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1// SPDX-License-Identifier: GPL-2.02/* Copyright (c) 2021 Facebook */3 4#include "vmlinux.h"5#include <bpf/bpf_helpers.h>6#include "bpf_misc.h"7 8char _license[] SEC("license") = "GPL";9 10struct callback_ctx {11 int output;12};13 14struct {15 __uint(type, BPF_MAP_TYPE_HASH);16 __uint(max_entries, 32);17 __type(key, int);18 __type(value, int);19} map1 SEC(".maps");20 21/* These should be set by the user program */22u32 nested_callback_nr_loops;23u32 stop_index = -1;24u32 nr_loops;25int pid;26int callback_selector;27 28/* Making these global variables so that the userspace program29 * can verify the output through the skeleton30 */31int nr_loops_returned;32int g_output;33int err;34 35static int callback(__u32 index, void *data)36{37 struct callback_ctx *ctx = data;38 39 if (index >= stop_index)40 return 1;41 42 ctx->output += index;43 44 return 0;45}46 47static int empty_callback(__u32 index, void *data)48{49 return 0;50}51 52static int nested_callback2(__u32 index, void *data)53{54 nr_loops_returned += bpf_loop(nested_callback_nr_loops, callback, data, 0);55 56 return 0;57}58 59static int nested_callback1(__u32 index, void *data)60{61 bpf_loop(nested_callback_nr_loops, nested_callback2, data, 0);62 return 0;63}64 65SEC("fentry/" SYS_PREFIX "sys_nanosleep")66int test_prog(void *ctx)67{68 struct callback_ctx data = {};69 70 if (bpf_get_current_pid_tgid() >> 32 != pid)71 return 0;72 73 nr_loops_returned = bpf_loop(nr_loops, callback, &data, 0);74 75 if (nr_loops_returned < 0)76 err = nr_loops_returned;77 else78 g_output = data.output;79 80 return 0;81}82 83SEC("fentry/" SYS_PREFIX "sys_nanosleep")84int prog_null_ctx(void *ctx)85{86 if (bpf_get_current_pid_tgid() >> 32 != pid)87 return 0;88 89 nr_loops_returned = bpf_loop(nr_loops, empty_callback, NULL, 0);90 91 return 0;92}93 94SEC("fentry/" SYS_PREFIX "sys_nanosleep")95int prog_invalid_flags(void *ctx)96{97 struct callback_ctx data = {};98 99 if (bpf_get_current_pid_tgid() >> 32 != pid)100 return 0;101 102 err = bpf_loop(nr_loops, callback, &data, 1);103 104 return 0;105}106 107SEC("fentry/" SYS_PREFIX "sys_nanosleep")108int prog_nested_calls(void *ctx)109{110 struct callback_ctx data = {};111 112 if (bpf_get_current_pid_tgid() >> 32 != pid)113 return 0;114 115 nr_loops_returned = 0;116 bpf_loop(nr_loops, nested_callback1, &data, 0);117 118 g_output = data.output;119 120 return 0;121}122 123static int callback_set_f0(int i, void *ctx)124{125 g_output = 0xF0;126 return 0;127}128 129static int callback_set_0f(int i, void *ctx)130{131 g_output = 0x0F;132 return 0;133}134 135/*136 * non-constant callback is a corner case for bpf_loop inline logic137 */138SEC("fentry/" SYS_PREFIX "sys_nanosleep")139int prog_non_constant_callback(void *ctx)140{141 if (bpf_get_current_pid_tgid() >> 32 != pid)142 return 0;143 144 int (*callback)(int i, void *ctx);145 146 g_output = 0;147 148 if (callback_selector == 0x0F)149 callback = callback_set_0f;150 else151 callback = callback_set_f0;152 153 bpf_loop(1, callback, NULL, 0);154 155 return 0;156}157 158static int stack_check_inner_callback(void *ctx)159{160 return 0;161}162 163static int map1_lookup_elem(int key)164{165 int *val = bpf_map_lookup_elem(&map1, &key);166 167 return val ? *val : -1;168}169 170static void map1_update_elem(int key, int val)171{172 bpf_map_update_elem(&map1, &key, &val, BPF_ANY);173}174 175static int stack_check_outer_callback(void *ctx)176{177 int a = map1_lookup_elem(1);178 int b = map1_lookup_elem(2);179 int c = map1_lookup_elem(3);180 int d = map1_lookup_elem(4);181 int e = map1_lookup_elem(5);182 int f = map1_lookup_elem(6);183 184 bpf_loop(1, stack_check_inner_callback, NULL, 0);185 186 map1_update_elem(1, a + 1);187 map1_update_elem(2, b + 1);188 map1_update_elem(3, c + 1);189 map1_update_elem(4, d + 1);190 map1_update_elem(5, e + 1);191 map1_update_elem(6, f + 1);192 193 return 0;194}195 196/* Some of the local variables in stack_check and197 * stack_check_outer_callback would be allocated on stack by198 * compiler. This test should verify that stack content for these199 * variables is preserved between calls to bpf_loop (might be an issue200 * if loop inlining allocates stack slots incorrectly).201 */202SEC("fentry/" SYS_PREFIX "sys_nanosleep")203int stack_check(void *ctx)204{205 if (bpf_get_current_pid_tgid() >> 32 != pid)206 return 0;207 208 int a = map1_lookup_elem(7);209 int b = map1_lookup_elem(8);210 int c = map1_lookup_elem(9);211 int d = map1_lookup_elem(10);212 int e = map1_lookup_elem(11);213 int f = map1_lookup_elem(12);214 215 bpf_loop(1, stack_check_outer_callback, NULL, 0);216 217 map1_update_elem(7, a + 1);218 map1_update_elem(8, b + 1);219 map1_update_elem(9, c + 1);220 map1_update_elem(10, d + 1);221 map1_update_elem(11, e + 1);222 map1_update_elem(12, f + 1);223 224 return 0;225}226