1 /* Machine-dependent ELF dynamic relocation inline functions. C-SKY version.
2 Copyright (C) 2018-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library. If not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #ifndef dl_machine_h
20 #define dl_machine_h
21
22 #define ELF_MACHINE_NAME "csky"
23
24 #include <sys/param.h>
25 #include <sysdep.h>
26 #include <dl-tls.h>
27 #include <dl-static-tls.h>
28 #include <dl-machine-rel.h>
29
30 /* Return nonzero if ELF header is compatible with the running host. */
31 static inline int
32 elf_machine_matches_host (const Elf32_Ehdr *ehdr)
33 {
34 return ehdr->e_machine == EM_CSKY;
35 }
36
37 /* Return the link-time address of _DYNAMIC.
38 This must be inlined in a function which uses global data. */
39 static inline Elf32_Addr
40 elf_machine_dynamic (void)
41 {
42 register Elf32_Addr *got __asm__ ("gb");
43 return *got;
44 }
45
46 /* Return the run-time load address ,of the shared object. */
47 static inline Elf32_Addr
48 elf_machine_load_address (void)
49 {
50 extern Elf32_Addr __dl_start (void *) asm ("_dl_start");
51 Elf32_Addr got_addr = (Elf32_Addr) &__dl_start;
52 Elf32_Addr pcrel_addr;
53 asm ("grs %0,_dl_start\n" : "=r" (pcrel_addr));
54
55 return pcrel_addr - got_addr;
56 }
57
58
59 /* Set up the loaded object described by L so its unrelocated PLT
60 entries will jump to the on-demand fixup code in dl-runtime.c. */
61
62 static inline int __attribute__ ((always_inline))
63 elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
64 int lazy, int profile)
65 {
66 Elf32_Addr *got;
67 extern void _dl_runtime_resolve (Elf32_Word);
68
69 if (l->l_info[DT_JMPREL] && lazy)
70 {
71 /* The GOT entries for functions in the PLT have not yet been
72 filled in. Their initial contents will arrange when called
73 to push an offset into the .rela.plt section, push
74 _GLOBAL_OFFSET_TABLE_[1], and then jump to
75 _GLOBAL_OFFSET_TABLE_[2]. */
76 got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
77
78 if (got[1])
79 l->l_mach.plt = got[1] + l->l_addr;
80 got[1] = (Elf32_Addr) l; /* Identify this shared object. */
81
82 /* The got[2] entry contains the address of a function which gets
83 called to get the address of a so far unresolved function and
84 jump to it. The profiling extension of the dynamic linker allows
85 to intercept the calls to collect information. In this case we
86 don't store the address in the GOT so that all future calls also
87 end in this function. */
88 got[2] = (Elf32_Addr) &_dl_runtime_resolve;
89 }
90 return lazy;
91 }
92
93 /* Mask identifying addresses reserved for the user program,
94 where the dynamic linker should not map anything. */
95 #define ELF_MACHINE_USER_ADDRESS_MASK 0x80000000UL
96
97 /* Initial entry point code for the dynamic linker.
98 The C function `_dl_start' is the real entry point;
99 its return value is the user program's entry point. */
100 #define RTLD_START asm ("\
101 .text\n\
102 .globl _start\n\
103 .type _start, @function\n\
104 .globl _dl_start_user\n\
105 .type _dl_start_user, @function\n\
106 _start:\n\
107 grs gb, .Lgetpc1\n\
108 .Lgetpc1:\n\
109 lrw t0, .Lgetpc1@GOTPC\n\
110 addu gb, t0\n\
111 mov a0, sp\n\
112 lrw t1, _dl_start@GOTOFF\n\
113 addu t1, gb\n\
114 jsr t1\n\
115 _dl_start_user:\n\
116 /* store program entry address in r10 */ \n\
117 mov r10, a0\n\
118 /* Get argc */\n\
119 ldw a1, (sp, 0)\n\
120 /* Get **argv */\n\
121 mov a2, sp\n\
122 addi a2, 4\n\
123 cmpnei r11, 0\n\
124 mov a3, a1\n\
125 lsli a3, 2\n\
126 add a3, a2\n\
127 addi a3, 4\n\
128 lrw a0, _rtld_local@GOTOFF\n\
129 addu a0, gb\n\
130 ldw a0, (a0, 0)\n\
131 lrw t1, _dl_init@PLT\n\
132 addu t1, gb\n\
133 ldw t1, (t1)\n\
134 jsr t1\n\
135 lrw a0, _dl_fini@GOTOFF\n\
136 addu a0, gb\n\
137 jmp r10\n\
138 ");
139
140 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
141 TLS variable, so undefined references should not be allowed to
142 define the value.
143 ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
144 of the main executable's symbols, as for a COPY reloc. */
145 #ifndef RTLD_BOOTSTRAP
146 # define elf_machine_type_class(type) \
147 ((((type) == R_CKCORE_JUMP_SLOT || (type) == R_CKCORE_TLS_DTPMOD32 \
148 || (type) == R_CKCORE_TLS_DTPOFF32 || (type) == R_CKCORE_TLS_TPOFF32) \
149 * ELF_RTYPE_CLASS_PLT) \
150 | (((type) == R_CKCORE_COPY) * ELF_RTYPE_CLASS_COPY))
151 #else
152 # define elf_machine_type_class(type) \
153 ((((type) == R_CKCORE_JUMP_SLOT \
154 | (((type) == R_CKCORE_COPY) * ELF_RTYPE_CLASS_COPY))
155 #endif
156
157 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
158 #define ELF_MACHINE_JMP_SLOT R_CKCORE_JUMP_SLOT
159
160 /* We define an initialization functions. This is called very early in
161 _dl_sysdep_start. */
162 #define DL_PLATFORM_INIT dl_platform_init ()
163
164 static inline void __attribute__ ((unused))
165 dl_platform_init (void)
166 {
167 if (GLRO(dl_platform) != NULL && *GLRO(dl_platform) == '\0')
168 /* Avoid an empty string which would disturb us. */
169 GLRO(dl_platform) = NULL;
170 }
171
172 static inline Elf32_Addr
173 elf_machine_fixup_plt (struct link_map *map, lookup_t t,
174 const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
175 const Elf32_Rela *reloc,
176 Elf32_Addr *reloc_addr, Elf32_Addr value)
177 {
178 return *reloc_addr = value;
179 }
180
181 /* Return the final value of a plt relocation. On the csky the JMP_SLOT
182 relocation ignores the addend. */
183 static inline Elf32_Addr
184 elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
185 Elf32_Addr value)
186 {
187 return value;
188 }
189
190 /* Names of the architecture-specific auditing callback functions. */
191 #define ARCH_LA_PLTENTER csky_gnu_pltenter
192 #define ARCH_LA_PLTEXIT csky_gnu_pltexit
193
194 #endif /* !dl_machine_h */
195 #ifdef RESOLVE_MAP
196
197 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
198 MAP is the object containing the reloc. */
199
200 static inline void __attribute__ ((unused, always_inline))
201 elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
202 const Elf32_Rela *reloc, const Elf32_Sym *sym,
203 const struct r_found_version *version,
204 void *const reloc_addr_arg, int skip_ifunc)
205 {
206 Elf32_Addr *const reloc_addr = reloc_addr_arg;
207 const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
208 unsigned short __attribute__ ((unused)) *opcode16_addr;
209 Elf32_Addr __attribute__ ((unused)) insn_opcode = 0x0;
210
211 if (__builtin_expect (r_type == R_CKCORE_RELATIVE, 0))
212 *reloc_addr = map->l_addr + reloc->r_addend;
213 else
214 {
215 const Elf32_Sym *const refsym = sym;
216 struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version,
217 r_type);
218 ElfW(Addr) value = SYMBOL_ADDRESS (sym_map, sym, true);
219 opcode16_addr = (unsigned short *)reloc_addr;
220
221 switch (r_type)
222 {
223 case R_CKCORE_COPY:
224 if (sym == NULL)
225 /* This can happen in trace mode if an object could not be
226 found. */
227 break;
228 if (sym->st_size > refsym->st_size
229 || (sym->st_size < refsym->st_size && GLRO(dl_verbose)))
230 {
231 const char *strtab;
232
233 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
234 _dl_error_printf ("\
235 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
236 rtld_progname ?: "<program name unknown>",
237 strtab + refsym->st_name);
238 }
239 memcpy (reloc_addr_arg, (void *) value,
240 MIN (sym->st_size, refsym->st_size));
241 break;
242 case R_CKCORE_GLOB_DAT:
243 case R_CKCORE_JUMP_SLOT:
244 *reloc_addr = value;
245 break;
246 case R_CKCORE_ADDR32:
247 *reloc_addr = value + reloc->r_addend;
248 break;
249 case R_CKCORE_PCREL32:
250 *reloc_addr = value + reloc->r_addend - (Elf32_Addr) reloc_addr;
251 break;
252 #if defined(__CK810__) || defined(__CK807__)
253 case R_CKCORE_ADDR_HI16:
254 insn_opcode = (*opcode16_addr << 16) | (*(opcode16_addr + 1));
255 insn_opcode = (insn_opcode & 0xffff0000)
256 | (((value + reloc->r_addend) >> 16) & 0xffff);
257 *(opcode16_addr++) = (unsigned short)(insn_opcode >> 16);
258 *opcode16_addr = (unsigned short)(insn_opcode & 0xffff);
259 break;
260 case R_CKCORE_ADDR_LO16:
261 insn_opcode = (*opcode16_addr << 16) | (*(opcode16_addr + 1));
262 insn_opcode = (insn_opcode & 0xffff0000)
263 | ((value + reloc->r_addend) & 0xffff);
264 *(opcode16_addr++) = (unsigned short)(insn_opcode >> 16);
265 *opcode16_addr = (unsigned short)(insn_opcode & 0xffff);
266 break;
267 case R_CKCORE_PCREL_IMM26BY2:
268 {
269 unsigned int offset = ((value + reloc->r_addend
270 - (unsigned int)reloc_addr) >> 1);
271 insn_opcode = (*opcode16_addr << 16) | (*(opcode16_addr + 1));
272 if (offset > 0x3ffffff){
273 const char *strtab;
274 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
275
276 _dl_error_printf ("\
277 %s:The reloc R_CKCORE_PCREL_IMM26BY2 cannot reach the symbol '%s'.\n",
278 rtld_progname ?: "<program name unknown>",
279 strtab + refsym->st_name);
280 break;
281 }
282 insn_opcode = (insn_opcode & ~0x3ffffff) | offset;
283 *(opcode16_addr++) = (unsigned short)(insn_opcode >> 16);
284 *opcode16_addr = (unsigned short)(insn_opcode & 0xffff);
285 break;
286 }
287 case R_CKCORE_PCREL_JSR_IMM26BY2:
288 break;
289 #endif
290 #ifndef RTLD_BOOTSTRAP
291 case R_CKCORE_TLS_DTPMOD32:
292 /* Get the information from the link map returned by the
293 resolv function. */
294 if (sym_map != NULL)
295 *reloc_addr = sym_map->l_tls_modid;
296 break;
297 case R_CKCORE_TLS_DTPOFF32:
298 if (sym != NULL)
299 *reloc_addr =(sym == NULL ? 0 : sym->st_value) + reloc->r_addend;
300 break;
301 case R_CKCORE_TLS_TPOFF32:
302 if (sym != NULL)
303 {
304 CHECK_STATIC_TLS (map, sym_map);
305 *reloc_addr = (sym->st_value + sym_map->l_tls_offset
306 + reloc->r_addend);
307 }
308 break;
309 #endif /* !RTLD_BOOTSTRAP */
310 case R_CKCORE_NONE:
311 break;
312 default:
313 break;
314 }
315 }
316 }
317
318 static inline void __attribute__ ((unused, always_inline))
319 elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc,
320 void *const reloc_addr_arg)
321 {
322 Elf32_Addr *const reloc_addr = reloc_addr_arg;
323 *reloc_addr = l_addr + reloc->r_addend;
324 }
325
326 static inline void __attribute__ ((unused, always_inline))
327 elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
328 Elf32_Addr l_addr, const Elf32_Rela *reloc,
329 int skip_ifunc)
330 {
331 Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
332 const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
333 if (ELF32_R_TYPE (reloc->r_info) == R_CKCORE_JUMP_SLOT)
334 {
335 /* Check for unexpected PLT reloc type. */
336 if (__builtin_expect (r_type == R_CKCORE_JUMP_SLOT, 1))
337 {
338 if (__builtin_expect (map->l_mach.plt, 0) == 0)
339 *reloc_addr = l_addr + reloc->r_addend;
340 else
341 *reloc_addr = map->l_mach.plt;
342 }
343 }
344 }
345
346 #endif /* RESOLVE_MAP */