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

Commit Message

Pu Lehui Aug. 23, 2023, 11:10 p.m. UTC

From: Pu Lehui <[e-mail]>

Add support signed div/mod instructions for RV64.

Signed-off-by: Pu Lehui <[e-mail]>
---
 arch/riscv/net/bpf_jit.h        | 20 ++++++++++++++++++++
 arch/riscv/net/bpf_jit_comp64.c | 26 ++++++++++++++++++++------
 2 files changed, 40 insertions(+), 6 deletions(-)

Comments

Björn Töpel Aug. 23, 2023, 6:23 p.m. UTC | #1

Pu Lehui <[e-mail]> writes:

> From: Pu Lehui <[e-mail]>
>
> Add support signed div/mod instructions for RV64.
>
> Signed-off-by: Pu Lehui <[e-mail]>

Acked-by: Björn Töpel <[e-mail]>

Patch

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 3d4e9182385d..027bd372c294 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;