tools/testing/selftests/bpf/progs/test_core_autosize.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2020 Facebook */
   3
   4 #include <linux/bpf.h>
   5 #include <stdint.h>
   6 #include <bpf/bpf_helpers.h>
   7 #include <bpf/bpf_core_read.h>
   8
   9 char _license[] SEC("license") = "GPL";
  10
  11 /* fields of exactly the same size */
  12 struct test_struct___samesize {
  13         void *ptr;
  14         unsigned long long val1;
  15         unsigned int val2;
  16         unsigned short val3;
  17         unsigned char val4;
  18 } __attribute((preserve_access_index));
  19
  20 /* unsigned fields that have to be downsized by libbpf */
  21 struct test_struct___downsize {
  22         void *ptr;
  23         unsigned long val1;
  24         unsigned long val2;
  25         unsigned long val3;
  26         unsigned long val4;
  27         /* total sz: 40 */
  28 } __attribute__((preserve_access_index));
  29
  30 /* fields with signed integers of wrong size, should be rejected */
  31 struct test_struct___signed {
  32         void *ptr;
  33         long val1;
  34         long val2;
  35         long val3;
  36         long val4;
  37 } __attribute((preserve_access_index));
  38
  39 /* real layout and sizes according to test's (32-bit) BTF */
  40 struct test_struct___real {
  41         unsigned int ptr; /* can't use `void *`, it is always 8 byte in BPF target */
  42         unsigned int val2;
  43         unsigned long long val1;
  44         unsigned short val3;
  45         unsigned char val4;
  46         unsigned char _pad;
  47         /* total sz: 20 */
  48 };
  49
  50 struct test_struct___real input = {
  51         .ptr = 0x01020304,
  52         .val1 = 0x1020304050607080,
  53         .val2 = 0x0a0b0c0d,
  54         .val3 = 0xfeed,
  55         .val4 = 0xb9,
  56         ._pad = 0xff, /* make sure no accidental zeros are present */
  57 };
  58
  59 unsigned long long ptr_samesized = 0;
  60 unsigned long long val1_samesized = 0;
  61 unsigned long long val2_samesized = 0;
  62 unsigned long long val3_samesized = 0;
  63 unsigned long long val4_samesized = 0;
  64 struct test_struct___real output_samesized = {};
  65
  66 unsigned long long ptr_downsized = 0;
  67 unsigned long long val1_downsized = 0;
  68 unsigned long long val2_downsized = 0;
  69 unsigned long long val3_downsized = 0;
  70 unsigned long long val4_downsized = 0;
  71 struct test_struct___real output_downsized = {};
  72
  73 unsigned long long ptr_probed = 0;
  74 unsigned long long val1_probed = 0;
  75 unsigned long long val2_probed = 0;
  76 unsigned long long val3_probed = 0;
  77 unsigned long long val4_probed = 0;
  78
  79 unsigned long long ptr_signed = 0;
  80 unsigned long long val1_signed = 0;
  81 unsigned long long val2_signed = 0;
  82 unsigned long long val3_signed = 0;
  83 unsigned long long val4_signed = 0;
  84 struct test_struct___real output_signed = {};
  85
  86 SEC("raw_tp/sys_exit")
  87 int handle_samesize(void *ctx)
  88 {
  89         struct test_struct___samesize *in = (void *)&input;
  90         struct test_struct___samesize *out = (void *)&output_samesized;
  91
  92         ptr_samesized = (unsigned long long)in->ptr;
  93         val1_samesized = in->val1;
  94         val2_samesized = in->val2;
  95         val3_samesized = in->val3;
  96         val4_samesized = in->val4;
  97
  98         out->ptr = in->ptr;
  99         out->val1 = in->val1;
 100         out->val2 = in->val2;
 101         out->val3 = in->val3;
 102         out->val4 = in->val4;
 103
 104         return 0;
 105 }
 106
 107 SEC("raw_tp/sys_exit")
 108 int handle_downsize(void *ctx)
 109 {
 110         struct test_struct___downsize *in = (void *)&input;
 111         struct test_struct___downsize *out = (void *)&output_downsized;
 112
 113         ptr_downsized = (unsigned long long)in->ptr;
 114         val1_downsized = in->val1;
 115         val2_downsized = in->val2;
 116         val3_downsized = in->val3;
 117         val4_downsized = in->val4;
 118
 119         out->ptr = in->ptr;
 120         out->val1 = in->val1;
 121         out->val2 = in->val2;
 122         out->val3 = in->val3;
 123         out->val4 = in->val4;
 124
 125         return 0;
 126 }
 127
 128 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 129 #define bpf_core_read_int bpf_core_read
 130 #else
 131 #define bpf_core_read_int(dst, sz, src) ({ \
 132         /* Prevent "subtraction from stack pointer prohibited" */ \
 133         volatile long __off = sizeof(*dst) - (sz); \
 134         bpf_core_read((char *)(dst) + __off, sz, src); \
 135 })
 136 #endif
 137
 138 SEC("raw_tp/sys_enter")
 139 int handle_probed(void *ctx)
 140 {
 141         struct test_struct___downsize *in = (void *)&input;
 142         __u64 tmp;
 143
 144         tmp = 0;
 145         bpf_core_read_int(&tmp, bpf_core_field_size(in->ptr), &in->ptr);
 146         ptr_probed = tmp;
 147
 148         tmp = 0;
 149         bpf_core_read_int(&tmp, bpf_core_field_size(in->val1), &in->val1);
 150         val1_probed = tmp;
 151
 152         tmp = 0;
 153         bpf_core_read_int(&tmp, bpf_core_field_size(in->val2), &in->val2);
 154         val2_probed = tmp;
 155
 156         tmp = 0;
 157         bpf_core_read_int(&tmp, bpf_core_field_size(in->val3), &in->val3);
 158         val3_probed = tmp;
 159
 160         tmp = 0;
 161         bpf_core_read_int(&tmp, bpf_core_field_size(in->val4), &in->val4);
 162         val4_probed = tmp;
 163
 164         return 0;
 165 }
 166
 167 SEC("raw_tp/sys_enter")
 168 int handle_signed(void *ctx)
 169 {
 170         struct test_struct___signed *in = (void *)&input;
 171         struct test_struct___signed *out = (void *)&output_signed;
 172
 173         val2_signed = in->val2;
 174         val3_signed = in->val3;
 175         val4_signed = in->val4;
 176
 177         out->val2= in->val2;
 178         out->val3= in->val3;
 179         out->val4= in->val4;
 180
 181         return 0;
 182 }