1 files changed, 104 insertions, 19 deletions

diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 50b129785aee..9393e231cbc2 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -166,7 +166,33 @@ static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
 	PPC_BLR();
 }
 
-static void bpf_jit_emit_func_call(u32 *image, struct codegen_context *ctx, u64 func)
+static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
+				       u64 func)
+{
+#ifdef PPC64_ELF_ABI_v1
+	/* func points to the function descriptor */
+	PPC_LI64(b2p[TMP_REG_2], func);
+	/* Load actual entry point from function descriptor */
+	PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);
+	/* ... and move it to LR */
+	PPC_MTLR(b2p[TMP_REG_1]);
+	/*
+	 * Load TOC from function descriptor at offset 8.
+	 * We can clobber r2 since we get called through a
+	 * function pointer (so caller will save/restore r2)
+	 * and since we don't use a TOC ourself.
+	 */
+	PPC_BPF_LL(2, b2p[TMP_REG_2], 8);
+#else
+	/* We can clobber r12 */
+	PPC_FUNC_ADDR(12, func);
+	PPC_MTLR(12);
+#endif
+	PPC_BLRL();
+}
+
+static void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx,
+				       u64 func)
 {
 	unsigned int i, ctx_idx = ctx->idx;
 
@@ -273,7 +299,7 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
 {
 	const struct bpf_insn *insn = fp->insnsi;
 	int flen = fp->len;
-	int i;
+	int i, ret;
 
 	/* Start of epilogue code - will only be valid 2nd pass onwards */
 	u32 exit_addr = addrs[flen];
@@ -284,8 +310,9 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
 		u32 src_reg = b2p[insn[i].src_reg];
 		s16 off = insn[i].off;
 		s32 imm = insn[i].imm;
+		bool func_addr_fixed;
+		u64 func_addr;
 		u64 imm64;
-		u8 *func;
 		u32 true_cond;
 		u32 tmp_idx;
 
@@ -711,23 +738,15 @@ emit_clear:
 		case BPF_JMP | BPF_CALL:
 			ctx->seen |= SEEN_FUNC;
 
-			/* bpf function call */
-			if (insn[i].src_reg == BPF_PSEUDO_CALL)
-				if (!extra_pass)
-					func = NULL;
-				else if (fp->aux->func && off < fp->aux->func_cnt)
-					/* use the subprog id from the off
-					 * field to lookup the callee address
-					 */
-					func = (u8 *) fp->aux->func[off]->bpf_func;
-				else
-					return -EINVAL;
-			/* kernel helper call */
-			else
-				func = (u8 *) __bpf_call_base + imm;
-
-			bpf_jit_emit_func_call(image, ctx, (u64)func);
+			ret = bpf_jit_get_func_addr(fp, &insn[i], extra_pass,
+						    &func_addr, &func_addr_fixed);
+			if (ret < 0)
+				return ret;
 
+			if (func_addr_fixed)
+				bpf_jit_emit_func_call_hlp(image, ctx, func_addr);
+			else
+				bpf_jit_emit_func_call_rel(image, ctx, func_addr);
 			/* move return value from r3 to BPF_REG_0 */
 			PPC_MR(b2p[BPF_REG_0], 3);
 			break;
@@ -872,6 +891,55 @@ cond_branch:
 	return 0;
 }
 
+/* Fix the branch target addresses for subprog calls */
+static int bpf_jit_fixup_subprog_calls(struct bpf_prog *fp, u32 *image,
+				       struct codegen_context *ctx, u32 *addrs)
+{
+	const struct bpf_insn *insn = fp->insnsi;
+	bool func_addr_fixed;
+	u64 func_addr;
+	u32 tmp_idx;
+	int i, ret;
+
+	for (i = 0; i < fp->len; i++) {
+		/*
+		 * During the extra pass, only the branch target addresses for
+		 * the subprog calls need to be fixed. All other instructions
+		 * can left untouched.
+		 *
+		 * The JITed image length does not change because we already
+		 * ensure that the JITed instruction sequence for these calls
+		 * are of fixed length by padding them with NOPs.
+		 */
+		if (insn[i].code == (BPF_JMP | BPF_CALL) &&
+		    insn[i].src_reg == BPF_PSEUDO_CALL) {
+			ret = bpf_jit_get_func_addr(fp, &insn[i], true,
+						    &func_addr,
+						    &func_addr_fixed);
+			if (ret < 0)
+				return ret;
+
+			/*
+			 * Save ctx->idx as this would currently point to the
+			 * end of the JITed image and set it to the offset of
+			 * the instruction sequence corresponding to the
+			 * subprog call temporarily.
+			 */
+			tmp_idx = ctx->idx;
+			ctx->idx = addrs[i] / 4;
+			bpf_jit_emit_func_call_rel(image, ctx, func_addr);
+
+			/*
+			 * Restore ctx->idx here. This is safe as the length
+			 * of the JITed sequence remains unchanged.
+			 */
+			ctx->idx = tmp_idx;
+		}
+	}
+
+	return 0;
+}
+
 struct powerpc64_jit_data {
 	struct bpf_binary_header *header;
 	u32 *addrs;
@@ -970,6 +1038,22 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
 skip_init_ctx:
 	code_base = (u32 *)(image + FUNCTION_DESCR_SIZE);
 
+	if (extra_pass) {
+		/*
+		 * Do not touch the prologue and epilogue as they will remain
+		 * unchanged. Only fix the branch target address for subprog
+		 * calls in the body.
+		 *
+		 * This does not change the offsets and lengths of the subprog
+		 * call instruction sequences and hence, the size of the JITed
+		 * image as well.
+		 */
+		bpf_jit_fixup_subprog_calls(fp, code_base, &cgctx, addrs);
+
+		/* There is no need to perform the usual passes. */
+		goto skip_codegen_passes;
+	}
+
 	/* Code generation passes 1-2 */
 	for (pass = 1; pass < 3; pass++) {
 		/* Now build the prologue, body code & epilogue for real. */
@@ -983,6 +1067,7 @@ skip_init_ctx:
 				proglen - (cgctx.idx * 4), cgctx.seen);
 	}
 
+skip_codegen_passes:
 	if (bpf_jit_enable > 1)
 		/*
 		 * Note that we output the base address of the code_base