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32 results

core.c

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  • core.c 60.30 KiB
    // SPDX-License-Identifier: GPL-2.0-or-later
    /*
     * 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>
     *
     * Andi Kleen - Fix a few bad bugs and races.
     * Kris Katterjohn - Added many additional checks in bpf_check_classic()
     */
    
    #include <uapi/linux/btf.h>
    #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/btf.h>
    #include <linux/objtool.h>
    #include <linux/rbtree_latch.h>
    #include <linux/kallsyms.h>
    #include <linux/rcupdate.h>
    #include <linux/perf_event.h>
    #include <linux/extable.h>
    #include <linux/log2.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 AX	regs[BPF_REG_AX]
    #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_no_stats(unsigned int size, gfp_t gfp_extra_flags)
    {
    	gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __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);
    	if (fp == NULL)
    		return NULL;
    
    	aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT | gfp_extra_flags);
    	if (aux == NULL) {
    		vfree(fp);
    		return NULL;
    	}
    
    	fp->pages = size / PAGE_SIZE;
    	fp->aux = aux;
    	fp->aux->prog = fp;
    	fp->jit_requested = ebpf_jit_enabled();
    
    	INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode);
    	mutex_init(&fp->aux->used_maps_mutex);
    	mutex_init(&fp->aux->dst_mutex);
    
    	return fp;
    }
    
    struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
    {
    	gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags;
    	struct bpf_prog *prog;
    	int cpu;
    
    	prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);
    	if (!prog)
    		return NULL;
    
    	prog->aux->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags);
    	if (!prog->aux->stats) {
    		kfree(prog->aux);
    		vfree(prog);
    		return NULL;
    	}
    
    	for_each_possible_cpu(cpu) {
    		struct bpf_prog_stats *pstats;
    
    		pstats = per_cpu_ptr(prog->aux->stats, cpu);
    		u64_stats_init(&pstats->syncp);
    	}
    	return prog;
    }
    EXPORT_SYMBOL_GPL(bpf_prog_alloc);
    
    int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog)
    {
    	if (!prog->aux->nr_linfo || !prog->jit_requested)
    		return 0;
    
    	prog->aux->jited_linfo = kcalloc(prog->aux->nr_linfo,
    					 sizeof(*prog->aux->jited_linfo),
    					 GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
    	if (!prog->aux->jited_linfo)
    		return -ENOMEM;
    
    	return 0;
    }
    
    void bpf_prog_free_jited_linfo(struct bpf_prog *prog)
    {
    	kfree(prog->aux->jited_linfo);
    	prog->aux->jited_linfo = NULL;
    }
    
    void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog)
    {
    	if (prog->aux->jited_linfo && !prog->aux->jited_linfo[0])
    		bpf_prog_free_jited_linfo(prog);
    }
    
    /* The jit engine is responsible to provide an array
     * for insn_off to the jited_off mapping (insn_to_jit_off).
     *
     * The idx to this array is the insn_off.  Hence, the insn_off
     * here is relative to the prog itself instead of the main prog.
     * This array has one entry for each xlated bpf insn.
     *
     * jited_off is the byte off to the last byte of the jited insn.
     *
     * Hence, with
     * insn_start:
     *      The first bpf insn off of the prog.  The insn off
     *      here is relative to the main prog.
     *      e.g. if prog is a subprog, insn_start > 0
     * linfo_idx:
     *      The prog's idx to prog->aux->linfo and jited_linfo
     *
     * jited_linfo[linfo_idx] = prog->bpf_func
     *
     * For i > linfo_idx,
     *
     * jited_linfo[i] = prog->bpf_func +
     *	insn_to_jit_off[linfo[i].insn_off - insn_start - 1]
     */
    void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
    			       const u32 *insn_to_jit_off)
    {
    	u32 linfo_idx, insn_start, insn_end, nr_linfo, i;
    	const struct bpf_line_info *linfo;
    	void **jited_linfo;
    
    	if (!prog->aux->jited_linfo)
    		/* Userspace did not provide linfo */
    		return;
    
    	linfo_idx = prog->aux->linfo_idx;
    	linfo = &prog->aux->linfo[linfo_idx];
    	insn_start = linfo[0].insn_off;
    	insn_end = insn_start + prog->len;
    
    	jited_linfo = &prog->aux->jited_linfo[linfo_idx];
    	jited_linfo[0] = prog->bpf_func;
    
    	nr_linfo = prog->aux->nr_linfo - linfo_idx;
    
    	for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++)
    		/* The verifier ensures that linfo[i].insn_off is
    		 * strictly increasing
    		 */
    		jited_linfo[i] = prog->bpf_func +
    			insn_to_jit_off[linfo[i].insn_off - insn_start - 1];
    }
    
    void bpf_prog_free_linfo(struct bpf_prog *prog)
    {
    	bpf_prog_free_jited_linfo(prog);
    	kvfree(prog->aux->linfo);
    }
    
    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_ACCOUNT | __GFP_ZERO | gfp_extra_flags;
    	struct bpf_prog *fp;
    	u32 pages;
    
    	size = round_up(size, PAGE_SIZE);
    	pages = size / PAGE_SIZE;
    	if (pages <= fp_old->pages)
    		return fp_old;
    
    	fp = __vmalloc(size, gfp_flags);
    	if (fp) {
    		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)
    {
    	if (fp->aux) {
    		mutex_destroy(&fp->aux->used_maps_mutex);
    		mutex_destroy(&fp->aux->dst_mutex);
    		free_percpu(fp->aux->stats);
    		kfree(fp->aux->poke_tab);
    		kfree(fp->aux);
    	}
    	vfree(fp);
    }
    
    int bpf_prog_calc_tag(struct bpf_prog *fp)
    {
    	const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
    	u32 raw_size = bpf_prog_tag_scratch_size(fp);
    	u32 digest[SHA1_DIGEST_WORDS];
    	u32 ws[SHA1_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;
    
    	sha1_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 ||
    		     dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) {
    			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, SHA1_BLOCK_SIZE);
    	blocks = bsize / SHA1_BLOCK_SIZE;
    	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--) {
    		sha1_transform(digest, todo, ws);
    		todo += SHA1_BLOCK_SIZE;
    	}
    
    	result = (__force __be32 *)digest;
    	for (i = 0; i < SHA1_DIGEST_WORDS; i++)
    		result[i] = cpu_to_be32(digest[i]);
    	memcpy(fp->tag, result, sizeof(fp->tag));
    
    	vfree(raw);
    	return 0;
    }
    
    static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old,
    				s32 end_new, s32 curr, const bool probe_pass)
    {
    	const s64 imm_min = S32_MIN, imm_max = S32_MAX;
    	s32 delta = end_new - end_old;
    	s64 imm = insn->imm;
    
    	if (curr < pos && curr + imm + 1 >= end_old)
    		imm += delta;
    	else if (curr >= end_new && curr + imm + 1 < end_new)
    		imm -= delta;
    	if (imm < imm_min || imm > imm_max)
    		return -ERANGE;
    	if (!probe_pass)
    		insn->imm = imm;
    	return 0;
    }
    
    static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old,
    				s32 end_new, s32 curr, const bool probe_pass)
    {
    	const s32 off_min = S16_MIN, off_max = S16_MAX;
    	s32 delta = end_new - end_old;
    	s32 off = insn->off;
    
    	if (curr < pos && curr + off + 1 >= end_old)
    		off += delta;
    	else if (curr >= end_new && curr + off + 1 < end_new)
    		off -= delta;
    	if (off < off_min || off > off_max)
    		return -ERANGE;
    	if (!probe_pass)
    		insn->off = off;
    	return 0;
    }
    
    static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old,
    			    s32 end_new, const bool probe_pass)
    {
    	u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0);
    	struct bpf_insn *insn = prog->insnsi;
    	int ret = 0;
    
    	for (i = 0; i < insn_cnt; i++, insn++) {
    		u8 code;
    
    		/* In the probing pass we still operate on the original,
    		 * unpatched image in order to check overflows before we
    		 * do any other adjustments. Therefore skip the patchlet.
    		 */
    		if (probe_pass && i == pos) {
    			i = end_new;
    			insn = prog->insnsi + end_old;
    		}
    		code = insn->code;
    		if ((BPF_CLASS(code) != BPF_JMP &&
    		     BPF_CLASS(code) != BPF_JMP32) ||
    		    BPF_OP(code) == BPF_EXIT)
    			continue;
    		/* Adjust offset of jmps if we cross patch boundaries. */
    		if (BPF_OP(code) == BPF_CALL) {
    			if (insn->src_reg != BPF_PSEUDO_CALL)
    				continue;
    			ret = bpf_adj_delta_to_imm(insn, pos, end_old,
    						   end_new, i, probe_pass);
    		} else {
    			ret = bpf_adj_delta_to_off(insn, pos, end_old,
    						   end_new, i, probe_pass);
    		}
    		if (ret)
    			break;
    	}
    
    	return ret;
    }
    
    static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta)
    {
    	struct bpf_line_info *linfo;
    	u32 i, nr_linfo;
    
    	nr_linfo = prog->aux->nr_linfo;
    	if (!nr_linfo || !delta)
    		return;
    
    	linfo = prog->aux->linfo;
    
    	for (i = 0; i < nr_linfo; i++)
    		if (off < linfo[i].insn_off)
    			break;
    
    	/* Push all off < linfo[i].insn_off by delta */
    	for (; i < nr_linfo; i++)
    		linfo[i].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;
    	const u32 cnt_max = S16_MAX;
    	struct bpf_prog *prog_adj;
    	int err;
    
    	/* 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;
    
    	/* Reject anything that would potentially let the insn->off
    	 * target overflow when we have excessive program expansions.
    	 * We need to probe here before we do any reallocation where
    	 * we afterwards may not fail anymore.
    	 */
    	if (insn_adj_cnt > cnt_max &&
    	    (err = bpf_adj_branches(prog, off, off + 1, off + len, true)))
    		return ERR_PTR(err);
    
    	/* 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 ERR_PTR(-ENOMEM);
    
    	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);
    
    	/* We are guaranteed to not fail at this point, otherwise
    	 * the ship has sailed to reverse to the original state. An
    	 * overflow cannot happen at this point.
    	 */
    	BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false));
    
    	bpf_adj_linfo(prog_adj, off, insn_delta);
    
    	return prog_adj;
    }
    
    int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt)
    {
    	/* Branch offsets can't overflow when program is shrinking, no need
    	 * to call bpf_adj_branches(..., true) here
    	 */
    	memmove(prog->insnsi + off, prog->insnsi + off + cnt,
    		sizeof(struct bpf_insn) * (prog->len - off - cnt));
    	prog->len -= cnt;
    
    	return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false));
    }
    
    static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)
    {
    	int i;
    
    	for (i = 0; i < fp->aux->func_cnt; i++)
    		bpf_prog_kallsyms_del(fp->aux->func[i]);
    }
    
    void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
    {
    	bpf_prog_kallsyms_del_subprogs(fp);
    	bpf_prog_kallsyms_del(fp);
    }
    
    #ifdef CONFIG_BPF_JIT
    /* All BPF JIT sysctl knobs here. */
    int bpf_jit_enable   __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
    int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
    int bpf_jit_harden   __read_mostly;
    long bpf_jit_limit   __read_mostly;
    
    static void
    bpf_prog_ksym_set_addr(struct bpf_prog *prog)
    {
    	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));
    
    	prog->aux->ksym.start = (unsigned long) prog->bpf_func;
    	prog->aux->ksym.end   = addr + hdr->pages * PAGE_SIZE;
    }
    
    static void
    bpf_prog_ksym_set_name(struct bpf_prog *prog)
    {
    	char *sym = prog->aux->ksym.name;
    	const char *end = sym + KSYM_NAME_LEN;
    	const struct btf_type *type;
    	const char *func_name;
    
    	BUILD_BUG_ON(sizeof("bpf_prog_") +
    		     sizeof(prog->tag) * 2 +
    		     /* name has been null terminated.
    		      * We should need +1 for the '_' preceding
    		      * the name.  However, the null character
    		      * is double counted between the name and the
    		      * sizeof("bpf_prog_") above, so we omit
    		      * the +1 here.
    		      */
    		     sizeof(prog->aux->name) > KSYM_NAME_LEN);
    
    	sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
    	sym  = bin2hex(sym, prog->tag, sizeof(prog->tag));
    
    	/* prog->aux->name will be ignored if full btf name is available */
    	if (prog->aux->func_info_cnt) {
    		type = btf_type_by_id(prog->aux->btf,
    				      prog->aux->func_info[prog->aux->func_idx].type_id);
    		func_name = btf_name_by_offset(prog->aux->btf, type->name_off);
    		snprintf(sym, (size_t)(end - sym), "_%s", func_name);
    		return;
    	}
    
    	if (prog->aux->name[0])
    		snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
    	else
    		*sym = 0;
    }
    
    static unsigned long bpf_get_ksym_start(struct latch_tree_node *n)
    {
    	return container_of(n, struct bpf_ksym, tnode)->start;
    }
    
    static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
    					  struct latch_tree_node *b)
    {
    	return bpf_get_ksym_start(a) < bpf_get_ksym_start(b);
    }
    
    static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
    {
    	unsigned long val = (unsigned long)key;
    	const struct bpf_ksym *ksym;
    
    	ksym = container_of(n, struct bpf_ksym, tnode);
    
    	if (val < ksym->start)
    		return -1;
    	if (val >= ksym->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;
    
    void bpf_ksym_add(struct bpf_ksym *ksym)
    {
    	spin_lock_bh(&bpf_lock);
    	WARN_ON_ONCE(!list_empty(&ksym->lnode));
    	list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms);
    	latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
    	spin_unlock_bh(&bpf_lock);
    }
    
    static void __bpf_ksym_del(struct bpf_ksym *ksym)
    {
    	if (list_empty(&ksym->lnode))
    		return;
    
    	latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
    	list_del_rcu(&ksym->lnode);
    }
    
    void bpf_ksym_del(struct bpf_ksym *ksym)
    {
    	spin_lock_bh(&bpf_lock);
    	__bpf_ksym_del(ksym);
    	spin_unlock_bh(&bpf_lock);
    }
    
    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)
    {
    	if (!bpf_prog_kallsyms_candidate(fp) ||
    	    !bpf_capable())
    		return;
    
    	bpf_prog_ksym_set_addr(fp);
    	bpf_prog_ksym_set_name(fp);
    	fp->aux->ksym.prog = true;
    
    	bpf_ksym_add(&fp->aux->ksym);
    }
    
    void bpf_prog_kallsyms_del(struct bpf_prog *fp)
    {
    	if (!bpf_prog_kallsyms_candidate(fp))
    		return;
    
    	bpf_ksym_del(&fp->aux->ksym);
    }
    
    static struct bpf_ksym *bpf_ksym_find(unsigned long addr)
    {
    	struct latch_tree_node *n;
    
    	n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
    	return n ? container_of(n, struct bpf_ksym, tnode) : NULL;
    }
    
    const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
    				 unsigned long *off, char *sym)
    {
    	struct bpf_ksym *ksym;
    	char *ret = NULL;
    
    	rcu_read_lock();
    	ksym = bpf_ksym_find(addr);
    	if (ksym) {
    		unsigned long symbol_start = ksym->start;
    		unsigned long symbol_end = ksym->end;
    
    		strncpy(sym, ksym->name, KSYM_NAME_LEN);
    
    		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_ksym_find(addr) != NULL;
    	rcu_read_unlock();
    
    	return ret;
    }
    
    static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr)
    {
    	struct bpf_ksym *ksym = bpf_ksym_find(addr);
    
    	return ksym && ksym->prog ?
    	       container_of(ksym, struct bpf_prog_aux, ksym)->prog :
    	       NULL;
    }
    
    const struct exception_table_entry *search_bpf_extables(unsigned long addr)
    {
    	const struct exception_table_entry *e = NULL;
    	struct bpf_prog *prog;
    
    	rcu_read_lock();
    	prog = bpf_prog_ksym_find(addr);
    	if (!prog)
    		goto out;
    	if (!prog->aux->num_exentries)
    		goto out;
    
    	e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr);
    out:
    	rcu_read_unlock();
    	return e;
    }
    
    int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
    		    char *sym)
    {
    	struct bpf_ksym *ksym;
    	unsigned int it = 0;
    	int ret = -ERANGE;
    
    	if (!bpf_jit_kallsyms_enabled())
    		return ret;
    
    	rcu_read_lock();
    	list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) {
    		if (it++ != symnum)
    			continue;
    
    		strncpy(sym, ksym->name, KSYM_NAME_LEN);
    
    		*value = ksym->start;
    		*type  = BPF_SYM_ELF_TYPE;
    
    		ret = 0;
    		break;
    	}
    	rcu_read_unlock();
    
    	return ret;
    }
    
    int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
    				struct bpf_jit_poke_descriptor *poke)
    {
    	struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
    	static const u32 poke_tab_max = 1024;
    	u32 slot = prog->aux->size_poke_tab;
    	u32 size = slot + 1;
    
    	if (size > poke_tab_max)
    		return -ENOSPC;
    	if (poke->tailcall_target || poke->tailcall_target_stable ||
    	    poke->tailcall_bypass || poke->adj_off || poke->bypass_addr)
    		return -EINVAL;
    
    	switch (poke->reason) {
    	case BPF_POKE_REASON_TAIL_CALL:
    		if (!poke->tail_call.map)
    			return -EINVAL;
    		break;
    	default:
    		return -EINVAL;
    	}
    
    	tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL);
    	if (!tab)
    		return -ENOMEM;
    
    	memcpy(&tab[slot], poke, sizeof(*poke));
    	prog->aux->size_poke_tab = size;
    	prog->aux->poke_tab = tab;
    
    	return slot;
    }
    
    static atomic_long_t bpf_jit_current;
    
    /* Can be overridden by an arch's JIT compiler if it has a custom,
     * dedicated BPF backend memory area, or if neither of the two
     * below apply.
     */
    u64 __weak bpf_jit_alloc_exec_limit(void)
    {
    #if defined(MODULES_VADDR)
    	return MODULES_END - MODULES_VADDR;
    #else
    	return VMALLOC_END - VMALLOC_START;
    #endif
    }
    
    static int __init bpf_jit_charge_init(void)
    {
    	/* Only used as heuristic here to derive limit. */
    	bpf_jit_limit = min_t(u64, round_up(bpf_jit_alloc_exec_limit() >> 2,
    					    PAGE_SIZE), LONG_MAX);
    	return 0;
    }
    pure_initcall(bpf_jit_charge_init);
    
    static int bpf_jit_charge_modmem(u32 pages)
    {
    	if (atomic_long_add_return(pages, &bpf_jit_current) >
    	    (bpf_jit_limit >> PAGE_SHIFT)) {
    		if (!capable(CAP_SYS_ADMIN)) {
    			atomic_long_sub(pages, &bpf_jit_current);
    			return -EPERM;
    		}
    	}
    
    	return 0;
    }
    
    static void bpf_jit_uncharge_modmem(u32 pages)
    {
    	atomic_long_sub(pages, &bpf_jit_current);
    }
    
    void *__weak bpf_jit_alloc_exec(unsigned long size)
    {
    	return module_alloc(size);
    }
    
    void __weak bpf_jit_free_exec(void *addr)
    {
    	module_memfree(addr);
    }
    
    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;
    	u32 size, hole, start, pages;
    
    	WARN_ON_ONCE(!is_power_of_2(alignment) ||
    		     alignment > BPF_IMAGE_ALIGNMENT);
    
    	/* 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);
    	pages = size / PAGE_SIZE;
    
    	if (bpf_jit_charge_modmem(pages))
    		return NULL;
    	hdr = bpf_jit_alloc_exec(size);
    	if (!hdr) {
    		bpf_jit_uncharge_modmem(pages);
    		return NULL;
    	}
    
    	/* Fill space with illegal/arch-dep instructions. */
    	bpf_fill_ill_insns(hdr, size);
    
    	hdr->pages = pages;
    	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)
    {
    	u32 pages = hdr->pages;
    
    	bpf_jit_free_exec(hdr);
    	bpf_jit_uncharge_modmem(pages);
    }
    
    /* 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_free(hdr);
    
    		WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
    	}
    
    	bpf_prog_unlock_free(fp);
    }
    
    int bpf_jit_get_func_addr(const struct bpf_prog *prog,
    			  const struct bpf_insn *insn, bool extra_pass,
    			  u64 *func_addr, bool *func_addr_fixed)
    {
    	s16 off = insn->off;
    	s32 imm = insn->imm;
    	u8 *addr;
    
    	*func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL;
    	if (!*func_addr_fixed) {
    		/* Place-holder address till the last pass has collected
    		 * all addresses for JITed subprograms in which case we
    		 * can pick them up from prog->aux.
    		 */
    		if (!extra_pass)
    			addr = NULL;
    		else if (prog->aux->func &&
    			 off >= 0 && off < prog->aux->func_cnt)
    			addr = (u8 *)prog->aux->func[off]->bpf_func;
    		else
    			return -EINVAL;
    	} else {
    		/* Address of a BPF helper call. Since part of the core
    		 * kernel, it's always at a fixed location. __bpf_call_base
    		 * and the helper with imm relative to it are both in core
    		 * kernel.
    		 */
    		addr = (u8 *)__bpf_call_base + imm;
    	}
    
    	*func_addr = (unsigned long)addr;
    	return 0;
    }
    
    static int bpf_jit_blind_insn(const struct bpf_insn *from,
    			      const struct bpf_insn *aux,
    			      struct bpf_insn *to_buff,
    			      bool emit_zext)
    {
    	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);
    
    	/* Constraints on AX register:
    	 *
    	 * AX register is inaccessible from user space. It is mapped in
    	 * all JITs, and used here for constant blinding rewrites. It is
    	 * typically "stateless" meaning its contents are only valid within
    	 * the executed instruction, but not across several instructions.
    	 * There are a few exceptions however which are further detailed
    	 * below.
    	 *
    	 * Constant blinding is only used by JITs, not in the interpreter.
    	 * The interpreter uses AX in some occasions as a local temporary
    	 * register e.g. in DIV or MOD instructions.
    	 *
    	 * In restricted circumstances, the verifier can also use the AX
    	 * register for rewrites as long as they do not interfere with
    	 * the above cases!
    	 */
    	if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX)
    		goto out;
    
    	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_JLT  | BPF_K:
    	case BPF_JMP | BPF_JGE  | BPF_K:
    	case BPF_JMP | BPF_JLE  | BPF_K:
    	case BPF_JMP | BPF_JSGT | BPF_K:
    	case BPF_JMP | BPF_JSLT | BPF_K:
    	case BPF_JMP | BPF_JSGE | BPF_K:
    	case BPF_JMP | BPF_JSLE | 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_JMP32 | BPF_JEQ  | BPF_K:
    	case BPF_JMP32 | BPF_JNE  | BPF_K:
    	case BPF_JMP32 | BPF_JGT  | BPF_K:
    	case BPF_JMP32 | BPF_JLT  | BPF_K:
    	case BPF_JMP32 | BPF_JGE  | BPF_K:
    	case BPF_JMP32 | BPF_JLE  | BPF_K:
    	case BPF_JMP32 | BPF_JSGT | BPF_K:
    	case BPF_JMP32 | BPF_JSLT | BPF_K:
    	case BPF_JMP32 | BPF_JSGE | BPF_K:
    	case BPF_JMP32 | BPF_JSLE | BPF_K:
    	case BPF_JMP32 | BPF_JSET | BPF_K:
    		/* Accommodate for extra offset in case of a backjump. */
    		off = from->off;
    		if (off < 0)
    			off -= 2;
    		*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_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX,
    				      off);
    		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);
    		if (emit_zext)
    			*to++ = BPF_ZEXT_REG(BPF_REG_AX);
    		*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_ZERO | gfp_extra_flags;
    	struct bpf_prog *fp;
    
    	fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags);
    	if (fp != NULL) {
    		/* 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(prog) || prog->blinded)
    		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,
    						clone->aux->verifier_zext);
    		if (!rewritten)
    			continue;
    
    		tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
    		if (IS_ERR(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 tmp;
    		}
    
    		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;
    	}
    
    	clone->blinded = 1;
    	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. This also needs
     * to go into kallsyms for correlation from e.g. bpftool, so naming
     * must not change.
     */
    noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
    {
    	return 0;
    }
    EXPORT_SYMBOL_GPL(__bpf_call_base);
    
    /* All UAPI available opcodes. */
    #define BPF_INSN_MAP(INSN_2, INSN_3)		\
    	/* 32 bit ALU operations. */		\
    	/*   Register based. */			\
    	INSN_3(ALU, ADD,  X),			\
    	INSN_3(ALU, SUB,  X),			\
    	INSN_3(ALU, AND,  X),			\
    	INSN_3(ALU, OR,   X),			\
    	INSN_3(ALU, LSH,  X),			\
    	INSN_3(ALU, RSH,  X),			\
    	INSN_3(ALU, XOR,  X),			\
    	INSN_3(ALU, MUL,  X),			\
    	INSN_3(ALU, MOV,  X),			\
    	INSN_3(ALU, ARSH, X),			\
    	INSN_3(ALU, DIV,  X),			\
    	INSN_3(ALU, MOD,  X),			\
    	INSN_2(ALU, NEG),			\
    	INSN_3(ALU, END, TO_BE),		\
    	INSN_3(ALU, END, TO_LE),		\
    	/*   Immediate based. */		\
    	INSN_3(ALU, ADD,  K),			\
    	INSN_3(ALU, SUB,  K),			\
    	INSN_3(ALU, AND,  K),			\
    	INSN_3(ALU, OR,   K),			\
    	INSN_3(ALU, LSH,  K),			\
    	INSN_3(ALU, RSH,  K),			\
    	INSN_3(ALU, XOR,  K),			\
    	INSN_3(ALU, MUL,  K),			\
    	INSN_3(ALU, MOV,  K),			\
    	INSN_3(ALU, ARSH, K),			\
    	INSN_3(ALU, DIV,  K),			\
    	INSN_3(ALU, MOD,  K),			\
    	/* 64 bit ALU operations. */		\
    	/*   Register based. */			\
    	INSN_3(ALU64, ADD,  X),			\
    	INSN_3(ALU64, SUB,  X),			\
    	INSN_3(ALU64, AND,  X),			\
    	INSN_3(ALU64, OR,   X),			\
    	INSN_3(ALU64, LSH,  X),			\
    	INSN_3(ALU64, RSH,  X),			\
    	INSN_3(ALU64, XOR,  X),			\
    	INSN_3(ALU64, MUL,  X),			\
    	INSN_3(ALU64, MOV,  X),			\
    	INSN_3(ALU64, ARSH, X),			\
    	INSN_3(ALU64, DIV,  X),			\
    	INSN_3(ALU64, MOD,  X),			\
    	INSN_2(ALU64, NEG),			\
    	/*   Immediate based. */		\
    	INSN_3(ALU64, ADD,  K),			\
    	INSN_3(ALU64, SUB,  K),			\
    	INSN_3(ALU64, AND,  K),			\
    	INSN_3(ALU64, OR,   K),			\
    	INSN_3(ALU64, LSH,  K),			\
    	INSN_3(ALU64, RSH,  K),			\
    	INSN_3(ALU64, XOR,  K),			\
    	INSN_3(ALU64, MUL,  K),			\
    	INSN_3(ALU64, MOV,  K),			\
    	INSN_3(ALU64, ARSH, K),			\
    	INSN_3(ALU64, DIV,  K),			\
    	INSN_3(ALU64, MOD,  K),			\
    	/* Call instruction. */			\
    	INSN_2(JMP, CALL),			\
    	/* Exit instruction. */			\
    	INSN_2(JMP, EXIT),			\
    	/* 32-bit Jump instructions. */		\
    	/*   Register based. */			\
    	INSN_3(JMP32, JEQ,  X),			\
    	INSN_3(JMP32, JNE,  X),			\
    	INSN_3(JMP32, JGT,  X),			\
    	INSN_3(JMP32, JLT,  X),			\
    	INSN_3(JMP32, JGE,  X),			\
    	INSN_3(JMP32, JLE,  X),			\
    	INSN_3(JMP32, JSGT, X),			\
    	INSN_3(JMP32, JSLT, X),			\
    	INSN_3(JMP32, JSGE, X),			\
    	INSN_3(JMP32, JSLE, X),			\
    	INSN_3(JMP32, JSET, X),			\
    	/*   Immediate based. */		\
    	INSN_3(JMP32, JEQ,  K),			\
    	INSN_3(JMP32, JNE,  K),			\
    	INSN_3(JMP32, JGT,  K),			\
    	INSN_3(JMP32, JLT,  K),			\
    	INSN_3(JMP32, JGE,  K),			\
    	INSN_3(JMP32, JLE,  K),			\
    	INSN_3(JMP32, JSGT, K),			\
    	INSN_3(JMP32, JSLT, K),			\
    	INSN_3(JMP32, JSGE, K),			\
    	INSN_3(JMP32, JSLE, K),			\
    	INSN_3(JMP32, JSET, K),			\
    	/* Jump instructions. */		\
    	/*   Register based. */			\
    	INSN_3(JMP, JEQ,  X),			\
    	INSN_3(JMP, JNE,  X),			\
    	INSN_3(JMP, JGT,  X),			\
    	INSN_3(JMP, JLT,  X),			\
    	INSN_3(JMP, JGE,  X),			\
    	INSN_3(JMP, JLE,  X),			\
    	INSN_3(JMP, JSGT, X),			\
    	INSN_3(JMP, JSLT, X),			\
    	INSN_3(JMP, JSGE, X),			\
    	INSN_3(JMP, JSLE, X),			\
    	INSN_3(JMP, JSET, X),			\
    	/*   Immediate based. */		\
    	INSN_3(JMP, JEQ,  K),			\
    	INSN_3(JMP, JNE,  K),			\
    	INSN_3(JMP, JGT,  K),			\
    	INSN_3(JMP, JLT,  K),			\
    	INSN_3(JMP, JGE,  K),			\
    	INSN_3(JMP, JLE,  K),			\
    	INSN_3(JMP, JSGT, K),			\
    	INSN_3(JMP, JSLT, K),			\
    	INSN_3(JMP, JSGE, K),			\
    	INSN_3(JMP, JSLE, K),			\
    	INSN_3(JMP, JSET, K),			\
    	INSN_2(JMP, JA),			\
    	/* Store instructions. */		\
    	/*   Register based. */			\
    	INSN_3(STX, MEM,  B),			\
    	INSN_3(STX, MEM,  H),			\
    	INSN_3(STX, MEM,  W),			\
    	INSN_3(STX, MEM,  DW),			\
    	INSN_3(STX, ATOMIC, W),			\
    	INSN_3(STX, ATOMIC, DW),		\
    	/*   Immediate based. */		\
    	INSN_3(ST, MEM, B),			\
    	INSN_3(ST, MEM, H),			\
    	INSN_3(ST, MEM, W),			\
    	INSN_3(ST, MEM, DW),			\
    	/* Load instructions. */		\
    	/*   Register based. */			\
    	INSN_3(LDX, MEM, B),			\
    	INSN_3(LDX, MEM, H),			\
    	INSN_3(LDX, MEM, W),			\
    	INSN_3(LDX, MEM, DW),			\
    	/*   Immediate based. */		\
    	INSN_3(LD, IMM, DW)
    
    bool bpf_opcode_in_insntable(u8 code)
    {
    #define BPF_INSN_2_TBL(x, y)    [BPF_##x | BPF_##y] = true
    #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
    	static const bool public_insntable[256] = {
    		[0 ... 255] = false,
    		/* Now overwrite non-defaults ... */
    		BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
    		/* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
    		[BPF_LD | BPF_ABS | BPF_B] = true,
    		[BPF_LD | BPF_ABS | BPF_H] = true,
    		[BPF_LD | BPF_ABS | BPF_W] = true,
    		[BPF_LD | BPF_IND | BPF_B] = true,
    		[BPF_LD | BPF_IND | BPF_H] = true,
    		[BPF_LD | BPF_IND | BPF_W] = true,
    	};
    #undef BPF_INSN_3_TBL
    #undef BPF_INSN_2_TBL
    	return public_insntable[code];
    }
    
    #ifndef CONFIG_BPF_JIT_ALWAYS_ON
    u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
    {
    	memset(dst, 0, size);
    	return -EFAULT;
    }
    
    /**
     *	__bpf_prog_run - run eBPF program on a given context
     *	@regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
     *	@insn: is the array of eBPF instructions
     *	@stack: is the eBPF storage stack
     *
     * Decode and execute eBPF instructions.
     */
    static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
    {
    #define BPF_INSN_2_LBL(x, y)    [BPF_##x | BPF_##y] = &&x##_##y
    #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
    	static const void * const jumptable[256] __annotate_jump_table = {
    		[0 ... 255] = &&default_label,
    		/* Now overwrite non-defaults ... */
    		BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
    		/* Non-UAPI available opcodes. */
    		[BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
    		[BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
    		[BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B,
    		[BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H,
    		[BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W,
    		[BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW,
    	};
    #undef BPF_INSN_3_LBL
    #undef BPF_INSN_2_LBL
    	u32 tail_call_cnt = 0;
    
    #define CONT	 ({ insn++; goto select_insn; })
    #define CONT_JMP ({ insn++; goto select_insn; })
    
    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;
    	ALU_ARSH_X:
    		DST = (u64) (u32) (((s32) DST) >> SRC);
    		CONT;
    	ALU_ARSH_K:
    		DST = (u64) (u32) (((s32) DST) >> IMM);
    		CONT;
    	ALU64_ARSH_X:
    		(*(s64 *) &DST) >>= SRC;
    		CONT;
    	ALU64_ARSH_K:
    		(*(s64 *) &DST) >>= IMM;
    		CONT;
    	ALU64_MOD_X:
    		div64_u64_rem(DST, SRC, &AX);
    		DST = AX;
    		CONT;
    	ALU_MOD_X:
    		AX = (u32) DST;
    		DST = do_div(AX, (u32) SRC);
    		CONT;
    	ALU64_MOD_K:
    		div64_u64_rem(DST, IMM, &AX);
    		DST = AX;
    		CONT;
    	ALU_MOD_K:
    		AX = (u32) DST;
    		DST = do_div(AX, (u32) IMM);
    		CONT;
    	ALU64_DIV_X:
    		DST = div64_u64(DST, SRC);
    		CONT;
    	ALU_DIV_X:
    		AX = (u32) DST;
    		do_div(AX, (u32) SRC);
    		DST = (u32) AX;
    		CONT;
    	ALU64_DIV_K:
    		DST = div64_u64(DST, IMM);
    		CONT;
    	ALU_DIV_K:
    		AX = (u32) DST;
    		do_div(AX, (u32) IMM);
    		DST = (u32) AX;
    		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_CALL_ARGS:
    		BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
    							    BPF_R3, BPF_R4,
    							    BPF_R5,
    							    insn + insn->off + 1);
    		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;
    		u32 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
    		 * handled 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_JA:
    		insn += insn->off;
    		CONT;
    	JMP_EXIT:
    		return BPF_R0;
    	/* JMP */
    #define COND_JMP(SIGN, OPCODE, CMP_OP)				\
    	JMP_##OPCODE##_X:					\
    		if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) {	\
    			insn += insn->off;			\
    			CONT_JMP;				\
    		}						\
    		CONT;						\
    	JMP32_##OPCODE##_X:					\
    		if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) {	\
    			insn += insn->off;			\
    			CONT_JMP;				\
    		}						\
    		CONT;						\
    	JMP_##OPCODE##_K:					\
    		if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) {	\
    			insn += insn->off;			\
    			CONT_JMP;				\
    		}						\
    		CONT;						\
    	JMP32_##OPCODE##_K:					\
    		if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) {	\
    			insn += insn->off;			\
    			CONT_JMP;				\
    		}						\
    		CONT;
    	COND_JMP(u, JEQ, ==)
    	COND_JMP(u, JNE, !=)
    	COND_JMP(u, JGT, >)
    	COND_JMP(u, JLT, <)
    	COND_JMP(u, JGE, >=)
    	COND_JMP(u, JLE, <=)
    	COND_JMP(u, JSET, &)
    	COND_JMP(s, JSGT, >)
    	COND_JMP(s, JSLT, <)
    	COND_JMP(s, JSGE, >=)
    	COND_JMP(s, JSLE, <=)
    #undef COND_JMP
    	/* 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
    #define LDX_PROBE(SIZEOP, SIZE)							\
    	LDX_PROBE_MEM_##SIZEOP:							\
    		bpf_probe_read_kernel(&DST, SIZE, (const void *)(long) (SRC + insn->off));	\
    		CONT;
    	LDX_PROBE(B,  1)
    	LDX_PROBE(H,  2)
    	LDX_PROBE(W,  4)
    	LDX_PROBE(DW, 8)
    #undef LDX_PROBE
    
    #define ATOMIC_ALU_OP(BOP, KOP)						\
    		case BOP:						\
    			if (BPF_SIZE(insn->code) == BPF_W)		\
    				atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \
    					     (DST + insn->off));	\
    			else						\
    				atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \
    					       (DST + insn->off));	\
    			break;						\
    		case BOP | BPF_FETCH:					\
    			if (BPF_SIZE(insn->code) == BPF_W)		\
    				SRC = (u32) atomic_fetch_##KOP(		\
    					(u32) SRC,			\
    					(atomic_t *)(unsigned long) (DST + insn->off)); \
    			else						\
    				SRC = (u64) atomic64_fetch_##KOP(	\
    					(u64) SRC,			\
    					(atomic64_t *)(unsigned long) (DST + insn->off)); \
    			break;
    
    	STX_ATOMIC_DW:
    	STX_ATOMIC_W:
    		switch (IMM) {
    		ATOMIC_ALU_OP(BPF_ADD, add)
    		ATOMIC_ALU_OP(BPF_AND, and)
    		ATOMIC_ALU_OP(BPF_OR, or)
    		ATOMIC_ALU_OP(BPF_XOR, xor)
    #undef ATOMIC_ALU_OP
    
    		case BPF_XCHG:
    			if (BPF_SIZE(insn->code) == BPF_W)
    				SRC = (u32) atomic_xchg(
    					(atomic_t *)(unsigned long) (DST + insn->off),
    					(u32) SRC);
    			else
    				SRC = (u64) atomic64_xchg(
    					(atomic64_t *)(unsigned long) (DST + insn->off),
    					(u64) SRC);
    			break;
    		case BPF_CMPXCHG:
    			if (BPF_SIZE(insn->code) == BPF_W)
    				BPF_R0 = (u32) atomic_cmpxchg(
    					(atomic_t *)(unsigned long) (DST + insn->off),
    					(u32) BPF_R0, (u32) SRC);
    			else
    				BPF_R0 = (u64) atomic64_cmpxchg(
    					(atomic64_t *)(unsigned long) (DST + insn->off),
    					(u64) BPF_R0, (u64) SRC);
    			break;
    
    		default:
    			goto default_label;
    		}
    		CONT;
    
    	default_label:
    		/* If we ever reach this, we have a bug somewhere. Die hard here
    		 * instead of just returning 0; we could be somewhere in a subprog,
    		 * so execution could continue otherwise which we do /not/ want.
    		 *
    		 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().
    		 */
    		pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n",
    			insn->code, insn->imm);
    		BUG_ON(1);
    		return 0;
    }
    
    #define PROG_NAME(stack_size) __bpf_prog_run##stack_size
    #define DEFINE_BPF_PROG_RUN(stack_size) \
    static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
    { \
    	u64 stack[stack_size / sizeof(u64)]; \
    	u64 regs[MAX_BPF_EXT_REG]; \
    \
    	FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
    	ARG1 = (u64) (unsigned long) ctx; \
    	return ___bpf_prog_run(regs, insn, stack); \
    }
    
    #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size
    #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \
    static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \
    				      const struct bpf_insn *insn) \
    { \
    	u64 stack[stack_size / sizeof(u64)]; \
    	u64 regs[MAX_BPF_EXT_REG]; \
    \
    	FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
    	BPF_R1 = r1; \
    	BPF_R2 = r2; \
    	BPF_R3 = r3; \
    	BPF_R4 = r4; \
    	BPF_R5 = r5; \
    	return ___bpf_prog_run(regs, insn, stack); \
    }
    
    #define EVAL1(FN, X) FN(X)
    #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
    #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
    #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
    #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
    #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
    
    EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
    EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
    EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
    
    EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);
    EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);
    EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512);
    
    #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
    
    static unsigned int (*interpreters[])(const void *ctx,
    				      const struct bpf_insn *insn) = {
    EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
    EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
    EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
    };
    #undef PROG_NAME_LIST
    #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
    static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
    				  const struct bpf_insn *insn) = {
    EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
    EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
    EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
    };
    #undef PROG_NAME_LIST
    
    void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
    {
    	stack_depth = max_t(u32, stack_depth, 1);
    	insn->off = (s16) insn->imm;
    	insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -
    		__bpf_call_base_args;
    	insn->code = BPF_JMP | BPF_CALL_ARGS;
    }
    
    #else
    static unsigned int __bpf_prog_ret0_warn(const void *ctx,
    					 const struct bpf_insn *insn)
    {
    	/* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
    	 * is not working properly, so warn about it!
    	 */
    	WARN_ON_ONCE(1);
    	return 0;
    }
    #endif
    
    bool bpf_prog_array_compatible(struct bpf_array *array,
    			       const struct bpf_prog *fp)
    {
    	if (fp->kprobe_override)
    		return false;
    
    	if (!array->aux->type) {
    		/* There's no owner yet where we could check for
    		 * compatibility.
    		 */
    		array->aux->type  = fp->type;
    		array->aux->jited = fp->jited;
    		return true;
    	}
    
    	return array->aux->type  == fp->type &&
    	       array->aux->jited == fp->jited;
    }
    
    static int bpf_check_tail_call(const struct bpf_prog *fp)
    {
    	struct bpf_prog_aux *aux = fp->aux;
    	int i, ret = 0;
    
    	mutex_lock(&aux->used_maps_mutex);
    	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)) {
    			ret = -EINVAL;
    			goto out;
    		}
    	}
    
    out:
    	mutex_unlock(&aux->used_maps_mutex);
    	return ret;
    }
    
    static void bpf_prog_select_func(struct bpf_prog *fp)
    {
    #ifndef CONFIG_BPF_JIT_ALWAYS_ON
    	u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
    
    	fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
    #else
    	fp->bpf_func = __bpf_prog_ret0_warn;
    #endif
    }
    
    /**
     *	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)
    {
    	/* In case of BPF to BPF calls, verifier did all the prep
    	 * work with regards to JITing, etc.
    	 */
    	if (fp->bpf_func)
    		goto finalize;
    
    	bpf_prog_select_func(fp);
    
    	/* 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.
    	 */
    	if (!bpf_prog_is_dev_bound(fp->aux)) {
    		*err = bpf_prog_alloc_jited_linfo(fp);
    		if (*err)
    			return fp;
    
    		fp = bpf_int_jit_compile(fp);
    		if (!fp->jited) {
    			bpf_prog_free_jited_linfo(fp);
    #ifdef CONFIG_BPF_JIT_ALWAYS_ON
    			*err = -ENOTSUPP;
    			return fp;
    #endif
    		} else {
    			bpf_prog_free_unused_jited_linfo(fp);
    		}
    	} else {
    		*err = bpf_prog_offload_compile(fp);
    		if (*err)
    			return fp;
    	}
    
    finalize:
    	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 unsigned int __bpf_prog_ret1(const void *ctx,
    				    const struct bpf_insn *insn)
    {
    	return 1;
    }
    
    static struct bpf_prog_dummy {
    	struct bpf_prog prog;
    } dummy_bpf_prog = {
    	.prog = {
    		.bpf_func = __bpf_prog_ret1,
    	},
    };
    
    /* to avoid allocating empty bpf_prog_array for cgroups that
     * don't have bpf program attached use one global 'empty_prog_array'
     * It will not be modified the caller of bpf_prog_array_alloc()
     * (since caller requested prog_cnt == 0)
     * that pointer should be 'freed' by bpf_prog_array_free()
     */
    static struct {
    	struct bpf_prog_array hdr;
    	struct bpf_prog *null_prog;
    } empty_prog_array = {
    	.null_prog = NULL,
    };
    
    struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
    {
    	if (prog_cnt)
    		return kzalloc(sizeof(struct bpf_prog_array) +
    			       sizeof(struct bpf_prog_array_item) *
    			       (prog_cnt + 1),
    			       flags);
    
    	return &empty_prog_array.hdr;
    }
    
    void bpf_prog_array_free(struct bpf_prog_array *progs)
    {
    	if (!progs || progs == &empty_prog_array.hdr)
    		return;
    	kfree_rcu(progs, rcu);
    }
    
    int bpf_prog_array_length(struct bpf_prog_array *array)
    {
    	struct bpf_prog_array_item *item;
    	u32 cnt = 0;
    
    	for (item = array->items; item->prog; item++)
    		if (item->prog != &dummy_bpf_prog.prog)
    			cnt++;
    	return cnt;
    }
    
    bool bpf_prog_array_is_empty(struct bpf_prog_array *array)
    {
    	struct bpf_prog_array_item *item;
    
    	for (item = array->items; item->prog; item++)
    		if (item->prog != &dummy_bpf_prog.prog)
    			return false;
    	return true;
    }
    
    static bool bpf_prog_array_copy_core(struct bpf_prog_array *array,
    				     u32 *prog_ids,
    				     u32 request_cnt)
    {
    	struct bpf_prog_array_item *item;
    	int i = 0;
    
    	for (item = array->items; item->prog; item++) {
    		if (item->prog == &dummy_bpf_prog.prog)
    			continue;
    		prog_ids[i] = item->prog->aux->id;
    		if (++i == request_cnt) {
    			item++;
    			break;
    		}
    	}
    
    	return !!(item->prog);
    }
    
    int bpf_prog_array_copy_to_user(struct bpf_prog_array *array,
    				__u32 __user *prog_ids, u32 cnt)
    {
    	unsigned long err = 0;
    	bool nospc;
    	u32 *ids;
    
    	/* users of this function are doing:
    	 * cnt = bpf_prog_array_length();
    	 * if (cnt > 0)
    	 *     bpf_prog_array_copy_to_user(..., cnt);
    	 * so below kcalloc doesn't need extra cnt > 0 check.
    	 */
    	ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
    	if (!ids)
    		return -ENOMEM;
    	nospc = bpf_prog_array_copy_core(array, ids, cnt);
    	err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
    	kfree(ids);
    	if (err)
    		return -EFAULT;
    	if (nospc)
    		return -ENOSPC;
    	return 0;
    }
    
    void bpf_prog_array_delete_safe(struct bpf_prog_array *array,
    				struct bpf_prog *old_prog)
    {
    	struct bpf_prog_array_item *item;
    
    	for (item = array->items; item->prog; item++)
    		if (item->prog == old_prog) {
    			WRITE_ONCE(item->prog, &dummy_bpf_prog.prog);
    			break;
    		}
    }
    
    /**
     * bpf_prog_array_delete_safe_at() - Replaces the program at the given
     *                                   index into the program array with
     *                                   a dummy no-op program.
     * @array: a bpf_prog_array
     * @index: the index of the program to replace
     *
     * Skips over dummy programs, by not counting them, when calculating
     * the position of the program to replace.
     *
     * Return:
     * * 0		- Success
     * * -EINVAL	- Invalid index value. Must be a non-negative integer.
     * * -ENOENT	- Index out of range
     */
    int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index)
    {
    	return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog);
    }
    
    /**
     * bpf_prog_array_update_at() - Updates the program at the given index
     *                              into the program array.
     * @array: a bpf_prog_array
     * @index: the index of the program to update
     * @prog: the program to insert into the array
     *
     * Skips over dummy programs, by not counting them, when calculating
     * the position of the program to update.
     *
     * Return:
     * * 0		- Success
     * * -EINVAL	- Invalid index value. Must be a non-negative integer.
     * * -ENOENT	- Index out of range
     */
    int bpf_prog_array_update_at(struct bpf_prog_array *array, int index,
    			     struct bpf_prog *prog)
    {
    	struct bpf_prog_array_item *item;
    
    	if (unlikely(index < 0))
    		return -EINVAL;
    
    	for (item = array->items; item->prog; item++) {
    		if (item->prog == &dummy_bpf_prog.prog)
    			continue;
    		if (!index) {
    			WRITE_ONCE(item->prog, prog);
    			return 0;
    		}
    		index--;
    	}
    	return -ENOENT;
    }
    
    int bpf_prog_array_copy(struct bpf_prog_array *old_array,
    			struct bpf_prog *exclude_prog,
    			struct bpf_prog *include_prog,
    			struct bpf_prog_array **new_array)
    {
    	int new_prog_cnt, carry_prog_cnt = 0;
    	struct bpf_prog_array_item *existing;
    	struct bpf_prog_array *array;
    	bool found_exclude = false;
    	int new_prog_idx = 0;
    
    	/* Figure out how many existing progs we need to carry over to
    	 * the new array.
    	 */
    	if (old_array) {
    		existing = old_array->items;
    		for (; existing->prog; existing++) {
    			if (existing->prog == exclude_prog) {
    				found_exclude = true;
    				continue;
    			}
    			if (existing->prog != &dummy_bpf_prog.prog)
    				carry_prog_cnt++;
    			if (existing->prog == include_prog)
    				return -EEXIST;
    		}
    	}
    
    	if (exclude_prog && !found_exclude)
    		return -ENOENT;
    
    	/* How many progs (not NULL) will be in the new array? */
    	new_prog_cnt = carry_prog_cnt;
    	if (include_prog)
    		new_prog_cnt += 1;
    
    	/* Do we have any prog (not NULL) in the new array? */
    	if (!new_prog_cnt) {
    		*new_array = NULL;
    		return 0;
    	}
    
    	/* +1 as the end of prog_array is marked with NULL */
    	array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
    	if (!array)
    		return -ENOMEM;
    
    	/* Fill in the new prog array */
    	if (carry_prog_cnt) {
    		existing = old_array->items;
    		for (; existing->prog; existing++)
    			if (existing->prog != exclude_prog &&
    			    existing->prog != &dummy_bpf_prog.prog) {
    				array->items[new_prog_idx++].prog =
    					existing->prog;
    			}
    	}
    	if (include_prog)
    		array->items[new_prog_idx++].prog = include_prog;
    	array->items[new_prog_idx].prog = NULL;
    	*new_array = array;
    	return 0;
    }
    
    int bpf_prog_array_copy_info(struct bpf_prog_array *array,
    			     u32 *prog_ids, u32 request_cnt,
    			     u32 *prog_cnt)
    {
    	u32 cnt = 0;
    
    	if (array)
    		cnt = bpf_prog_array_length(array);
    
    	*prog_cnt = cnt;
    
    	/* return early if user requested only program count or nothing to copy */
    	if (!request_cnt || !cnt)
    		return 0;
    
    	/* this function is called under trace/bpf_trace.c: bpf_event_mutex */
    	return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC
    								     : 0;
    }
    
    void __bpf_free_used_maps(struct bpf_prog_aux *aux,
    			  struct bpf_map **used_maps, u32 len)
    {
    	struct bpf_map *map;
    	u32 i;
    
    	for (i = 0; i < len; i++) {
    		map = used_maps[i];
    		if (map->ops->map_poke_untrack)
    			map->ops->map_poke_untrack(map, aux);
    		bpf_map_put(map);
    	}
    }
    
    static void bpf_free_used_maps(struct bpf_prog_aux *aux)
    {
    	__bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt);
    	kfree(aux->used_maps);
    }
    
    void __bpf_free_used_btfs(struct bpf_prog_aux *aux,
    			  struct btf_mod_pair *used_btfs, u32 len)
    {
    #ifdef CONFIG_BPF_SYSCALL
    	struct btf_mod_pair *btf_mod;
    	u32 i;
    
    	for (i = 0; i < len; i++) {
    		btf_mod = &used_btfs[i];
    		if (btf_mod->module)
    			module_put(btf_mod->module);
    		btf_put(btf_mod->btf);
    	}
    #endif
    }
    
    static void bpf_free_used_btfs(struct bpf_prog_aux *aux)
    {
    	__bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt);
    	kfree(aux->used_btfs);
    }
    
    static void bpf_prog_free_deferred(struct work_struct *work)
    {
    	struct bpf_prog_aux *aux;
    	int i;
    
    	aux = container_of(work, struct bpf_prog_aux, work);
    	bpf_free_used_maps(aux);
    	bpf_free_used_btfs(aux);
    	if (bpf_prog_is_dev_bound(aux))
    		bpf_prog_offload_destroy(aux->prog);
    #ifdef CONFIG_PERF_EVENTS
    	if (aux->prog->has_callchain_buf)
    		put_callchain_buffers();
    #endif
    	if (aux->dst_trampoline)
    		bpf_trampoline_put(aux->dst_trampoline);
    	for (i = 0; i < aux->func_cnt; i++)
    		bpf_jit_free(aux->func[i]);
    	if (aux->func_cnt) {
    		kfree(aux->func);
    		bpf_prog_unlock_free(aux->prog);
    	} else {
    		bpf_jit_free(aux->prog);
    	}
    }
    
    /* Free internal BPF program */
    void bpf_prog_free(struct bpf_prog *fp)
    {
    	struct bpf_prog_aux *aux = fp->aux;
    
    	if (aux->dst_prog)
    		bpf_prog_put(aux->dst_prog);
    	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;
    }
    
    BPF_CALL_0(bpf_get_raw_cpu_id)
    {
    	return raw_smp_processor_id();
    }
    
    /* 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_map_push_elem_proto __weak;
    const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
    const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
    const struct bpf_func_proto bpf_spin_lock_proto __weak;
    const struct bpf_func_proto bpf_spin_unlock_proto __weak;
    const struct bpf_func_proto bpf_jiffies64_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_ktime_get_boot_ns_proto __weak;
    const struct bpf_func_proto bpf_ktime_get_coarse_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 bpf_get_current_cgroup_id_proto __weak;
    const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak;
    const struct bpf_func_proto bpf_get_local_storage_proto __weak;
    const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak;
    const struct bpf_func_proto bpf_snprintf_btf_proto __weak;
    const struct bpf_func_proto bpf_seq_printf_btf_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;
    }
    EXPORT_SYMBOL_GPL(bpf_event_output);
    
    /* 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;
    }
    
    /* Return TRUE if the JIT backend wants verifier to enable sub-register usage
     * analysis code and wants explicit zero extension inserted by verifier.
     * Otherwise, return FALSE.
     */
    bool __weak bpf_jit_needs_zext(void)
    {
    	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;
    }
    
    int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
    			      void *addr1, void *addr2)
    {
    	return -ENOTSUPP;
    }
    
    DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
    EXPORT_SYMBOL(bpf_stats_enabled_key);
    
    /* 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(xdp_bulk_tx);