/*
 * 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 <linux/bpf.h>
#include <linux/frame.h>
#include <linux/rbtree_latch.h>
#include <linux/kallsyms.h>
#include <linux/rcupdate.h>

#include <asm/unaligned.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;

        kmemcheck_annotate_bitfield(fp, meta);

        aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
        if (aux == NULL) {
                vfree(fp);
                return NULL;
        }

        fp->pages = size / PAGE_SIZE;
        fp->aux = aux;
        fp->aux->prog = fp;

        INIT_LIST_HEAD_RCU(&fp->aux->ksym_lnode);

        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;
        u32 pages, delta;
        int ret;

        BUG_ON(fp_old == NULL);

        size = round_up(size, PAGE_SIZE);
        pages = size / PAGE_SIZE;
        if (pages <= fp_old->pages)
                return fp_old;

        delta = pages - fp_old->pages;
        ret = __bpf_prog_charge(fp_old->aux->user, delta);
        if (ret)
                return NULL;

        fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
        if (fp == NULL) {
                __bpf_prog_uncharge(fp_old->aux->user, delta);
        } else {
                kmemcheck_annotate_bitfield(fp, meta);

                memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
                fp->pages = pages;
                fp->aux->prog = fp;

                /* We keep fp->aux from fp_old around in the new
                 * reallocated structure.
                 */
                fp_old->aux = NULL;
                __bpf_prog_free(fp_old);
        }

        return fp;
}

void __bpf_prog_free(struct bpf_prog *fp)
{
        kfree(fp->aux);
        vfree(fp);
}

int bpf_prog_calc_tag(struct bpf_prog *fp)
{
        const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64);
        u32 raw_size = bpf_prog_tag_scratch_size(fp);
        u32 digest[SHA_DIGEST_WORDS];
        u32 ws[SHA_WORKSPACE_WORDS];
        u32 i, bsize, psize, blocks;
        struct bpf_insn *dst;
        bool was_ld_map;
        u8 *raw, *todo;
        __be32 *result;
        __be64 *bits;

        raw = vmalloc(raw_size);
        if (!raw)
                return -ENOMEM;

        sha_init(digest);
        memset(ws, 0, sizeof(ws));

        /* We need to take out the map fd for the digest calculation
         * since they are unstable from user space side.
         */
        dst = (void *)raw;
        for (i = 0, was_ld_map = false; i < fp->len; i++) {
                dst[i] = fp->insnsi[i];
                if (!was_ld_map &&
                    dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
                    dst[i].src_reg == BPF_PSEUDO_MAP_FD) {
                        was_ld_map = true;
                        dst[i].imm = 0;
                } else if (was_ld_map &&
                           dst[i].code == 0 &&
                           dst[i].dst_reg == 0 &&
                           dst[i].src_reg == 0 &&
                           dst[i].off == 0) {
                        was_ld_map = false;
                        dst[i].imm = 0;
                } else {
                        was_ld_map = false;
                }
        }

        psize = bpf_prog_insn_size(fp);
        memset(&raw[psize], 0, raw_size - psize);
        raw[psize++] = 0x80;

        bsize  = round_up(psize, SHA_MESSAGE_BYTES);
        blocks = bsize / SHA_MESSAGE_BYTES;
        todo   = raw;
        if (bsize - psize >= sizeof(__be64)) {
                bits = (__be64 *)(todo + bsize - sizeof(__be64));
        } else {
                bits = (__be64 *)(todo + bsize + bits_offset);
                blocks++;
        }
        *bits = cpu_to_be64((psize - 1) << 3);

        while (blocks--) {
                sha_transform(digest, todo, ws);
                todo += SHA_MESSAGE_BYTES;
        }

        result = (__force __be32 *)digest;
        for (i = 0; i < SHA_DIGEST_WORDS; i++)
                result[i] = cpu_to_be32(digest[i]);
        memcpy(fp->tag, result, sizeof(fp->tag));

        vfree(raw);
        return 0;
}

static bool bpf_is_jmp_and_has_target(const struct bpf_insn *insn)
{
        return BPF_CLASS(insn->code) == BPF_JMP  &&
               /* Call and Exit are both special jumps with no
                * target inside the BPF instruction image.
                */
               BPF_OP(insn->code) != BPF_CALL &&
               BPF_OP(insn->code) != BPF_EXIT;
}

static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta)
{
        struct bpf_insn *insn = prog->insnsi;
        u32 i, insn_cnt = prog->len;

        for (i = 0; i < insn_cnt; i++, insn++) {
                if (!bpf_is_jmp_and_has_target(insn))
                        continue;

                /* Adjust offset of jmps if we cross boundaries. */
                if (i < pos && i + insn->off + 1 > pos)
                        insn->off += delta;
                else if (i > pos + delta && i + insn->off + 1 <= pos + delta)
                        insn->off -= delta;
        }
}

struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
                                       const struct bpf_insn *patch, u32 len)
{
        u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
        struct bpf_prog *prog_adj;

        /* Since our patchlet doesn't expand the image, we're done. */
        if (insn_delta == 0) {
                memcpy(prog->insnsi + off, patch, sizeof(*patch));
                return prog;
        }

        insn_adj_cnt = prog->len + insn_delta;

        /* Several new instructions need to be inserted. Make room
         * for them. Likely, there's no need for a new allocation as
         * last page could have large enough tailroom.
         */
        prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
                                    GFP_USER);
        if (!prog_adj)
                return NULL;

        prog_adj->len = insn_adj_cnt;

        /* Patching happens in 3 steps:
         *
         * 1) Move over tail of insnsi from next instruction onwards,
         *    so we can patch the single target insn with one or more
         *    new ones (patching is always from 1 to n insns, n > 0).
         * 2) Inject new instructions at the target location.
         * 3) Adjust branch offsets if necessary.
         */
        insn_rest = insn_adj_cnt - off - len;

        memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
                sizeof(*patch) * insn_rest);
        memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);

        bpf_adj_branches(prog_adj, off, insn_delta);

        return prog_adj;
}

#ifdef CONFIG_BPF_JIT
static __always_inline void
bpf_get_prog_addr_region(const struct bpf_prog *prog,
                         unsigned long *symbol_start,
                         unsigned long *symbol_end)
{
        const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
        unsigned long addr = (unsigned long)hdr;

        WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));

        *symbol_start = addr;
        *symbol_end   = addr + hdr->pages * PAGE_SIZE;
}

static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
{
        BUILD_BUG_ON(sizeof("bpf_prog_") +
                     sizeof(prog->tag) * 2 + 1 > KSYM_NAME_LEN);

        sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
        sym  = bin2hex(sym, prog->tag, sizeof(prog->tag));
        *sym = 0;
}

static __always_inline unsigned long
bpf_get_prog_addr_start(struct latch_tree_node *n)
{
        unsigned long symbol_start, symbol_end;
        const struct bpf_prog_aux *aux;

        aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
        bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);

        return symbol_start;
}

static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
                                          struct latch_tree_node *b)
{
        return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b);
}

static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
{
        unsigned long val = (unsigned long)key;
        unsigned long symbol_start, symbol_end;
        const struct bpf_prog_aux *aux;

        aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
        bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);

        if (val < symbol_start)
                return -1;
        if (val >= symbol_end)
                return  1;

        return 0;
}

static const struct latch_tree_ops bpf_tree_ops = {
        .less   = bpf_tree_less,
        .comp   = bpf_tree_comp,
};

static DEFINE_SPINLOCK(bpf_lock);
static LIST_HEAD(bpf_kallsyms);
static struct latch_tree_root bpf_tree __cacheline_aligned;

int bpf_jit_kallsyms __read_mostly;

static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
{
        WARN_ON_ONCE(!list_empty(&aux->ksym_lnode));
        list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms);
        latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
}

static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)
{
        if (list_empty(&aux->ksym_lnode))
                return;

        latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
        list_del_rcu(&aux->ksym_lnode);
}

static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
{
        return fp->jited && !bpf_prog_was_classic(fp);
}

static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
{
        return list_empty(&fp->aux->ksym_lnode) ||
               fp->aux->ksym_lnode.prev == LIST_POISON2;
}

void bpf_prog_kallsyms_add(struct bpf_prog *fp)
{
        unsigned long flags;

        if (!bpf_prog_kallsyms_candidate(fp) ||
            !capable(CAP_SYS_ADMIN))
                return;

        spin_lock_irqsave(&bpf_lock, flags);
        bpf_prog_ksym_node_add(fp->aux);
        spin_unlock_irqrestore(&bpf_lock, flags);
}

void bpf_prog_kallsyms_del(struct bpf_prog *fp)
{
        unsigned long flags;

        if (!bpf_prog_kallsyms_candidate(fp))
                return;

        spin_lock_irqsave(&bpf_lock, flags);
        bpf_prog_ksym_node_del(fp->aux);
        spin_unlock_irqrestore(&bpf_lock, flags);
}

static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
{
        struct latch_tree_node *n;

        if (!bpf_jit_kallsyms_enabled())
                return NULL;

        n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
        return n ?
               container_of(n, struct bpf_prog_aux, ksym_tnode)->prog :
               NULL;
}

const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
                                 unsigned long *off, char *sym)
{
        unsigned long symbol_start, symbol_end;
        struct bpf_prog *prog;
        char *ret = NULL;

        rcu_read_lock();
        prog = bpf_prog_kallsyms_find(addr);
        if (prog) {
                bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end);
                bpf_get_prog_name(prog, sym);

                ret = sym;
                if (size)
                        *size = symbol_end - symbol_start;
                if (off)
                        *off  = addr - symbol_start;
        }
        rcu_read_unlock();

        return ret;
}

bool is_bpf_text_address(unsigned long addr)
{
        bool ret;

        rcu_read_lock();
        ret = bpf_prog_kallsyms_find(addr) != NULL;
        rcu_read_unlock();

        return ret;
}

int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
                    char *sym)
{
        unsigned long symbol_start, symbol_end;
        struct bpf_prog_aux *aux;
        unsigned int it = 0;
        int ret = -ERANGE;

        if (!bpf_jit_kallsyms_enabled())
                return ret;

        rcu_read_lock();
        list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) {
                if (it++ != symnum)
                        continue;

                bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
                bpf_get_prog_name(aux->prog, sym);

                *value = symbol_start;
                *type  = BPF_SYM_ELF_TYPE;

                ret = 0;
                break;
        }
        rcu_read_unlock();

        return ret;
}

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 = (get_random_int() % 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);
}

/* This symbol is only overridden by archs that have different
 * requirements than the usual eBPF JITs, f.e. when they only
 * implement cBPF JIT, do not set images read-only, etc.
 */
void __weak bpf_jit_free(struct bpf_prog *fp)
{
        if (fp->jited) {
                struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);

                bpf_jit_binary_unlock_ro(hdr);
                bpf_jit_binary_free(hdr);

                WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
        }

        bpf_prog_unlock_free(fp);
}

int bpf_jit_harden __read_mostly;

static int bpf_jit_blind_insn(const struct bpf_insn *from,
                              const struct bpf_insn *aux,
                              struct bpf_insn *to_buff)
{
        struct bpf_insn *to = to_buff;
        u32 imm_rnd = get_random_int();
        s16 off;

        BUILD_BUG_ON(BPF_REG_AX  + 1 != MAX_BPF_JIT_REG);
        BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);

        if (from->imm == 0 &&
            (from->code == (BPF_ALU   | BPF_MOV | BPF_K) ||
             from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
                *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
                goto out;
        }

        switch (from->code) {
        case BPF_ALU | BPF_ADD | BPF_K:
        case BPF_ALU | BPF_SUB | BPF_K:
        case BPF_ALU | BPF_AND | BPF_K:
        case BPF_ALU | BPF_OR  | BPF_K:
        case BPF_ALU | BPF_XOR | BPF_K:
        case BPF_ALU | BPF_MUL | BPF_K:
        case BPF_ALU | BPF_MOV | BPF_K:
        case BPF_ALU | BPF_DIV | BPF_K:
        case BPF_ALU | BPF_MOD | BPF_K:
                *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
                *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
                *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
                break;

        case BPF_ALU64 | BPF_ADD | BPF_K:
        case BPF_ALU64 | BPF_SUB | BPF_K:
        case BPF_ALU64 | BPF_AND | BPF_K:
        case BPF_ALU64 | BPF_OR  | BPF_K:
        case BPF_ALU64 | BPF_XOR | BPF_K:
        case BPF_ALU64 | BPF_MUL | BPF_K:
        case BPF_ALU64 | BPF_MOV | BPF_K:
        case BPF_ALU64 | BPF_DIV | BPF_K:
        case BPF_ALU64 | BPF_MOD | BPF_K:
                *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
                *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
                *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
                break;

        case BPF_JMP | BPF_JEQ  | BPF_K:
        case BPF_JMP | BPF_JNE  | BPF_K:
        case BPF_JMP | BPF_JGT  | BPF_K:
        case BPF_JMP | BPF_JGE  | BPF_K:
        case BPF_JMP | BPF_JSGT | BPF_K:
        case BPF_JMP | BPF_JSGE | BPF_K:
        case BPF_JMP | BPF_JSET | BPF_K:
                /* Accommodate for extra offset in case of a backjump. */
                off = from->off;
                if (off < 0)
                        off -= 2;
                *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
                *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
                *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
                break;

        case BPF_LD | BPF_ABS | BPF_W:
        case BPF_LD | BPF_ABS | BPF_H:
        case BPF_LD | BPF_ABS | BPF_B:
                *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
                *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
                *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
                break;

        case BPF_LD | BPF_IND | BPF_W:
        case BPF_LD | BPF_IND | BPF_H:
        case BPF_LD | BPF_IND | BPF_B:
                *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
                *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
                *to++ = BPF_ALU32_REG(BPF_ADD, BPF_REG_AX, from->src_reg);
                *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
                break;

        case BPF_LD | BPF_IMM | BPF_DW:
                *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
                *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
                *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
                *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
                break;
        case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
                *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
                *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
                *to++ = BPF_ALU64_REG(BPF_OR,  aux[0].dst_reg, BPF_REG_AX);
                break;

        case BPF_ST | BPF_MEM | BPF_DW:
        case BPF_ST | BPF_MEM | BPF_W:
        case BPF_ST | BPF_MEM | BPF_H:
        case BPF_ST | BPF_MEM | BPF_B:
                *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
                *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
                *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
                break;
        }
out:
        return to - to_buff;
}

static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
                                              gfp_t gfp_extra_flags)
{
        gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
                          gfp_extra_flags;
        struct bpf_prog *fp;

        fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);
        if (fp != NULL) {
                kmemcheck_annotate_bitfield(fp, meta);

                /* aux->prog still points to the fp_other one, so
                 * when promoting the clone to the real program,
                 * this still needs to be adapted.
                 */
                memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
        }

        return fp;
}

static void bpf_prog_clone_free(struct bpf_prog *fp)
{
        /* aux was stolen by the other clone, so we cannot free
         * it from this path! It will be freed eventually by the
         * other program on release.
         *
         * At this point, we don't need a deferred release since
         * clone is guaranteed to not be locked.
         */
        fp->aux = NULL;
        __bpf_prog_free(fp);
}

void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
{
        /* We have to repoint aux->prog to self, as we don't
         * know whether fp here is the clone or the original.
         */
        fp->aux->prog = fp;
        bpf_prog_clone_free(fp_other);
}

struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
{
        struct bpf_insn insn_buff[16], aux[2];
        struct bpf_prog *clone, *tmp;
        int insn_delta, insn_cnt;
        struct bpf_insn *insn;
        int i, rewritten;

        if (!bpf_jit_blinding_enabled())
                return prog;

        clone = bpf_prog_clone_create(prog, GFP_USER);
        if (!clone)
                return ERR_PTR(-ENOMEM);

        insn_cnt = clone->len;
        insn = clone->insnsi;

        for (i = 0; i < insn_cnt; i++, insn++) {
                /* We temporarily need to hold the original ld64 insn
                 * so that we can still access the first part in the
                 * second blinding run.
                 */
                if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
                    insn[1].code == 0)
                        memcpy(aux, insn, sizeof(aux));

                rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);
                if (!rewritten)
                        continue;

                tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
                if (!tmp) {
                        /* Patching may have repointed aux->prog during
                         * realloc from the original one, so we need to
                         * fix it up here on error.
                         */
                        bpf_jit_prog_release_other(prog, clone);
                        return ERR_PTR(-ENOMEM);
                }

                clone = tmp;
                insn_delta = rewritten - 1;

                /* Walk new program and skip insns we just inserted. */
                insn = clone->insnsi + i + insn_delta;
                insn_cnt += insn_delta;
                i        += insn_delta;
        }

        return clone;
}
#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;
}
EXPORT_SYMBOL_GPL(__bpf_call_base);

/**
 *      __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,
                [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_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,
        };
        u32 tail_call_cnt = 0;
        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;

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_TAIL_CALL: {
                struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
                struct bpf_array *array = container_of(map, struct bpf_array, map);
                struct bpf_prog *prog;
                u64 index = BPF_R3;

                if (unlikely(index >= array->map.max_entries))
                        goto out;
                if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
                        goto out;

                tail_call_cnt++;

                prog = READ_ONCE(array->ptrs[index]);
                if (!prog)
                        goto out;

                /* ARG1 at this point is guaranteed to point to CTX from
                 * the verifier side due to the fact that the tail call is
                 * handeled like a helper, that is, bpf_tail_call_proto,
                 * where arg1_type is ARG_PTR_TO_CTX.
                 */
                insn = prog->insnsi;
                goto select_insn;
out:
                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
                 * (see may_access_skb() in the verifier). 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;
}
STACK_FRAME_NON_STANDARD(__bpf_prog_run); /* jump table */

bool bpf_prog_array_compatible(struct bpf_array *array,
                               const struct bpf_prog *fp)
{
        if (!array->owner_prog_type) {
                /* There's no owner yet where we could check for
                 * compatibility.
                 */
                array->owner_prog_type = fp->type;
                array->owner_jited = fp->jited;

                return true;
        }

        return array->owner_prog_type == fp->type &&
               array->owner_jited == fp->jited;
}

static int bpf_check_tail_call(const struct bpf_prog *fp)
{
        struct bpf_prog_aux *aux = fp->aux;
        int i;

        for (i = 0; i < aux->used_map_cnt; i++) {
                struct bpf_map *map = aux->used_maps[i];
                struct bpf_array *array;

                if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
                        continue;

                array = container_of(map, struct bpf_array, map);
                if (!bpf_prog_array_compatible(array, fp))
                        return -EINVAL;
        }

        return 0;
}

/**
 *      bpf_prog_select_runtime - select exec runtime for BPF program
 *      @fp: bpf_prog populated with internal BPF program
 *      @err: pointer to error variable
 *
 * Try to JIT eBPF program, if JIT is not available, use interpreter.
 * The BPF program will be executed via BPF_PROG_RUN() macro.
 */
struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
{
        fp->bpf_func = (void *) __bpf_prog_run;

        /* eBPF JITs can rewrite the program in case constant
         * blinding is active. However, in case of error during
         * blinding, bpf_int_jit_compile() must always return a
         * valid program, which in this case would simply not
         * be JITed, but falls back to the interpreter.
         */
        fp = bpf_int_jit_compile(fp);
        bpf_prog_lock_ro(fp);

        /* The tail call compatibility check can only be done at
         * this late stage as we need to determine, if we deal
         * with JITed or non JITed program concatenations and not
         * all eBPF JITs might immediately support all features.
         */
        *err = bpf_check_tail_call(fp);

        return 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);
        schedule_work(&aux->work);
}
EXPORT_SYMBOL_GPL(bpf_prog_free);

/* RNG for unpriviledged user space with separated state from prandom_u32(). */
static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);

void bpf_user_rnd_init_once(void)
{
        prandom_init_once(&bpf_user_rnd_state);
}

BPF_CALL_0(bpf_user_rnd_u32)
{
        /* Should someone ever have the rather unwise idea to use some
         * of the registers passed into this function, then note that
         * this function is called from native eBPF and classic-to-eBPF
         * transformations. Register assignments from both sides are
         * different, f.e. classic always sets fn(ctx, A, X) here.
         */
        struct rnd_state *state;
        u32 res;

        state = &get_cpu_var(bpf_user_rnd_state);
        res = prandom_u32_state(state);
        put_cpu_var(bpf_user_rnd_state);

        return res;
}

/* 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;
const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;

const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
const struct bpf_func_proto bpf_get_current_comm_proto __weak;

const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
{
        return NULL;
}

u64 __weak
bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
                 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
{
        return -ENOTSUPP;
}

/* Always built-in helper functions. */
const struct bpf_func_proto bpf_tail_call_proto = {
        .func           = NULL,
        .gpl_only       = false,
        .ret_type       = RET_VOID,
        .arg1_type      = ARG_PTR_TO_CTX,
        .arg2_type      = ARG_CONST_MAP_PTR,
        .arg3_type      = ARG_ANYTHING,
};

/* Stub for JITs that only support cBPF. eBPF programs are interpreted.
 * It is encouraged to implement bpf_int_jit_compile() instead, so that
 * eBPF and implicitly also cBPF can get JITed!
 */
struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
{
        return prog;
}

/* Stub for JITs that support eBPF. All cBPF code gets transformed into
 * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
 */
void __weak bpf_jit_compile(struct bpf_prog *prog)
{
}

bool __weak bpf_helper_changes_pkt_data(void *func)
{
        return false;
}

/* 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;
}

/* All definitions of tracepoints related to BPF. */
#define CREATE_TRACE_POINTS
#include <linux/bpf_trace.h>

EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);

EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_get_type);
EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_put_rcu);