Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / kernel / bpf / core.c
diff --git a/kernel/kernel/bpf/core.c b/kernel/kernel/bpf/core.c
new file mode 100644 (file)
index 0000000..54f0e7f
--- /dev/null
@@ -0,0 +1,674 @@
+/*
+ * Linux Socket Filter - Kernel level socket filtering
+ *
+ * Based on the design of the Berkeley Packet Filter. The new
+ * internal format has been designed by PLUMgrid:
+ *
+ *     Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
+ *
+ * Authors:
+ *
+ *     Jay Schulist <jschlst@samba.org>
+ *     Alexei Starovoitov <ast@plumgrid.com>
+ *     Daniel Borkmann <dborkman@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Andi Kleen - Fix a few bad bugs and races.
+ * Kris Katterjohn - Added many additional checks in bpf_check_classic()
+ */
+
+#include <linux/filter.h>
+#include <linux/skbuff.h>
+#include <linux/vmalloc.h>
+#include <linux/random.h>
+#include <linux/moduleloader.h>
+#include <asm/unaligned.h>
+#include <linux/bpf.h>
+
+/* Registers */
+#define BPF_R0 regs[BPF_REG_0]
+#define BPF_R1 regs[BPF_REG_1]
+#define BPF_R2 regs[BPF_REG_2]
+#define BPF_R3 regs[BPF_REG_3]
+#define BPF_R4 regs[BPF_REG_4]
+#define BPF_R5 regs[BPF_REG_5]
+#define BPF_R6 regs[BPF_REG_6]
+#define BPF_R7 regs[BPF_REG_7]
+#define BPF_R8 regs[BPF_REG_8]
+#define BPF_R9 regs[BPF_REG_9]
+#define BPF_R10        regs[BPF_REG_10]
+
+/* Named registers */
+#define DST    regs[insn->dst_reg]
+#define SRC    regs[insn->src_reg]
+#define FP     regs[BPF_REG_FP]
+#define ARG1   regs[BPF_REG_ARG1]
+#define CTX    regs[BPF_REG_CTX]
+#define IMM    insn->imm
+
+/* No hurry in this branch
+ *
+ * Exported for the bpf jit load helper.
+ */
+void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
+{
+       u8 *ptr = NULL;
+
+       if (k >= SKF_NET_OFF)
+               ptr = skb_network_header(skb) + k - SKF_NET_OFF;
+       else if (k >= SKF_LL_OFF)
+               ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
+       if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
+               return ptr;
+
+       return NULL;
+}
+
+struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
+{
+       gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
+                         gfp_extra_flags;
+       struct bpf_prog_aux *aux;
+       struct bpf_prog *fp;
+
+       size = round_up(size, PAGE_SIZE);
+       fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
+       if (fp == NULL)
+               return NULL;
+
+       aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
+       if (aux == NULL) {
+               vfree(fp);
+               return NULL;
+       }
+
+       fp->pages = size / PAGE_SIZE;
+       fp->aux = aux;
+
+       return fp;
+}
+EXPORT_SYMBOL_GPL(bpf_prog_alloc);
+
+struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
+                                 gfp_t gfp_extra_flags)
+{
+       gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
+                         gfp_extra_flags;
+       struct bpf_prog *fp;
+
+       BUG_ON(fp_old == NULL);
+
+       size = round_up(size, PAGE_SIZE);
+       if (size <= fp_old->pages * PAGE_SIZE)
+               return fp_old;
+
+       fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
+       if (fp != NULL) {
+               memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
+               fp->pages = size / PAGE_SIZE;
+
+               /* We keep fp->aux from fp_old around in the new
+                * reallocated structure.
+                */
+               fp_old->aux = NULL;
+               __bpf_prog_free(fp_old);
+       }
+
+       return fp;
+}
+EXPORT_SYMBOL_GPL(bpf_prog_realloc);
+
+void __bpf_prog_free(struct bpf_prog *fp)
+{
+       kfree(fp->aux);
+       vfree(fp);
+}
+EXPORT_SYMBOL_GPL(__bpf_prog_free);
+
+#ifdef CONFIG_BPF_JIT
+struct bpf_binary_header *
+bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
+                    unsigned int alignment,
+                    bpf_jit_fill_hole_t bpf_fill_ill_insns)
+{
+       struct bpf_binary_header *hdr;
+       unsigned int size, hole, start;
+
+       /* Most of BPF filters are really small, but if some of them
+        * fill a page, allow at least 128 extra bytes to insert a
+        * random section of illegal instructions.
+        */
+       size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
+       hdr = module_alloc(size);
+       if (hdr == NULL)
+               return NULL;
+
+       /* Fill space with illegal/arch-dep instructions. */
+       bpf_fill_ill_insns(hdr, size);
+
+       hdr->pages = size / PAGE_SIZE;
+       hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
+                    PAGE_SIZE - sizeof(*hdr));
+       start = (prandom_u32() % hole) & ~(alignment - 1);
+
+       /* Leave a random number of instructions before BPF code. */
+       *image_ptr = &hdr->image[start];
+
+       return hdr;
+}
+
+void bpf_jit_binary_free(struct bpf_binary_header *hdr)
+{
+       module_memfree(hdr);
+}
+#endif /* CONFIG_BPF_JIT */
+
+/* Base function for offset calculation. Needs to go into .text section,
+ * therefore keeping it non-static as well; will also be used by JITs
+ * anyway later on, so do not let the compiler omit it.
+ */
+noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+       return 0;
+}
+
+/**
+ *     __bpf_prog_run - run eBPF program on a given context
+ *     @ctx: is the data we are operating on
+ *     @insn: is the array of eBPF instructions
+ *
+ * Decode and execute eBPF instructions.
+ */
+static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
+{
+       u64 stack[MAX_BPF_STACK / sizeof(u64)];
+       u64 regs[MAX_BPF_REG], tmp;
+       static const void *jumptable[256] = {
+               [0 ... 255] = &&default_label,
+               /* Now overwrite non-defaults ... */
+               /* 32 bit ALU operations */
+               [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
+               [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
+               [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
+               [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
+               [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
+               [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
+               [BPF_ALU | BPF_OR | BPF_X]  = &&ALU_OR_X,
+               [BPF_ALU | BPF_OR | BPF_K]  = &&ALU_OR_K,
+               [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
+               [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
+               [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
+               [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
+               [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
+               [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
+               [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
+               [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
+               [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
+               [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
+               [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
+               [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
+               [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
+               [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
+               [BPF_ALU | BPF_NEG] = &&ALU_NEG,
+               [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
+               [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
+               /* 64 bit ALU operations */
+               [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
+               [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
+               [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
+               [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
+               [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
+               [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
+               [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
+               [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
+               [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
+               [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
+               [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
+               [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
+               [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
+               [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
+               [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
+               [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
+               [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
+               [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
+               [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
+               [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
+               [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
+               [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
+               [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
+               [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
+               [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
+               /* Call instruction */
+               [BPF_JMP | BPF_CALL] = &&JMP_CALL,
+               /* Jumps */
+               [BPF_JMP | BPF_JA] = &&JMP_JA,
+               [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
+               [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
+               [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
+               [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
+               [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
+               [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
+               [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
+               [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
+               [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
+               [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
+               [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
+               [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
+               [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
+               [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
+               /* Program return */
+               [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
+               /* Store instructions */
+               [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
+               [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
+               [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
+               [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
+               [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
+               [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
+               [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
+               [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
+               [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
+               [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
+               /* Load instructions */
+               [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
+               [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
+               [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
+               [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
+               [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
+               [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
+               [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
+               [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
+               [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
+               [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
+               [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
+       };
+       void *ptr;
+       int off;
+
+#define CONT    ({ insn++; goto select_insn; })
+#define CONT_JMP ({ insn++; goto select_insn; })
+
+       FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
+       ARG1 = (u64) (unsigned long) ctx;
+
+       /* Registers used in classic BPF programs need to be reset first. */
+       regs[BPF_REG_A] = 0;
+       regs[BPF_REG_X] = 0;
+
+select_insn:
+       goto *jumptable[insn->code];
+
+       /* ALU */
+#define ALU(OPCODE, OP)                        \
+       ALU64_##OPCODE##_X:             \
+               DST = DST OP SRC;       \
+               CONT;                   \
+       ALU_##OPCODE##_X:               \
+               DST = (u32) DST OP (u32) SRC;   \
+               CONT;                   \
+       ALU64_##OPCODE##_K:             \
+               DST = DST OP IMM;               \
+               CONT;                   \
+       ALU_##OPCODE##_K:               \
+               DST = (u32) DST OP (u32) IMM;   \
+               CONT;
+
+       ALU(ADD,  +)
+       ALU(SUB,  -)
+       ALU(AND,  &)
+       ALU(OR,   |)
+       ALU(LSH, <<)
+       ALU(RSH, >>)
+       ALU(XOR,  ^)
+       ALU(MUL,  *)
+#undef ALU
+       ALU_NEG:
+               DST = (u32) -DST;
+               CONT;
+       ALU64_NEG:
+               DST = -DST;
+               CONT;
+       ALU_MOV_X:
+               DST = (u32) SRC;
+               CONT;
+       ALU_MOV_K:
+               DST = (u32) IMM;
+               CONT;
+       ALU64_MOV_X:
+               DST = SRC;
+               CONT;
+       ALU64_MOV_K:
+               DST = IMM;
+               CONT;
+       LD_IMM_DW:
+               DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
+               insn++;
+               CONT;
+       ALU64_ARSH_X:
+               (*(s64 *) &DST) >>= SRC;
+               CONT;
+       ALU64_ARSH_K:
+               (*(s64 *) &DST) >>= IMM;
+               CONT;
+       ALU64_MOD_X:
+               if (unlikely(SRC == 0))
+                       return 0;
+               div64_u64_rem(DST, SRC, &tmp);
+               DST = tmp;
+               CONT;
+       ALU_MOD_X:
+               if (unlikely(SRC == 0))
+                       return 0;
+               tmp = (u32) DST;
+               DST = do_div(tmp, (u32) SRC);
+               CONT;
+       ALU64_MOD_K:
+               div64_u64_rem(DST, IMM, &tmp);
+               DST = tmp;
+               CONT;
+       ALU_MOD_K:
+               tmp = (u32) DST;
+               DST = do_div(tmp, (u32) IMM);
+               CONT;
+       ALU64_DIV_X:
+               if (unlikely(SRC == 0))
+                       return 0;
+               DST = div64_u64(DST, SRC);
+               CONT;
+       ALU_DIV_X:
+               if (unlikely(SRC == 0))
+                       return 0;
+               tmp = (u32) DST;
+               do_div(tmp, (u32) SRC);
+               DST = (u32) tmp;
+               CONT;
+       ALU64_DIV_K:
+               DST = div64_u64(DST, IMM);
+               CONT;
+       ALU_DIV_K:
+               tmp = (u32) DST;
+               do_div(tmp, (u32) IMM);
+               DST = (u32) tmp;
+               CONT;
+       ALU_END_TO_BE:
+               switch (IMM) {
+               case 16:
+                       DST = (__force u16) cpu_to_be16(DST);
+                       break;
+               case 32:
+                       DST = (__force u32) cpu_to_be32(DST);
+                       break;
+               case 64:
+                       DST = (__force u64) cpu_to_be64(DST);
+                       break;
+               }
+               CONT;
+       ALU_END_TO_LE:
+               switch (IMM) {
+               case 16:
+                       DST = (__force u16) cpu_to_le16(DST);
+                       break;
+               case 32:
+                       DST = (__force u32) cpu_to_le32(DST);
+                       break;
+               case 64:
+                       DST = (__force u64) cpu_to_le64(DST);
+                       break;
+               }
+               CONT;
+
+       /* CALL */
+       JMP_CALL:
+               /* Function call scratches BPF_R1-BPF_R5 registers,
+                * preserves BPF_R6-BPF_R9, and stores return value
+                * into BPF_R0.
+                */
+               BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
+                                                      BPF_R4, BPF_R5);
+               CONT;
+
+       /* JMP */
+       JMP_JA:
+               insn += insn->off;
+               CONT;
+       JMP_JEQ_X:
+               if (DST == SRC) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JEQ_K:
+               if (DST == IMM) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JNE_X:
+               if (DST != SRC) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JNE_K:
+               if (DST != IMM) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JGT_X:
+               if (DST > SRC) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JGT_K:
+               if (DST > IMM) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JGE_X:
+               if (DST >= SRC) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JGE_K:
+               if (DST >= IMM) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JSGT_X:
+               if (((s64) DST) > ((s64) SRC)) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JSGT_K:
+               if (((s64) DST) > ((s64) IMM)) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JSGE_X:
+               if (((s64) DST) >= ((s64) SRC)) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JSGE_K:
+               if (((s64) DST) >= ((s64) IMM)) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JSET_X:
+               if (DST & SRC) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_JSET_K:
+               if (DST & IMM) {
+                       insn += insn->off;
+                       CONT_JMP;
+               }
+               CONT;
+       JMP_EXIT:
+               return BPF_R0;
+
+       /* STX and ST and LDX*/
+#define LDST(SIZEOP, SIZE)                                             \
+       STX_MEM_##SIZEOP:                                               \
+               *(SIZE *)(unsigned long) (DST + insn->off) = SRC;       \
+               CONT;                                                   \
+       ST_MEM_##SIZEOP:                                                \
+               *(SIZE *)(unsigned long) (DST + insn->off) = IMM;       \
+               CONT;                                                   \
+       LDX_MEM_##SIZEOP:                                               \
+               DST = *(SIZE *)(unsigned long) (SRC + insn->off);       \
+               CONT;
+
+       LDST(B,   u8)
+       LDST(H,  u16)
+       LDST(W,  u32)
+       LDST(DW, u64)
+#undef LDST
+       STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
+               atomic_add((u32) SRC, (atomic_t *)(unsigned long)
+                          (DST + insn->off));
+               CONT;
+       STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
+               atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
+                            (DST + insn->off));
+               CONT;
+       LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
+               off = IMM;
+load_word:
+               /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
+                * only appearing in the programs where ctx ==
+                * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
+                * == BPF_R6, bpf_convert_filter() saves it in BPF_R6,
+                * internal BPF verifier will check that BPF_R6 ==
+                * ctx.
+                *
+                * BPF_ABS and BPF_IND are wrappers of function calls,
+                * so they scratch BPF_R1-BPF_R5 registers, preserve
+                * BPF_R6-BPF_R9, and store return value into BPF_R0.
+                *
+                * Implicit input:
+                *   ctx == skb == BPF_R6 == CTX
+                *
+                * Explicit input:
+                *   SRC == any register
+                *   IMM == 32-bit immediate
+                *
+                * Output:
+                *   BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
+                */
+
+               ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
+               if (likely(ptr != NULL)) {
+                       BPF_R0 = get_unaligned_be32(ptr);
+                       CONT;
+               }
+
+               return 0;
+       LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
+               off = IMM;
+load_half:
+               ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
+               if (likely(ptr != NULL)) {
+                       BPF_R0 = get_unaligned_be16(ptr);
+                       CONT;
+               }
+
+               return 0;
+       LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
+               off = IMM;
+load_byte:
+               ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
+               if (likely(ptr != NULL)) {
+                       BPF_R0 = *(u8 *)ptr;
+                       CONT;
+               }
+
+               return 0;
+       LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
+               off = IMM + SRC;
+               goto load_word;
+       LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
+               off = IMM + SRC;
+               goto load_half;
+       LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
+               off = IMM + SRC;
+               goto load_byte;
+
+       default_label:
+               /* If we ever reach this, we have a bug somewhere. */
+               WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
+               return 0;
+}
+
+void __weak bpf_int_jit_compile(struct bpf_prog *prog)
+{
+}
+
+/**
+ *     bpf_prog_select_runtime - select execution runtime for BPF program
+ *     @fp: bpf_prog populated with internal BPF program
+ *
+ * try to JIT internal BPF program, if JIT is not available select interpreter
+ * BPF program will be executed via BPF_PROG_RUN() macro
+ */
+void bpf_prog_select_runtime(struct bpf_prog *fp)
+{
+       fp->bpf_func = (void *) __bpf_prog_run;
+
+       /* Probe if internal BPF can be JITed */
+       bpf_int_jit_compile(fp);
+       /* Lock whole bpf_prog as read-only */
+       bpf_prog_lock_ro(fp);
+}
+EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
+
+static void bpf_prog_free_deferred(struct work_struct *work)
+{
+       struct bpf_prog_aux *aux;
+
+       aux = container_of(work, struct bpf_prog_aux, work);
+       bpf_jit_free(aux->prog);
+}
+
+/* Free internal BPF program */
+void bpf_prog_free(struct bpf_prog *fp)
+{
+       struct bpf_prog_aux *aux = fp->aux;
+
+       INIT_WORK(&aux->work, bpf_prog_free_deferred);
+       aux->prog = fp;
+       schedule_work(&aux->work);
+}
+EXPORT_SYMBOL_GPL(bpf_prog_free);
+
+/* Weak definitions of helper functions in case we don't have bpf syscall. */
+const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
+const struct bpf_func_proto bpf_map_update_elem_proto __weak;
+const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
+
+const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
+const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
+
+/* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
+ * skb_copy_bits(), so provide a weak definition of it for NET-less config.
+ */
+int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
+                        int len)
+{
+       return -EFAULT;
+}