PPC: net: bpf_jit_comp: add XOR instruction for BPF JIT

This patch is a follow-up for patch "filter: add XOR instruction for use
with X/K" that implements BPF PowerPC JIT parts for the BPF XOR operation.

Signed-off-by: Daniel Borkmann <[e-mail]>
Cc: Matt Evans <[e-mail]>
Cc: Benjamin Herrenschmidt <[e-mail]>
Acked-by: Matt Evans <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

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

···
 #define PPC_INST_AND			0x7c000038
 #define PPC_INST_ANDDOT			0x7c000039
 #define PPC_INST_OR			0x7c000378
+#define PPC_INST_XOR			0x7c000278
 #define PPC_INST_ANDI			0x70000000
 #define PPC_INST_ORI			0x60000000
 #define PPC_INST_ORIS			0x64000000
+#define PPC_INST_XORI			0x68000000
+#define PPC_INST_XORIS			0x6c000000
 #define PPC_INST_NEG			0x7c0000d0
 #define PPC_INST_BRANCH			0x48000000
 #define PPC_INST_BRANCH_COND		0x40800000

arch/powerpc/net/bpf_jit.h

···
 				     ___PPC_RS(a) | IMM_L(i))
 #define PPC_ORIS(d, a, i)	EMIT(PPC_INST_ORIS | ___PPC_RA(d) |	      \
 				     ___PPC_RS(a) | IMM_L(i))
+#define PPC_XOR(d, a, b)	EMIT(PPC_INST_XOR | ___PPC_RA(d) |	      \
+				     ___PPC_RS(a) | ___PPC_RB(b))
+#define PPC_XORI(d, a, i)	EMIT(PPC_INST_XORI | ___PPC_RA(d) |	      \
+				     ___PPC_RS(a) | IMM_L(i))
+#define PPC_XORIS(d, a, i)	EMIT(PPC_INST_XORIS | ___PPC_RA(d) |	      \
+				     ___PPC_RS(a) | IMM_L(i))
 #define PPC_SLW(d, a, s)	EMIT(PPC_INST_SLW | ___PPC_RA(d) |	      \
 				     ___PPC_RS(a) | ___PPC_RB(s))
 #define PPC_SRW(d, a, s)	EMIT(PPC_INST_SRW | ___PPC_RA(d) |	      \

arch/powerpc/net/bpf_jit_comp.c

···
 			if (K >= 65536)
 				PPC_ORIS(r_A, r_A, IMM_H(K));
 			break;
+		case BPF_S_ANC_ALU_XOR_X:
+		case BPF_S_ALU_XOR_X: /* A ^= X */
+			ctx->seen |= SEEN_XREG;
+			PPC_XOR(r_A, r_A, r_X);
+			break;
+		case BPF_S_ALU_XOR_K: /* A ^= K */
+			if (IMM_L(K))
+				PPC_XORI(r_A, r_A, IMM_L(K));
+			if (K >= 65536)
+				PPC_XORIS(r_A, r_A, IMM_H(K));
+			break;
 		case BPF_S_ALU_LSH_X: /* A <<= X; */
 			ctx->seen |= SEEN_XREG;
 			PPC_SLW(r_A, r_A, r_X);