1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Stack dumping functions
4 *
5 * Copyright IBM Corp. 1999, 2013
6 */
7
8 #include <linux/kallsyms.h>
9 #include <linux/hardirq.h>
10 #include <linux/kprobes.h>
11 #include <linux/utsname.h>
12 #include <linux/export.h>
13 #include <linux/kdebug.h>
14 #include <linux/ptrace.h>
15 #include <linux/mm.h>
16 #include <linux/module.h>
17 #include <linux/sched.h>
18 #include <linux/sched/debug.h>
19 #include <linux/sched/task_stack.h>
20 #include <asm/processor.h>
21 #include <asm/debug.h>
22 #include <asm/dis.h>
23 #include <asm/ipl.h>
24 #include <asm/unwind.h>
25
26 const char *stack_type_name(enum stack_type type)
27 {
28 switch (type) {
29 case STACK_TYPE_TASK:
30 return "task";
31 case STACK_TYPE_IRQ:
32 return "irq";
33 case STACK_TYPE_NODAT:
34 return "nodat";
35 case STACK_TYPE_RESTART:
36 return "restart";
37 default:
38 return "unknown";
39 }
40 }
41 EXPORT_SYMBOL_GPL(stack_type_name);
42
43 static inline bool in_stack(unsigned long sp, struct stack_info *info,
44 enum stack_type type, unsigned long stack)
45 {
46 if (sp < stack || sp >= stack + THREAD_SIZE)
47 return false;
48 info->type = type;
49 info->begin = stack;
50 info->end = stack + THREAD_SIZE;
51 return true;
52 }
53
54 static bool in_task_stack(unsigned long sp, struct task_struct *task,
55 struct stack_info *info)
56 {
57 unsigned long stack = (unsigned long)task_stack_page(task);
58
59 return in_stack(sp, info, STACK_TYPE_TASK, stack);
60 }
61
62 static bool in_irq_stack(unsigned long sp, struct stack_info *info)
63 {
64 unsigned long stack = get_lowcore()->async_stack - STACK_INIT_OFFSET;
65
66 return in_stack(sp, info, STACK_TYPE_IRQ, stack);
67 }
68
69 static bool in_nodat_stack(unsigned long sp, struct stack_info *info)
70 {
71 unsigned long stack = get_lowcore()->nodat_stack - STACK_INIT_OFFSET;
72
73 return in_stack(sp, info, STACK_TYPE_NODAT, stack);
74 }
75
76 static bool in_mcck_stack(unsigned long sp, struct stack_info *info)
77 {
78 unsigned long stack = get_lowcore()->mcck_stack - STACK_INIT_OFFSET;
79
80 return in_stack(sp, info, STACK_TYPE_MCCK, stack);
81 }
82
83 static bool in_restart_stack(unsigned long sp, struct stack_info *info)
84 {
85 unsigned long stack = get_lowcore()->restart_stack - STACK_INIT_OFFSET;
86
87 return in_stack(sp, info, STACK_TYPE_RESTART, stack);
88 }
89
90 int get_stack_info(unsigned long sp, struct task_struct *task,
91 struct stack_info *info, unsigned long *visit_mask)
92 {
93 if (!sp)
94 goto unknown;
95
96 /* Sanity check: ABI requires SP to be aligned 8 bytes. */
97 if (sp & 0x7)
98 goto unknown;
99
100 /* Check per-task stack */
101 if (in_task_stack(sp, task, info))
102 goto recursion_check;
103
104 if (task != current)
105 goto unknown;
106
107 /* Check per-cpu stacks */
108 if (!in_irq_stack(sp, info) &&
109 !in_nodat_stack(sp, info) &&
110 !in_restart_stack(sp, info) &&
111 !in_mcck_stack(sp, info))
112 goto unknown;
113
114 recursion_check:
115 /*
116 * Make sure we don't iterate through any given stack more than once.
117 * If it comes up a second time then there's something wrong going on:
118 * just break out and report an unknown stack type.
119 */
120 if (*visit_mask & (1UL << info->type))
121 goto unknown;
122 *visit_mask |= 1UL << info->type;
123 return 0;
124 unknown:
125 info->type = STACK_TYPE_UNKNOWN;
126 return -EINVAL;
127 }
128
129 void show_stack(struct task_struct *task, unsigned long *stack,
130 const char *loglvl)
131 {
132 struct unwind_state state;
133
134 printk("%sCall Trace:\n", loglvl);
135 unwind_for_each_frame(&state, task, NULL, (unsigned long) stack)
136 printk(state.reliable ? "%s [<%016lx>] %pSR \n" :
137 "%s([<%016lx>] %pSR)\n",
138 loglvl, state.ip, (void *) state.ip);
139 debug_show_held_locks(task ? : current);
140 }
141
142 static void show_last_breaking_event(struct pt_regs *regs)
143 {
144 printk("Last Breaking-Event-Address:\n");
145 printk(" [<%016lx>] ", regs->last_break);
146 if (user_mode(regs)) {
147 print_vma_addr(KERN_CONT, regs->last_break);
148 pr_cont("\n");
149 } else {
150 pr_cont("%pSR\n", (void *)regs->last_break);
151 }
152 }
153
154 void show_registers(struct pt_regs *regs)
155 {
156 struct psw_bits *psw = &psw_bits(regs->psw);
157 char *mode;
158
159 mode = user_mode(regs) ? "User" : "Krnl";
160 printk("%s PSW : %px %px", mode, (void *)regs->psw.mask, (void *)regs->psw.addr);
161 if (!user_mode(regs))
162 pr_cont(" (%pSR)", (void *)regs->psw.addr);
163 pr_cont("\n");
164 printk(" R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
165 "P:%x AS:%x CC:%x PM:%x", psw->per, psw->dat, psw->io, psw->ext,
166 psw->key, psw->mcheck, psw->wait, psw->pstate, psw->as, psw->cc, psw->pm);
167 pr_cont(" RI:%x EA:%x\n", psw->ri, psw->eaba);
168 printk("%s GPRS: %016lx %016lx %016lx %016lx\n", mode,
169 regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
170 printk(" %016lx %016lx %016lx %016lx\n",
171 regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
172 printk(" %016lx %016lx %016lx %016lx\n",
173 regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
174 printk(" %016lx %016lx %016lx %016lx\n",
175 regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
176 show_code(regs);
177 }
178
179 void show_regs(struct pt_regs *regs)
180 {
181 show_regs_print_info(KERN_DEFAULT);
182 show_registers(regs);
183 /* Show stack backtrace if pt_regs is from kernel mode */
184 if (!user_mode(regs))
185 show_stack(NULL, (unsigned long *) regs->gprs[15], KERN_DEFAULT);
186 show_last_breaking_event(regs);
187 }
188
189 static DEFINE_SPINLOCK(die_lock);
190
191 void __noreturn die(struct pt_regs *regs, const char *str)
192 {
193 static int die_counter;
194
195 oops_enter();
196 lgr_info_log();
197 debug_stop_all();
198 console_verbose();
199 spin_lock_irq(&die_lock);
200 bust_spinlocks(1);
201 printk("%s: %04x ilc:%d [#%d] ", str, regs->int_code & 0xffff,
202 regs->int_code >> 17, ++die_counter);
203 #ifdef CONFIG_PREEMPT
204 pr_cont("PREEMPT ");
205 #elif defined(CONFIG_PREEMPT_RT)
206 pr_cont("PREEMPT_RT ");
207 #endif
208 pr_cont("SMP ");
209 if (debug_pagealloc_enabled())
210 pr_cont("DEBUG_PAGEALLOC");
211 pr_cont("\n");
212 notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
213 print_modules();
214 show_regs(regs);
215 bust_spinlocks(0);
216 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
217 spin_unlock_irq(&die_lock);
218 if (in_interrupt())
219 panic("Fatal exception in interrupt");
220 if (panic_on_oops)
221 panic("Fatal exception: panic_on_oops");
222 oops_exit();
223 make_task_dead(SIGSEGV);
224 }
225
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