Merge remote-tracking branches 'regulator/topic/ltc3589', 'regulator/topic/max77620...

[karo-tx-linux.git] / arch / arm64 / net / bpf_jit_comp.c

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index d6a53ef2350be81a090c07ab7d6df409d99c6a37..a34420a5df9a2e5134beb26964f08c57d97c0d16 100644 (file)
--- 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
@@ -139,6 +139,12 @@ static inline int epilogue_offset(const struct jit_ctx *ctx)
 /* Stack must be multiples of 16B */
 #define STACK_ALIGN(sz) (((sz) + 15) & ~15)
 
+#define _STACK_SIZE \
+       (MAX_BPF_STACK \
+        + 4 /* extra for skb_copy_bits buffer */)
+
+#define STACK_SIZE STACK_ALIGN(_STACK_SIZE)
+
 static void build_prologue(struct jit_ctx *ctx)
 {
        const u8 r6 = bpf2a64[BPF_REG_6];
@@ -146,14 +152,8 @@ 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];
-       int stack_size = MAX_BPF_STACK;
-
-       stack_size += 4; /* extra for skb_copy_bits buffer */
-       stack_size = STACK_ALIGN(stack_size);
 
        /*
         * BPF prog stack layout
@@ -165,12 +165,13 @@ static void build_prologue(struct jit_ctx *ctx)
         *                        | ... | callee saved registers
         *                        +-----+
         *                        |     | x25/x26
-        * BPF fp register => -80:+-----+
+        * BPF fp register => -80:+-----+ <= (BPF_FP)
         *                        |     |
         *                        | ... | BPF prog stack
         *                        |     |
-        *                        |     |
-        * current A64_SP =>      +-----+
+        *                        +-----+ <= (BPF_FP - MAX_BPF_STACK)
+        *                        |RSVD | JIT scratchpad
+        * current A64_SP =>      +-----+ <= (BPF_FP - STACK_SIZE)
         *                        |     |
         *                        | ... | Function call stack
         *                        |     |
@@ -196,11 +197,7 @@ static void build_prologue(struct jit_ctx *ctx)
        emit(A64_MOV(1, fp, A64_SP), 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);
+       emit(A64_SUB_I(1, A64_SP, A64_SP, STACK_SIZE), ctx);
 }
 
 static void build_epilogue(struct jit_ctx *ctx)
@@ -213,13 +210,9 @@ static void build_epilogue(struct jit_ctx *ctx)
        const u8 fp = bpf2a64[BPF_REG_FP];
        const u8 tmp1 = bpf2a64[TMP_REG_1];
        const u8 tmp2 = bpf2a64[TMP_REG_2];
-       int stack_size = MAX_BPF_STACK;
-
-       stack_size += 4; /* extra for skb_copy_bits buffer */
-       stack_size = STACK_ALIGN(stack_size);
 
        /* We're done with BPF stack */
-       emit(A64_ADD_I(1, A64_SP, A64_SP, stack_size), ctx);
+       emit(A64_ADD_I(1, A64_SP, A64_SP, STACK_SIZE), ctx);
 
        /* Restore fs (x25) and x26 */
        emit(A64_POP(fp, A64_R(26), A64_SP), ctx);
@@ -591,7 +584,25 @@ emit_cond_jmp:
        case BPF_ST | BPF_MEM | BPF_H:
        case BPF_ST | BPF_MEM | BPF_B:
        case BPF_ST | BPF_MEM | BPF_DW:
-               goto notyet;
+               /* Load imm to a register then store it */
+               ctx->tmp_used = 1;
+               emit_a64_mov_i(1, tmp2, off, ctx);
+               emit_a64_mov_i(1, tmp, imm, ctx);
+               switch (BPF_SIZE(code)) {
+               case BPF_W:
+                       emit(A64_STR32(tmp, dst, tmp2), ctx);
+                       break;
+               case BPF_H:
+                       emit(A64_STRH(tmp, dst, tmp2), ctx);
+                       break;
+               case BPF_B:
+                       emit(A64_STRB(tmp, dst, tmp2), ctx);
+                       break;
+               case BPF_DW:
+                       emit(A64_STR64(tmp, dst, tmp2), ctx);
+                       break;
+               }
+               break;
 
        /* STX: *(size *)(dst + off) = src */
        case BPF_STX | BPF_MEM | BPF_W:
@@ -658,7 +669,7 @@ emit_cond_jmp:
                        return -EINVAL;
                }
                emit_a64_mov_i64(r3, size, ctx);
-               emit(A64_ADD_I(1, r4, fp, MAX_BPF_STACK), ctx);
+               emit(A64_SUB_I(1, r4, fp, STACK_SIZE), ctx);
                emit_a64_mov_i64(r5, (unsigned long)bpf_load_pointer, ctx);
                emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
                emit(A64_MOV(1, A64_FP, A64_SP), ctx);
@@ -726,6 +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);
@@ -788,6 +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);