/* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com

   * Copyright (c) 2016 Facebook

   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of version 2 of the GNU General Public
   * License as published by the Free Software Foundation.
   */
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/slab.h>
  #include <linux/bpf.h>

  #include <linux/bpf_perf_event.h>

  #include <linux/filter.h>
  #include <linux/uaccess.h>

  #include <linux/ctype.h>

  #include "trace.h"

  /**
   * trace_call_bpf - invoke BPF program
   * @prog: BPF program
   * @ctx: opaque context pointer
   *
   * kprobe handlers execute BPF programs via this helper.
   * Can be used from static tracepoints in the future.
   *
   * Return: BPF programs always return an integer which is interpreted by
   * kprobe handler as:
   * 0 - return from kprobe (event is filtered out)
   * 1 - store kprobe event into ring buffer
   * Other values are reserved and currently alias to 1
   */
  unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx)
  {
  	unsigned int ret;
  
  	if (in_nmi()) /* not supported yet */
  		return 1;
  
  	preempt_disable();
  
  	if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
  		/*
  		 * since some bpf program is already running on this cpu,
  		 * don't call into another bpf program (same or different)
  		 * and don't send kprobe event into ring-buffer,
  		 * so return zero here
  		 */
  		ret = 0;
  		goto out;
  	}
  
  	rcu_read_lock();
  	ret = BPF_PROG_RUN(prog, ctx);
  	rcu_read_unlock();
  
   out:
  	__this_cpu_dec(bpf_prog_active);
  	preempt_enable();
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(trace_call_bpf);

  BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr)

  {

  	int ret;

  	ret = probe_kernel_read(dst, unsafe_ptr, size);
  	if (unlikely(ret < 0))
  		memset(dst, 0, size);
  
  	return ret;

  }
  
  static const struct bpf_func_proto bpf_probe_read_proto = {
  	.func		= bpf_probe_read,
  	.gpl_only	= true,
  	.ret_type	= RET_INTEGER,

  	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
  	.arg2_type	= ARG_CONST_SIZE,

  	.arg3_type	= ARG_ANYTHING,
  };

  BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src,
  	   u32, size)

  {

  	/*
  	 * Ensure we're in user context which is safe for the helper to
  	 * run. This helper has no business in a kthread.
  	 *
  	 * access_ok() should prevent writing to non-user memory, but in
  	 * some situations (nommu, temporary switch, etc) access_ok() does
  	 * not provide enough validation, hence the check on KERNEL_DS.
  	 */
  
  	if (unlikely(in_interrupt() ||
  		     current->flags & (PF_KTHREAD | PF_EXITING)))
  		return -EPERM;

  	if (unlikely(uaccess_kernel()))

  		return -EPERM;
  	if (!access_ok(VERIFY_WRITE, unsafe_ptr, size))
  		return -EPERM;
  
  	return probe_kernel_write(unsafe_ptr, src, size);
  }
  
  static const struct bpf_func_proto bpf_probe_write_user_proto = {
  	.func		= bpf_probe_write_user,
  	.gpl_only	= true,
  	.ret_type	= RET_INTEGER,
  	.arg1_type	= ARG_ANYTHING,

  	.arg2_type	= ARG_PTR_TO_MEM,
  	.arg3_type	= ARG_CONST_SIZE,

  };
  
  static const struct bpf_func_proto *bpf_get_probe_write_proto(void)
  {
  	pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!",
  			    current->comm, task_pid_nr(current));
  
  	return &bpf_probe_write_user_proto;
  }

  /*

   * Only limited trace_printk() conversion specifiers allowed:
   * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s

   */

  BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
  	   u64, arg2, u64, arg3)

  {

  	bool str_seen = false;

  	int mod[3] = {};
  	int fmt_cnt = 0;

  	u64 unsafe_addr;
  	char buf[64];

  	int i;
  
  	/*
  	 * bpf_check()->check_func_arg()->check_stack_boundary()
  	 * guarantees that fmt points to bpf program stack,
  	 * fmt_size bytes of it were initialized and fmt_size > 0
  	 */
  	if (fmt[--fmt_size] != 0)
  		return -EINVAL;
  
  	/* check format string for allowed specifiers */
  	for (i = 0; i < fmt_size; i++) {
  		if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i]))
  			return -EINVAL;
  
  		if (fmt[i] != '%')
  			continue;
  
  		if (fmt_cnt >= 3)
  			return -EINVAL;
  
  		/* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */
  		i++;
  		if (fmt[i] == 'l') {
  			mod[fmt_cnt]++;
  			i++;

  		} else if (fmt[i] == 'p' || fmt[i] == 's') {

  			mod[fmt_cnt]++;

  			/* disallow any further format extensions */
  			if (fmt[i + 1] != 0 &&
  			    !isspace(fmt[i + 1]) &&
  			    !ispunct(fmt[i + 1]))

  				return -EINVAL;
  			fmt_cnt++;

  			if (fmt[i] == 's') {

  				if (str_seen)
  					/* allow only one '%s' per fmt string */
  					return -EINVAL;
  				str_seen = true;
  
  				switch (fmt_cnt) {
  				case 1:

  					unsafe_addr = arg1;
  					arg1 = (long) buf;

  					break;
  				case 2:

  					unsafe_addr = arg2;
  					arg2 = (long) buf;

  					break;
  				case 3:

  					unsafe_addr = arg3;
  					arg3 = (long) buf;

  					break;
  				}
  				buf[0] = 0;
  				strncpy_from_unsafe(buf,
  						    (void *) (long) unsafe_addr,
  						    sizeof(buf));
  			}

  			continue;
  		}
  
  		if (fmt[i] == 'l') {
  			mod[fmt_cnt]++;
  			i++;
  		}

  		if (fmt[i] != 'i' && fmt[i] != 'd' &&
  		    fmt[i] != 'u' && fmt[i] != 'x')

  			return -EINVAL;
  		fmt_cnt++;
  	}

  /* Horrid workaround for getting va_list handling working with different
   * argument type combinations generically for 32 and 64 bit archs.
   */
  #define __BPF_TP_EMIT()	__BPF_ARG3_TP()
  #define __BPF_TP(...)							\
  	__trace_printk(1 /* Fake ip will not be printed. */,		\
  		       fmt, ##__VA_ARGS__)
  
  #define __BPF_ARG1_TP(...)						\
  	((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64))	\
  	  ? __BPF_TP(arg1, ##__VA_ARGS__)				\
  	  : ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32))	\
  	      ? __BPF_TP((long)arg1, ##__VA_ARGS__)			\
  	      : __BPF_TP((u32)arg1, ##__VA_ARGS__)))
  
  #define __BPF_ARG2_TP(...)						\
  	((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64))	\
  	  ? __BPF_ARG1_TP(arg2, ##__VA_ARGS__)				\
  	  : ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32))	\
  	      ? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__)		\
  	      : __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__)))
  
  #define __BPF_ARG3_TP(...)						\
  	((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64))	\
  	  ? __BPF_ARG2_TP(arg3, ##__VA_ARGS__)				\
  	  : ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32))	\
  	      ? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__)		\
  	      : __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__)))
  
  	return __BPF_TP_EMIT();

  }
  
  static const struct bpf_func_proto bpf_trace_printk_proto = {
  	.func		= bpf_trace_printk,
  	.gpl_only	= true,
  	.ret_type	= RET_INTEGER,

  	.arg1_type	= ARG_PTR_TO_MEM,
  	.arg2_type	= ARG_CONST_SIZE,

  };

  const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
  {
  	/*
  	 * this program might be calling bpf_trace_printk,
  	 * so allocate per-cpu printk buffers
  	 */
  	trace_printk_init_buffers();
  
  	return &bpf_trace_printk_proto;
  }

  BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)

  {

  	struct bpf_array *array = container_of(map, struct bpf_array, map);

  	unsigned int cpu = smp_processor_id();
  	u64 index = flags & BPF_F_INDEX_MASK;

  	struct bpf_event_entry *ee;

  	u64 value = 0;
  	int err;

  	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
  		return -EINVAL;
  	if (index == BPF_F_CURRENT_CPU)
  		index = cpu;

  	if (unlikely(index >= array->map.max_entries))
  		return -E2BIG;

  	ee = READ_ONCE(array->ptrs[index]);

  	if (!ee)

  		return -ENOENT;

  	err = perf_event_read_local(ee->event, &value);

  	/*

  	 * this api is ugly since we miss [-22..-2] range of valid
  	 * counter values, but that's uapi

  	 */

  	if (err)
  		return err;
  	return value;

  }

  static const struct bpf_func_proto bpf_perf_event_read_proto = {

  	.func		= bpf_perf_event_read,

  	.gpl_only	= true,

  	.ret_type	= RET_INTEGER,
  	.arg1_type	= ARG_CONST_MAP_PTR,
  	.arg2_type	= ARG_ANYTHING,
  };

  static DEFINE_PER_CPU(struct perf_sample_data, bpf_trace_sd);

  static __always_inline u64
  __bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,

  			u64 flags, struct perf_sample_data *sd)

  {

  	struct bpf_array *array = container_of(map, struct bpf_array, map);

  	unsigned int cpu = smp_processor_id();

  	u64 index = flags & BPF_F_INDEX_MASK;

  	struct bpf_event_entry *ee;

  	struct perf_event *event;

  	if (index == BPF_F_CURRENT_CPU)

  		index = cpu;

  	if (unlikely(index >= array->map.max_entries))
  		return -E2BIG;

  	ee = READ_ONCE(array->ptrs[index]);

  	if (!ee)

  		return -ENOENT;

  	event = ee->event;

  	if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE ||
  		     event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))
  		return -EINVAL;

  	if (unlikely(event->oncpu != cpu))

  		return -EOPNOTSUPP;

  	perf_event_output(event, sd, regs);

  	return 0;
  }

  BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map,
  	   u64, flags, void *, data, u64, size)

  {

  	struct perf_sample_data *sd = this_cpu_ptr(&bpf_trace_sd);

  	struct perf_raw_record raw = {
  		.frag = {
  			.size = size,
  			.data = data,
  		},
  	};
  
  	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
  		return -EINVAL;

  	perf_sample_data_init(sd, 0, 0);
  	sd->raw = &raw;
  
  	return __bpf_perf_event_output(regs, map, flags, sd);

  }

  static const struct bpf_func_proto bpf_perf_event_output_proto = {
  	.func		= bpf_perf_event_output,

  	.gpl_only	= true,

  	.ret_type	= RET_INTEGER,
  	.arg1_type	= ARG_PTR_TO_CTX,
  	.arg2_type	= ARG_CONST_MAP_PTR,
  	.arg3_type	= ARG_ANYTHING,

  	.arg4_type	= ARG_PTR_TO_MEM,
  	.arg5_type	= ARG_CONST_SIZE,

  };

  static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs);

  static DEFINE_PER_CPU(struct perf_sample_data, bpf_misc_sd);

  u64 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)

  {

  	struct perf_sample_data *sd = this_cpu_ptr(&bpf_misc_sd);

  	struct pt_regs *regs = this_cpu_ptr(&bpf_pt_regs);

  	struct perf_raw_frag frag = {
  		.copy		= ctx_copy,
  		.size		= ctx_size,
  		.data		= ctx,
  	};
  	struct perf_raw_record raw = {
  		.frag = {

  			{
  				.next	= ctx_size ? &frag : NULL,
  			},

  			.size	= meta_size,
  			.data	= meta,
  		},
  	};

  
  	perf_fetch_caller_regs(regs);

  	perf_sample_data_init(sd, 0, 0);
  	sd->raw = &raw;

  	return __bpf_perf_event_output(regs, map, flags, sd);

  }

  BPF_CALL_0(bpf_get_current_task)

  {
  	return (long) current;
  }
  
  static const struct bpf_func_proto bpf_get_current_task_proto = {
  	.func		= bpf_get_current_task,
  	.gpl_only	= true,
  	.ret_type	= RET_INTEGER,
  };

  BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx)

  {

  	struct bpf_array *array = container_of(map, struct bpf_array, map);
  	struct cgroup *cgrp;

  
  	if (unlikely(in_interrupt()))
  		return -EINVAL;

  	if (unlikely(idx >= array->map.max_entries))
  		return -E2BIG;
  
  	cgrp = READ_ONCE(array->ptrs[idx]);
  	if (unlikely(!cgrp))
  		return -EAGAIN;
  
  	return task_under_cgroup_hierarchy(current, cgrp);
  }
  
  static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = {
  	.func           = bpf_current_task_under_cgroup,
  	.gpl_only       = false,
  	.ret_type       = RET_INTEGER,
  	.arg1_type      = ARG_CONST_MAP_PTR,
  	.arg2_type      = ARG_ANYTHING,
  };

  BPF_CALL_3(bpf_probe_read_str, void *, dst, u32, size,
  	   const void *, unsafe_ptr)
  {
  	int ret;
  
  	/*
  	 * The strncpy_from_unsafe() call will likely not fill the entire
  	 * buffer, but that's okay in this circumstance as we're probing
  	 * arbitrary memory anyway similar to bpf_probe_read() and might
  	 * as well probe the stack. Thus, memory is explicitly cleared
  	 * only in error case, so that improper users ignoring return
  	 * code altogether don't copy garbage; otherwise length of string
  	 * is returned that can be used for bpf_perf_event_output() et al.
  	 */
  	ret = strncpy_from_unsafe(dst, unsafe_ptr, size);
  	if (unlikely(ret < 0))
  		memset(dst, 0, size);
  
  	return ret;
  }
  
  static const struct bpf_func_proto bpf_probe_read_str_proto = {
  	.func		= bpf_probe_read_str,
  	.gpl_only	= true,
  	.ret_type	= RET_INTEGER,
  	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
  	.arg2_type	= ARG_CONST_SIZE,
  	.arg3_type	= ARG_ANYTHING,
  };

  static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id)

  {
  	switch (func_id) {
  	case BPF_FUNC_map_lookup_elem:
  		return &bpf_map_lookup_elem_proto;
  	case BPF_FUNC_map_update_elem:
  		return &bpf_map_update_elem_proto;
  	case BPF_FUNC_map_delete_elem:
  		return &bpf_map_delete_elem_proto;
  	case BPF_FUNC_probe_read:
  		return &bpf_probe_read_proto;

  	case BPF_FUNC_ktime_get_ns:
  		return &bpf_ktime_get_ns_proto;

  	case BPF_FUNC_tail_call:
  		return &bpf_tail_call_proto;

  	case BPF_FUNC_get_current_pid_tgid:
  		return &bpf_get_current_pid_tgid_proto;

  	case BPF_FUNC_get_current_task:
  		return &bpf_get_current_task_proto;

  	case BPF_FUNC_get_current_uid_gid:
  		return &bpf_get_current_uid_gid_proto;
  	case BPF_FUNC_get_current_comm:
  		return &bpf_get_current_comm_proto;

  	case BPF_FUNC_trace_printk:

  		return bpf_get_trace_printk_proto();

  	case BPF_FUNC_get_smp_processor_id:
  		return &bpf_get_smp_processor_id_proto;

  	case BPF_FUNC_get_numa_node_id:
  		return &bpf_get_numa_node_id_proto;

  	case BPF_FUNC_perf_event_read:
  		return &bpf_perf_event_read_proto;

  	case BPF_FUNC_probe_write_user:
  		return bpf_get_probe_write_proto();

  	case BPF_FUNC_current_task_under_cgroup:
  		return &bpf_current_task_under_cgroup_proto;

  	case BPF_FUNC_get_prandom_u32:
  		return &bpf_get_prandom_u32_proto;

  	case BPF_FUNC_probe_read_str:
  		return &bpf_probe_read_str_proto;

  	default:
  		return NULL;
  	}
  }
  
  static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id)
  {
  	switch (func_id) {

  	case BPF_FUNC_perf_event_output:
  		return &bpf_perf_event_output_proto;

  	case BPF_FUNC_get_stackid:
  		return &bpf_get_stackid_proto;

  	default:

  		return tracing_func_proto(func_id);

  	}
  }
  
  /* bpf+kprobe programs can access fields of 'struct pt_regs' */

  static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type,

  					struct bpf_insn_access_aux *info)

  {

  	if (off < 0 || off >= sizeof(struct pt_regs))
  		return false;

  	if (type != BPF_READ)
  		return false;

  	if (off % size != 0)
  		return false;

  	/*
  	 * Assertion for 32 bit to make sure last 8 byte access
  	 * (BPF_DW) to the last 4 byte member is disallowed.
  	 */
  	if (off + size > sizeof(struct pt_regs))
  		return false;

  	return true;
  }

  const struct bpf_verifier_ops kprobe_prog_ops = {

  	.get_func_proto  = kprobe_prog_func_proto,
  	.is_valid_access = kprobe_prog_is_valid_access,
  };

  BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map,
  	   u64, flags, void *, data, u64, size)

  {

  	struct pt_regs *regs = *(struct pt_regs **)tp_buff;

  	/*
  	 * r1 points to perf tracepoint buffer where first 8 bytes are hidden
  	 * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it

  	 * from there and call the same bpf_perf_event_output() helper inline.

  	 */

  	return ____bpf_perf_event_output(regs, map, flags, data, size);

  }
  
  static const struct bpf_func_proto bpf_perf_event_output_proto_tp = {
  	.func		= bpf_perf_event_output_tp,
  	.gpl_only	= true,
  	.ret_type	= RET_INTEGER,
  	.arg1_type	= ARG_PTR_TO_CTX,
  	.arg2_type	= ARG_CONST_MAP_PTR,
  	.arg3_type	= ARG_ANYTHING,

  	.arg4_type	= ARG_PTR_TO_MEM,
  	.arg5_type	= ARG_CONST_SIZE,

  };

  BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map,
  	   u64, flags)

  {

  	struct pt_regs *regs = *(struct pt_regs **)tp_buff;

  	/*
  	 * Same comment as in bpf_perf_event_output_tp(), only that this time
  	 * the other helper's function body cannot be inlined due to being
  	 * external, thus we need to call raw helper function.
  	 */
  	return bpf_get_stackid((unsigned long) regs, (unsigned long) map,
  			       flags, 0, 0);

  }
  
  static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
  	.func		= bpf_get_stackid_tp,
  	.gpl_only	= true,
  	.ret_type	= RET_INTEGER,
  	.arg1_type	= ARG_PTR_TO_CTX,
  	.arg2_type	= ARG_CONST_MAP_PTR,
  	.arg3_type	= ARG_ANYTHING,
  };

  static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
  {
  	switch (func_id) {
  	case BPF_FUNC_perf_event_output:

  		return &bpf_perf_event_output_proto_tp;

  	case BPF_FUNC_get_stackid:

  		return &bpf_get_stackid_proto_tp;

  	default:
  		return tracing_func_proto(func_id);
  	}
  }

  static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type,

  				    struct bpf_insn_access_aux *info)

  {
  	if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE)
  		return false;
  	if (type != BPF_READ)
  		return false;
  	if (off % size != 0)
  		return false;

  
  	BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64));

  	return true;
  }

  const struct bpf_verifier_ops tracepoint_prog_ops = {

  	.get_func_proto  = tp_prog_func_proto,
  	.is_valid_access = tp_prog_is_valid_access,
  };

  static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type,

  				    struct bpf_insn_access_aux *info)

  {

  	const int size_sp = FIELD_SIZEOF(struct bpf_perf_event_data,
  					 sample_period);

  	if (off < 0 || off >= sizeof(struct bpf_perf_event_data))
  		return false;
  	if (type != BPF_READ)
  		return false;
  	if (off % size != 0)
  		return false;

  	switch (off) {
  	case bpf_ctx_range(struct bpf_perf_event_data, sample_period):
  		bpf_ctx_record_field_size(info, size_sp);
  		if (!bpf_ctx_narrow_access_ok(off, size, size_sp))

  			return false;

  		break;
  	default:

  		if (size != sizeof(long))
  			return false;
  	}

  	return true;
  }

  static u32 pe_prog_convert_ctx_access(enum bpf_access_type type,
  				      const struct bpf_insn *si,

  				      struct bpf_insn *insn_buf,

  				      struct bpf_prog *prog, u32 *target_size)

  {
  	struct bpf_insn *insn = insn_buf;

  	switch (si->off) {

  	case offsetof(struct bpf_perf_event_data, sample_period):

  		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,

  						       data), si->dst_reg, si->src_reg,

  				      offsetof(struct bpf_perf_event_data_kern, data));

  		*insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,

  				      bpf_target_off(struct perf_sample_data, period, 8,
  						     target_size));

  		break;
  	default:

  		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,

  						       regs), si->dst_reg, si->src_reg,

  				      offsetof(struct bpf_perf_event_data_kern, regs));

  		*insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg,
  				      si->off);

  		break;
  	}
  
  	return insn - insn_buf;
  }

  const struct bpf_verifier_ops perf_event_prog_ops = {

  	.get_func_proto		= tp_prog_func_proto,
  	.is_valid_access	= pe_prog_is_valid_access,
  	.convert_ctx_access	= pe_prog_convert_ctx_access,
  };