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-rw-r--r--arch/tile/kernel/stack.c486
1 files changed, 486 insertions, 0 deletions
diff --git a/arch/tile/kernel/stack.c b/arch/tile/kernel/stack.c
new file mode 100644
index 000000000000..b6268d3ae869
--- /dev/null
+++ b/arch/tile/kernel/stack.c
@@ -0,0 +1,486 @@
1/*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
12 * more details.
13 */
14
15#include <linux/sched.h>
16#include <linux/kernel.h>
17#include <linux/kprobes.h>
18#include <linux/module.h>
19#include <linux/pfn.h>
20#include <linux/kallsyms.h>
21#include <linux/stacktrace.h>
22#include <linux/uaccess.h>
23#include <linux/mmzone.h>
24#include <asm/backtrace.h>
25#include <asm/page.h>
26#include <asm/tlbflush.h>
27#include <asm/ucontext.h>
28#include <asm/sigframe.h>
29#include <asm/stack.h>
30#include <arch/abi.h>
31#include <arch/interrupts.h>
32
33
34/* Is address on the specified kernel stack? */
35static int in_kernel_stack(struct KBacktraceIterator *kbt, VirtualAddress sp)
36{
37 ulong kstack_base = (ulong) kbt->task->stack;
38 if (kstack_base == 0) /* corrupt task pointer; just follow stack... */
39 return sp >= PAGE_OFFSET && sp < (unsigned long)high_memory;
40 return sp >= kstack_base && sp < kstack_base + THREAD_SIZE;
41}
42
43/* Is address in the specified kernel code? */
44static int in_kernel_text(VirtualAddress address)
45{
46 return (address >= MEM_SV_INTRPT &&
47 address < MEM_SV_INTRPT + HPAGE_SIZE);
48}
49
50/* Is address valid for reading? */
51static int valid_address(struct KBacktraceIterator *kbt, VirtualAddress address)
52{
53 HV_PTE *l1_pgtable = kbt->pgtable;
54 HV_PTE *l2_pgtable;
55 unsigned long pfn;
56 HV_PTE pte;
57 struct page *page;
58
59 if (l1_pgtable == NULL)
60 return 0; /* can't read user space in other tasks */
61
62 pte = l1_pgtable[HV_L1_INDEX(address)];
63 if (!hv_pte_get_present(pte))
64 return 0;
65 pfn = hv_pte_get_pfn(pte);
66 if (pte_huge(pte)) {
67 if (!pfn_valid(pfn)) {
68 pr_err("huge page has bad pfn %#lx\n", pfn);
69 return 0;
70 }
71 return hv_pte_get_present(pte) && hv_pte_get_readable(pte);
72 }
73
74 page = pfn_to_page(pfn);
75 if (PageHighMem(page)) {
76 pr_err("L2 page table not in LOWMEM (%#llx)\n",
77 HV_PFN_TO_CPA(pfn));
78 return 0;
79 }
80 l2_pgtable = (HV_PTE *)pfn_to_kaddr(pfn);
81 pte = l2_pgtable[HV_L2_INDEX(address)];
82 return hv_pte_get_present(pte) && hv_pte_get_readable(pte);
83}
84
85/* Callback for backtracer; basically a glorified memcpy */
86static bool read_memory_func(void *result, VirtualAddress address,
87 unsigned int size, void *vkbt)
88{
89 int retval;
90 struct KBacktraceIterator *kbt = (struct KBacktraceIterator *)vkbt;
91 if (in_kernel_text(address)) {
92 /* OK to read kernel code. */
93 } else if (address >= PAGE_OFFSET) {
94 /* We only tolerate kernel-space reads of this task's stack */
95 if (!in_kernel_stack(kbt, address))
96 return 0;
97 } else if (!valid_address(kbt, address)) {
98 return 0; /* invalid user-space address */
99 }
100 pagefault_disable();
101 retval = __copy_from_user_inatomic(result,
102 (void __user __force *)address,
103 size);
104 pagefault_enable();
105 return (retval == 0);
106}
107
108/* Return a pt_regs pointer for a valid fault handler frame */
109static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt)
110{
111#ifndef __tilegx__
112 const char *fault = NULL; /* happy compiler */
113 char fault_buf[64];
114 VirtualAddress sp = kbt->it.sp;
115 struct pt_regs *p;
116
117 if (!in_kernel_stack(kbt, sp))
118 return NULL;
119 if (!in_kernel_stack(kbt, sp + C_ABI_SAVE_AREA_SIZE + PTREGS_SIZE-1))
120 return NULL;
121 p = (struct pt_regs *)(sp + C_ABI_SAVE_AREA_SIZE);
122 if (p->faultnum == INT_SWINT_1 || p->faultnum == INT_SWINT_1_SIGRETURN)
123 fault = "syscall";
124 else {
125 if (kbt->verbose) { /* else we aren't going to use it */
126 snprintf(fault_buf, sizeof(fault_buf),
127 "interrupt %ld", p->faultnum);
128 fault = fault_buf;
129 }
130 }
131 if (EX1_PL(p->ex1) == KERNEL_PL &&
132 in_kernel_text(p->pc) &&
133 in_kernel_stack(kbt, p->sp) &&
134 p->sp >= sp) {
135 if (kbt->verbose)
136 pr_err(" <%s while in kernel mode>\n", fault);
137 } else if (EX1_PL(p->ex1) == USER_PL &&
138 p->pc < PAGE_OFFSET &&
139 p->sp < PAGE_OFFSET) {
140 if (kbt->verbose)
141 pr_err(" <%s while in user mode>\n", fault);
142 } else if (kbt->verbose) {
143 pr_err(" (odd fault: pc %#lx, sp %#lx, ex1 %#lx?)\n",
144 p->pc, p->sp, p->ex1);
145 p = NULL;
146 }
147 if (!kbt->profile || (INT_MASK(p->faultnum) & QUEUED_INTERRUPTS) == 0)
148 return p;
149#endif
150 return NULL;
151}
152
153/* Is the pc pointing to a sigreturn trampoline? */
154static int is_sigreturn(VirtualAddress pc)
155{
156 return (pc == VDSO_BASE);
157}
158
159/* Return a pt_regs pointer for a valid signal handler frame */
160static struct pt_regs *valid_sigframe(struct KBacktraceIterator* kbt)
161{
162 BacktraceIterator *b = &kbt->it;
163
164 if (b->pc == VDSO_BASE) {
165 struct rt_sigframe *frame;
166 unsigned long sigframe_top =
167 b->sp + sizeof(struct rt_sigframe) - 1;
168 if (!valid_address(kbt, b->sp) ||
169 !valid_address(kbt, sigframe_top)) {
170 if (kbt->verbose)
171 pr_err(" (odd signal: sp %#lx?)\n",
172 (unsigned long)(b->sp));
173 return NULL;
174 }
175 frame = (struct rt_sigframe *)b->sp;
176 if (kbt->verbose) {
177 pr_err(" <received signal %d>\n",
178 frame->info.si_signo);
179 }
180 return &frame->uc.uc_mcontext.regs;
181 }
182 return NULL;
183}
184
185static int KBacktraceIterator_is_sigreturn(struct KBacktraceIterator *kbt)
186{
187 return is_sigreturn(kbt->it.pc);
188}
189
190static int KBacktraceIterator_restart(struct KBacktraceIterator *kbt)
191{
192 struct pt_regs *p;
193
194 p = valid_fault_handler(kbt);
195 if (p == NULL)
196 p = valid_sigframe(kbt);
197 if (p == NULL)
198 return 0;
199 backtrace_init(&kbt->it, read_memory_func, kbt,
200 p->pc, p->lr, p->sp, p->regs[52]);
201 kbt->new_context = 1;
202 return 1;
203}
204
205/* Find a frame that isn't a sigreturn, if there is one. */
206static int KBacktraceIterator_next_item_inclusive(
207 struct KBacktraceIterator *kbt)
208{
209 for (;;) {
210 do {
211 if (!KBacktraceIterator_is_sigreturn(kbt))
212 return 1;
213 } while (backtrace_next(&kbt->it));
214
215 if (!KBacktraceIterator_restart(kbt))
216 return 0;
217 }
218}
219
220/*
221 * If the current sp is on a page different than what we recorded
222 * as the top-of-kernel-stack last time we context switched, we have
223 * probably blown the stack, and nothing is going to work out well.
224 * If we can at least get out a warning, that may help the debug,
225 * though we probably won't be able to backtrace into the code that
226 * actually did the recursive damage.
227 */
228static void validate_stack(struct pt_regs *regs)
229{
230 int cpu = smp_processor_id();
231 unsigned long ksp0 = get_current_ksp0();
232 unsigned long ksp0_base = ksp0 - THREAD_SIZE;
233 unsigned long sp = stack_pointer;
234
235 if (EX1_PL(regs->ex1) == KERNEL_PL && regs->sp >= ksp0) {
236 pr_err("WARNING: cpu %d: kernel stack page %#lx underrun!\n"
237 " sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n",
238 cpu, ksp0_base, sp, regs->sp, regs->pc, regs->lr);
239 }
240
241 else if (sp < ksp0_base + sizeof(struct thread_info)) {
242 pr_err("WARNING: cpu %d: kernel stack page %#lx overrun!\n"
243 " sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n",
244 cpu, ksp0_base, sp, regs->sp, regs->pc, regs->lr);
245 }
246}
247
248void KBacktraceIterator_init(struct KBacktraceIterator *kbt,
249 struct task_struct *t, struct pt_regs *regs)
250{
251 VirtualAddress pc, lr, sp, r52;
252 int is_current;
253
254 /*
255 * Set up callback information. We grab the kernel stack base
256 * so we will allow reads of that address range, and if we're
257 * asking about the current process we grab the page table
258 * so we can check user accesses before trying to read them.
259 * We flush the TLB to avoid any weird skew issues.
260 */
261 is_current = (t == NULL);
262 kbt->is_current = is_current;
263 if (is_current)
264 t = validate_current();
265 kbt->task = t;
266 kbt->pgtable = NULL;
267 kbt->verbose = 0; /* override in caller if desired */
268 kbt->profile = 0; /* override in caller if desired */
269 kbt->end = 0;
270 kbt->new_context = 0;
271 if (is_current) {
272 HV_PhysAddr pgdir_pa = hv_inquire_context().page_table;
273 if (pgdir_pa == (unsigned long)swapper_pg_dir - PAGE_OFFSET) {
274 /*
275 * Not just an optimization: this also allows
276 * this to work at all before va/pa mappings
277 * are set up.
278 */
279 kbt->pgtable = swapper_pg_dir;
280 } else {
281 struct page *page = pfn_to_page(PFN_DOWN(pgdir_pa));
282 if (!PageHighMem(page))
283 kbt->pgtable = __va(pgdir_pa);
284 else
285 pr_err("page table not in LOWMEM"
286 " (%#llx)\n", pgdir_pa);
287 }
288 local_flush_tlb_all();
289 validate_stack(regs);
290 }
291
292 if (regs == NULL) {
293 if (is_current || t->state == TASK_RUNNING) {
294 /* Can't do this; we need registers */
295 kbt->end = 1;
296 return;
297 }
298 pc = get_switch_to_pc();
299 lr = t->thread.pc;
300 sp = t->thread.ksp;
301 r52 = 0;
302 } else {
303 pc = regs->pc;
304 lr = regs->lr;
305 sp = regs->sp;
306 r52 = regs->regs[52];
307 }
308
309 backtrace_init(&kbt->it, read_memory_func, kbt, pc, lr, sp, r52);
310 kbt->end = !KBacktraceIterator_next_item_inclusive(kbt);
311}
312EXPORT_SYMBOL(KBacktraceIterator_init);
313
314int KBacktraceIterator_end(struct KBacktraceIterator *kbt)
315{
316 return kbt->end;
317}
318EXPORT_SYMBOL(KBacktraceIterator_end);
319
320void KBacktraceIterator_next(struct KBacktraceIterator *kbt)
321{
322 kbt->new_context = 0;
323 if (!backtrace_next(&kbt->it) &&
324 !KBacktraceIterator_restart(kbt)) {
325 kbt->end = 1;
326 return;
327 }
328
329 kbt->end = !KBacktraceIterator_next_item_inclusive(kbt);
330}
331EXPORT_SYMBOL(KBacktraceIterator_next);
332
333/*
334 * This method wraps the backtracer's more generic support.
335 * It is only invoked from the architecture-specific code; show_stack()
336 * and dump_stack() (in entry.S) are architecture-independent entry points.
337 */
338void tile_show_stack(struct KBacktraceIterator *kbt, int headers)
339{
340 int i;
341
342 if (headers) {
343 /*
344 * Add a blank line since if we are called from panic(),
345 * then bust_spinlocks() spit out a space in front of us
346 * and it will mess up our KERN_ERR.
347 */
348 pr_err("\n");
349 pr_err("Starting stack dump of tid %d, pid %d (%s)"
350 " on cpu %d at cycle %lld\n",
351 kbt->task->pid, kbt->task->tgid, kbt->task->comm,
352 smp_processor_id(), get_cycles());
353 }
354#ifdef __tilegx__
355 if (kbt->is_current) {
356 __insn_mtspr(SPR_SIM_CONTROL,
357 SIM_DUMP_SPR_ARG(SIM_DUMP_BACKTRACE));
358 }
359#endif
360 kbt->verbose = 1;
361 i = 0;
362 for (; !KBacktraceIterator_end(kbt); KBacktraceIterator_next(kbt)) {
363 char *modname;
364 const char *name;
365 unsigned long address = kbt->it.pc;
366 unsigned long offset, size;
367 char namebuf[KSYM_NAME_LEN+100];
368
369 if (address >= PAGE_OFFSET)
370 name = kallsyms_lookup(address, &size, &offset,
371 &modname, namebuf);
372 else
373 name = NULL;
374
375 if (!name)
376 namebuf[0] = '\0';
377 else {
378 size_t namelen = strlen(namebuf);
379 size_t remaining = (sizeof(namebuf) - 1) - namelen;
380 char *p = namebuf + namelen;
381 int rc = snprintf(p, remaining, "+%#lx/%#lx ",
382 offset, size);
383 if (modname && rc < remaining)
384 snprintf(p + rc, remaining - rc,
385 "[%s] ", modname);
386 namebuf[sizeof(namebuf)-1] = '\0';
387 }
388
389 pr_err(" frame %d: 0x%lx %s(sp 0x%lx)\n",
390 i++, address, namebuf, (unsigned long)(kbt->it.sp));
391
392 if (i >= 100) {
393 pr_err("Stack dump truncated"
394 " (%d frames)\n", i);
395 break;
396 }
397 }
398 if (headers)
399 pr_err("Stack dump complete\n");
400}
401EXPORT_SYMBOL(tile_show_stack);
402
403
404/* This is called from show_regs() and _dump_stack() */
405void dump_stack_regs(struct pt_regs *regs)
406{
407 struct KBacktraceIterator kbt;
408 KBacktraceIterator_init(&kbt, NULL, regs);
409 tile_show_stack(&kbt, 1);
410}
411EXPORT_SYMBOL(dump_stack_regs);
412
413static struct pt_regs *regs_to_pt_regs(struct pt_regs *regs,
414 ulong pc, ulong lr, ulong sp, ulong r52)
415{
416 memset(regs, 0, sizeof(struct pt_regs));
417 regs->pc = pc;
418 regs->lr = lr;
419 regs->sp = sp;
420 regs->regs[52] = r52;
421 return regs;
422}
423
424/* This is called from dump_stack() and just converts to pt_regs */
425void _dump_stack(int dummy, ulong pc, ulong lr, ulong sp, ulong r52)
426{
427 struct pt_regs regs;
428 dump_stack_regs(regs_to_pt_regs(&regs, pc, lr, sp, r52));
429}
430
431/* This is called from KBacktraceIterator_init_current() */
432void _KBacktraceIterator_init_current(struct KBacktraceIterator *kbt, ulong pc,
433 ulong lr, ulong sp, ulong r52)
434{
435 struct pt_regs regs;
436 KBacktraceIterator_init(kbt, NULL,
437 regs_to_pt_regs(&regs, pc, lr, sp, r52));
438}
439
440/* This is called only from kernel/sched.c, with esp == NULL */
441void show_stack(struct task_struct *task, unsigned long *esp)
442{
443 struct KBacktraceIterator kbt;
444 if (task == NULL || task == current)
445 KBacktraceIterator_init_current(&kbt);
446 else
447 KBacktraceIterator_init(&kbt, task, NULL);
448 tile_show_stack(&kbt, 0);
449}
450
451#ifdef CONFIG_STACKTRACE
452
453/* Support generic Linux stack API too */
454
455void save_stack_trace_tsk(struct task_struct *task, struct stack_trace *trace)
456{
457 struct KBacktraceIterator kbt;
458 int skip = trace->skip;
459 int i = 0;
460
461 if (task == NULL || task == current)
462 KBacktraceIterator_init_current(&kbt);
463 else
464 KBacktraceIterator_init(&kbt, task, NULL);
465 for (; !KBacktraceIterator_end(&kbt); KBacktraceIterator_next(&kbt)) {
466 if (skip) {
467 --skip;
468 continue;
469 }
470 if (i >= trace->max_entries || kbt.it.pc < PAGE_OFFSET)
471 break;
472 trace->entries[i++] = kbt.it.pc;
473 }
474 trace->nr_entries = i;
475}
476EXPORT_SYMBOL(save_stack_trace_tsk);
477
478void save_stack_trace(struct stack_trace *trace)
479{
480 save_stack_trace_tsk(NULL, trace);
481}
482
483#endif
484
485/* In entry.S */
486EXPORT_SYMBOL(KBacktraceIterator_init_current);
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