linux-kernel - [PATCH bpf-next v2 5/7] riscv, bpf: Support signed div/mod insns

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Date:   Thu, 24 Aug 2023 09:49:59 +0000
From:   Pu Lehui <pulehui@...weicloud.com>
To:     linux-riscv@...ts.infradead.org, bpf@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Björn Töpel <bjorn@...nel.org>,
        Yonghong Song <yhs@...com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <martin.lau@...ux.dev>,
        Song Liu <song@...nel.org>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>,
        Stanislav Fomichev <sdf@...gle.com>,
        Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
        Palmer Dabbelt <palmer@...belt.com>,
        Xu Kuohai <xukuohai@...wei.com>,
        Puranjay Mohan <puranjay12@...il.com>,
        Pu Lehui <pulehui@...wei.com>,
        Pu Lehui <pulehui@...weicloud.com>
Subject: [PATCH bpf-next v2 5/7] riscv, bpf: Support signed div/mod insns

From: Pu Lehui <pulehui@...wei.com>

Add support signed div/mod instructions for RV64.

Signed-off-by: Pu Lehui <pulehui@...wei.com>
Acked-by: Björn Töpel <bjorn@...nel.org>
---
 arch/riscv/net/bpf_jit.h        | 20 ++++++++++++++++++++
 arch/riscv/net/bpf_jit_comp64.c | 26 ++++++++++++++++++++------
 2 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/arch/riscv/net/bpf_jit.h b/arch/riscv/net/bpf_jit.h
index a52a3dda18c3..d21c6c92a683 100644
--- a/arch/riscv/net/bpf_jit.h
+++ b/arch/riscv/net/bpf_jit.h
@@ -431,11 +431,21 @@ static inline u32 rv_mulhu(u8 rd, u8 rs1, u8 rs2)
 	return rv_r_insn(1, rs2, rs1, 3, rd, 0x33);
 }
 
+static inline u32 rv_div(u8 rd, u8 rs1, u8 rs2)
+{
+	return rv_r_insn(1, rs2, rs1, 4, rd, 0x33);
+}
+
 static inline u32 rv_divu(u8 rd, u8 rs1, u8 rs2)
 {
 	return rv_r_insn(1, rs2, rs1, 5, rd, 0x33);
 }
 
+static inline u32 rv_rem(u8 rd, u8 rs1, u8 rs2)
+{
+	return rv_r_insn(1, rs2, rs1, 6, rd, 0x33);
+}
+
 static inline u32 rv_remu(u8 rd, u8 rs1, u8 rs2)
 {
 	return rv_r_insn(1, rs2, rs1, 7, rd, 0x33);
@@ -776,11 +786,21 @@ static inline u32 rv_mulw(u8 rd, u8 rs1, u8 rs2)
 	return rv_r_insn(1, rs2, rs1, 0, rd, 0x3b);
 }
 
+static inline u32 rv_divw(u8 rd, u8 rs1, u8 rs2)
+{
+	return rv_r_insn(1, rs2, rs1, 4, rd, 0x3b);
+}
+
 static inline u32 rv_divuw(u8 rd, u8 rs1, u8 rs2)
 {
 	return rv_r_insn(1, rs2, rs1, 5, rd, 0x3b);
 }
 
+static inline u32 rv_remw(u8 rd, u8 rs1, u8 rs2)
+{
+	return rv_r_insn(1, rs2, rs1, 6, rd, 0x3b);
+}
+
 static inline u32 rv_remuw(u8 rd, u8 rs1, u8 rs2)
 {
 	return rv_r_insn(1, rs2, rs1, 7, rd, 0x3b);
diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index 076619f4aa82..ba4535ac194f 100644
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -1107,13 +1107,19 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 		break;
 	case BPF_ALU | BPF_DIV | BPF_X:
 	case BPF_ALU64 | BPF_DIV | BPF_X:
-		emit(is64 ? rv_divu(rd, rd, rs) : rv_divuw(rd, rd, rs), ctx);
+		if (off)
+			emit(is64 ? rv_div(rd, rd, rs) : rv_divw(rd, rd, rs), ctx);
+		else
+			emit(is64 ? rv_divu(rd, rd, rs) : rv_divuw(rd, rd, rs), ctx);
 		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_MOD | BPF_X:
 	case BPF_ALU64 | BPF_MOD | BPF_X:
-		emit(is64 ? rv_remu(rd, rd, rs) : rv_remuw(rd, rd, rs), ctx);
+		if (off)
+			emit(is64 ? rv_rem(rd, rd, rs) : rv_remw(rd, rd, rs), ctx);
+		else
+			emit(is64 ? rv_remu(rd, rd, rs) : rv_remuw(rd, rd, rs), ctx);
 		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
@@ -1284,16 +1290,24 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
 	case BPF_ALU | BPF_DIV | BPF_K:
 	case BPF_ALU64 | BPF_DIV | BPF_K:
 		emit_imm(RV_REG_T1, imm, ctx);
-		emit(is64 ? rv_divu(rd, rd, RV_REG_T1) :
-		     rv_divuw(rd, rd, RV_REG_T1), ctx);
+		if (off)
+			emit(is64 ? rv_div(rd, rd, RV_REG_T1) :
+			     rv_divw(rd, rd, RV_REG_T1), ctx);
+		else
+			emit(is64 ? rv_divu(rd, rd, RV_REG_T1) :
+			     rv_divuw(rd, rd, RV_REG_T1), ctx);
 		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
 	case BPF_ALU | BPF_MOD | BPF_K:
 	case BPF_ALU64 | BPF_MOD | BPF_K:
 		emit_imm(RV_REG_T1, imm, ctx);
-		emit(is64 ? rv_remu(rd, rd, RV_REG_T1) :
-		     rv_remuw(rd, rd, RV_REG_T1), ctx);
+		if (off)
+			emit(is64 ? rv_rem(rd, rd, RV_REG_T1) :
+			     rv_remw(rd, rd, RV_REG_T1), ctx);
+		else
+			emit(is64 ? rv_remu(rd, rd, RV_REG_T1) :
+			     rv_remuw(rd, rd, RV_REG_T1), ctx);
 		if (!is64 && !aux->verifier_zext)
 			emit_zext_32(rd, ctx);
 		break;
-- 
2.39.2