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17ce452f JW |
1 | /* |
2 | * PowerPC backend to the KGDB stub. | |
3 | * | |
4 | * 1998 (c) Michael AK Tesch (tesch@cs.wisc.edu) | |
5 | * Copyright (C) 2003 Timesys Corporation. | |
6 | * Copyright (C) 2004-2006 MontaVista Software, Inc. | |
7 | * PPC64 Mods (C) 2005 Frank Rowand (frowand@mvista.com) | |
8 | * PPC32 support restored by Vitaly Wool <vwool@ru.mvista.com> and | |
9 | * Sergei Shtylyov <sshtylyov@ru.mvista.com> | |
10 | * Copyright (C) 2007-2008 Wind River Systems, Inc. | |
11 | * | |
12 | * This file is licensed under the terms of the GNU General Public License | |
13 | * version 2. This program as licensed "as is" without any warranty of any | |
14 | * kind, whether express or implied. | |
15 | */ | |
16 | ||
17 | #include <linux/kernel.h> | |
18 | #include <linux/init.h> | |
19 | #include <linux/kgdb.h> | |
20 | #include <linux/smp.h> | |
21 | #include <linux/signal.h> | |
22 | #include <linux/ptrace.h> | |
ba797b28 | 23 | #include <linux/kdebug.h> |
17ce452f JW |
24 | #include <asm/current.h> |
25 | #include <asm/processor.h> | |
26 | #include <asm/machdep.h> | |
27 | ||
28 | /* | |
29 | * This table contains the mapping between PowerPC hardware trap types, and | |
30 | * signals, which are primarily what GDB understands. GDB and the kernel | |
31 | * don't always agree on values, so we use constants taken from gdb-6.2. | |
32 | */ | |
33 | static struct hard_trap_info | |
34 | { | |
35 | unsigned int tt; /* Trap type code for powerpc */ | |
36 | unsigned char signo; /* Signal that we map this trap into */ | |
37 | } hard_trap_info[] = { | |
38 | { 0x0100, 0x02 /* SIGINT */ }, /* system reset */ | |
39 | { 0x0200, 0x0b /* SIGSEGV */ }, /* machine check */ | |
40 | { 0x0300, 0x0b /* SIGSEGV */ }, /* data access */ | |
41 | { 0x0400, 0x0b /* SIGSEGV */ }, /* instruction access */ | |
42 | { 0x0500, 0x02 /* SIGINT */ }, /* external interrupt */ | |
43 | { 0x0600, 0x0a /* SIGBUS */ }, /* alignment */ | |
44 | { 0x0700, 0x05 /* SIGTRAP */ }, /* program check */ | |
45 | { 0x0800, 0x08 /* SIGFPE */ }, /* fp unavailable */ | |
46 | { 0x0900, 0x0e /* SIGALRM */ }, /* decrementer */ | |
47 | { 0x0c00, 0x14 /* SIGCHLD */ }, /* system call */ | |
48 | #if defined(CONFIG_40x) || defined(CONFIG_BOOKE) | |
49 | { 0x2002, 0x05 /* SIGTRAP */ }, /* debug */ | |
50 | #if defined(CONFIG_FSL_BOOKE) | |
51 | { 0x2010, 0x08 /* SIGFPE */ }, /* spe unavailable */ | |
52 | { 0x2020, 0x08 /* SIGFPE */ }, /* spe unavailable */ | |
53 | { 0x2030, 0x08 /* SIGFPE */ }, /* spe fp data */ | |
54 | { 0x2040, 0x08 /* SIGFPE */ }, /* spe fp data */ | |
55 | { 0x2050, 0x08 /* SIGFPE */ }, /* spe fp round */ | |
af901ca1 | 56 | { 0x2060, 0x0e /* SIGILL */ }, /* performance monitor */ |
17ce452f JW |
57 | { 0x2900, 0x08 /* SIGFPE */ }, /* apu unavailable */ |
58 | { 0x3100, 0x0e /* SIGALRM */ }, /* fixed interval timer */ | |
59 | { 0x3200, 0x02 /* SIGINT */ }, /* watchdog */ | |
60 | #else /* ! CONFIG_FSL_BOOKE */ | |
61 | { 0x1000, 0x0e /* SIGALRM */ }, /* prog interval timer */ | |
62 | { 0x1010, 0x0e /* SIGALRM */ }, /* fixed interval timer */ | |
63 | { 0x1020, 0x02 /* SIGINT */ }, /* watchdog */ | |
64 | { 0x2010, 0x08 /* SIGFPE */ }, /* fp unavailable */ | |
65 | { 0x2020, 0x08 /* SIGFPE */ }, /* ap unavailable */ | |
66 | #endif | |
67 | #else /* ! (defined(CONFIG_40x) || defined(CONFIG_BOOKE)) */ | |
68 | { 0x0d00, 0x05 /* SIGTRAP */ }, /* single-step */ | |
69 | #if defined(CONFIG_8xx) | |
70 | { 0x1000, 0x04 /* SIGILL */ }, /* software emulation */ | |
71 | #else /* ! CONFIG_8xx */ | |
72 | { 0x0f00, 0x04 /* SIGILL */ }, /* performance monitor */ | |
73 | { 0x0f20, 0x08 /* SIGFPE */ }, /* altivec unavailable */ | |
74 | { 0x1300, 0x05 /* SIGTRAP */ }, /* instruction address break */ | |
75 | #if defined(CONFIG_PPC64) | |
76 | { 0x1200, 0x05 /* SIGILL */ }, /* system error */ | |
77 | { 0x1500, 0x04 /* SIGILL */ }, /* soft patch */ | |
78 | { 0x1600, 0x04 /* SIGILL */ }, /* maintenance */ | |
79 | { 0x1700, 0x08 /* SIGFPE */ }, /* altivec assist */ | |
80 | { 0x1800, 0x04 /* SIGILL */ }, /* thermal */ | |
81 | #else /* ! CONFIG_PPC64 */ | |
82 | { 0x1400, 0x02 /* SIGINT */ }, /* SMI */ | |
83 | { 0x1600, 0x08 /* SIGFPE */ }, /* altivec assist */ | |
84 | { 0x1700, 0x04 /* SIGILL */ }, /* TAU */ | |
85 | { 0x2000, 0x05 /* SIGTRAP */ }, /* run mode */ | |
86 | #endif | |
87 | #endif | |
88 | #endif | |
89 | { 0x0000, 0x00 } /* Must be last */ | |
90 | }; | |
91 | ||
92 | static int computeSignal(unsigned int tt) | |
93 | { | |
94 | struct hard_trap_info *ht; | |
95 | ||
96 | for (ht = hard_trap_info; ht->tt && ht->signo; ht++) | |
97 | if (ht->tt == tt) | |
98 | return ht->signo; | |
99 | ||
100 | return SIGHUP; /* default for things we don't know about */ | |
101 | } | |
102 | ||
103 | static int kgdb_call_nmi_hook(struct pt_regs *regs) | |
104 | { | |
105 | kgdb_nmicallback(raw_smp_processor_id(), regs); | |
106 | return 0; | |
107 | } | |
108 | ||
109 | #ifdef CONFIG_SMP | |
110 | void kgdb_roundup_cpus(unsigned long flags) | |
111 | { | |
112 | smp_send_debugger_break(MSG_ALL_BUT_SELF); | |
113 | } | |
114 | #endif | |
115 | ||
116 | /* KGDB functions to use existing PowerPC64 hooks. */ | |
117 | static int kgdb_debugger(struct pt_regs *regs) | |
118 | { | |
ba797b28 JW |
119 | return !kgdb_handle_exception(1, computeSignal(TRAP(regs)), |
120 | DIE_OOPS, regs); | |
17ce452f JW |
121 | } |
122 | ||
123 | static int kgdb_handle_breakpoint(struct pt_regs *regs) | |
124 | { | |
125 | if (user_mode(regs)) | |
126 | return 0; | |
127 | ||
ba797b28 | 128 | if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0) |
17ce452f JW |
129 | return 0; |
130 | ||
131 | if (*(u32 *) (regs->nip) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr)) | |
3f0a55e3 | 132 | regs->nip += BREAK_INSTR_SIZE; |
17ce452f JW |
133 | |
134 | return 1; | |
135 | } | |
136 | ||
137 | static int kgdb_singlestep(struct pt_regs *regs) | |
138 | { | |
139 | struct thread_info *thread_info, *exception_thread_info; | |
140 | ||
141 | if (user_mode(regs)) | |
142 | return 0; | |
143 | ||
144 | /* | |
145 | * On Book E and perhaps other processsors, singlestep is handled on | |
146 | * the critical exception stack. This causes current_thread_info() | |
147 | * to fail, since it it locates the thread_info by masking off | |
148 | * the low bits of the current stack pointer. We work around | |
149 | * this issue by copying the thread_info from the kernel stack | |
150 | * before calling kgdb_handle_exception, and copying it back | |
151 | * afterwards. On most processors the copy is avoided since | |
152 | * exception_thread_info == thread_info. | |
153 | */ | |
154 | thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1)); | |
155 | exception_thread_info = current_thread_info(); | |
156 | ||
157 | if (thread_info != exception_thread_info) | |
158 | memcpy(exception_thread_info, thread_info, sizeof *thread_info); | |
159 | ||
160 | kgdb_handle_exception(0, SIGTRAP, 0, regs); | |
161 | ||
162 | if (thread_info != exception_thread_info) | |
163 | memcpy(thread_info, exception_thread_info, sizeof *thread_info); | |
164 | ||
165 | return 1; | |
166 | } | |
167 | ||
168 | static int kgdb_iabr_match(struct pt_regs *regs) | |
169 | { | |
170 | if (user_mode(regs)) | |
171 | return 0; | |
172 | ||
173 | if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) | |
174 | return 0; | |
175 | return 1; | |
176 | } | |
177 | ||
178 | static int kgdb_dabr_match(struct pt_regs *regs) | |
179 | { | |
180 | if (user_mode(regs)) | |
181 | return 0; | |
182 | ||
183 | if (kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs) != 0) | |
184 | return 0; | |
185 | return 1; | |
186 | } | |
187 | ||
188 | #define PACK64(ptr, src) do { *(ptr++) = (src); } while (0) | |
189 | ||
190 | #define PACK32(ptr, src) do { \ | |
191 | u32 *ptr32; \ | |
192 | ptr32 = (u32 *)ptr; \ | |
193 | *(ptr32++) = (src); \ | |
194 | ptr = (unsigned long *)ptr32; \ | |
195 | } while (0) | |
196 | ||
197 | ||
198 | void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) | |
199 | { | |
200 | unsigned long *ptr = gdb_regs; | |
201 | int reg; | |
202 | ||
203 | memset(gdb_regs, 0, NUMREGBYTES); | |
204 | ||
205 | for (reg = 0; reg < 32; reg++) | |
206 | PACK64(ptr, regs->gpr[reg]); | |
207 | ||
208 | #ifdef CONFIG_FSL_BOOKE | |
209 | #ifdef CONFIG_SPE | |
210 | for (reg = 0; reg < 32; reg++) | |
211 | PACK64(ptr, current->thread.evr[reg]); | |
212 | #else | |
213 | ptr += 32; | |
214 | #endif | |
215 | #else | |
216 | /* fp registers not used by kernel, leave zero */ | |
217 | ptr += 32 * 8 / sizeof(long); | |
218 | #endif | |
219 | ||
220 | PACK64(ptr, regs->nip); | |
221 | PACK64(ptr, regs->msr); | |
222 | PACK32(ptr, regs->ccr); | |
223 | PACK64(ptr, regs->link); | |
224 | PACK64(ptr, regs->ctr); | |
225 | PACK32(ptr, regs->xer); | |
226 | ||
227 | BUG_ON((unsigned long)ptr > | |
228 | (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); | |
229 | } | |
230 | ||
231 | void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) | |
232 | { | |
233 | struct pt_regs *regs = (struct pt_regs *)(p->thread.ksp + | |
234 | STACK_FRAME_OVERHEAD); | |
235 | unsigned long *ptr = gdb_regs; | |
236 | int reg; | |
237 | ||
238 | memset(gdb_regs, 0, NUMREGBYTES); | |
239 | ||
240 | /* Regs GPR0-2 */ | |
241 | for (reg = 0; reg < 3; reg++) | |
242 | PACK64(ptr, regs->gpr[reg]); | |
243 | ||
244 | /* Regs GPR3-13 are caller saved, not in regs->gpr[] */ | |
245 | ptr += 11; | |
246 | ||
247 | /* Regs GPR14-31 */ | |
248 | for (reg = 14; reg < 32; reg++) | |
249 | PACK64(ptr, regs->gpr[reg]); | |
250 | ||
251 | #ifdef CONFIG_FSL_BOOKE | |
252 | #ifdef CONFIG_SPE | |
253 | for (reg = 0; reg < 32; reg++) | |
254 | PACK64(ptr, p->thread.evr[reg]); | |
255 | #else | |
256 | ptr += 32; | |
257 | #endif | |
258 | #else | |
259 | /* fp registers not used by kernel, leave zero */ | |
260 | ptr += 32 * 8 / sizeof(long); | |
261 | #endif | |
262 | ||
263 | PACK64(ptr, regs->nip); | |
264 | PACK64(ptr, regs->msr); | |
265 | PACK32(ptr, regs->ccr); | |
266 | PACK64(ptr, regs->link); | |
267 | PACK64(ptr, regs->ctr); | |
268 | PACK32(ptr, regs->xer); | |
269 | ||
270 | BUG_ON((unsigned long)ptr > | |
271 | (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); | |
272 | } | |
273 | ||
274 | #define UNPACK64(dest, ptr) do { dest = *(ptr++); } while (0) | |
275 | ||
276 | #define UNPACK32(dest, ptr) do { \ | |
277 | u32 *ptr32; \ | |
278 | ptr32 = (u32 *)ptr; \ | |
279 | dest = *(ptr32++); \ | |
280 | ptr = (unsigned long *)ptr32; \ | |
281 | } while (0) | |
282 | ||
283 | void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) | |
284 | { | |
285 | unsigned long *ptr = gdb_regs; | |
286 | int reg; | |
17ce452f JW |
287 | |
288 | for (reg = 0; reg < 32; reg++) | |
289 | UNPACK64(regs->gpr[reg], ptr); | |
290 | ||
291 | #ifdef CONFIG_FSL_BOOKE | |
292 | #ifdef CONFIG_SPE | |
293 | for (reg = 0; reg < 32; reg++) | |
294 | UNPACK64(current->thread.evr[reg], ptr); | |
295 | #else | |
296 | ptr += 32; | |
297 | #endif | |
298 | #else | |
299 | /* fp registers not used by kernel, leave zero */ | |
300 | ptr += 32 * 8 / sizeof(int); | |
301 | #endif | |
302 | ||
303 | UNPACK64(regs->nip, ptr); | |
304 | UNPACK64(regs->msr, ptr); | |
305 | UNPACK32(regs->ccr, ptr); | |
306 | UNPACK64(regs->link, ptr); | |
307 | UNPACK64(regs->ctr, ptr); | |
308 | UNPACK32(regs->xer, ptr); | |
309 | ||
310 | BUG_ON((unsigned long)ptr > | |
311 | (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); | |
312 | } | |
313 | ||
dcc78711 JW |
314 | void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) |
315 | { | |
316 | regs->nip = pc; | |
317 | } | |
318 | ||
17ce452f JW |
319 | /* |
320 | * This function does PowerPC specific procesing for interfacing to gdb. | |
321 | */ | |
322 | int kgdb_arch_handle_exception(int vector, int signo, int err_code, | |
323 | char *remcom_in_buffer, char *remcom_out_buffer, | |
324 | struct pt_regs *linux_regs) | |
325 | { | |
326 | char *ptr = &remcom_in_buffer[1]; | |
327 | unsigned long addr; | |
328 | ||
329 | switch (remcom_in_buffer[0]) { | |
330 | /* | |
331 | * sAA..AA Step one instruction from AA..AA | |
332 | * This will return an error to gdb .. | |
333 | */ | |
334 | case 's': | |
335 | case 'c': | |
336 | /* handle the optional parameter */ | |
337 | if (kgdb_hex2long(&ptr, &addr)) | |
338 | linux_regs->nip = addr; | |
339 | ||
340 | atomic_set(&kgdb_cpu_doing_single_step, -1); | |
341 | /* set the trace bit if we're stepping */ | |
342 | if (remcom_in_buffer[0] == 's') { | |
172ae2e7 | 343 | #ifdef CONFIG_PPC_ADV_DEBUG_REGS |
17ce452f JW |
344 | mtspr(SPRN_DBCR0, |
345 | mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM); | |
346 | linux_regs->msr |= MSR_DE; | |
347 | #else | |
348 | linux_regs->msr |= MSR_SE; | |
349 | #endif | |
350 | kgdb_single_step = 1; | |
d7161a65 JW |
351 | atomic_set(&kgdb_cpu_doing_single_step, |
352 | raw_smp_processor_id()); | |
17ce452f JW |
353 | } |
354 | return 0; | |
355 | } | |
356 | ||
357 | return -1; | |
358 | } | |
359 | ||
360 | /* | |
361 | * Global data | |
362 | */ | |
363 | struct kgdb_arch arch_kgdb_ops = { | |
364 | .gdb_bpt_instr = {0x7d, 0x82, 0x10, 0x08}, | |
365 | }; | |
366 | ||
367 | static int kgdb_not_implemented(struct pt_regs *regs) | |
368 | { | |
369 | return 0; | |
370 | } | |
371 | ||
372 | static void *old__debugger_ipi; | |
373 | static void *old__debugger; | |
374 | static void *old__debugger_bpt; | |
375 | static void *old__debugger_sstep; | |
376 | static void *old__debugger_iabr_match; | |
377 | static void *old__debugger_dabr_match; | |
378 | static void *old__debugger_fault_handler; | |
379 | ||
380 | int kgdb_arch_init(void) | |
381 | { | |
382 | old__debugger_ipi = __debugger_ipi; | |
383 | old__debugger = __debugger; | |
384 | old__debugger_bpt = __debugger_bpt; | |
385 | old__debugger_sstep = __debugger_sstep; | |
386 | old__debugger_iabr_match = __debugger_iabr_match; | |
387 | old__debugger_dabr_match = __debugger_dabr_match; | |
388 | old__debugger_fault_handler = __debugger_fault_handler; | |
389 | ||
390 | __debugger_ipi = kgdb_call_nmi_hook; | |
391 | __debugger = kgdb_debugger; | |
392 | __debugger_bpt = kgdb_handle_breakpoint; | |
393 | __debugger_sstep = kgdb_singlestep; | |
394 | __debugger_iabr_match = kgdb_iabr_match; | |
395 | __debugger_dabr_match = kgdb_dabr_match; | |
396 | __debugger_fault_handler = kgdb_not_implemented; | |
397 | ||
398 | return 0; | |
399 | } | |
400 | ||
401 | void kgdb_arch_exit(void) | |
402 | { | |
403 | __debugger_ipi = old__debugger_ipi; | |
404 | __debugger = old__debugger; | |
405 | __debugger_bpt = old__debugger_bpt; | |
406 | __debugger_sstep = old__debugger_sstep; | |
407 | __debugger_iabr_match = old__debugger_iabr_match; | |
408 | __debugger_dabr_match = old__debugger_dabr_match; | |
409 | __debugger_fault_handler = old__debugger_fault_handler; | |
410 | } |