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
26const 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}
41EXPORT_SYMBOL_GPL(stack_type_name);
42
43static 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
54static 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
62static bool in_irq_stack(unsigned long sp, struct stack_info *info)
63{
64	unsigned long stack = S390_lowcore.async_stack - STACK_INIT_OFFSET;
65
66	return in_stack(sp, info, STACK_TYPE_IRQ, stack);
67}
68
69static bool in_nodat_stack(unsigned long sp, struct stack_info *info)
70{
71	unsigned long stack = S390_lowcore.nodat_stack - STACK_INIT_OFFSET;
72
73	return in_stack(sp, info, STACK_TYPE_NODAT, stack);
74}
75
76static bool in_mcck_stack(unsigned long sp, struct stack_info *info)
77{
78	unsigned long stack = S390_lowcore.mcck_stack - STACK_INIT_OFFSET;
79
80	return in_stack(sp, info, STACK_TYPE_MCCK, stack);
81}
82
83static bool in_restart_stack(unsigned long sp, struct stack_info *info)
84{
85	unsigned long stack = S390_lowcore.restart_stack - STACK_INIT_OFFSET;
86
87	return in_stack(sp, info, STACK_TYPE_RESTART, stack);
88}
89
90int 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
114recursion_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;
124unknown:
125	info->type = STACK_TYPE_UNKNOWN;
126	return -EINVAL;
127}
128
129void 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
142static 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
154void 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
179void 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
189static DEFINE_SPINLOCK(die_lock);
190
191void __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