1 files changed, 87 insertions, 18 deletions

diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c
index 0da31d41d413..faaebd446cad 100644
--- a/arch/powerpc/net/bpf_jit_comp32.c
+++ b/arch/powerpc/net/bpf_jit_comp32.c
@@ -221,13 +221,13 @@ static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 o
 	PPC_BCC(COND_GE, out);
 
 	/*
-	 * if (tail_call_cnt > MAX_TAIL_CALL_CNT)
+	 * if (tail_call_cnt >= MAX_TAIL_CALL_CNT)
 	 *   goto out;
 	 */
 	EMIT(PPC_RAW_CMPLWI(_R0, MAX_TAIL_CALL_CNT));
 	/* tail_call_cnt++; */
 	EMIT(PPC_RAW_ADDIC(_R0, _R0, 1));
-	PPC_BCC(COND_GT, out);
+	PPC_BCC(COND_GE, out);
 
 	/* prog = array->ptrs[index]; */
 	EMIT(PPC_RAW_RLWINM(_R3, b2p_index, 2, 0, 29));
@@ -268,7 +268,7 @@ static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 o
 
 /* Assemble the body code between the prologue & epilogue */
 int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx,
-		       u32 *addrs, bool extra_pass)
+		       u32 *addrs, int pass)
 {
 	const struct bpf_insn *insn = fp->insnsi;
 	int flen = fp->len;
@@ -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 +813,91 @@ 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_PROBE_MEM | BPF_B:
 		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_PROBE_MEM | BPF_H:
 		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_PROBE_MEM | BPF_W:
 		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));
+		case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
+			/*
+			 * As PTR_TO_BTF_ID that uses BPF_PROBE_MEM mode could either be a valid
+			 * kernel pointer or NULL but not a userspace address, execute BPF_PROBE_MEM
+			 * load only if addr is kernel address (see is_kernel_addr()), otherwise
+			 * set dst_reg=0 and move on.
+			 */
+			if (BPF_MODE(code) == BPF_PROBE_MEM) {
+				PPC_LI32(_R0, TASK_SIZE - off);
+				EMIT(PPC_RAW_CMPLW(src_reg, _R0));
+				PPC_BCC(COND_GT, (ctx->idx + 5) * 4);
+				EMIT(PPC_RAW_LI(dst_reg, 0));
+				/*
+				 * For BPF_DW case, "li reg_h,0" would be needed when
+				 * !fp->aux->verifier_zext. Emit NOP otherwise.
+				 *
+				 * Note that "li reg_h,0" is emitted for BPF_B/H/W case,
+				 * if necessary. So, jump there insted of emitting an
+				 * additional "li reg_h,0" instruction.
+				 */
+				if (size == BPF_DW && !fp->aux->verifier_zext)
+					EMIT(PPC_RAW_LI(dst_reg_h, 0));
+				else
+					EMIT(PPC_RAW_NOP());
+				/*
+				 * Need to jump two instructions instead of one for BPF_DW case
+				 * as there are two load instructions for dst_reg_h & dst_reg
+				 * respectively.
+				 */
+				if (size == BPF_DW)
+					PPC_JMP((ctx->idx + 3) * 4);
+				else
+					PPC_JMP((ctx->idx + 2) * 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));
+
+			if (BPF_MODE(code) == BPF_PROBE_MEM) {
+				int insn_idx = ctx->idx - 1;
+				int jmp_off = 4;
+
+				/*
+				 * In case of BPF_DW, two lwz instructions are emitted, one
+				 * for higher 32-bit and another for lower 32-bit. So, set
+				 * ex->insn to the first of the two and jump over both
+				 * instructions in fixup.
+				 *
+				 * Similarly, with !verifier_zext, two instructions are
+				 * emitted for BPF_B/H/W case. So, set ex->insn to the
+				 * instruction that could fault and skip over both
+				 * instructions.
+				 */
+				if (size == BPF_DW || !fp->aux->verifier_zext) {
+					insn_idx -= 1;
+					jmp_off += 4;
+				}
+
+				ret = bpf_add_extable_entry(fp, image, pass, ctx, insn_idx,
+							    jmp_off, dst_reg);
+				if (ret)
+					return ret;
+			}
 			break;
 
 		/*
@@ -862,7 +931,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
 		case BPF_JMP | BPF_CALL:
 			ctx->seen |= SEEN_FUNC;
 
-			ret = bpf_jit_get_func_addr(fp, &insn[i], extra_pass,
+			ret = bpf_jit_get_func_addr(fp, &insn[i], false,
 						    &func_addr, &func_addr_fixed);
 			if (ret < 0)
 				return ret;