4 files changed, 33 insertions, 5 deletions

diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h
index 25a7190bcee9..e58cf29bb0cf 100644
--- a/arch/powerpc/net/bpf_jit.h
+++ b/arch/powerpc/net/bpf_jit.h
@@ -148,6 +148,7 @@ struct codegen_context {
 	unsigned int stack_size;
 	int b2p[ARRAY_SIZE(b2p)];
 	unsigned int exentry_idx;
+	unsigned int alt_exit_addr;
 };
 
 #ifdef CONFIG_PPC32
@@ -183,6 +184,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
 void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx);
 void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx);
 void bpf_jit_realloc_regs(struct codegen_context *ctx);
+int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr);
 
 int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, int pass, struct codegen_context *ctx,
 			  int insn_idx, int jmp_off, int dst_reg);
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 56dd1f4e3e44..141e64585b64 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -89,6 +89,22 @@ static int bpf_jit_fixup_addresses(struct bpf_prog *fp, u32 *image,
 	return 0;
 }
 
+int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr)
+{
+	if (!exit_addr || is_offset_in_branch_range(exit_addr - (ctx->idx * 4))) {
+		PPC_JMP(exit_addr);
+	} else if (ctx->alt_exit_addr) {
+		if (WARN_ON(!is_offset_in_branch_range((long)ctx->alt_exit_addr - (ctx->idx * 4))))
+			return -1;
+		PPC_JMP(ctx->alt_exit_addr);
+	} else {
+		ctx->alt_exit_addr = ctx->idx * 4;
+		bpf_jit_build_epilogue(image, ctx);
+	}
+
+	return 0;
+}
+
 struct powerpc64_jit_data {
 	struct bpf_binary_header *header;
 	u32 *addrs;
@@ -177,8 +193,10 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
 	 * If we have seen a tail call, we need a second pass.
 	 * This is because bpf_jit_emit_common_epilogue() is called
 	 * from bpf_jit_emit_tail_call() with a not yet stable ctx->seen.
+	 * We also need a second pass if we ended up with too large
+	 * a program so as to ensure BPF_EXIT branches are in range.
 	 */
-	if (cgctx.seen & SEEN_TAILCALL) {
+	if (cgctx.seen & SEEN_TAILCALL || !is_offset_in_branch_range((long)cgctx.idx * 4)) {
 		cgctx.idx = 0;
 		if (bpf_jit_build_body(fp, 0, &cgctx, addrs, 0)) {
 			fp = org_fp;
@@ -193,6 +211,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
 	 * calculate total size from idx.
 	 */
 	bpf_jit_build_prologue(0, &cgctx);
+	addrs[fp->len] = cgctx.idx * 4;
 	bpf_jit_build_epilogue(0, &cgctx);
 
 	fixup_len = fp->aux->num_exentries * BPF_FIXUP_LEN * 4;
@@ -233,6 +252,7 @@ skip_init_ctx:
 	for (pass = 1; pass < 3; pass++) {
 		/* Now build the prologue, body code & epilogue for real. */
 		cgctx.idx = 0;
+		cgctx.alt_exit_addr = 0;
 		bpf_jit_build_prologue(code_base, &cgctx);
 		if (bpf_jit_build_body(fp, code_base, &cgctx, addrs, pass)) {
 			bpf_jit_binary_free(bpf_hdr);
diff --git a/arch/powerpc/net/bpf_jit_comp32.c b/arch/powerpc/net/bpf_jit_comp32.c
index 5ba5340a6387..8e743b7bf8f5 100644
--- a/arch/powerpc/net/bpf_jit_comp32.c
+++ b/arch/powerpc/net/bpf_jit_comp32.c
@@ -937,8 +937,11 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
 			 * the epilogue. If we _are_ the last instruction,
 			 * we'll just fall through to the epilogue.
 			 */
-			if (i != flen - 1)
-				PPC_JMP(exit_addr);
+			if (i != flen - 1) {
+				ret = bpf_jit_emit_exit_insn(image, ctx, _R0, exit_addr);
+				if (ret)
+					return ret;
+			}
 			/* else fall through to the epilogue */
 			break;
 
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index b1ed8611091d..371bd5a16859 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -871,8 +871,11 @@ emit_clear:
 			 * the epilogue. If we _are_ the last instruction,
 			 * we'll just fall through to the epilogue.
 			 */
-			if (i != flen - 1)
-				PPC_JMP(exit_addr);
+			if (i != flen - 1) {
+				ret = bpf_jit_emit_exit_insn(image, ctx, b2p[TMP_REG_1], exit_addr);
+				if (ret)
+					return ret;
+			}
 			/* else fall through to the epilogue */
 			break;