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faf5f7ad | 1 | /* GNU/Linux on ARM target support. |
0fd88904 | 2 | |
0fb0cc75 | 3 | Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, |
4c38e0a4 | 4 | 2009, 2010 Free Software Foundation, Inc. |
faf5f7ad SB |
5 | |
6 | This file is part of GDB. | |
7 | ||
8 | This program is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 10 | the Free Software Foundation; either version 3 of the License, or |
faf5f7ad SB |
11 | (at your option) any later version. |
12 | ||
13 | This program is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
faf5f7ad SB |
20 | |
21 | #include "defs.h" | |
c20f6dea SB |
22 | #include "target.h" |
23 | #include "value.h" | |
faf5f7ad | 24 | #include "gdbtypes.h" |
134e61c4 | 25 | #include "floatformat.h" |
2a451106 KB |
26 | #include "gdbcore.h" |
27 | #include "frame.h" | |
4e052eda | 28 | #include "regcache.h" |
d16aafd8 | 29 | #include "doublest.h" |
7aa1783e | 30 | #include "solib-svr4.h" |
4be87837 | 31 | #include "osabi.h" |
cb587d83 | 32 | #include "regset.h" |
8e9d1a24 DJ |
33 | #include "trad-frame.h" |
34 | #include "tramp-frame.h" | |
daddc3c1 | 35 | #include "breakpoint.h" |
faf5f7ad | 36 | |
34e8f22d | 37 | #include "arm-tdep.h" |
cb587d83 | 38 | #include "arm-linux-tdep.h" |
4aa995e1 | 39 | #include "linux-tdep.h" |
0670c0aa | 40 | #include "glibc-tdep.h" |
cca44b1b JB |
41 | #include "arch-utils.h" |
42 | #include "inferior.h" | |
43 | #include "gdbthread.h" | |
44 | #include "symfile.h" | |
a52e6aac | 45 | |
8e9d1a24 DJ |
46 | #include "gdb_string.h" |
47 | ||
cb587d83 DJ |
48 | extern int arm_apcs_32; |
49 | ||
fdf39c9a RE |
50 | /* Under ARM GNU/Linux the traditional way of performing a breakpoint |
51 | is to execute a particular software interrupt, rather than use a | |
52 | particular undefined instruction to provoke a trap. Upon exection | |
53 | of the software interrupt the kernel stops the inferior with a | |
498b1f87 | 54 | SIGTRAP, and wakes the debugger. */ |
66e810cd | 55 | |
2ef47cd0 DJ |
56 | static const char arm_linux_arm_le_breakpoint[] = { 0x01, 0x00, 0x9f, 0xef }; |
57 | ||
58 | static const char arm_linux_arm_be_breakpoint[] = { 0xef, 0x9f, 0x00, 0x01 }; | |
66e810cd | 59 | |
c75a2cc8 DJ |
60 | /* However, the EABI syscall interface (new in Nov. 2005) does not look at |
61 | the operand of the swi if old-ABI compatibility is disabled. Therefore, | |
62 | use an undefined instruction instead. This is supported as of kernel | |
63 | version 2.5.70 (May 2003), so should be a safe assumption for EABI | |
64 | binaries. */ | |
65 | ||
66 | static const char eabi_linux_arm_le_breakpoint[] = { 0xf0, 0x01, 0xf0, 0xe7 }; | |
67 | ||
68 | static const char eabi_linux_arm_be_breakpoint[] = { 0xe7, 0xf0, 0x01, 0xf0 }; | |
69 | ||
70 | /* All the kernels which support Thumb support using a specific undefined | |
71 | instruction for the Thumb breakpoint. */ | |
72 | ||
498b1f87 DJ |
73 | static const char arm_linux_thumb_be_breakpoint[] = {0xde, 0x01}; |
74 | ||
75 | static const char arm_linux_thumb_le_breakpoint[] = {0x01, 0xde}; | |
76 | ||
177321bd DJ |
77 | /* Because the 16-bit Thumb breakpoint is affected by Thumb-2 IT blocks, |
78 | we must use a length-appropriate breakpoint for 32-bit Thumb | |
79 | instructions. See also thumb_get_next_pc. */ | |
80 | ||
81 | static const char arm_linux_thumb2_be_breakpoint[] = { 0xf7, 0xf0, 0xa0, 0x00 }; | |
82 | ||
83 | static const char arm_linux_thumb2_le_breakpoint[] = { 0xf0, 0xf7, 0x00, 0xa0 }; | |
84 | ||
9df628e0 | 85 | /* Description of the longjmp buffer. */ |
7a5ea0d4 | 86 | #define ARM_LINUX_JB_ELEMENT_SIZE INT_REGISTER_SIZE |
a6cdd8c5 | 87 | #define ARM_LINUX_JB_PC 21 |
faf5f7ad | 88 | |
f38e884d | 89 | /* |
fdf39c9a RE |
90 | Dynamic Linking on ARM GNU/Linux |
91 | -------------------------------- | |
f38e884d SB |
92 | |
93 | Note: PLT = procedure linkage table | |
94 | GOT = global offset table | |
95 | ||
96 | As much as possible, ELF dynamic linking defers the resolution of | |
97 | jump/call addresses until the last minute. The technique used is | |
98 | inspired by the i386 ELF design, and is based on the following | |
99 | constraints. | |
100 | ||
101 | 1) The calling technique should not force a change in the assembly | |
102 | code produced for apps; it MAY cause changes in the way assembly | |
103 | code is produced for position independent code (i.e. shared | |
104 | libraries). | |
105 | ||
106 | 2) The technique must be such that all executable areas must not be | |
107 | modified; and any modified areas must not be executed. | |
108 | ||
109 | To do this, there are three steps involved in a typical jump: | |
110 | ||
111 | 1) in the code | |
112 | 2) through the PLT | |
113 | 3) using a pointer from the GOT | |
114 | ||
115 | When the executable or library is first loaded, each GOT entry is | |
116 | initialized to point to the code which implements dynamic name | |
117 | resolution and code finding. This is normally a function in the | |
fdf39c9a RE |
118 | program interpreter (on ARM GNU/Linux this is usually |
119 | ld-linux.so.2, but it does not have to be). On the first | |
120 | invocation, the function is located and the GOT entry is replaced | |
121 | with the real function address. Subsequent calls go through steps | |
122 | 1, 2 and 3 and end up calling the real code. | |
f38e884d SB |
123 | |
124 | 1) In the code: | |
125 | ||
126 | b function_call | |
127 | bl function_call | |
128 | ||
129 | This is typical ARM code using the 26 bit relative branch or branch | |
130 | and link instructions. The target of the instruction | |
131 | (function_call is usually the address of the function to be called. | |
132 | In position independent code, the target of the instruction is | |
133 | actually an entry in the PLT when calling functions in a shared | |
134 | library. Note that this call is identical to a normal function | |
135 | call, only the target differs. | |
136 | ||
137 | 2) In the PLT: | |
138 | ||
139 | The PLT is a synthetic area, created by the linker. It exists in | |
140 | both executables and libraries. It is an array of stubs, one per | |
141 | imported function call. It looks like this: | |
142 | ||
143 | PLT[0]: | |
144 | str lr, [sp, #-4]! @push the return address (lr) | |
145 | ldr lr, [pc, #16] @load from 6 words ahead | |
146 | add lr, pc, lr @form an address for GOT[0] | |
147 | ldr pc, [lr, #8]! @jump to the contents of that addr | |
148 | ||
149 | The return address (lr) is pushed on the stack and used for | |
150 | calculations. The load on the second line loads the lr with | |
151 | &GOT[3] - . - 20. The addition on the third leaves: | |
152 | ||
153 | lr = (&GOT[3] - . - 20) + (. + 8) | |
154 | lr = (&GOT[3] - 12) | |
155 | lr = &GOT[0] | |
156 | ||
157 | On the fourth line, the pc and lr are both updated, so that: | |
158 | ||
159 | pc = GOT[2] | |
160 | lr = &GOT[0] + 8 | |
161 | = &GOT[2] | |
162 | ||
163 | NOTE: PLT[0] borrows an offset .word from PLT[1]. This is a little | |
164 | "tight", but allows us to keep all the PLT entries the same size. | |
165 | ||
166 | PLT[n+1]: | |
167 | ldr ip, [pc, #4] @load offset from gotoff | |
168 | add ip, pc, ip @add the offset to the pc | |
169 | ldr pc, [ip] @jump to that address | |
170 | gotoff: .word GOT[n+3] - . | |
171 | ||
172 | The load on the first line, gets an offset from the fourth word of | |
173 | the PLT entry. The add on the second line makes ip = &GOT[n+3], | |
174 | which contains either a pointer to PLT[0] (the fixup trampoline) or | |
175 | a pointer to the actual code. | |
176 | ||
177 | 3) In the GOT: | |
178 | ||
179 | The GOT contains helper pointers for both code (PLT) fixups and | |
180 | data fixups. The first 3 entries of the GOT are special. The next | |
181 | M entries (where M is the number of entries in the PLT) belong to | |
182 | the PLT fixups. The next D (all remaining) entries belong to | |
183 | various data fixups. The actual size of the GOT is 3 + M + D. | |
184 | ||
185 | The GOT is also a synthetic area, created by the linker. It exists | |
186 | in both executables and libraries. When the GOT is first | |
187 | initialized , all the GOT entries relating to PLT fixups are | |
188 | pointing to code back at PLT[0]. | |
189 | ||
190 | The special entries in the GOT are: | |
191 | ||
192 | GOT[0] = linked list pointer used by the dynamic loader | |
193 | GOT[1] = pointer to the reloc table for this module | |
194 | GOT[2] = pointer to the fixup/resolver code | |
195 | ||
196 | The first invocation of function call comes through and uses the | |
197 | fixup/resolver code. On the entry to the fixup/resolver code: | |
198 | ||
199 | ip = &GOT[n+3] | |
200 | lr = &GOT[2] | |
201 | stack[0] = return address (lr) of the function call | |
202 | [r0, r1, r2, r3] are still the arguments to the function call | |
203 | ||
204 | This is enough information for the fixup/resolver code to work | |
205 | with. Before the fixup/resolver code returns, it actually calls | |
206 | the requested function and repairs &GOT[n+3]. */ | |
207 | ||
2a451106 KB |
208 | /* The constants below were determined by examining the following files |
209 | in the linux kernel sources: | |
210 | ||
211 | arch/arm/kernel/signal.c | |
212 | - see SWI_SYS_SIGRETURN and SWI_SYS_RT_SIGRETURN | |
213 | include/asm-arm/unistd.h | |
214 | - see __NR_sigreturn, __NR_rt_sigreturn, and __NR_SYSCALL_BASE */ | |
215 | ||
216 | #define ARM_LINUX_SIGRETURN_INSTR 0xef900077 | |
217 | #define ARM_LINUX_RT_SIGRETURN_INSTR 0xef9000ad | |
218 | ||
edfb1a26 DJ |
219 | /* For ARM EABI, the syscall number is not in the SWI instruction |
220 | (instead it is loaded into r7). We recognize the pattern that | |
221 | glibc uses... alternatively, we could arrange to do this by | |
222 | function name, but they are not always exported. */ | |
8e9d1a24 DJ |
223 | #define ARM_SET_R7_SIGRETURN 0xe3a07077 |
224 | #define ARM_SET_R7_RT_SIGRETURN 0xe3a070ad | |
225 | #define ARM_EABI_SYSCALL 0xef000000 | |
2a451106 | 226 | |
f1973203 MR |
227 | /* OABI syscall restart trampoline, used for EABI executables too |
228 | whenever OABI support has been enabled in the kernel. */ | |
229 | #define ARM_OABI_SYSCALL_RESTART_SYSCALL 0xef900000 | |
230 | #define ARM_LDR_PC_SP_12 0xe49df00c | |
231 | ||
8e9d1a24 | 232 | static void |
a262aec2 | 233 | arm_linux_sigtramp_cache (struct frame_info *this_frame, |
8e9d1a24 DJ |
234 | struct trad_frame_cache *this_cache, |
235 | CORE_ADDR func, int regs_offset) | |
2a451106 | 236 | { |
a262aec2 | 237 | CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM); |
8e9d1a24 DJ |
238 | CORE_ADDR base = sp + regs_offset; |
239 | int i; | |
2a451106 | 240 | |
8e9d1a24 DJ |
241 | for (i = 0; i < 16; i++) |
242 | trad_frame_set_reg_addr (this_cache, i, base + i * 4); | |
2a451106 | 243 | |
8e9d1a24 | 244 | trad_frame_set_reg_addr (this_cache, ARM_PS_REGNUM, base + 16 * 4); |
2a451106 | 245 | |
8e9d1a24 DJ |
246 | /* The VFP or iWMMXt registers may be saved on the stack, but there's |
247 | no reliable way to restore them (yet). */ | |
2a451106 | 248 | |
8e9d1a24 DJ |
249 | /* Save a frame ID. */ |
250 | trad_frame_set_id (this_cache, frame_id_build (sp, func)); | |
251 | } | |
2a451106 | 252 | |
edfb1a26 DJ |
253 | /* There are a couple of different possible stack layouts that |
254 | we need to support. | |
255 | ||
256 | Before version 2.6.18, the kernel used completely independent | |
257 | layouts for non-RT and RT signals. For non-RT signals the stack | |
258 | began directly with a struct sigcontext. For RT signals the stack | |
259 | began with two redundant pointers (to the siginfo and ucontext), | |
260 | and then the siginfo and ucontext. | |
261 | ||
262 | As of version 2.6.18, the non-RT signal frame layout starts with | |
263 | a ucontext and the RT signal frame starts with a siginfo and then | |
264 | a ucontext. Also, the ucontext now has a designated save area | |
265 | for coprocessor registers. | |
266 | ||
267 | For RT signals, it's easy to tell the difference: we look for | |
268 | pinfo, the pointer to the siginfo. If it has the expected | |
269 | value, we have an old layout. If it doesn't, we have the new | |
270 | layout. | |
271 | ||
272 | For non-RT signals, it's a bit harder. We need something in one | |
273 | layout or the other with a recognizable offset and value. We can't | |
274 | use the return trampoline, because ARM usually uses SA_RESTORER, | |
275 | in which case the stack return trampoline is not filled in. | |
276 | We can't use the saved stack pointer, because sigaltstack might | |
277 | be in use. So for now we guess the new layout... */ | |
278 | ||
279 | /* There are three words (trap_no, error_code, oldmask) in | |
280 | struct sigcontext before r0. */ | |
281 | #define ARM_SIGCONTEXT_R0 0xc | |
282 | ||
283 | /* There are five words (uc_flags, uc_link, and three for uc_stack) | |
284 | in the ucontext_t before the sigcontext. */ | |
285 | #define ARM_UCONTEXT_SIGCONTEXT 0x14 | |
286 | ||
287 | /* There are three elements in an rt_sigframe before the ucontext: | |
288 | pinfo, puc, and info. The first two are pointers and the third | |
289 | is a struct siginfo, with size 128 bytes. We could follow puc | |
290 | to the ucontext, but it's simpler to skip the whole thing. */ | |
291 | #define ARM_OLD_RT_SIGFRAME_SIGINFO 0x8 | |
292 | #define ARM_OLD_RT_SIGFRAME_UCONTEXT 0x88 | |
293 | ||
294 | #define ARM_NEW_RT_SIGFRAME_UCONTEXT 0x80 | |
295 | ||
296 | #define ARM_NEW_SIGFRAME_MAGIC 0x5ac3c35a | |
297 | ||
8e9d1a24 DJ |
298 | static void |
299 | arm_linux_sigreturn_init (const struct tramp_frame *self, | |
a262aec2 | 300 | struct frame_info *this_frame, |
8e9d1a24 DJ |
301 | struct trad_frame_cache *this_cache, |
302 | CORE_ADDR func) | |
2a451106 | 303 | { |
e17a4113 UW |
304 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
305 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
a262aec2 | 306 | CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM); |
e17a4113 | 307 | ULONGEST uc_flags = read_memory_unsigned_integer (sp, 4, byte_order); |
edfb1a26 DJ |
308 | |
309 | if (uc_flags == ARM_NEW_SIGFRAME_MAGIC) | |
a262aec2 | 310 | arm_linux_sigtramp_cache (this_frame, this_cache, func, |
edfb1a26 DJ |
311 | ARM_UCONTEXT_SIGCONTEXT |
312 | + ARM_SIGCONTEXT_R0); | |
313 | else | |
a262aec2 | 314 | arm_linux_sigtramp_cache (this_frame, this_cache, func, |
edfb1a26 | 315 | ARM_SIGCONTEXT_R0); |
8e9d1a24 | 316 | } |
2a451106 | 317 | |
8e9d1a24 DJ |
318 | static void |
319 | arm_linux_rt_sigreturn_init (const struct tramp_frame *self, | |
a262aec2 | 320 | struct frame_info *this_frame, |
8e9d1a24 DJ |
321 | struct trad_frame_cache *this_cache, |
322 | CORE_ADDR func) | |
323 | { | |
e17a4113 UW |
324 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
325 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
a262aec2 | 326 | CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM); |
e17a4113 | 327 | ULONGEST pinfo = read_memory_unsigned_integer (sp, 4, byte_order); |
edfb1a26 DJ |
328 | |
329 | if (pinfo == sp + ARM_OLD_RT_SIGFRAME_SIGINFO) | |
a262aec2 | 330 | arm_linux_sigtramp_cache (this_frame, this_cache, func, |
edfb1a26 DJ |
331 | ARM_OLD_RT_SIGFRAME_UCONTEXT |
332 | + ARM_UCONTEXT_SIGCONTEXT | |
333 | + ARM_SIGCONTEXT_R0); | |
334 | else | |
a262aec2 | 335 | arm_linux_sigtramp_cache (this_frame, this_cache, func, |
edfb1a26 DJ |
336 | ARM_NEW_RT_SIGFRAME_UCONTEXT |
337 | + ARM_UCONTEXT_SIGCONTEXT | |
338 | + ARM_SIGCONTEXT_R0); | |
2a451106 KB |
339 | } |
340 | ||
f1973203 MR |
341 | static void |
342 | arm_linux_restart_syscall_init (const struct tramp_frame *self, | |
343 | struct frame_info *this_frame, | |
344 | struct trad_frame_cache *this_cache, | |
345 | CORE_ADDR func) | |
346 | { | |
347 | CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM); | |
348 | ||
349 | trad_frame_set_reg_addr (this_cache, ARM_PC_REGNUM, sp); | |
350 | trad_frame_set_reg_value (this_cache, ARM_SP_REGNUM, sp + 12); | |
351 | ||
352 | /* Save a frame ID. */ | |
353 | trad_frame_set_id (this_cache, frame_id_build (sp, func)); | |
354 | } | |
355 | ||
8e9d1a24 DJ |
356 | static struct tramp_frame arm_linux_sigreturn_tramp_frame = { |
357 | SIGTRAMP_FRAME, | |
358 | 4, | |
359 | { | |
360 | { ARM_LINUX_SIGRETURN_INSTR, -1 }, | |
361 | { TRAMP_SENTINEL_INSN } | |
362 | }, | |
363 | arm_linux_sigreturn_init | |
364 | }; | |
365 | ||
366 | static struct tramp_frame arm_linux_rt_sigreturn_tramp_frame = { | |
367 | SIGTRAMP_FRAME, | |
368 | 4, | |
369 | { | |
370 | { ARM_LINUX_RT_SIGRETURN_INSTR, -1 }, | |
371 | { TRAMP_SENTINEL_INSN } | |
372 | }, | |
373 | arm_linux_rt_sigreturn_init | |
374 | }; | |
375 | ||
376 | static struct tramp_frame arm_eabi_linux_sigreturn_tramp_frame = { | |
377 | SIGTRAMP_FRAME, | |
378 | 4, | |
379 | { | |
380 | { ARM_SET_R7_SIGRETURN, -1 }, | |
381 | { ARM_EABI_SYSCALL, -1 }, | |
382 | { TRAMP_SENTINEL_INSN } | |
383 | }, | |
384 | arm_linux_sigreturn_init | |
385 | }; | |
386 | ||
387 | static struct tramp_frame arm_eabi_linux_rt_sigreturn_tramp_frame = { | |
388 | SIGTRAMP_FRAME, | |
389 | 4, | |
390 | { | |
391 | { ARM_SET_R7_RT_SIGRETURN, -1 }, | |
392 | { ARM_EABI_SYSCALL, -1 }, | |
393 | { TRAMP_SENTINEL_INSN } | |
394 | }, | |
395 | arm_linux_rt_sigreturn_init | |
396 | }; | |
397 | ||
f1973203 MR |
398 | static struct tramp_frame arm_linux_restart_syscall_tramp_frame = { |
399 | NORMAL_FRAME, | |
400 | 4, | |
401 | { | |
402 | { ARM_OABI_SYSCALL_RESTART_SYSCALL, -1 }, | |
403 | { ARM_LDR_PC_SP_12, -1 }, | |
404 | { TRAMP_SENTINEL_INSN } | |
405 | }, | |
406 | arm_linux_restart_syscall_init | |
407 | }; | |
408 | ||
cb587d83 DJ |
409 | /* Core file and register set support. */ |
410 | ||
411 | #define ARM_LINUX_SIZEOF_GREGSET (18 * INT_REGISTER_SIZE) | |
412 | ||
413 | void | |
414 | arm_linux_supply_gregset (const struct regset *regset, | |
415 | struct regcache *regcache, | |
416 | int regnum, const void *gregs_buf, size_t len) | |
417 | { | |
e17a4113 UW |
418 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
419 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
cb587d83 DJ |
420 | const gdb_byte *gregs = gregs_buf; |
421 | int regno; | |
422 | CORE_ADDR reg_pc; | |
423 | gdb_byte pc_buf[INT_REGISTER_SIZE]; | |
424 | ||
425 | for (regno = ARM_A1_REGNUM; regno < ARM_PC_REGNUM; regno++) | |
426 | if (regnum == -1 || regnum == regno) | |
427 | regcache_raw_supply (regcache, regno, | |
428 | gregs + INT_REGISTER_SIZE * regno); | |
429 | ||
430 | if (regnum == ARM_PS_REGNUM || regnum == -1) | |
431 | { | |
432 | if (arm_apcs_32) | |
433 | regcache_raw_supply (regcache, ARM_PS_REGNUM, | |
17c12639 | 434 | gregs + INT_REGISTER_SIZE * ARM_CPSR_GREGNUM); |
cb587d83 DJ |
435 | else |
436 | regcache_raw_supply (regcache, ARM_PS_REGNUM, | |
437 | gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM); | |
438 | } | |
439 | ||
440 | if (regnum == ARM_PC_REGNUM || regnum == -1) | |
441 | { | |
442 | reg_pc = extract_unsigned_integer (gregs | |
443 | + INT_REGISTER_SIZE * ARM_PC_REGNUM, | |
e17a4113 UW |
444 | INT_REGISTER_SIZE, byte_order); |
445 | reg_pc = gdbarch_addr_bits_remove (gdbarch, reg_pc); | |
446 | store_unsigned_integer (pc_buf, INT_REGISTER_SIZE, byte_order, reg_pc); | |
cb587d83 DJ |
447 | regcache_raw_supply (regcache, ARM_PC_REGNUM, pc_buf); |
448 | } | |
449 | } | |
450 | ||
451 | void | |
452 | arm_linux_collect_gregset (const struct regset *regset, | |
453 | const struct regcache *regcache, | |
454 | int regnum, void *gregs_buf, size_t len) | |
455 | { | |
456 | gdb_byte *gregs = gregs_buf; | |
457 | int regno; | |
458 | ||
459 | for (regno = ARM_A1_REGNUM; regno < ARM_PC_REGNUM; regno++) | |
460 | if (regnum == -1 || regnum == regno) | |
461 | regcache_raw_collect (regcache, regno, | |
462 | gregs + INT_REGISTER_SIZE * regno); | |
463 | ||
464 | if (regnum == ARM_PS_REGNUM || regnum == -1) | |
465 | { | |
466 | if (arm_apcs_32) | |
467 | regcache_raw_collect (regcache, ARM_PS_REGNUM, | |
17c12639 | 468 | gregs + INT_REGISTER_SIZE * ARM_CPSR_GREGNUM); |
cb587d83 DJ |
469 | else |
470 | regcache_raw_collect (regcache, ARM_PS_REGNUM, | |
471 | gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM); | |
472 | } | |
473 | ||
474 | if (regnum == ARM_PC_REGNUM || regnum == -1) | |
475 | regcache_raw_collect (regcache, ARM_PC_REGNUM, | |
476 | gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM); | |
477 | } | |
478 | ||
479 | /* Support for register format used by the NWFPE FPA emulator. */ | |
480 | ||
481 | #define typeNone 0x00 | |
482 | #define typeSingle 0x01 | |
483 | #define typeDouble 0x02 | |
484 | #define typeExtended 0x03 | |
485 | ||
486 | void | |
487 | supply_nwfpe_register (struct regcache *regcache, int regno, | |
488 | const gdb_byte *regs) | |
489 | { | |
490 | const gdb_byte *reg_data; | |
491 | gdb_byte reg_tag; | |
492 | gdb_byte buf[FP_REGISTER_SIZE]; | |
493 | ||
494 | reg_data = regs + (regno - ARM_F0_REGNUM) * FP_REGISTER_SIZE; | |
495 | reg_tag = regs[(regno - ARM_F0_REGNUM) + NWFPE_TAGS_OFFSET]; | |
496 | memset (buf, 0, FP_REGISTER_SIZE); | |
497 | ||
498 | switch (reg_tag) | |
499 | { | |
500 | case typeSingle: | |
501 | memcpy (buf, reg_data, 4); | |
502 | break; | |
503 | case typeDouble: | |
504 | memcpy (buf, reg_data + 4, 4); | |
505 | memcpy (buf + 4, reg_data, 4); | |
506 | break; | |
507 | case typeExtended: | |
508 | /* We want sign and exponent, then least significant bits, | |
509 | then most significant. NWFPE does sign, most, least. */ | |
510 | memcpy (buf, reg_data, 4); | |
511 | memcpy (buf + 4, reg_data + 8, 4); | |
512 | memcpy (buf + 8, reg_data + 4, 4); | |
513 | break; | |
514 | default: | |
515 | break; | |
516 | } | |
517 | ||
518 | regcache_raw_supply (regcache, regno, buf); | |
519 | } | |
520 | ||
521 | void | |
522 | collect_nwfpe_register (const struct regcache *regcache, int regno, | |
523 | gdb_byte *regs) | |
524 | { | |
525 | gdb_byte *reg_data; | |
526 | gdb_byte reg_tag; | |
527 | gdb_byte buf[FP_REGISTER_SIZE]; | |
528 | ||
529 | regcache_raw_collect (regcache, regno, buf); | |
530 | ||
531 | /* NOTE drow/2006-06-07: This code uses the tag already in the | |
532 | register buffer. I've preserved that when moving the code | |
533 | from the native file to the target file. But this doesn't | |
534 | always make sense. */ | |
535 | ||
536 | reg_data = regs + (regno - ARM_F0_REGNUM) * FP_REGISTER_SIZE; | |
537 | reg_tag = regs[(regno - ARM_F0_REGNUM) + NWFPE_TAGS_OFFSET]; | |
538 | ||
539 | switch (reg_tag) | |
540 | { | |
541 | case typeSingle: | |
542 | memcpy (reg_data, buf, 4); | |
543 | break; | |
544 | case typeDouble: | |
545 | memcpy (reg_data, buf + 4, 4); | |
546 | memcpy (reg_data + 4, buf, 4); | |
547 | break; | |
548 | case typeExtended: | |
549 | memcpy (reg_data, buf, 4); | |
550 | memcpy (reg_data + 4, buf + 8, 4); | |
551 | memcpy (reg_data + 8, buf + 4, 4); | |
552 | break; | |
553 | default: | |
554 | break; | |
555 | } | |
556 | } | |
557 | ||
558 | void | |
559 | arm_linux_supply_nwfpe (const struct regset *regset, | |
560 | struct regcache *regcache, | |
561 | int regnum, const void *regs_buf, size_t len) | |
562 | { | |
563 | const gdb_byte *regs = regs_buf; | |
564 | int regno; | |
565 | ||
566 | if (regnum == ARM_FPS_REGNUM || regnum == -1) | |
567 | regcache_raw_supply (regcache, ARM_FPS_REGNUM, | |
568 | regs + NWFPE_FPSR_OFFSET); | |
569 | ||
570 | for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++) | |
571 | if (regnum == -1 || regnum == regno) | |
572 | supply_nwfpe_register (regcache, regno, regs); | |
573 | } | |
574 | ||
575 | void | |
576 | arm_linux_collect_nwfpe (const struct regset *regset, | |
577 | const struct regcache *regcache, | |
578 | int regnum, void *regs_buf, size_t len) | |
579 | { | |
580 | gdb_byte *regs = regs_buf; | |
581 | int regno; | |
582 | ||
583 | for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++) | |
584 | if (regnum == -1 || regnum == regno) | |
585 | collect_nwfpe_register (regcache, regno, regs); | |
586 | ||
587 | if (regnum == ARM_FPS_REGNUM || regnum == -1) | |
588 | regcache_raw_collect (regcache, ARM_FPS_REGNUM, | |
589 | regs + INT_REGISTER_SIZE * ARM_FPS_REGNUM); | |
590 | } | |
591 | ||
592 | /* Return the appropriate register set for the core section identified | |
593 | by SECT_NAME and SECT_SIZE. */ | |
594 | ||
595 | static const struct regset * | |
596 | arm_linux_regset_from_core_section (struct gdbarch *gdbarch, | |
597 | const char *sect_name, size_t sect_size) | |
598 | { | |
599 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
600 | ||
601 | if (strcmp (sect_name, ".reg") == 0 | |
602 | && sect_size == ARM_LINUX_SIZEOF_GREGSET) | |
603 | { | |
604 | if (tdep->gregset == NULL) | |
605 | tdep->gregset = regset_alloc (gdbarch, arm_linux_supply_gregset, | |
606 | arm_linux_collect_gregset); | |
607 | return tdep->gregset; | |
608 | } | |
609 | ||
610 | if (strcmp (sect_name, ".reg2") == 0 | |
611 | && sect_size == ARM_LINUX_SIZEOF_NWFPE) | |
612 | { | |
613 | if (tdep->fpregset == NULL) | |
614 | tdep->fpregset = regset_alloc (gdbarch, arm_linux_supply_nwfpe, | |
615 | arm_linux_collect_nwfpe); | |
616 | return tdep->fpregset; | |
617 | } | |
618 | ||
619 | return NULL; | |
620 | } | |
621 | ||
daddc3c1 DJ |
622 | /* Insert a single step breakpoint at the next executed instruction. */ |
623 | ||
63807e1d | 624 | static int |
daddc3c1 DJ |
625 | arm_linux_software_single_step (struct frame_info *frame) |
626 | { | |
a6d9a66e | 627 | struct gdbarch *gdbarch = get_frame_arch (frame); |
6c95b8df | 628 | struct address_space *aspace = get_frame_address_space (frame); |
daddc3c1 DJ |
629 | CORE_ADDR next_pc = arm_get_next_pc (frame, get_frame_pc (frame)); |
630 | ||
631 | /* The Linux kernel offers some user-mode helpers in a high page. We can | |
632 | not read this page (as of 2.6.23), and even if we could then we couldn't | |
633 | set breakpoints in it, and even if we could then the atomic operations | |
634 | would fail when interrupted. They are all called as functions and return | |
635 | to the address in LR, so step to there instead. */ | |
636 | if (next_pc > 0xffff0000) | |
637 | next_pc = get_frame_register_unsigned (frame, ARM_LR_REGNUM); | |
638 | ||
6c95b8df | 639 | insert_single_step_breakpoint (gdbarch, aspace, next_pc); |
daddc3c1 DJ |
640 | |
641 | return 1; | |
642 | } | |
643 | ||
cca44b1b JB |
644 | /* Support for displaced stepping of Linux SVC instructions. */ |
645 | ||
646 | static void | |
647 | arm_linux_cleanup_svc (struct gdbarch *gdbarch ATTRIBUTE_UNUSED, | |
648 | struct regcache *regs, | |
649 | struct displaced_step_closure *dsc) | |
650 | { | |
651 | CORE_ADDR from = dsc->insn_addr; | |
652 | ULONGEST apparent_pc; | |
653 | int within_scratch; | |
654 | ||
655 | regcache_cooked_read_unsigned (regs, ARM_PC_REGNUM, &apparent_pc); | |
656 | ||
657 | within_scratch = (apparent_pc >= dsc->scratch_base | |
658 | && apparent_pc < (dsc->scratch_base | |
659 | + DISPLACED_MODIFIED_INSNS * 4 + 4)); | |
660 | ||
661 | if (debug_displaced) | |
662 | { | |
663 | fprintf_unfiltered (gdb_stdlog, "displaced: PC is apparently %.8lx after " | |
664 | "SVC step ", (unsigned long) apparent_pc); | |
665 | if (within_scratch) | |
666 | fprintf_unfiltered (gdb_stdlog, "(within scratch space)\n"); | |
667 | else | |
668 | fprintf_unfiltered (gdb_stdlog, "(outside scratch space)\n"); | |
669 | } | |
670 | ||
671 | if (within_scratch) | |
672 | displaced_write_reg (regs, dsc, ARM_PC_REGNUM, from + 4, BRANCH_WRITE_PC); | |
673 | } | |
674 | ||
675 | static int | |
676 | arm_linux_copy_svc (struct gdbarch *gdbarch, uint32_t insn, CORE_ADDR to, | |
677 | struct regcache *regs, struct displaced_step_closure *dsc) | |
678 | { | |
679 | CORE_ADDR from = dsc->insn_addr; | |
680 | struct frame_info *frame; | |
681 | unsigned int svc_number = displaced_read_reg (regs, from, 7); | |
682 | ||
683 | if (debug_displaced) | |
684 | fprintf_unfiltered (gdb_stdlog, "displaced: copying Linux svc insn %.8lx\n", | |
685 | (unsigned long) insn); | |
686 | ||
687 | frame = get_current_frame (); | |
688 | ||
689 | /* Is this a sigreturn or rt_sigreturn syscall? Note: these are only useful | |
690 | for EABI. */ | |
691 | if (svc_number == 119 || svc_number == 173) | |
692 | { | |
693 | if (get_frame_type (frame) == SIGTRAMP_FRAME) | |
694 | { | |
695 | CORE_ADDR return_to; | |
696 | struct symtab_and_line sal; | |
697 | ||
698 | if (debug_displaced) | |
699 | fprintf_unfiltered (gdb_stdlog, "displaced: found " | |
700 | "sigreturn/rt_sigreturn SVC call. PC in frame = %lx\n", | |
701 | (unsigned long) get_frame_pc (frame)); | |
702 | ||
703 | return_to = frame_unwind_caller_pc (frame); | |
704 | if (debug_displaced) | |
705 | fprintf_unfiltered (gdb_stdlog, "displaced: unwind pc = %lx. " | |
706 | "Setting momentary breakpoint.\n", (unsigned long) return_to); | |
707 | ||
708 | gdb_assert (inferior_thread ()->step_resume_breakpoint == NULL); | |
709 | ||
710 | sal = find_pc_line (return_to, 0); | |
711 | sal.pc = return_to; | |
712 | sal.section = find_pc_overlay (return_to); | |
713 | sal.explicit_pc = 1; | |
714 | ||
715 | frame = get_prev_frame (frame); | |
716 | ||
717 | if (frame) | |
718 | { | |
719 | inferior_thread ()->step_resume_breakpoint | |
720 | = set_momentary_breakpoint (gdbarch, sal, get_frame_id (frame), | |
721 | bp_step_resume); | |
722 | ||
723 | /* We need to make sure we actually insert the momentary | |
724 | breakpoint set above. */ | |
725 | insert_breakpoints (); | |
726 | } | |
727 | else if (debug_displaced) | |
728 | fprintf_unfiltered (gdb_stderr, "displaced: couldn't find previous " | |
729 | "frame to set momentary breakpoint for " | |
730 | "sigreturn/rt_sigreturn\n"); | |
731 | } | |
732 | else if (debug_displaced) | |
733 | fprintf_unfiltered (gdb_stdlog, "displaced: sigreturn/rt_sigreturn " | |
734 | "SVC call not in signal trampoline frame\n"); | |
735 | } | |
736 | ||
737 | /* Preparation: If we detect sigreturn, set momentary breakpoint at resume | |
738 | location, else nothing. | |
739 | Insn: unmodified svc. | |
740 | Cleanup: if pc lands in scratch space, pc <- insn_addr + 4 | |
741 | else leave pc alone. */ | |
742 | ||
743 | dsc->modinsn[0] = insn; | |
744 | ||
745 | dsc->cleanup = &arm_linux_cleanup_svc; | |
746 | /* Pretend we wrote to the PC, so cleanup doesn't set PC to the next | |
747 | instruction. */ | |
748 | dsc->wrote_to_pc = 1; | |
749 | ||
750 | return 0; | |
751 | } | |
752 | ||
753 | ||
754 | /* The following two functions implement single-stepping over calls to Linux | |
755 | kernel helper routines, which perform e.g. atomic operations on architecture | |
756 | variants which don't support them natively. | |
757 | ||
758 | When this function is called, the PC will be pointing at the kernel helper | |
759 | (at an address inaccessible to GDB), and r14 will point to the return | |
760 | address. Displaced stepping always executes code in the copy area: | |
761 | so, make the copy-area instruction branch back to the kernel helper (the | |
762 | "from" address), and make r14 point to the breakpoint in the copy area. In | |
763 | that way, we regain control once the kernel helper returns, and can clean | |
764 | up appropriately (as if we had just returned from the kernel helper as it | |
765 | would have been called from the non-displaced location). */ | |
766 | ||
767 | static void | |
768 | cleanup_kernel_helper_return (struct gdbarch *gdbarch ATTRIBUTE_UNUSED, | |
769 | struct regcache *regs, | |
770 | struct displaced_step_closure *dsc) | |
771 | { | |
772 | displaced_write_reg (regs, dsc, ARM_LR_REGNUM, dsc->tmp[0], CANNOT_WRITE_PC); | |
773 | displaced_write_reg (regs, dsc, ARM_PC_REGNUM, dsc->tmp[0], BRANCH_WRITE_PC); | |
774 | } | |
775 | ||
776 | static void | |
777 | arm_catch_kernel_helper_return (struct gdbarch *gdbarch, CORE_ADDR from, | |
778 | CORE_ADDR to, struct regcache *regs, | |
779 | struct displaced_step_closure *dsc) | |
780 | { | |
781 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
782 | ||
783 | dsc->numinsns = 1; | |
784 | dsc->insn_addr = from; | |
785 | dsc->cleanup = &cleanup_kernel_helper_return; | |
786 | /* Say we wrote to the PC, else cleanup will set PC to the next | |
787 | instruction in the helper, which isn't helpful. */ | |
788 | dsc->wrote_to_pc = 1; | |
789 | ||
790 | /* Preparation: tmp[0] <- r14 | |
791 | r14 <- <scratch space>+4 | |
792 | *(<scratch space>+8) <- from | |
793 | Insn: ldr pc, [r14, #4] | |
794 | Cleanup: r14 <- tmp[0], pc <- tmp[0]. */ | |
795 | ||
796 | dsc->tmp[0] = displaced_read_reg (regs, from, ARM_LR_REGNUM); | |
797 | displaced_write_reg (regs, dsc, ARM_LR_REGNUM, (ULONGEST) to + 4, | |
798 | CANNOT_WRITE_PC); | |
799 | write_memory_unsigned_integer (to + 8, 4, byte_order, from); | |
800 | ||
801 | dsc->modinsn[0] = 0xe59ef004; /* ldr pc, [lr, #4]. */ | |
802 | } | |
803 | ||
804 | /* Linux-specific displaced step instruction copying function. Detects when | |
805 | the program has stepped into a Linux kernel helper routine (which must be | |
806 | handled as a special case), falling back to arm_displaced_step_copy_insn() | |
807 | if it hasn't. */ | |
808 | ||
809 | static struct displaced_step_closure * | |
810 | arm_linux_displaced_step_copy_insn (struct gdbarch *gdbarch, | |
811 | CORE_ADDR from, CORE_ADDR to, | |
812 | struct regcache *regs) | |
813 | { | |
814 | struct displaced_step_closure *dsc | |
815 | = xmalloc (sizeof (struct displaced_step_closure)); | |
816 | ||
817 | /* Detect when we enter an (inaccessible by GDB) Linux kernel helper, and | |
818 | stop at the return location. */ | |
819 | if (from > 0xffff0000) | |
820 | { | |
821 | if (debug_displaced) | |
822 | fprintf_unfiltered (gdb_stdlog, "displaced: detected kernel helper " | |
823 | "at %.8lx\n", (unsigned long) from); | |
824 | ||
825 | arm_catch_kernel_helper_return (gdbarch, from, to, regs, dsc); | |
826 | } | |
827 | else | |
828 | { | |
829 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
830 | uint32_t insn = read_memory_unsigned_integer (from, 4, byte_order); | |
831 | ||
832 | if (debug_displaced) | |
833 | fprintf_unfiltered (gdb_stdlog, "displaced: stepping insn %.8lx " | |
834 | "at %.8lx\n", (unsigned long) insn, | |
835 | (unsigned long) from); | |
836 | ||
837 | /* Override the default handling of SVC instructions. */ | |
838 | dsc->u.svc.copy_svc_os = arm_linux_copy_svc; | |
839 | ||
840 | arm_process_displaced_insn (gdbarch, insn, from, to, regs, dsc); | |
841 | } | |
842 | ||
843 | arm_displaced_init_closure (gdbarch, from, to, dsc); | |
844 | ||
845 | return dsc; | |
846 | } | |
847 | ||
97e03143 RE |
848 | static void |
849 | arm_linux_init_abi (struct gdbarch_info info, | |
850 | struct gdbarch *gdbarch) | |
851 | { | |
852 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
853 | ||
854 | tdep->lowest_pc = 0x8000; | |
2ef47cd0 | 855 | if (info.byte_order == BFD_ENDIAN_BIG) |
498b1f87 | 856 | { |
c75a2cc8 DJ |
857 | if (tdep->arm_abi == ARM_ABI_AAPCS) |
858 | tdep->arm_breakpoint = eabi_linux_arm_be_breakpoint; | |
859 | else | |
860 | tdep->arm_breakpoint = arm_linux_arm_be_breakpoint; | |
498b1f87 | 861 | tdep->thumb_breakpoint = arm_linux_thumb_be_breakpoint; |
177321bd | 862 | tdep->thumb2_breakpoint = arm_linux_thumb2_be_breakpoint; |
498b1f87 | 863 | } |
2ef47cd0 | 864 | else |
498b1f87 | 865 | { |
c75a2cc8 DJ |
866 | if (tdep->arm_abi == ARM_ABI_AAPCS) |
867 | tdep->arm_breakpoint = eabi_linux_arm_le_breakpoint; | |
868 | else | |
869 | tdep->arm_breakpoint = arm_linux_arm_le_breakpoint; | |
498b1f87 | 870 | tdep->thumb_breakpoint = arm_linux_thumb_le_breakpoint; |
177321bd | 871 | tdep->thumb2_breakpoint = arm_linux_thumb2_le_breakpoint; |
498b1f87 | 872 | } |
66e810cd | 873 | tdep->arm_breakpoint_size = sizeof (arm_linux_arm_le_breakpoint); |
498b1f87 | 874 | tdep->thumb_breakpoint_size = sizeof (arm_linux_thumb_le_breakpoint); |
177321bd | 875 | tdep->thumb2_breakpoint_size = sizeof (arm_linux_thumb2_le_breakpoint); |
9df628e0 | 876 | |
28e97307 DJ |
877 | if (tdep->fp_model == ARM_FLOAT_AUTO) |
878 | tdep->fp_model = ARM_FLOAT_FPA; | |
fd50bc42 | 879 | |
a6cdd8c5 RE |
880 | tdep->jb_pc = ARM_LINUX_JB_PC; |
881 | tdep->jb_elt_size = ARM_LINUX_JB_ELEMENT_SIZE; | |
19d3fc80 | 882 | |
7aa1783e | 883 | set_solib_svr4_fetch_link_map_offsets |
76a9d10f | 884 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); |
7aa1783e | 885 | |
190dce09 | 886 | /* Single stepping. */ |
daddc3c1 | 887 | set_gdbarch_software_single_step (gdbarch, arm_linux_software_single_step); |
190dce09 | 888 | |
0e18d038 | 889 | /* Shared library handling. */ |
0e18d038 | 890 | set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); |
bb41a796 | 891 | set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); |
b2756930 KB |
892 | |
893 | /* Enable TLS support. */ | |
894 | set_gdbarch_fetch_tls_load_module_address (gdbarch, | |
895 | svr4_fetch_objfile_link_map); | |
8e9d1a24 DJ |
896 | |
897 | tramp_frame_prepend_unwinder (gdbarch, | |
898 | &arm_linux_sigreturn_tramp_frame); | |
899 | tramp_frame_prepend_unwinder (gdbarch, | |
900 | &arm_linux_rt_sigreturn_tramp_frame); | |
901 | tramp_frame_prepend_unwinder (gdbarch, | |
902 | &arm_eabi_linux_sigreturn_tramp_frame); | |
903 | tramp_frame_prepend_unwinder (gdbarch, | |
904 | &arm_eabi_linux_rt_sigreturn_tramp_frame); | |
f1973203 MR |
905 | tramp_frame_prepend_unwinder (gdbarch, |
906 | &arm_linux_restart_syscall_tramp_frame); | |
cb587d83 DJ |
907 | |
908 | /* Core file support. */ | |
909 | set_gdbarch_regset_from_core_section (gdbarch, | |
910 | arm_linux_regset_from_core_section); | |
4aa995e1 PA |
911 | |
912 | set_gdbarch_get_siginfo_type (gdbarch, linux_get_siginfo_type); | |
cca44b1b JB |
913 | |
914 | /* Displaced stepping. */ | |
915 | set_gdbarch_displaced_step_copy_insn (gdbarch, | |
916 | arm_linux_displaced_step_copy_insn); | |
917 | set_gdbarch_displaced_step_fixup (gdbarch, arm_displaced_step_fixup); | |
918 | set_gdbarch_displaced_step_free_closure (gdbarch, | |
919 | simple_displaced_step_free_closure); | |
920 | set_gdbarch_displaced_step_location (gdbarch, displaced_step_at_entry_point); | |
97e03143 RE |
921 | } |
922 | ||
63807e1d PA |
923 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
924 | extern initialize_file_ftype _initialize_arm_linux_tdep; | |
925 | ||
faf5f7ad SB |
926 | void |
927 | _initialize_arm_linux_tdep (void) | |
928 | { | |
05816f70 MK |
929 | gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_LINUX, |
930 | arm_linux_init_abi); | |
faf5f7ad | 931 | } |