ppc: bpf: implement jitting of BPF_ALU | BPF_ARSH | BPF_*

This patch implements code-gen for BPF_ALU | BPF_ARSH | BPF_*.

Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

arch/powerpc/include/asm/ppc-opcode.h

@@ -342,6 +342,8 @@
 #define PPC_INST_SLW			0x7c000030
 #define PPC_INST_SLD			0x7c000036
 #define PPC_INST_SRW			0x7c000430
+#define PPC_INST_SRAW			0x7c000630
+#define PPC_INST_SRAWI			0x7c000670
 #define PPC_INST_SRD			0x7c000436
 #define PPC_INST_SRAD			0x7c000634
 #define PPC_INST_SRADI			0x7c000674

arch/powerpc/net/bpf_jit.h

@@ -152,6 +152,10 @@
 				     ___PPC_RS(a) | ___PPC_RB(s))
 #define PPC_SRW(d, a, s)	EMIT(PPC_INST_SRW | ___PPC_RA(d) |	      \
 				     ___PPC_RS(a) | ___PPC_RB(s))
+#define PPC_SRAW(d, a, s)	EMIT(PPC_INST_SRAW | ___PPC_RA(d) |	      \
+				     ___PPC_RS(a) | ___PPC_RB(s))
+#define PPC_SRAWI(d, a, i)	EMIT(PPC_INST_SRAWI | ___PPC_RA(d) |	      \
+				     ___PPC_RS(a) | __PPC_SH(i))
 #define PPC_SRD(d, a, s)	EMIT(PPC_INST_SRD | ___PPC_RA(d) |	      \
 				     ___PPC_RS(a) | ___PPC_RB(s))
 #define PPC_SRAD(d, a, s)	EMIT(PPC_INST_SRAD | ___PPC_RA(d) |	      \

arch/powerpc/net/bpf_jit_comp64.c

@@ -529,9 +529,15 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
 			if (imm != 0)
 				PPC_SRDI(dst_reg, dst_reg, imm);
 			break;
+		case BPF_ALU | BPF_ARSH | BPF_X: /* (s32) dst >>= src */
+			PPC_SRAW(dst_reg, dst_reg, src_reg);
+			goto bpf_alu32_trunc;
 		case BPF_ALU64 | BPF_ARSH | BPF_X: /* (s64) dst >>= src */
 			PPC_SRAD(dst_reg, dst_reg, src_reg);
 			break;
+		case BPF_ALU | BPF_ARSH | BPF_K: /* (s32) dst >>= imm */
+			PPC_SRAWI(dst_reg, dst_reg, imm);
+			goto bpf_alu32_trunc;
 		case BPF_ALU64 | BPF_ARSH | BPF_K: /* (s64) dst >>= imm */
 			if (imm != 0)
 				PPC_SRADI(dst_reg, dst_reg, imm);