1 files changed, 21 insertions, 7 deletions

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index b162ad70effc..a34420a5df9a 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -1,7 +1,7 @@
 /*
  * BPF JIT compiler for ARM64
  *
- * Copyright (C) 2014-2015 Zi Shen Lim <zlim.lnx@gmail.com>
+ * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -152,8 +152,6 @@ static void build_prologue(struct jit_ctx *ctx)
         const u8 r8 = bpf2a64[BPF_REG_8];
         const u8 r9 = bpf2a64[BPF_REG_9];
         const u8 fp = bpf2a64[BPF_REG_FP];
-        const u8 ra = bpf2a64[BPF_REG_A];
-        const u8 rx = bpf2a64[BPF_REG_X];
         const u8 tmp1 = bpf2a64[TMP_REG_1];
         const u8 tmp2 = bpf2a64[TMP_REG_2];
 
@@ -200,10 +198,6 @@ static void build_prologue(struct jit_ctx *ctx)
 
         /* Set up function call stack */
         emit(A64_SUB_I(1, A64_SP, A64_SP, STACK_SIZE), ctx);
-
-        /* Clear registers A and X */
-        emit_a64_mov_i64(ra, 0, ctx);
-        emit_a64_mov_i64(rx, 0, ctx);
 }
 
 static void build_epilogue(struct jit_ctx *ctx)
@@ -743,6 +737,20 @@ static int build_body(struct jit_ctx *ctx)
         return 0;
 }
 
+static int validate_code(struct jit_ctx *ctx)
+{
+        int i;
+
+        for (i = 0; i < ctx->idx; i++) {
+                u32 a64_insn = le32_to_cpu(ctx->image[i]);
+
+                if (a64_insn == AARCH64_BREAK_FAULT)
+                        return -1;
+        }
+
+        return 0;
+}
+
 static inline void bpf_flush_icache(void *start, void *end)
 {
         flush_icache_range((unsigned long)start, (unsigned long)end);
@@ -805,6 +813,12 @@ void bpf_int_jit_compile(struct bpf_prog *prog)
 
         build_epilogue(&ctx);
 
+        /* 3. Extra pass to validate JITed code. */
+        if (validate_code(&ctx)) {
+                bpf_jit_binary_free(header);
+                goto out;
+        }
+
         /* And we're done. */
         if (bpf_jit_enable > 1)
                 bpf_jit_dump(prog->len, image_size, 2, ctx.image);