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16#include <linux/export.h>
17#include <linux/kallsyms.h>
18#include <linux/kernel.h>
19#include <linux/sched.h>
20#include <linux/sched/task_stack.h>
21#include <linux/stacktrace.h>
22#include <linux/types.h>
23#include <linux/errno.h>
24#include <linux/io.h>
25#include <asm/sections.h>
26#include <asm/exceptions.h>
27#include <asm/unwind.h>
28#include <asm/switch_to.h>
29
30struct stack_trace;
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63static inline long get_frame_size(unsigned long instr)
64{
65 return abs((s16)(instr & 0xFFFF));
66}
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76
77static unsigned long *find_frame_creation(unsigned long *pc)
78{
79 int i;
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85
86 for (i = 0; i < 1000; i++, pc--) {
87 unsigned long instr;
88 s16 frame_size;
89
90 if (!kernel_text_address((unsigned long) pc))
91 return NULL;
92
93 instr = *pc;
94
95
96 if ((instr & 0xFFFF0000) != 0x30210000)
97 continue;
98
99 frame_size = get_frame_size(instr);
100 if ((frame_size < 8) || (frame_size & 3)) {
101 pr_debug(" Invalid frame size %d at 0x%p\n",
102 frame_size, pc);
103 return NULL;
104 }
105
106 pr_debug(" Found frame creation at 0x%p, size %d\n", pc,
107 frame_size);
108 return pc;
109 }
110
111 return NULL;
112}
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125static int lookup_prev_stack_frame(unsigned long fp, unsigned long pc,
126 unsigned long leaf_return,
127 unsigned long *pprev_fp,
128 unsigned long *pprev_pc)
129{
130 unsigned long *prologue = NULL;
131
132
133 if (pc != (unsigned long) &_switch_to)
134 prologue = find_frame_creation((unsigned long *)pc);
135
136 if (prologue) {
137 long frame_size = get_frame_size(*prologue);
138
139 *pprev_fp = fp + frame_size;
140 *pprev_pc = *(unsigned long *)fp;
141 } else {
142 if (!leaf_return)
143 return -EINVAL;
144 *pprev_pc = leaf_return;
145 *pprev_fp = fp;
146 }
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150
151 return (!*pprev_pc || (*pprev_pc & 3)) ? -EINVAL : 0;
152}
153
154static void microblaze_unwind_inner(struct task_struct *task,
155 unsigned long pc, unsigned long fp,
156 unsigned long leaf_return,
157 struct stack_trace *trace,
158 const char *loglvl);
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164static inline void unwind_trap(struct task_struct *task, unsigned long pc,
165 unsigned long fp, struct stack_trace *trace,
166 const char *loglvl)
167{
168
169}
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182static void microblaze_unwind_inner(struct task_struct *task,
183 unsigned long pc, unsigned long fp,
184 unsigned long leaf_return,
185 struct stack_trace *trace,
186 const char *loglvl)
187{
188 int ofs = 0;
189
190 pr_debug(" Unwinding with PC=%p, FP=%p\n", (void *)pc, (void *)fp);
191 if (!pc || !fp || (pc & 3) || (fp & 3)) {
192 pr_debug(" Invalid state for unwind, aborting\n");
193 return;
194 }
195 for (; pc != 0;) {
196 unsigned long next_fp, next_pc = 0;
197 unsigned long return_to = pc + 2 * sizeof(unsigned long);
198 const struct trap_handler_info *handler =
199 µblaze_trap_handlers;
200
201
202 if ((return_to >= (unsigned long)&_hw_exception_handler)
203 &&(return_to < (unsigned long)&ex_handler_unhandled)) {
204
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207
208 printk("%sHW EXCEPTION\n", loglvl);
209 return;
210 }
211
212
213 for (; handler->start_addr; ++handler) {
214 if ((return_to >= handler->start_addr)
215 && (return_to <= handler->end_addr)) {
216 if (!trace)
217 printk("%s%s\n", loglvl, handler->trap_name);
218 unwind_trap(task, pc, fp, trace, loglvl);
219 return;
220 }
221 }
222 pc -= ofs;
223
224 if (trace) {
225#ifdef CONFIG_STACKTRACE
226 if (trace->skip > 0)
227 trace->skip--;
228 else
229 trace->entries[trace->nr_entries++] = pc;
230
231 if (trace->nr_entries >= trace->max_entries)
232 break;
233#endif
234 } else {
235
236 if (unlikely(pc == task_pt_regs(task)->pc)) {
237 printk("%s[<%p>] PID %lu [%s]\n",
238 loglvl, (void *) pc,
239 (unsigned long) task->pid,
240 task->comm);
241 break;
242 } else
243 print_ip_sym(loglvl, pc);
244 }
245
246
247 if (!kernel_text_address(pc))
248 break;
249
250 if (lookup_prev_stack_frame(fp, pc, leaf_return, &next_fp,
251 &next_pc) == 0) {
252 ofs = sizeof(unsigned long);
253 pc = next_pc & ~3;
254 fp = next_fp;
255 leaf_return = 0;
256 } else {
257 pr_debug(" Failed to find previous stack frame\n");
258 break;
259 }
260
261 pr_debug(" Next PC=%p, next FP=%p\n",
262 (void *)next_pc, (void *)next_fp);
263 }
264}
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273void microblaze_unwind(struct task_struct *task, struct stack_trace *trace,
274 const char *loglvl)
275{
276 if (task) {
277 if (task == current) {
278 const struct pt_regs *regs = task_pt_regs(task);
279 microblaze_unwind_inner(task, regs->pc, regs->r1,
280 regs->r15, trace, loglvl);
281 } else {
282 struct thread_info *thread_info =
283 (struct thread_info *)(task->stack);
284 const struct cpu_context *cpu_context =
285 &thread_info->cpu_context;
286
287 microblaze_unwind_inner(task,
288 (unsigned long) &_switch_to,
289 cpu_context->r1,
290 cpu_context->r15,
291 trace, loglvl);
292 }
293 } else {
294 unsigned long pc, fp;
295
296 __asm__ __volatile__ ("or %0, r1, r0" : "=r" (fp));
297
298 __asm__ __volatile__ (
299 "brlid %0, 0f;"
300 "nop;"
301 "0:"
302 : "=r" (pc)
303 );
304
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306 microblaze_unwind_inner(current, pc, fp, 0, trace, loglvl);
307 }
308}
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310