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faf5f7ad | 1 | /* GNU/Linux on ARM target support. |
0fd88904 | 2 | |
0b302171 | 3 | Copyright (C) 1999-2012 Free Software Foundation, Inc. |
faf5f7ad SB |
4 | |
5 | This file is part of GDB. | |
6 | ||
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 | |
a9762ec7 | 9 | the Free Software Foundation; either version 3 of the License, or |
faf5f7ad SB |
10 | (at your option) any later version. |
11 | ||
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. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
faf5f7ad SB |
19 | |
20 | #include "defs.h" | |
c20f6dea SB |
21 | #include "target.h" |
22 | #include "value.h" | |
faf5f7ad | 23 | #include "gdbtypes.h" |
134e61c4 | 24 | #include "floatformat.h" |
2a451106 KB |
25 | #include "gdbcore.h" |
26 | #include "frame.h" | |
4e052eda | 27 | #include "regcache.h" |
d16aafd8 | 28 | #include "doublest.h" |
7aa1783e | 29 | #include "solib-svr4.h" |
4be87837 | 30 | #include "osabi.h" |
cb587d83 | 31 | #include "regset.h" |
8e9d1a24 DJ |
32 | #include "trad-frame.h" |
33 | #include "tramp-frame.h" | |
daddc3c1 | 34 | #include "breakpoint.h" |
ef7e8358 | 35 | #include "auxv.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 | ||
ef7e8358 UW |
48 | /* This is defined in <elf.h> on ARM GNU/Linux systems. */ |
49 | #define AT_HWCAP 16 | |
50 | ||
cb587d83 DJ |
51 | extern int arm_apcs_32; |
52 | ||
fdf39c9a RE |
53 | /* Under ARM GNU/Linux the traditional way of performing a breakpoint |
54 | is to execute a particular software interrupt, rather than use a | |
55 | particular undefined instruction to provoke a trap. Upon exection | |
56 | of the software interrupt the kernel stops the inferior with a | |
498b1f87 | 57 | SIGTRAP, and wakes the debugger. */ |
66e810cd | 58 | |
2ef47cd0 DJ |
59 | static const char arm_linux_arm_le_breakpoint[] = { 0x01, 0x00, 0x9f, 0xef }; |
60 | ||
61 | static const char arm_linux_arm_be_breakpoint[] = { 0xef, 0x9f, 0x00, 0x01 }; | |
66e810cd | 62 | |
c75a2cc8 DJ |
63 | /* However, the EABI syscall interface (new in Nov. 2005) does not look at |
64 | the operand of the swi if old-ABI compatibility is disabled. Therefore, | |
65 | use an undefined instruction instead. This is supported as of kernel | |
66 | version 2.5.70 (May 2003), so should be a safe assumption for EABI | |
67 | binaries. */ | |
68 | ||
69 | static const char eabi_linux_arm_le_breakpoint[] = { 0xf0, 0x01, 0xf0, 0xe7 }; | |
70 | ||
71 | static const char eabi_linux_arm_be_breakpoint[] = { 0xe7, 0xf0, 0x01, 0xf0 }; | |
72 | ||
73 | /* All the kernels which support Thumb support using a specific undefined | |
74 | instruction for the Thumb breakpoint. */ | |
75 | ||
498b1f87 DJ |
76 | static const char arm_linux_thumb_be_breakpoint[] = {0xde, 0x01}; |
77 | ||
78 | static const char arm_linux_thumb_le_breakpoint[] = {0x01, 0xde}; | |
79 | ||
177321bd DJ |
80 | /* Because the 16-bit Thumb breakpoint is affected by Thumb-2 IT blocks, |
81 | we must use a length-appropriate breakpoint for 32-bit Thumb | |
82 | instructions. See also thumb_get_next_pc. */ | |
83 | ||
84 | static const char arm_linux_thumb2_be_breakpoint[] = { 0xf7, 0xf0, 0xa0, 0x00 }; | |
85 | ||
86 | static const char arm_linux_thumb2_le_breakpoint[] = { 0xf0, 0xf7, 0x00, 0xa0 }; | |
87 | ||
f8624c62 MGD |
88 | /* Description of the longjmp buffer. The buffer is treated as an array of |
89 | elements of size ARM_LINUX_JB_ELEMENT_SIZE. | |
90 | ||
91 | The location of saved registers in this buffer (in particular the PC | |
92 | to use after longjmp is called) varies depending on the ABI (in | |
93 | particular the FP model) and also (possibly) the C Library. | |
94 | ||
95 | For glibc, eglibc, and uclibc the following holds: If the FP model is | |
96 | SoftVFP or VFP (which implies EABI) then the PC is at offset 9 in the | |
97 | buffer. This is also true for the SoftFPA model. However, for the FPA | |
98 | model the PC is at offset 21 in the buffer. */ | |
7a5ea0d4 | 99 | #define ARM_LINUX_JB_ELEMENT_SIZE INT_REGISTER_SIZE |
f8624c62 MGD |
100 | #define ARM_LINUX_JB_PC_FPA 21 |
101 | #define ARM_LINUX_JB_PC_EABI 9 | |
faf5f7ad | 102 | |
f38e884d | 103 | /* |
fdf39c9a RE |
104 | Dynamic Linking on ARM GNU/Linux |
105 | -------------------------------- | |
f38e884d SB |
106 | |
107 | Note: PLT = procedure linkage table | |
108 | GOT = global offset table | |
109 | ||
110 | As much as possible, ELF dynamic linking defers the resolution of | |
0963b4bd | 111 | jump/call addresses until the last minute. The technique used is |
f38e884d SB |
112 | inspired by the i386 ELF design, and is based on the following |
113 | constraints. | |
114 | ||
115 | 1) The calling technique should not force a change in the assembly | |
116 | code produced for apps; it MAY cause changes in the way assembly | |
117 | code is produced for position independent code (i.e. shared | |
118 | libraries). | |
119 | ||
120 | 2) The technique must be such that all executable areas must not be | |
121 | modified; and any modified areas must not be executed. | |
122 | ||
123 | To do this, there are three steps involved in a typical jump: | |
124 | ||
125 | 1) in the code | |
126 | 2) through the PLT | |
127 | 3) using a pointer from the GOT | |
128 | ||
129 | When the executable or library is first loaded, each GOT entry is | |
130 | initialized to point to the code which implements dynamic name | |
131 | resolution and code finding. This is normally a function in the | |
fdf39c9a RE |
132 | program interpreter (on ARM GNU/Linux this is usually |
133 | ld-linux.so.2, but it does not have to be). On the first | |
134 | invocation, the function is located and the GOT entry is replaced | |
135 | with the real function address. Subsequent calls go through steps | |
136 | 1, 2 and 3 and end up calling the real code. | |
f38e884d SB |
137 | |
138 | 1) In the code: | |
139 | ||
140 | b function_call | |
141 | bl function_call | |
142 | ||
143 | This is typical ARM code using the 26 bit relative branch or branch | |
144 | and link instructions. The target of the instruction | |
145 | (function_call is usually the address of the function to be called. | |
146 | In position independent code, the target of the instruction is | |
147 | actually an entry in the PLT when calling functions in a shared | |
148 | library. Note that this call is identical to a normal function | |
149 | call, only the target differs. | |
150 | ||
151 | 2) In the PLT: | |
152 | ||
0963b4bd MS |
153 | The PLT is a synthetic area, created by the linker. It exists in |
154 | both executables and libraries. It is an array of stubs, one per | |
155 | imported function call. It looks like this: | |
f38e884d SB |
156 | |
157 | PLT[0]: | |
158 | str lr, [sp, #-4]! @push the return address (lr) | |
159 | ldr lr, [pc, #16] @load from 6 words ahead | |
160 | add lr, pc, lr @form an address for GOT[0] | |
161 | ldr pc, [lr, #8]! @jump to the contents of that addr | |
162 | ||
163 | The return address (lr) is pushed on the stack and used for | |
164 | calculations. The load on the second line loads the lr with | |
165 | &GOT[3] - . - 20. The addition on the third leaves: | |
166 | ||
167 | lr = (&GOT[3] - . - 20) + (. + 8) | |
168 | lr = (&GOT[3] - 12) | |
169 | lr = &GOT[0] | |
170 | ||
171 | On the fourth line, the pc and lr are both updated, so that: | |
172 | ||
173 | pc = GOT[2] | |
174 | lr = &GOT[0] + 8 | |
175 | = &GOT[2] | |
176 | ||
0963b4bd | 177 | NOTE: PLT[0] borrows an offset .word from PLT[1]. This is a little |
f38e884d SB |
178 | "tight", but allows us to keep all the PLT entries the same size. |
179 | ||
180 | PLT[n+1]: | |
181 | ldr ip, [pc, #4] @load offset from gotoff | |
182 | add ip, pc, ip @add the offset to the pc | |
183 | ldr pc, [ip] @jump to that address | |
184 | gotoff: .word GOT[n+3] - . | |
185 | ||
186 | The load on the first line, gets an offset from the fourth word of | |
187 | the PLT entry. The add on the second line makes ip = &GOT[n+3], | |
188 | which contains either a pointer to PLT[0] (the fixup trampoline) or | |
189 | a pointer to the actual code. | |
190 | ||
191 | 3) In the GOT: | |
192 | ||
193 | The GOT contains helper pointers for both code (PLT) fixups and | |
0963b4bd | 194 | data fixups. The first 3 entries of the GOT are special. The next |
f38e884d | 195 | M entries (where M is the number of entries in the PLT) belong to |
0963b4bd MS |
196 | the PLT fixups. The next D (all remaining) entries belong to |
197 | various data fixups. The actual size of the GOT is 3 + M + D. | |
f38e884d | 198 | |
0963b4bd | 199 | The GOT is also a synthetic area, created by the linker. It exists |
f38e884d SB |
200 | in both executables and libraries. When the GOT is first |
201 | initialized , all the GOT entries relating to PLT fixups are | |
202 | pointing to code back at PLT[0]. | |
203 | ||
204 | The special entries in the GOT are: | |
205 | ||
206 | GOT[0] = linked list pointer used by the dynamic loader | |
207 | GOT[1] = pointer to the reloc table for this module | |
208 | GOT[2] = pointer to the fixup/resolver code | |
209 | ||
210 | The first invocation of function call comes through and uses the | |
211 | fixup/resolver code. On the entry to the fixup/resolver code: | |
212 | ||
213 | ip = &GOT[n+3] | |
214 | lr = &GOT[2] | |
215 | stack[0] = return address (lr) of the function call | |
216 | [r0, r1, r2, r3] are still the arguments to the function call | |
217 | ||
218 | This is enough information for the fixup/resolver code to work | |
219 | with. Before the fixup/resolver code returns, it actually calls | |
220 | the requested function and repairs &GOT[n+3]. */ | |
221 | ||
2a451106 KB |
222 | /* The constants below were determined by examining the following files |
223 | in the linux kernel sources: | |
224 | ||
225 | arch/arm/kernel/signal.c | |
226 | - see SWI_SYS_SIGRETURN and SWI_SYS_RT_SIGRETURN | |
227 | include/asm-arm/unistd.h | |
228 | - see __NR_sigreturn, __NR_rt_sigreturn, and __NR_SYSCALL_BASE */ | |
229 | ||
230 | #define ARM_LINUX_SIGRETURN_INSTR 0xef900077 | |
231 | #define ARM_LINUX_RT_SIGRETURN_INSTR 0xef9000ad | |
232 | ||
edfb1a26 DJ |
233 | /* For ARM EABI, the syscall number is not in the SWI instruction |
234 | (instead it is loaded into r7). We recognize the pattern that | |
235 | glibc uses... alternatively, we could arrange to do this by | |
236 | function name, but they are not always exported. */ | |
8e9d1a24 DJ |
237 | #define ARM_SET_R7_SIGRETURN 0xe3a07077 |
238 | #define ARM_SET_R7_RT_SIGRETURN 0xe3a070ad | |
239 | #define ARM_EABI_SYSCALL 0xef000000 | |
2a451106 | 240 | |
f1973203 MR |
241 | /* OABI syscall restart trampoline, used for EABI executables too |
242 | whenever OABI support has been enabled in the kernel. */ | |
243 | #define ARM_OABI_SYSCALL_RESTART_SYSCALL 0xef900000 | |
244 | #define ARM_LDR_PC_SP_12 0xe49df00c | |
478fd957 | 245 | #define ARM_LDR_PC_SP_4 0xe49df004 |
f1973203 | 246 | |
8e9d1a24 | 247 | static void |
a262aec2 | 248 | arm_linux_sigtramp_cache (struct frame_info *this_frame, |
8e9d1a24 DJ |
249 | struct trad_frame_cache *this_cache, |
250 | CORE_ADDR func, int regs_offset) | |
2a451106 | 251 | { |
a262aec2 | 252 | CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM); |
8e9d1a24 DJ |
253 | CORE_ADDR base = sp + regs_offset; |
254 | int i; | |
2a451106 | 255 | |
8e9d1a24 DJ |
256 | for (i = 0; i < 16; i++) |
257 | trad_frame_set_reg_addr (this_cache, i, base + i * 4); | |
2a451106 | 258 | |
8e9d1a24 | 259 | trad_frame_set_reg_addr (this_cache, ARM_PS_REGNUM, base + 16 * 4); |
2a451106 | 260 | |
8e9d1a24 DJ |
261 | /* The VFP or iWMMXt registers may be saved on the stack, but there's |
262 | no reliable way to restore them (yet). */ | |
2a451106 | 263 | |
8e9d1a24 DJ |
264 | /* Save a frame ID. */ |
265 | trad_frame_set_id (this_cache, frame_id_build (sp, func)); | |
266 | } | |
2a451106 | 267 | |
edfb1a26 DJ |
268 | /* There are a couple of different possible stack layouts that |
269 | we need to support. | |
270 | ||
271 | Before version 2.6.18, the kernel used completely independent | |
272 | layouts for non-RT and RT signals. For non-RT signals the stack | |
273 | began directly with a struct sigcontext. For RT signals the stack | |
274 | began with two redundant pointers (to the siginfo and ucontext), | |
275 | and then the siginfo and ucontext. | |
276 | ||
277 | As of version 2.6.18, the non-RT signal frame layout starts with | |
278 | a ucontext and the RT signal frame starts with a siginfo and then | |
279 | a ucontext. Also, the ucontext now has a designated save area | |
280 | for coprocessor registers. | |
281 | ||
282 | For RT signals, it's easy to tell the difference: we look for | |
283 | pinfo, the pointer to the siginfo. If it has the expected | |
284 | value, we have an old layout. If it doesn't, we have the new | |
285 | layout. | |
286 | ||
287 | For non-RT signals, it's a bit harder. We need something in one | |
288 | layout or the other with a recognizable offset and value. We can't | |
289 | use the return trampoline, because ARM usually uses SA_RESTORER, | |
290 | in which case the stack return trampoline is not filled in. | |
291 | We can't use the saved stack pointer, because sigaltstack might | |
292 | be in use. So for now we guess the new layout... */ | |
293 | ||
294 | /* There are three words (trap_no, error_code, oldmask) in | |
295 | struct sigcontext before r0. */ | |
296 | #define ARM_SIGCONTEXT_R0 0xc | |
297 | ||
298 | /* There are five words (uc_flags, uc_link, and three for uc_stack) | |
299 | in the ucontext_t before the sigcontext. */ | |
300 | #define ARM_UCONTEXT_SIGCONTEXT 0x14 | |
301 | ||
302 | /* There are three elements in an rt_sigframe before the ucontext: | |
303 | pinfo, puc, and info. The first two are pointers and the third | |
304 | is a struct siginfo, with size 128 bytes. We could follow puc | |
305 | to the ucontext, but it's simpler to skip the whole thing. */ | |
306 | #define ARM_OLD_RT_SIGFRAME_SIGINFO 0x8 | |
307 | #define ARM_OLD_RT_SIGFRAME_UCONTEXT 0x88 | |
308 | ||
309 | #define ARM_NEW_RT_SIGFRAME_UCONTEXT 0x80 | |
310 | ||
311 | #define ARM_NEW_SIGFRAME_MAGIC 0x5ac3c35a | |
312 | ||
8e9d1a24 DJ |
313 | static void |
314 | arm_linux_sigreturn_init (const struct tramp_frame *self, | |
a262aec2 | 315 | struct frame_info *this_frame, |
8e9d1a24 DJ |
316 | struct trad_frame_cache *this_cache, |
317 | CORE_ADDR func) | |
2a451106 | 318 | { |
e17a4113 UW |
319 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
320 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
a262aec2 | 321 | CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM); |
e17a4113 | 322 | ULONGEST uc_flags = read_memory_unsigned_integer (sp, 4, byte_order); |
edfb1a26 DJ |
323 | |
324 | if (uc_flags == ARM_NEW_SIGFRAME_MAGIC) | |
a262aec2 | 325 | arm_linux_sigtramp_cache (this_frame, this_cache, func, |
edfb1a26 DJ |
326 | ARM_UCONTEXT_SIGCONTEXT |
327 | + ARM_SIGCONTEXT_R0); | |
328 | else | |
a262aec2 | 329 | arm_linux_sigtramp_cache (this_frame, this_cache, func, |
edfb1a26 | 330 | ARM_SIGCONTEXT_R0); |
8e9d1a24 | 331 | } |
2a451106 | 332 | |
8e9d1a24 DJ |
333 | static void |
334 | arm_linux_rt_sigreturn_init (const struct tramp_frame *self, | |
a262aec2 | 335 | struct frame_info *this_frame, |
8e9d1a24 DJ |
336 | struct trad_frame_cache *this_cache, |
337 | CORE_ADDR func) | |
338 | { | |
e17a4113 UW |
339 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
340 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
a262aec2 | 341 | CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM); |
e17a4113 | 342 | ULONGEST pinfo = read_memory_unsigned_integer (sp, 4, byte_order); |
edfb1a26 DJ |
343 | |
344 | if (pinfo == sp + ARM_OLD_RT_SIGFRAME_SIGINFO) | |
a262aec2 | 345 | arm_linux_sigtramp_cache (this_frame, this_cache, func, |
edfb1a26 DJ |
346 | ARM_OLD_RT_SIGFRAME_UCONTEXT |
347 | + ARM_UCONTEXT_SIGCONTEXT | |
348 | + ARM_SIGCONTEXT_R0); | |
349 | else | |
a262aec2 | 350 | arm_linux_sigtramp_cache (this_frame, this_cache, func, |
edfb1a26 DJ |
351 | ARM_NEW_RT_SIGFRAME_UCONTEXT |
352 | + ARM_UCONTEXT_SIGCONTEXT | |
353 | + ARM_SIGCONTEXT_R0); | |
2a451106 KB |
354 | } |
355 | ||
f1973203 MR |
356 | static void |
357 | arm_linux_restart_syscall_init (const struct tramp_frame *self, | |
358 | struct frame_info *this_frame, | |
359 | struct trad_frame_cache *this_cache, | |
360 | CORE_ADDR func) | |
361 | { | |
478fd957 | 362 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
f1973203 | 363 | CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM); |
478fd957 UW |
364 | CORE_ADDR pc = get_frame_memory_unsigned (this_frame, sp, 4); |
365 | CORE_ADDR cpsr = get_frame_register_unsigned (this_frame, ARM_PS_REGNUM); | |
366 | ULONGEST t_bit = arm_psr_thumb_bit (gdbarch); | |
367 | int sp_offset; | |
368 | ||
369 | /* There are two variants of this trampoline; with older kernels, the | |
370 | stub is placed on the stack, while newer kernels use the stub from | |
371 | the vector page. They are identical except that the older version | |
372 | increments SP by 12 (to skip stored PC and the stub itself), while | |
373 | the newer version increments SP only by 4 (just the stored PC). */ | |
374 | if (self->insn[1].bytes == ARM_LDR_PC_SP_4) | |
375 | sp_offset = 4; | |
376 | else | |
377 | sp_offset = 12; | |
378 | ||
379 | /* Update Thumb bit in CPSR. */ | |
380 | if (pc & 1) | |
381 | cpsr |= t_bit; | |
382 | else | |
383 | cpsr &= ~t_bit; | |
f1973203 | 384 | |
478fd957 UW |
385 | /* Remove Thumb bit from PC. */ |
386 | pc = gdbarch_addr_bits_remove (gdbarch, pc); | |
387 | ||
388 | /* Save previous register values. */ | |
389 | trad_frame_set_reg_value (this_cache, ARM_SP_REGNUM, sp + sp_offset); | |
390 | trad_frame_set_reg_value (this_cache, ARM_PC_REGNUM, pc); | |
391 | trad_frame_set_reg_value (this_cache, ARM_PS_REGNUM, cpsr); | |
f1973203 MR |
392 | |
393 | /* Save a frame ID. */ | |
394 | trad_frame_set_id (this_cache, frame_id_build (sp, func)); | |
395 | } | |
396 | ||
8e9d1a24 DJ |
397 | static struct tramp_frame arm_linux_sigreturn_tramp_frame = { |
398 | SIGTRAMP_FRAME, | |
399 | 4, | |
400 | { | |
401 | { ARM_LINUX_SIGRETURN_INSTR, -1 }, | |
402 | { TRAMP_SENTINEL_INSN } | |
403 | }, | |
404 | arm_linux_sigreturn_init | |
405 | }; | |
406 | ||
407 | static struct tramp_frame arm_linux_rt_sigreturn_tramp_frame = { | |
408 | SIGTRAMP_FRAME, | |
409 | 4, | |
410 | { | |
411 | { ARM_LINUX_RT_SIGRETURN_INSTR, -1 }, | |
412 | { TRAMP_SENTINEL_INSN } | |
413 | }, | |
414 | arm_linux_rt_sigreturn_init | |
415 | }; | |
416 | ||
417 | static struct tramp_frame arm_eabi_linux_sigreturn_tramp_frame = { | |
418 | SIGTRAMP_FRAME, | |
419 | 4, | |
420 | { | |
421 | { ARM_SET_R7_SIGRETURN, -1 }, | |
422 | { ARM_EABI_SYSCALL, -1 }, | |
423 | { TRAMP_SENTINEL_INSN } | |
424 | }, | |
425 | arm_linux_sigreturn_init | |
426 | }; | |
427 | ||
428 | static struct tramp_frame arm_eabi_linux_rt_sigreturn_tramp_frame = { | |
429 | SIGTRAMP_FRAME, | |
430 | 4, | |
431 | { | |
432 | { ARM_SET_R7_RT_SIGRETURN, -1 }, | |
433 | { ARM_EABI_SYSCALL, -1 }, | |
434 | { TRAMP_SENTINEL_INSN } | |
435 | }, | |
436 | arm_linux_rt_sigreturn_init | |
437 | }; | |
438 | ||
f1973203 MR |
439 | static struct tramp_frame arm_linux_restart_syscall_tramp_frame = { |
440 | NORMAL_FRAME, | |
441 | 4, | |
442 | { | |
443 | { ARM_OABI_SYSCALL_RESTART_SYSCALL, -1 }, | |
444 | { ARM_LDR_PC_SP_12, -1 }, | |
445 | { TRAMP_SENTINEL_INSN } | |
446 | }, | |
447 | arm_linux_restart_syscall_init | |
448 | }; | |
449 | ||
478fd957 UW |
450 | static struct tramp_frame arm_kernel_linux_restart_syscall_tramp_frame = { |
451 | NORMAL_FRAME, | |
452 | 4, | |
453 | { | |
454 | { ARM_OABI_SYSCALL_RESTART_SYSCALL, -1 }, | |
455 | { ARM_LDR_PC_SP_4, -1 }, | |
456 | { TRAMP_SENTINEL_INSN } | |
457 | }, | |
458 | arm_linux_restart_syscall_init | |
459 | }; | |
460 | ||
cb587d83 DJ |
461 | /* Core file and register set support. */ |
462 | ||
463 | #define ARM_LINUX_SIZEOF_GREGSET (18 * INT_REGISTER_SIZE) | |
464 | ||
465 | void | |
466 | arm_linux_supply_gregset (const struct regset *regset, | |
467 | struct regcache *regcache, | |
468 | int regnum, const void *gregs_buf, size_t len) | |
469 | { | |
e17a4113 UW |
470 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
471 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
cb587d83 DJ |
472 | const gdb_byte *gregs = gregs_buf; |
473 | int regno; | |
474 | CORE_ADDR reg_pc; | |
475 | gdb_byte pc_buf[INT_REGISTER_SIZE]; | |
476 | ||
477 | for (regno = ARM_A1_REGNUM; regno < ARM_PC_REGNUM; regno++) | |
478 | if (regnum == -1 || regnum == regno) | |
479 | regcache_raw_supply (regcache, regno, | |
480 | gregs + INT_REGISTER_SIZE * regno); | |
481 | ||
482 | if (regnum == ARM_PS_REGNUM || regnum == -1) | |
483 | { | |
484 | if (arm_apcs_32) | |
485 | regcache_raw_supply (regcache, ARM_PS_REGNUM, | |
17c12639 | 486 | gregs + INT_REGISTER_SIZE * ARM_CPSR_GREGNUM); |
cb587d83 DJ |
487 | else |
488 | regcache_raw_supply (regcache, ARM_PS_REGNUM, | |
489 | gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM); | |
490 | } | |
491 | ||
492 | if (regnum == ARM_PC_REGNUM || regnum == -1) | |
493 | { | |
494 | reg_pc = extract_unsigned_integer (gregs | |
495 | + INT_REGISTER_SIZE * ARM_PC_REGNUM, | |
e17a4113 UW |
496 | INT_REGISTER_SIZE, byte_order); |
497 | reg_pc = gdbarch_addr_bits_remove (gdbarch, reg_pc); | |
498 | store_unsigned_integer (pc_buf, INT_REGISTER_SIZE, byte_order, reg_pc); | |
cb587d83 DJ |
499 | regcache_raw_supply (regcache, ARM_PC_REGNUM, pc_buf); |
500 | } | |
501 | } | |
502 | ||
503 | void | |
504 | arm_linux_collect_gregset (const struct regset *regset, | |
505 | const struct regcache *regcache, | |
506 | int regnum, void *gregs_buf, size_t len) | |
507 | { | |
508 | gdb_byte *gregs = gregs_buf; | |
509 | int regno; | |
510 | ||
511 | for (regno = ARM_A1_REGNUM; regno < ARM_PC_REGNUM; regno++) | |
512 | if (regnum == -1 || regnum == regno) | |
513 | regcache_raw_collect (regcache, regno, | |
514 | gregs + INT_REGISTER_SIZE * regno); | |
515 | ||
516 | if (regnum == ARM_PS_REGNUM || regnum == -1) | |
517 | { | |
518 | if (arm_apcs_32) | |
519 | regcache_raw_collect (regcache, ARM_PS_REGNUM, | |
17c12639 | 520 | gregs + INT_REGISTER_SIZE * ARM_CPSR_GREGNUM); |
cb587d83 DJ |
521 | else |
522 | regcache_raw_collect (regcache, ARM_PS_REGNUM, | |
523 | gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM); | |
524 | } | |
525 | ||
526 | if (regnum == ARM_PC_REGNUM || regnum == -1) | |
527 | regcache_raw_collect (regcache, ARM_PC_REGNUM, | |
528 | gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM); | |
529 | } | |
530 | ||
531 | /* Support for register format used by the NWFPE FPA emulator. */ | |
532 | ||
533 | #define typeNone 0x00 | |
534 | #define typeSingle 0x01 | |
535 | #define typeDouble 0x02 | |
536 | #define typeExtended 0x03 | |
537 | ||
538 | void | |
539 | supply_nwfpe_register (struct regcache *regcache, int regno, | |
540 | const gdb_byte *regs) | |
541 | { | |
542 | const gdb_byte *reg_data; | |
543 | gdb_byte reg_tag; | |
544 | gdb_byte buf[FP_REGISTER_SIZE]; | |
545 | ||
546 | reg_data = regs + (regno - ARM_F0_REGNUM) * FP_REGISTER_SIZE; | |
547 | reg_tag = regs[(regno - ARM_F0_REGNUM) + NWFPE_TAGS_OFFSET]; | |
548 | memset (buf, 0, FP_REGISTER_SIZE); | |
549 | ||
550 | switch (reg_tag) | |
551 | { | |
552 | case typeSingle: | |
553 | memcpy (buf, reg_data, 4); | |
554 | break; | |
555 | case typeDouble: | |
556 | memcpy (buf, reg_data + 4, 4); | |
557 | memcpy (buf + 4, reg_data, 4); | |
558 | break; | |
559 | case typeExtended: | |
560 | /* We want sign and exponent, then least significant bits, | |
561 | then most significant. NWFPE does sign, most, least. */ | |
562 | memcpy (buf, reg_data, 4); | |
563 | memcpy (buf + 4, reg_data + 8, 4); | |
564 | memcpy (buf + 8, reg_data + 4, 4); | |
565 | break; | |
566 | default: | |
567 | break; | |
568 | } | |
569 | ||
570 | regcache_raw_supply (regcache, regno, buf); | |
571 | } | |
572 | ||
573 | void | |
574 | collect_nwfpe_register (const struct regcache *regcache, int regno, | |
575 | gdb_byte *regs) | |
576 | { | |
577 | gdb_byte *reg_data; | |
578 | gdb_byte reg_tag; | |
579 | gdb_byte buf[FP_REGISTER_SIZE]; | |
580 | ||
581 | regcache_raw_collect (regcache, regno, buf); | |
582 | ||
583 | /* NOTE drow/2006-06-07: This code uses the tag already in the | |
584 | register buffer. I've preserved that when moving the code | |
585 | from the native file to the target file. But this doesn't | |
586 | always make sense. */ | |
587 | ||
588 | reg_data = regs + (regno - ARM_F0_REGNUM) * FP_REGISTER_SIZE; | |
589 | reg_tag = regs[(regno - ARM_F0_REGNUM) + NWFPE_TAGS_OFFSET]; | |
590 | ||
591 | switch (reg_tag) | |
592 | { | |
593 | case typeSingle: | |
594 | memcpy (reg_data, buf, 4); | |
595 | break; | |
596 | case typeDouble: | |
597 | memcpy (reg_data, buf + 4, 4); | |
598 | memcpy (reg_data + 4, buf, 4); | |
599 | break; | |
600 | case typeExtended: | |
601 | memcpy (reg_data, buf, 4); | |
602 | memcpy (reg_data + 4, buf + 8, 4); | |
603 | memcpy (reg_data + 8, buf + 4, 4); | |
604 | break; | |
605 | default: | |
606 | break; | |
607 | } | |
608 | } | |
609 | ||
610 | void | |
611 | arm_linux_supply_nwfpe (const struct regset *regset, | |
612 | struct regcache *regcache, | |
613 | int regnum, const void *regs_buf, size_t len) | |
614 | { | |
615 | const gdb_byte *regs = regs_buf; | |
616 | int regno; | |
617 | ||
618 | if (regnum == ARM_FPS_REGNUM || regnum == -1) | |
619 | regcache_raw_supply (regcache, ARM_FPS_REGNUM, | |
620 | regs + NWFPE_FPSR_OFFSET); | |
621 | ||
622 | for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++) | |
623 | if (regnum == -1 || regnum == regno) | |
624 | supply_nwfpe_register (regcache, regno, regs); | |
625 | } | |
626 | ||
627 | void | |
628 | arm_linux_collect_nwfpe (const struct regset *regset, | |
629 | const struct regcache *regcache, | |
630 | int regnum, void *regs_buf, size_t len) | |
631 | { | |
632 | gdb_byte *regs = regs_buf; | |
633 | int regno; | |
634 | ||
635 | for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++) | |
636 | if (regnum == -1 || regnum == regno) | |
637 | collect_nwfpe_register (regcache, regno, regs); | |
638 | ||
639 | if (regnum == ARM_FPS_REGNUM || regnum == -1) | |
640 | regcache_raw_collect (regcache, ARM_FPS_REGNUM, | |
641 | regs + INT_REGISTER_SIZE * ARM_FPS_REGNUM); | |
642 | } | |
643 | ||
ef7e8358 UW |
644 | /* Support VFP register format. */ |
645 | ||
646 | #define ARM_LINUX_SIZEOF_VFP (32 * 8 + 4) | |
647 | ||
648 | static void | |
649 | arm_linux_supply_vfp (const struct regset *regset, | |
650 | struct regcache *regcache, | |
651 | int regnum, const void *regs_buf, size_t len) | |
652 | { | |
653 | const gdb_byte *regs = regs_buf; | |
654 | int regno; | |
655 | ||
656 | if (regnum == ARM_FPSCR_REGNUM || regnum == -1) | |
657 | regcache_raw_supply (regcache, ARM_FPSCR_REGNUM, regs + 32 * 8); | |
658 | ||
659 | for (regno = ARM_D0_REGNUM; regno <= ARM_D31_REGNUM; regno++) | |
660 | if (regnum == -1 || regnum == regno) | |
661 | regcache_raw_supply (regcache, regno, | |
662 | regs + (regno - ARM_D0_REGNUM) * 8); | |
663 | } | |
664 | ||
665 | static void | |
666 | arm_linux_collect_vfp (const struct regset *regset, | |
667 | const struct regcache *regcache, | |
668 | int regnum, void *regs_buf, size_t len) | |
669 | { | |
670 | gdb_byte *regs = regs_buf; | |
671 | int regno; | |
672 | ||
673 | if (regnum == ARM_FPSCR_REGNUM || regnum == -1) | |
674 | regcache_raw_collect (regcache, ARM_FPSCR_REGNUM, regs + 32 * 8); | |
675 | ||
676 | for (regno = ARM_D0_REGNUM; regno <= ARM_D31_REGNUM; regno++) | |
677 | if (regnum == -1 || regnum == regno) | |
678 | regcache_raw_collect (regcache, regno, | |
679 | regs + (regno - ARM_D0_REGNUM) * 8); | |
680 | } | |
681 | ||
cb587d83 DJ |
682 | /* Return the appropriate register set for the core section identified |
683 | by SECT_NAME and SECT_SIZE. */ | |
684 | ||
685 | static const struct regset * | |
686 | arm_linux_regset_from_core_section (struct gdbarch *gdbarch, | |
687 | const char *sect_name, size_t sect_size) | |
688 | { | |
689 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
690 | ||
691 | if (strcmp (sect_name, ".reg") == 0 | |
692 | && sect_size == ARM_LINUX_SIZEOF_GREGSET) | |
693 | { | |
694 | if (tdep->gregset == NULL) | |
695 | tdep->gregset = regset_alloc (gdbarch, arm_linux_supply_gregset, | |
696 | arm_linux_collect_gregset); | |
697 | return tdep->gregset; | |
698 | } | |
699 | ||
700 | if (strcmp (sect_name, ".reg2") == 0 | |
701 | && sect_size == ARM_LINUX_SIZEOF_NWFPE) | |
702 | { | |
703 | if (tdep->fpregset == NULL) | |
704 | tdep->fpregset = regset_alloc (gdbarch, arm_linux_supply_nwfpe, | |
705 | arm_linux_collect_nwfpe); | |
706 | return tdep->fpregset; | |
707 | } | |
708 | ||
ef7e8358 UW |
709 | if (strcmp (sect_name, ".reg-arm-vfp") == 0 |
710 | && sect_size == ARM_LINUX_SIZEOF_VFP) | |
711 | { | |
712 | if (tdep->vfpregset == NULL) | |
713 | tdep->vfpregset = regset_alloc (gdbarch, arm_linux_supply_vfp, | |
714 | arm_linux_collect_vfp); | |
715 | return tdep->vfpregset; | |
716 | } | |
717 | ||
718 | return NULL; | |
719 | } | |
720 | ||
721 | /* Core file register set sections. */ | |
722 | ||
723 | static struct core_regset_section arm_linux_fpa_regset_sections[] = | |
724 | { | |
725 | { ".reg", ARM_LINUX_SIZEOF_GREGSET, "general-purpose" }, | |
726 | { ".reg2", ARM_LINUX_SIZEOF_NWFPE, "FPA floating-point" }, | |
727 | { NULL, 0} | |
728 | }; | |
729 | ||
730 | static struct core_regset_section arm_linux_vfp_regset_sections[] = | |
731 | { | |
732 | { ".reg", ARM_LINUX_SIZEOF_GREGSET, "general-purpose" }, | |
733 | { ".reg-arm-vfp", ARM_LINUX_SIZEOF_VFP, "VFP floating-point" }, | |
734 | { NULL, 0} | |
735 | }; | |
736 | ||
737 | /* Determine target description from core file. */ | |
738 | ||
739 | static const struct target_desc * | |
740 | arm_linux_core_read_description (struct gdbarch *gdbarch, | |
741 | struct target_ops *target, | |
742 | bfd *abfd) | |
743 | { | |
744 | CORE_ADDR arm_hwcap = 0; | |
745 | ||
746 | if (target_auxv_search (target, AT_HWCAP, &arm_hwcap) != 1) | |
747 | return NULL; | |
748 | ||
749 | if (arm_hwcap & HWCAP_VFP) | |
750 | { | |
751 | /* NEON implies VFPv3-D32 or no-VFP unit. Say that we only support | |
752 | Neon with VFPv3-D32. */ | |
753 | if (arm_hwcap & HWCAP_NEON) | |
754 | return tdesc_arm_with_neon; | |
755 | else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPv3D16)) == HWCAP_VFPv3) | |
756 | return tdesc_arm_with_vfpv3; | |
757 | else | |
758 | return tdesc_arm_with_vfpv2; | |
759 | } | |
760 | ||
cb587d83 DJ |
761 | return NULL; |
762 | } | |
763 | ||
ef7e8358 | 764 | |
25b41d01 | 765 | /* Copy the value of next pc of sigreturn and rt_sigrturn into PC, |
18819fa6 UW |
766 | return 1. In addition, set IS_THUMB depending on whether we |
767 | will return to ARM or Thumb code. Return 0 if it is not a | |
768 | rt_sigreturn/sigreturn syscall. */ | |
25b41d01 YQ |
769 | static int |
770 | arm_linux_sigreturn_return_addr (struct frame_info *frame, | |
771 | unsigned long svc_number, | |
18819fa6 | 772 | CORE_ADDR *pc, int *is_thumb) |
25b41d01 YQ |
773 | { |
774 | /* Is this a sigreturn or rt_sigreturn syscall? */ | |
775 | if (svc_number == 119 || svc_number == 173) | |
776 | { | |
777 | if (get_frame_type (frame) == SIGTRAMP_FRAME) | |
778 | { | |
18819fa6 UW |
779 | ULONGEST t_bit = arm_psr_thumb_bit (frame_unwind_arch (frame)); |
780 | CORE_ADDR cpsr | |
781 | = frame_unwind_register_unsigned (frame, ARM_PS_REGNUM); | |
782 | ||
783 | *is_thumb = (cpsr & t_bit) != 0; | |
25b41d01 YQ |
784 | *pc = frame_unwind_caller_pc (frame); |
785 | return 1; | |
786 | } | |
787 | } | |
788 | return 0; | |
789 | } | |
790 | ||
791 | /* When FRAME is at a syscall instruction, return the PC of the next | |
792 | instruction to be executed. */ | |
793 | ||
794 | static CORE_ADDR | |
795 | arm_linux_syscall_next_pc (struct frame_info *frame) | |
796 | { | |
797 | CORE_ADDR pc = get_frame_pc (frame); | |
798 | CORE_ADDR return_addr = 0; | |
799 | int is_thumb = arm_frame_is_thumb (frame); | |
800 | ULONGEST svc_number = 0; | |
25b41d01 YQ |
801 | |
802 | if (is_thumb) | |
803 | { | |
804 | svc_number = get_frame_register_unsigned (frame, 7); | |
18819fa6 | 805 | return_addr = pc + 2; |
25b41d01 YQ |
806 | } |
807 | else | |
808 | { | |
809 | struct gdbarch *gdbarch = get_frame_arch (frame); | |
810 | enum bfd_endian byte_order_for_code = | |
811 | gdbarch_byte_order_for_code (gdbarch); | |
812 | unsigned long this_instr = | |
813 | read_memory_unsigned_integer (pc, 4, byte_order_for_code); | |
814 | ||
815 | unsigned long svc_operand = (0x00ffffff & this_instr); | |
816 | if (svc_operand) /* OABI. */ | |
817 | { | |
818 | svc_number = svc_operand - 0x900000; | |
819 | } | |
820 | else /* EABI. */ | |
821 | { | |
822 | svc_number = get_frame_register_unsigned (frame, 7); | |
823 | } | |
18819fa6 UW |
824 | |
825 | return_addr = pc + 4; | |
25b41d01 YQ |
826 | } |
827 | ||
18819fa6 | 828 | arm_linux_sigreturn_return_addr (frame, svc_number, &return_addr, &is_thumb); |
25b41d01 | 829 | |
18819fa6 | 830 | /* Addresses for calling Thumb functions have the bit 0 set. */ |
25b41d01 | 831 | if (is_thumb) |
18819fa6 | 832 | return_addr |= 1; |
25b41d01 YQ |
833 | |
834 | return return_addr; | |
835 | } | |
836 | ||
837 | ||
daddc3c1 DJ |
838 | /* Insert a single step breakpoint at the next executed instruction. */ |
839 | ||
63807e1d | 840 | static int |
daddc3c1 DJ |
841 | arm_linux_software_single_step (struct frame_info *frame) |
842 | { | |
a6d9a66e | 843 | struct gdbarch *gdbarch = get_frame_arch (frame); |
6c95b8df | 844 | struct address_space *aspace = get_frame_address_space (frame); |
35f73cfc UW |
845 | CORE_ADDR next_pc; |
846 | ||
847 | if (arm_deal_with_atomic_sequence (frame)) | |
848 | return 1; | |
849 | ||
850 | next_pc = arm_get_next_pc (frame, get_frame_pc (frame)); | |
daddc3c1 DJ |
851 | |
852 | /* The Linux kernel offers some user-mode helpers in a high page. We can | |
853 | not read this page (as of 2.6.23), and even if we could then we couldn't | |
854 | set breakpoints in it, and even if we could then the atomic operations | |
855 | would fail when interrupted. They are all called as functions and return | |
856 | to the address in LR, so step to there instead. */ | |
857 | if (next_pc > 0xffff0000) | |
858 | next_pc = get_frame_register_unsigned (frame, ARM_LR_REGNUM); | |
859 | ||
18819fa6 | 860 | arm_insert_single_step_breakpoint (gdbarch, aspace, next_pc); |
daddc3c1 DJ |
861 | |
862 | return 1; | |
863 | } | |
864 | ||
cca44b1b JB |
865 | /* Support for displaced stepping of Linux SVC instructions. */ |
866 | ||
867 | static void | |
6e39997a | 868 | arm_linux_cleanup_svc (struct gdbarch *gdbarch, |
cca44b1b JB |
869 | struct regcache *regs, |
870 | struct displaced_step_closure *dsc) | |
871 | { | |
872 | CORE_ADDR from = dsc->insn_addr; | |
873 | ULONGEST apparent_pc; | |
874 | int within_scratch; | |
875 | ||
876 | regcache_cooked_read_unsigned (regs, ARM_PC_REGNUM, &apparent_pc); | |
877 | ||
878 | within_scratch = (apparent_pc >= dsc->scratch_base | |
879 | && apparent_pc < (dsc->scratch_base | |
880 | + DISPLACED_MODIFIED_INSNS * 4 + 4)); | |
881 | ||
882 | if (debug_displaced) | |
883 | { | |
884 | fprintf_unfiltered (gdb_stdlog, "displaced: PC is apparently %.8lx after " | |
885 | "SVC step ", (unsigned long) apparent_pc); | |
886 | if (within_scratch) | |
887 | fprintf_unfiltered (gdb_stdlog, "(within scratch space)\n"); | |
888 | else | |
889 | fprintf_unfiltered (gdb_stdlog, "(outside scratch space)\n"); | |
890 | } | |
891 | ||
892 | if (within_scratch) | |
893 | displaced_write_reg (regs, dsc, ARM_PC_REGNUM, from + 4, BRANCH_WRITE_PC); | |
894 | } | |
895 | ||
896 | static int | |
bd18283a YQ |
897 | arm_linux_copy_svc (struct gdbarch *gdbarch, struct regcache *regs, |
898 | struct displaced_step_closure *dsc) | |
cca44b1b | 899 | { |
25b41d01 YQ |
900 | CORE_ADDR return_to = 0; |
901 | ||
cca44b1b | 902 | struct frame_info *frame; |
36073a92 | 903 | unsigned int svc_number = displaced_read_reg (regs, dsc, 7); |
25b41d01 | 904 | int is_sigreturn = 0; |
18819fa6 | 905 | int is_thumb; |
cca44b1b | 906 | |
cca44b1b JB |
907 | frame = get_current_frame (); |
908 | ||
25b41d01 | 909 | is_sigreturn = arm_linux_sigreturn_return_addr(frame, svc_number, |
18819fa6 | 910 | &return_to, &is_thumb); |
25b41d01 | 911 | if (is_sigreturn) |
cca44b1b | 912 | { |
cca44b1b JB |
913 | struct symtab_and_line sal; |
914 | ||
915 | if (debug_displaced) | |
916 | fprintf_unfiltered (gdb_stdlog, "displaced: found " | |
0963b4bd | 917 | "sigreturn/rt_sigreturn SVC call. PC in frame = %lx\n", |
cca44b1b JB |
918 | (unsigned long) get_frame_pc (frame)); |
919 | ||
cca44b1b | 920 | if (debug_displaced) |
0963b4bd | 921 | fprintf_unfiltered (gdb_stdlog, "displaced: unwind pc = %lx. " |
cca44b1b JB |
922 | "Setting momentary breakpoint.\n", (unsigned long) return_to); |
923 | ||
8358c15c JK |
924 | gdb_assert (inferior_thread ()->control.step_resume_breakpoint |
925 | == NULL); | |
cca44b1b JB |
926 | |
927 | sal = find_pc_line (return_to, 0); | |
928 | sal.pc = return_to; | |
929 | sal.section = find_pc_overlay (return_to); | |
930 | sal.explicit_pc = 1; | |
931 | ||
932 | frame = get_prev_frame (frame); | |
933 | ||
934 | if (frame) | |
935 | { | |
8358c15c | 936 | inferior_thread ()->control.step_resume_breakpoint |
cca44b1b JB |
937 | = set_momentary_breakpoint (gdbarch, sal, get_frame_id (frame), |
938 | bp_step_resume); | |
939 | ||
c70a6932 JK |
940 | /* set_momentary_breakpoint invalidates FRAME. */ |
941 | frame = NULL; | |
942 | ||
cca44b1b JB |
943 | /* We need to make sure we actually insert the momentary |
944 | breakpoint set above. */ | |
945 | insert_breakpoints (); | |
946 | } | |
947 | else if (debug_displaced) | |
948 | fprintf_unfiltered (gdb_stderr, "displaced: couldn't find previous " | |
949 | "frame to set momentary breakpoint for " | |
950 | "sigreturn/rt_sigreturn\n"); | |
951 | } | |
952 | else if (debug_displaced) | |
953 | fprintf_unfiltered (gdb_stdlog, "displaced: sigreturn/rt_sigreturn " | |
954 | "SVC call not in signal trampoline frame\n"); | |
25b41d01 | 955 | |
cca44b1b JB |
956 | |
957 | /* Preparation: If we detect sigreturn, set momentary breakpoint at resume | |
958 | location, else nothing. | |
959 | Insn: unmodified svc. | |
960 | Cleanup: if pc lands in scratch space, pc <- insn_addr + 4 | |
961 | else leave pc alone. */ | |
962 | ||
cca44b1b JB |
963 | |
964 | dsc->cleanup = &arm_linux_cleanup_svc; | |
965 | /* Pretend we wrote to the PC, so cleanup doesn't set PC to the next | |
966 | instruction. */ | |
967 | dsc->wrote_to_pc = 1; | |
968 | ||
969 | return 0; | |
970 | } | |
971 | ||
972 | ||
973 | /* The following two functions implement single-stepping over calls to Linux | |
974 | kernel helper routines, which perform e.g. atomic operations on architecture | |
975 | variants which don't support them natively. | |
976 | ||
977 | When this function is called, the PC will be pointing at the kernel helper | |
978 | (at an address inaccessible to GDB), and r14 will point to the return | |
979 | address. Displaced stepping always executes code in the copy area: | |
980 | so, make the copy-area instruction branch back to the kernel helper (the | |
981 | "from" address), and make r14 point to the breakpoint in the copy area. In | |
982 | that way, we regain control once the kernel helper returns, and can clean | |
983 | up appropriately (as if we had just returned from the kernel helper as it | |
984 | would have been called from the non-displaced location). */ | |
985 | ||
986 | static void | |
6e39997a | 987 | cleanup_kernel_helper_return (struct gdbarch *gdbarch, |
cca44b1b JB |
988 | struct regcache *regs, |
989 | struct displaced_step_closure *dsc) | |
990 | { | |
991 | displaced_write_reg (regs, dsc, ARM_LR_REGNUM, dsc->tmp[0], CANNOT_WRITE_PC); | |
992 | displaced_write_reg (regs, dsc, ARM_PC_REGNUM, dsc->tmp[0], BRANCH_WRITE_PC); | |
993 | } | |
994 | ||
995 | static void | |
996 | arm_catch_kernel_helper_return (struct gdbarch *gdbarch, CORE_ADDR from, | |
997 | CORE_ADDR to, struct regcache *regs, | |
998 | struct displaced_step_closure *dsc) | |
999 | { | |
1000 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
1001 | ||
1002 | dsc->numinsns = 1; | |
1003 | dsc->insn_addr = from; | |
1004 | dsc->cleanup = &cleanup_kernel_helper_return; | |
1005 | /* Say we wrote to the PC, else cleanup will set PC to the next | |
1006 | instruction in the helper, which isn't helpful. */ | |
1007 | dsc->wrote_to_pc = 1; | |
1008 | ||
1009 | /* Preparation: tmp[0] <- r14 | |
1010 | r14 <- <scratch space>+4 | |
1011 | *(<scratch space>+8) <- from | |
1012 | Insn: ldr pc, [r14, #4] | |
1013 | Cleanup: r14 <- tmp[0], pc <- tmp[0]. */ | |
1014 | ||
36073a92 | 1015 | dsc->tmp[0] = displaced_read_reg (regs, dsc, ARM_LR_REGNUM); |
cca44b1b JB |
1016 | displaced_write_reg (regs, dsc, ARM_LR_REGNUM, (ULONGEST) to + 4, |
1017 | CANNOT_WRITE_PC); | |
1018 | write_memory_unsigned_integer (to + 8, 4, byte_order, from); | |
1019 | ||
1020 | dsc->modinsn[0] = 0xe59ef004; /* ldr pc, [lr, #4]. */ | |
1021 | } | |
1022 | ||
1023 | /* Linux-specific displaced step instruction copying function. Detects when | |
1024 | the program has stepped into a Linux kernel helper routine (which must be | |
1025 | handled as a special case), falling back to arm_displaced_step_copy_insn() | |
1026 | if it hasn't. */ | |
1027 | ||
1028 | static struct displaced_step_closure * | |
1029 | arm_linux_displaced_step_copy_insn (struct gdbarch *gdbarch, | |
1030 | CORE_ADDR from, CORE_ADDR to, | |
1031 | struct regcache *regs) | |
1032 | { | |
1033 | struct displaced_step_closure *dsc | |
1034 | = xmalloc (sizeof (struct displaced_step_closure)); | |
1035 | ||
1036 | /* Detect when we enter an (inaccessible by GDB) Linux kernel helper, and | |
1037 | stop at the return location. */ | |
1038 | if (from > 0xffff0000) | |
1039 | { | |
1040 | if (debug_displaced) | |
1041 | fprintf_unfiltered (gdb_stdlog, "displaced: detected kernel helper " | |
1042 | "at %.8lx\n", (unsigned long) from); | |
1043 | ||
1044 | arm_catch_kernel_helper_return (gdbarch, from, to, regs, dsc); | |
1045 | } | |
1046 | else | |
1047 | { | |
cca44b1b JB |
1048 | /* Override the default handling of SVC instructions. */ |
1049 | dsc->u.svc.copy_svc_os = arm_linux_copy_svc; | |
1050 | ||
b434a28f | 1051 | arm_process_displaced_insn (gdbarch, from, to, regs, dsc); |
cca44b1b JB |
1052 | } |
1053 | ||
1054 | arm_displaced_init_closure (gdbarch, from, to, dsc); | |
1055 | ||
1056 | return dsc; | |
1057 | } | |
1058 | ||
97e03143 RE |
1059 | static void |
1060 | arm_linux_init_abi (struct gdbarch_info info, | |
1061 | struct gdbarch *gdbarch) | |
1062 | { | |
1063 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
1064 | ||
a5ee0f0c PA |
1065 | linux_init_abi (info, gdbarch); |
1066 | ||
97e03143 | 1067 | tdep->lowest_pc = 0x8000; |
2ef47cd0 | 1068 | if (info.byte_order == BFD_ENDIAN_BIG) |
498b1f87 | 1069 | { |
c75a2cc8 DJ |
1070 | if (tdep->arm_abi == ARM_ABI_AAPCS) |
1071 | tdep->arm_breakpoint = eabi_linux_arm_be_breakpoint; | |
1072 | else | |
1073 | tdep->arm_breakpoint = arm_linux_arm_be_breakpoint; | |
498b1f87 | 1074 | tdep->thumb_breakpoint = arm_linux_thumb_be_breakpoint; |
177321bd | 1075 | tdep->thumb2_breakpoint = arm_linux_thumb2_be_breakpoint; |
498b1f87 | 1076 | } |
2ef47cd0 | 1077 | else |
498b1f87 | 1078 | { |
c75a2cc8 DJ |
1079 | if (tdep->arm_abi == ARM_ABI_AAPCS) |
1080 | tdep->arm_breakpoint = eabi_linux_arm_le_breakpoint; | |
1081 | else | |
1082 | tdep->arm_breakpoint = arm_linux_arm_le_breakpoint; | |
498b1f87 | 1083 | tdep->thumb_breakpoint = arm_linux_thumb_le_breakpoint; |
177321bd | 1084 | tdep->thumb2_breakpoint = arm_linux_thumb2_le_breakpoint; |
498b1f87 | 1085 | } |
66e810cd | 1086 | tdep->arm_breakpoint_size = sizeof (arm_linux_arm_le_breakpoint); |
498b1f87 | 1087 | tdep->thumb_breakpoint_size = sizeof (arm_linux_thumb_le_breakpoint); |
177321bd | 1088 | tdep->thumb2_breakpoint_size = sizeof (arm_linux_thumb2_le_breakpoint); |
9df628e0 | 1089 | |
28e97307 DJ |
1090 | if (tdep->fp_model == ARM_FLOAT_AUTO) |
1091 | tdep->fp_model = ARM_FLOAT_FPA; | |
fd50bc42 | 1092 | |
f8624c62 MGD |
1093 | switch (tdep->fp_model) |
1094 | { | |
1095 | case ARM_FLOAT_FPA: | |
1096 | tdep->jb_pc = ARM_LINUX_JB_PC_FPA; | |
1097 | break; | |
1098 | case ARM_FLOAT_SOFT_FPA: | |
1099 | case ARM_FLOAT_SOFT_VFP: | |
1100 | case ARM_FLOAT_VFP: | |
1101 | tdep->jb_pc = ARM_LINUX_JB_PC_EABI; | |
1102 | break; | |
1103 | default: | |
1104 | internal_error | |
1105 | (__FILE__, __LINE__, | |
1106 | _("arm_linux_init_abi: Floating point model not supported")); | |
1107 | break; | |
1108 | } | |
a6cdd8c5 | 1109 | tdep->jb_elt_size = ARM_LINUX_JB_ELEMENT_SIZE; |
19d3fc80 | 1110 | |
7aa1783e | 1111 | set_solib_svr4_fetch_link_map_offsets |
76a9d10f | 1112 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); |
7aa1783e | 1113 | |
190dce09 | 1114 | /* Single stepping. */ |
daddc3c1 | 1115 | set_gdbarch_software_single_step (gdbarch, arm_linux_software_single_step); |
190dce09 | 1116 | |
0e18d038 | 1117 | /* Shared library handling. */ |
0e18d038 | 1118 | set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); |
bb41a796 | 1119 | set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); |
b2756930 KB |
1120 | |
1121 | /* Enable TLS support. */ | |
1122 | set_gdbarch_fetch_tls_load_module_address (gdbarch, | |
1123 | svr4_fetch_objfile_link_map); | |
8e9d1a24 DJ |
1124 | |
1125 | tramp_frame_prepend_unwinder (gdbarch, | |
1126 | &arm_linux_sigreturn_tramp_frame); | |
1127 | tramp_frame_prepend_unwinder (gdbarch, | |
1128 | &arm_linux_rt_sigreturn_tramp_frame); | |
1129 | tramp_frame_prepend_unwinder (gdbarch, | |
1130 | &arm_eabi_linux_sigreturn_tramp_frame); | |
1131 | tramp_frame_prepend_unwinder (gdbarch, | |
1132 | &arm_eabi_linux_rt_sigreturn_tramp_frame); | |
f1973203 MR |
1133 | tramp_frame_prepend_unwinder (gdbarch, |
1134 | &arm_linux_restart_syscall_tramp_frame); | |
478fd957 UW |
1135 | tramp_frame_prepend_unwinder (gdbarch, |
1136 | &arm_kernel_linux_restart_syscall_tramp_frame); | |
cb587d83 DJ |
1137 | |
1138 | /* Core file support. */ | |
1139 | set_gdbarch_regset_from_core_section (gdbarch, | |
1140 | arm_linux_regset_from_core_section); | |
ef7e8358 UW |
1141 | set_gdbarch_core_read_description (gdbarch, arm_linux_core_read_description); |
1142 | ||
1143 | if (tdep->have_vfp_registers) | |
1144 | set_gdbarch_core_regset_sections (gdbarch, arm_linux_vfp_regset_sections); | |
1145 | else if (tdep->have_fpa_registers) | |
1146 | set_gdbarch_core_regset_sections (gdbarch, arm_linux_fpa_regset_sections); | |
4aa995e1 PA |
1147 | |
1148 | set_gdbarch_get_siginfo_type (gdbarch, linux_get_siginfo_type); | |
cca44b1b JB |
1149 | |
1150 | /* Displaced stepping. */ | |
1151 | set_gdbarch_displaced_step_copy_insn (gdbarch, | |
1152 | arm_linux_displaced_step_copy_insn); | |
1153 | set_gdbarch_displaced_step_fixup (gdbarch, arm_displaced_step_fixup); | |
1154 | set_gdbarch_displaced_step_free_closure (gdbarch, | |
1155 | simple_displaced_step_free_closure); | |
1156 | set_gdbarch_displaced_step_location (gdbarch, displaced_step_at_entry_point); | |
25b41d01 | 1157 | |
72508ac0 PO |
1158 | /* Reversible debugging, process record. */ |
1159 | set_gdbarch_process_record (gdbarch, arm_process_record); | |
25b41d01 YQ |
1160 | |
1161 | tdep->syscall_next_pc = arm_linux_syscall_next_pc; | |
72508ac0 PO |
1162 | |
1163 | /* Syscall record. */ | |
1164 | tdep->arm_swi_record = NULL; | |
97e03143 RE |
1165 | } |
1166 | ||
63807e1d PA |
1167 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
1168 | extern initialize_file_ftype _initialize_arm_linux_tdep; | |
1169 | ||
faf5f7ad SB |
1170 | void |
1171 | _initialize_arm_linux_tdep (void) | |
1172 | { | |
05816f70 MK |
1173 | gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_LINUX, |
1174 | arm_linux_init_abi); | |
faf5f7ad | 1175 | } |