)
@@ -1256,7 +1261,9 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext
 
 	case BPF_STX | BPF_ATOMIC | BPF_W:
 	case BPF_STX | BPF_ATOMIC | BPF_DW:
-		emit_atomic(insn, ctx);
+		ret = emit_atomic_rmw(insn, ctx);
+		if (ret)
+			return ret;
 		break;
 
 	/* Speculation barrier */
-- 
2.42.0


  parent reply	other threads:[~2026-04-13  4:05 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-13  4:05 [PATCH v3 0/5] LoongArch: BPF: Support more atomic instructions Tiezhu Yang
2026-04-13  4:05 ` [PATCH v3 1/5] LoongArch: Define instruction formats for AM{SWAP/ADD}.{B/H} and DBAR Tiezhu Yang
2026-04-15  2:24   ` Hengqi Chen
2026-04-13  4:05 ` Tiezhu Yang [this message]
2026-04-15  2:24   ` [PATCH v3 2/5] LoongArch: BPF: Add the default case in emit_atomic() and rename it Hengqi Chen
2026-04-13  4:05 ` [PATCH v3 3/5] LoongArch: BPF: Support 8 and 16 bit read-modify-write instructions Tiezhu Yang
2026-04-13  4:49   ` bot+bpf-ci
2026-04-13  8:05     ` WANG Rui
2026-04-13  4:05 ` [PATCH v3 4/5] LoongArch: BPF: Support load-acquire and store-release instructions Tiezhu Yang
2026-04-15  2:25   ` Hengqi Chen
2026-04-13  4:05 ` [PATCH v3 5/5] selftests/bpf: Make CAN_USE_LOAD_ACQ_STORE_REL usable for LoongArch Tiezhu Yang
2026-04-15  2:27   ` Hengqi Chen
2026-04-21 12:38 ` [PATCH v3 0/5] LoongArch: BPF: Support more atomic instructions Huacai Chen
2026-04-21 13:25   ` Tiezhu Yang
2026-04-21 13:46     ` Tiezhu Yang
2026-04-22  8:15     ` Huacai Chen
2026-04-23  2:56       ` Tiezhu Yang

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