bpf powerpc: refactor JIT compiler code

Refactor powerpc LDX JITing code to simplify adding BPF_PROBE_MEM
support.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211012123056.485795-4-hbathini@linux.ibm.com

arch/powerpc/net/bpf_jit_comp32.c

@@ -284,6 +284,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
 		u32 src_reg = bpf_to_ppc(ctx, insn[i].src_reg);
 		u32 src_reg_h = src_reg - 1;
 		u32 tmp_reg = bpf_to_ppc(ctx, TMP_REG);
+		u32 size = BPF_SIZE(code);
 		s16 off = insn[i].off;
 		s32 imm = insn[i].imm;
 		bool func_addr_fixed;
@@ -812,23 +813,27 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
 		 * BPF_LDX
 		 */
 		case BPF_LDX | BPF_MEM | BPF_B: /* dst = *(u8 *)(ul) (src + off) */
-			EMIT(PPC_RAW_LBZ(dst_reg, src_reg, off));
-			if (!fp->aux->verifier_zext)
-				EMIT(PPC_RAW_LI(dst_reg_h, 0));
-			break;
 		case BPF_LDX | BPF_MEM | BPF_H: /* dst = *(u16 *)(ul) (src + off) */
-			EMIT(PPC_RAW_LHZ(dst_reg, src_reg, off));
-			if (!fp->aux->verifier_zext)
-				EMIT(PPC_RAW_LI(dst_reg_h, 0));
-			break;
 		case BPF_LDX | BPF_MEM | BPF_W: /* dst = *(u32 *)(ul) (src + off) */
-			EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off));
-			if (!fp->aux->verifier_zext)
-				EMIT(PPC_RAW_LI(dst_reg_h, 0));
-			break;
 		case BPF_LDX | BPF_MEM | BPF_DW: /* dst = *(u64 *)(ul) (src + off) */
-			EMIT(PPC_RAW_LWZ(dst_reg_h, src_reg, off));
-			EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off + 4));
+			switch (size) {
+			case BPF_B:
+				EMIT(PPC_RAW_LBZ(dst_reg, src_reg, off));
+				break;
+			case BPF_H:
+				EMIT(PPC_RAW_LHZ(dst_reg, src_reg, off));
+				break;
+			case BPF_W:
+				EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off));
+				break;
+			case BPF_DW:
+				EMIT(PPC_RAW_LWZ(dst_reg_h, src_reg, off));
+				EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off + 4));
+				break;
+			}
+
+			if (size != BPF_DW && !fp->aux->verifier_zext)
+				EMIT(PPC_RAW_LI(dst_reg_h, 0));
 			break;
 
 		/*

arch/powerpc/net/bpf_jit_comp64.c

@@ -311,6 +311,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
 		u32 code = insn[i].code;
 		u32 dst_reg = b2p[insn[i].dst_reg];
 		u32 src_reg = b2p[insn[i].src_reg];
+		u32 size = BPF_SIZE(code);
 		s16 off = insn[i].off;
 		s32 imm = insn[i].imm;
 		bool func_addr_fixed;
@@ -778,25 +779,29 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
 		 */
 		/* dst = *(u8 *)(ul) (src + off) */
 		case BPF_LDX | BPF_MEM | BPF_B:
-			EMIT(PPC_RAW_LBZ(dst_reg, src_reg, off));
-			if (insn_is_zext(&insn[i + 1]))
-				addrs[++i] = ctx->idx * 4;
-			break;
 		/* dst = *(u16 *)(ul) (src + off) */
 		case BPF_LDX | BPF_MEM | BPF_H:
-			EMIT(PPC_RAW_LHZ(dst_reg, src_reg, off));
-			if (insn_is_zext(&insn[i + 1]))
-				addrs[++i] = ctx->idx * 4;
-			break;
 		/* dst = *(u32 *)(ul) (src + off) */
 		case BPF_LDX | BPF_MEM | BPF_W:
-			EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off));
-			if (insn_is_zext(&insn[i + 1]))
-				addrs[++i] = ctx->idx * 4;
-			break;
 		/* dst = *(u64 *)(ul) (src + off) */
 		case BPF_LDX | BPF_MEM | BPF_DW:
-			PPC_BPF_LL(dst_reg, src_reg, off);
+			switch (size) {
+			case BPF_B:
+				EMIT(PPC_RAW_LBZ(dst_reg, src_reg, off));
+				break;
+			case BPF_H:
+				EMIT(PPC_RAW_LHZ(dst_reg, src_reg, off));
+				break;
+			case BPF_W:
+				EMIT(PPC_RAW_LWZ(dst_reg, src_reg, off));
+				break;
+			case BPF_DW:
+				PPC_BPF_LL(dst_reg, src_reg, off);
+				break;
+			}
+
+			if (size != BPF_DW && insn_is_zext(&insn[i + 1]))
+				addrs[++i] = ctx->idx * 4;
 			break;
 
 		/*