1 /* Linux bpf specific support for 64-bit ELF
2 Copyright (C) 2019 Free Software Foundation, Inc.
3 Contributed by Oracle Inc.
5 This file is part of BFD, the Binary File Descriptor library.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, USA. */
27 #include "libiberty.h"
29 /* In case we're on a 32-bit machine, construct a 64-bit "-1" value. */
30 #define MINUS_ONE (~ (bfd_vma) 0)
32 #define BASEADDR(SEC) ((SEC)->output_section->vma + (SEC)->output_offset)
34 /* Handler for PC-relative relocations, which must be handled in
37 static bfd_reloc_status_type
38 bpf_elf_insn_disp_reloc (bfd
*abfd
,
42 asection
*input_section
,
44 char **error_message ATTRIBUTE_UNUSED
)
46 bfd_signed_vma relocation
;
47 bfd_signed_vma addend
;
48 reloc_howto_type
*howto
= reloc_entry
->howto
;
50 /* This part is from bfd_elf_generic_reloc. */
51 if (output_bfd
!= NULL
52 && (symbol
->flags
& BSF_SECTION_SYM
) == 0
53 && (! reloc_entry
->howto
->partial_inplace
54 || reloc_entry
->addend
== 0))
56 reloc_entry
->address
+= input_section
->output_offset
;
60 /* This works because partial_inplace is FALSE. */
61 if (output_bfd
!= NULL
)
62 return bfd_reloc_continue
;
64 if (reloc_entry
->address
> bfd_get_section_limit (abfd
, input_section
))
65 return bfd_reloc_outofrange
;
67 relocation
= (symbol
->value
68 + symbol
->section
->output_section
->vma
69 + symbol
->section
->output_offset
);
70 /* Make it PC relative. */
71 relocation
-= (input_section
->output_section
->vma
72 + input_section
->output_offset
);
73 relocation
-= reloc_entry
->address
;
74 /* Make it 64-bit words. */
75 relocation
= relocation
/ 8;
77 /* Get the addend from the instruction and apply it. */
78 switch (howto
->bitsize
)
84 addend
= bfd_get_16 (abfd
, (bfd_byte
*) data
+ reloc_entry
->address
+ 2);
87 addend
= bfd_get_32 (abfd
, (bfd_byte
*) data
+ reloc_entry
->address
+ 4);
91 if ((addend
& (((~howto
->src_mask
) >> 1) & howto
->src_mask
)) != 0)
92 addend
-= (((~howto
->src_mask
) >> 1) & howto
->src_mask
) << 1;
95 /* Write out the relocated value. */
96 switch (howto
->bitsize
)
102 bfd_put_16 (abfd
, relocation
, (bfd_byte
*) data
+ reloc_entry
->address
+ 2);
105 bfd_put_32 (abfd
, relocation
, (bfd_byte
*) data
+ reloc_entry
->address
+ 4);
109 /* Check for overflow. */
110 if (howto
->complain_on_overflow
== complain_overflow_signed
)
112 bfd_signed_vma reloc_signed_max
= (1 << (howto
->bitsize
- 1)) - 1;
113 bfd_signed_vma reloc_signed_min
= ~reloc_signed_max
;
115 if (relocation
> reloc_signed_max
|| relocation
< reloc_signed_min
)
116 return bfd_reloc_overflow
;
124 /* Relocation tables. */
125 static reloc_howto_type bpf_elf_howto_table
[] =
127 /* This reloc does nothing. */
128 HOWTO (R_BPF_NONE
, /* type */
130 3, /* size (0 = byte, 1 = short, 2 = long) */
132 FALSE
, /* pc_relative */
134 complain_overflow_dont
, /* complain_on_overflow */
135 bfd_elf_generic_reloc
, /* special_function */
136 "R_BPF_NONE", /* name */
137 FALSE
, /* partial_inplace */
140 FALSE
), /* pcrel_offset */
142 /* 64-immediate in LDDW instruction. */
143 HOWTO (R_BPF_INSN_64
, /* type */
145 4, /* size (0 = byte, 1 = short, 2 = long) */
147 FALSE
, /* pc_relative */
149 complain_overflow_signed
, /* complain_on_overflow */
150 bfd_elf_generic_reloc
, /* special_function */
151 "R_BPF_INSN_64", /* name */
152 FALSE
, /* partial_inplace */
154 MINUS_ONE
, /* dst_mask */
155 TRUE
), /* pcrel_offset */
157 /* 32-immediate in LDDW instruction. */
158 HOWTO (R_BPF_INSN_32
, /* type */
160 2, /* size (0 = byte, 1 = short, 2 = long) */
162 FALSE
, /* pc_relative */
164 complain_overflow_signed
, /* complain_on_overflow */
165 bfd_elf_generic_reloc
, /* special_function */
166 "R_BPF_INSN_32", /* name */
167 FALSE
, /* partial_inplace */
169 0xffffffff, /* dst_mask */
170 TRUE
), /* pcrel_offset */
172 /* 16-bit offsets in instructions. */
173 HOWTO (R_BPF_INSN_16
, /* type */
175 1, /* size (0 = byte, 1 = short, 2 = long) */
177 FALSE
, /* pc_relative */
179 complain_overflow_signed
, /* complain_on_overflow */
180 bfd_elf_generic_reloc
, /* special_function */
181 "R_BPF_INSN_16", /* name */
182 FALSE
, /* partial_inplace */
184 0x0000ffff, /* dst_mask */
185 TRUE
), /* pcrel_offset */
187 /* 16-bit PC-relative address in jump instructions. */
188 HOWTO (R_BPF_INSN_DISP16
, /* type */
190 1, /* size (0 = byte, 1 = short, 2 = long) */
192 TRUE
, /* pc_relative */
194 complain_overflow_signed
, /* complain_on_overflow */
195 bpf_elf_insn_disp_reloc
, /* special_function */
196 "R_BPF_INSN_DISP16", /* name */
197 FALSE
, /* partial_inplace */
198 0xffff, /* src_mask */
199 0xffff, /* dst_mask */
200 TRUE
), /* pcrel_offset */
202 HOWTO (R_BPF_DATA_8_PCREL
,
204 0, /* size (0 = byte, 1 = short, 2 = long) */
206 TRUE
, /* pc_relative */
208 complain_overflow_signed
, /* complain_on_overflow */
209 bfd_elf_generic_reloc
, /* special_function */
210 "R_BPF_8_PCREL", /* name */
211 FALSE
, /* partial_inplace */
214 TRUE
), /* pcrel_offset */
216 HOWTO (R_BPF_DATA_16_PCREL
,
218 1, /* size (0 = byte, 1 = short, 2 = long) */
220 TRUE
, /* pc_relative */
222 complain_overflow_signed
, /* complain_on_overflow */
223 bfd_elf_generic_reloc
, /* special_function */
224 "R_BPF_16_PCREL", /* name */
225 FALSE
, /* partial_inplace */
227 0xffff, /* dst_mask */
228 TRUE
), /* pcrel_offset */
230 HOWTO (R_BPF_DATA_32_PCREL
,
232 2, /* size (0 = byte, 1 = short, 2 = long) */
234 TRUE
, /* pc_relative */
236 complain_overflow_signed
, /* complain_on_overflow */
237 bfd_elf_generic_reloc
, /* special_function */
238 "R_BPF_32_PCREL", /* name */
239 FALSE
, /* partial_inplace */
241 0xffffffff, /* dst_mask */
242 TRUE
), /* pcrel_offset */
246 0, /* size (0 = byte, 1 = short, 2 = long) */
248 FALSE
, /* pc_relative */
250 complain_overflow_unsigned
, /* complain_on_overflow */
251 bfd_elf_generic_reloc
, /* special_function */
252 "R_BPF_DATA_8", /* name */
253 FALSE
, /* partial_inplace */
256 FALSE
), /* pcrel_offset */
258 HOWTO (R_BPF_DATA_16
,
260 1, /* size (0 = byte, 1 = short, 2 = long) */
262 FALSE
, /* pc_relative */
264 complain_overflow_unsigned
, /* complain_on_overflow */
265 bfd_elf_generic_reloc
, /* special_function */
266 "R_BPF_DATA_16", /* name */
267 FALSE
, /* partial_inplace */
269 0xffff, /* dst_mask */
270 FALSE
), /* pcrel_offset */
272 /* 32-bit PC-relative address in call instructions. */
273 HOWTO (R_BPF_INSN_DISP32
, /* type */
275 2, /* size (0 = byte, 1 = short, 2 = long) */
277 TRUE
, /* pc_relative */
279 complain_overflow_signed
, /* complain_on_overflow */
280 bpf_elf_insn_disp_reloc
, /* special_function */
281 "R_BPF_INSN_DISP32", /* name */
282 FALSE
, /* partial_inplace */
283 0xffffffff, /* src_mask */
284 0xffffffff, /* dst_mask */
285 TRUE
), /* pcrel_offset */
288 HOWTO (R_BPF_DATA_32
, /* type */
290 2, /* size (0 = byte, 1 = short, 2 = long) */
292 FALSE
, /* pc_relative */
294 complain_overflow_bitfield
, /* complain_on_overflow */
295 bfd_elf_generic_reloc
, /* special_function */
296 "R_BPF_DATA_32", /* name */
297 FALSE
, /* partial_inplace */
299 0xffffffff, /* dst_mask */
300 TRUE
), /* pcrel_offset */
303 HOWTO (R_BPF_DATA_64
, /* type */
305 4, /* size (0 = byte, 1 = short, 2 = long) */
307 FALSE
, /* pc_relative */
309 complain_overflow_bitfield
, /* complain_on_overflow */
310 bfd_elf_generic_reloc
, /* special_function */
311 "R_BPF_DATA_64", /* name */
312 FALSE
, /* partial_inplace */
314 MINUS_ONE
, /* dst_mask */
315 TRUE
), /* pcrel_offset */
317 HOWTO (R_BPF_DATA_64_PCREL
,
319 4, /* size (0 = byte, 1 = short, 2 = long) */
321 TRUE
, /* pc_relative */
323 complain_overflow_signed
, /* complain_on_overflow */
324 bfd_elf_generic_reloc
, /* special_function */
325 "R_BPF_64_PCREL", /* name */
326 FALSE
, /* partial_inplace */
328 MINUS_ONE
, /* dst_mask */
329 TRUE
), /* pcrel_offset */
333 /* Map BFD reloc types to bpf ELF reloc types. */
335 static reloc_howto_type
*
336 bpf_reloc_type_lookup (bfd
* abfd ATTRIBUTE_UNUSED
,
337 bfd_reloc_code_real_type code
)
339 /* Note that the bpf_elf_howto_table is indxed by the R_
340 constants. Thus, the order that the howto records appear in the
341 table *must* match the order of the relocation types defined in
342 include/elf/bpf.h. */
347 return &bpf_elf_howto_table
[ (int) R_BPF_NONE
];
349 case BFD_RELOC_8_PCREL
:
350 return &bpf_elf_howto_table
[ (int) R_BPF_DATA_8_PCREL
];
351 case BFD_RELOC_16_PCREL
:
352 return &bpf_elf_howto_table
[ (int) R_BPF_DATA_16_PCREL
];
353 case BFD_RELOC_32_PCREL
:
354 return &bpf_elf_howto_table
[ (int) R_BPF_DATA_32_PCREL
];
355 case BFD_RELOC_64_PCREL
:
356 return &bpf_elf_howto_table
[ (int) R_BPF_DATA_64_PCREL
];
359 return &bpf_elf_howto_table
[ (int) R_BPF_DATA_8
];
361 return &bpf_elf_howto_table
[ (int) R_BPF_DATA_16
];
363 return &bpf_elf_howto_table
[ (int) R_BPF_DATA_32
];
365 return &bpf_elf_howto_table
[ (int) R_BPF_DATA_64
];
367 case BFD_RELOC_BPF_64
:
368 return &bpf_elf_howto_table
[ (int) R_BPF_INSN_64
];
369 case BFD_RELOC_BPF_32
:
370 return &bpf_elf_howto_table
[ (int) R_BPF_INSN_32
];
371 case BFD_RELOC_BPF_16
:
372 return &bpf_elf_howto_table
[ (int) R_BPF_INSN_16
];
373 case BFD_RELOC_BPF_DISP16
:
374 return &bpf_elf_howto_table
[ (int) R_BPF_INSN_DISP16
];
375 case BFD_RELOC_BPF_DISP32
:
376 return &bpf_elf_howto_table
[ (int) R_BPF_INSN_DISP32
];
379 /* Pacify gcc -Wall. */
385 /* Map BFD reloc names to bpf ELF reloc names. */
387 static reloc_howto_type
*
388 bpf_reloc_name_lookup (bfd
*abfd ATTRIBUTE_UNUSED
, const char *r_name
)
392 for (i
= 0; i
< ARRAY_SIZE (bpf_elf_howto_table
); i
++)
393 if (bpf_elf_howto_table
[i
].name
!= NULL
394 && strcasecmp (bpf_elf_howto_table
[i
].name
, r_name
) == 0)
395 return &bpf_elf_howto_table
[i
];
400 /* Set the howto pointer for a bpf reloc. */
403 bpf_info_to_howto (bfd
*abfd
, arelent
*bfd_reloc
,
404 Elf_Internal_Rela
*elf_reloc
)
408 r_type
= ELF64_R_TYPE (elf_reloc
->r_info
);
409 if (r_type
>= (unsigned int) R_BPF_max
)
411 /* xgettext:c-format */
412 _bfd_error_handler (_("%pB: unsupported relocation type %#x"),
414 bfd_set_error (bfd_error_bad_value
);
418 bfd_reloc
->howto
= &bpf_elf_howto_table
[r_type
];
422 /* Merge backend specific data from an object file to the output
423 object file when linking. */
426 elf64_bpf_merge_private_bfd_data (bfd
*ibfd
, struct bfd_link_info
*info
)
428 /* Check if we have the same endianness. */
429 if (! _bfd_generic_verify_endian_match (ibfd
, info
))
435 /* The macros below configure the architecture. */
437 #define TARGET_LITTLE_SYM bpf_elf64_le_vec
438 #define TARGET_LITTLE_NAME "elf64-bpfle"
440 #define TARGET_BIG_SYM bpf_elf64_be_vec
441 #define TARGET_BIG_NAME "elf64-bpfbe"
443 #define ELF_ARCH bfd_arch_bpf
444 #define ELF_MACHINE_CODE EM_BPF
446 #define ELF_MAXPAGESIZE 0x100000
448 #define elf_info_to_howto_rel bpf_info_to_howto
449 #define elf_info_to_howto bpf_info_to_howto
451 #define elf_backend_may_use_rel_p 1
452 #define elf_backend_may_use_rela_p 0
453 #define elf_backend_default_use_rela_p 0
455 #define elf_backend_can_gc_sections 0
457 #define elf_symbol_leading_char '_'
458 #define bfd_elf64_bfd_reloc_type_lookup bpf_reloc_type_lookup
459 #define bfd_elf64_bfd_reloc_name_lookup bpf_reloc_name_lookup
461 #define bfd_elf64_bfd_merge_private_bfd_data elf64_bpf_merge_private_bfd_data
463 #include "elf64-target.h"