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 low,
 45			    unsigned long high)
 46{
 47	if (sp < low || sp >= high)
 48		return false;
 49	info->type = type;
 50	info->begin = low;
 51	info->end = high;
 52	return true;
 53}
 54
 55static bool in_task_stack(unsigned long sp, struct task_struct *task,
 56			  struct stack_info *info)
 57{
 58	unsigned long stack;
 59
 60	stack = (unsigned long) task_stack_page(task);
 61	return in_stack(sp, info, STACK_TYPE_TASK, stack, stack + THREAD_SIZE);
 62}
 63
 64static bool in_irq_stack(unsigned long sp, struct stack_info *info)
 65{
 66	unsigned long frame_size, top;
 67
 68	frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
 69	top = S390_lowcore.async_stack + frame_size;
 70	return in_stack(sp, info, STACK_TYPE_IRQ, top - THREAD_SIZE, top);
 71}
 72
 73static bool in_nodat_stack(unsigned long sp, struct stack_info *info)
 74{
 75	unsigned long frame_size, top;
 76
 77	frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
 78	top = S390_lowcore.nodat_stack + frame_size;
 79	return in_stack(sp, info, STACK_TYPE_NODAT, top - THREAD_SIZE, top);
 80}
 81
 82static bool in_mcck_stack(unsigned long sp, struct stack_info *info)
 83{
 84	unsigned long frame_size, top;
 85
 86	frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
 87	top = S390_lowcore.mcck_stack + frame_size;
 88	return in_stack(sp, info, STACK_TYPE_MCCK, top - THREAD_SIZE, top);
 89}
 90
 91static bool in_restart_stack(unsigned long sp, struct stack_info *info)
 92{
 93	unsigned long frame_size, top;
 94
 95	frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
 96	top = S390_lowcore.restart_stack + frame_size;
 97	return in_stack(sp, info, STACK_TYPE_RESTART, top - THREAD_SIZE, top);
 98}
 99
100int get_stack_info(unsigned long sp, struct task_struct *task,
101		   struct stack_info *info, unsigned long *visit_mask)
102{
103	if (!sp)
104		goto unknown;
105
106	/* Sanity check: ABI requires SP to be aligned 8 bytes. */
107	if (sp & 0x7)
108		goto unknown;
109
110	/* Check per-task stack */
111	if (in_task_stack(sp, task, info))
112		goto recursion_check;
113
114	if (task != current)
115		goto unknown;
116
117	/* Check per-cpu stacks */
118	if (!in_irq_stack(sp, info) &&
119	    !in_nodat_stack(sp, info) &&
120	    !in_restart_stack(sp, info) &&
121	    !in_mcck_stack(sp, info))
122		goto unknown;
123
124recursion_check:
125	/*
126	 * Make sure we don't iterate through any given stack more than once.
127	 * If it comes up a second time then there's something wrong going on:
128	 * just break out and report an unknown stack type.
129	 */
130	if (*visit_mask & (1UL << info->type))
131		goto unknown;
132	*visit_mask |= 1UL << info->type;
133	return 0;
134unknown:
135	info->type = STACK_TYPE_UNKNOWN;
136	return -EINVAL;
137}
138
139void show_stack(struct task_struct *task, unsigned long *stack,
140		       const char *loglvl)
141{
142	struct unwind_state state;
143
144	printk("%sCall Trace:\n", loglvl);
145	unwind_for_each_frame(&state, task, NULL, (unsigned long) stack)
146		printk(state.reliable ? "%s [<%016lx>] %pSR \n" :
147					"%s([<%016lx>] %pSR)\n",
148		       loglvl, state.ip, (void *) state.ip);
149	debug_show_held_locks(task ? : current);
150}
151
152static void show_last_breaking_event(struct pt_regs *regs)
153{
154	printk("Last Breaking-Event-Address:\n");
155	printk(" [<%016lx>] %pSR\n", regs->last_break, (void *)regs->last_break);
156}
157
158void show_registers(struct pt_regs *regs)
159{
160	struct psw_bits *psw = &psw_bits(regs->psw);
161	char *mode;
162
163	mode = user_mode(regs) ? "User" : "Krnl";
164	printk("%s PSW : %px %px", mode, (void *)regs->psw.mask, (void *)regs->psw.addr);
165	if (!user_mode(regs))
166		pr_cont(" (%pSR)", (void *)regs->psw.addr);
167	pr_cont("\n");
168	printk("           R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
169	       "P:%x AS:%x CC:%x PM:%x", psw->per, psw->dat, psw->io, psw->ext,
170	       psw->key, psw->mcheck, psw->wait, psw->pstate, psw->as, psw->cc, psw->pm);
171	pr_cont(" RI:%x EA:%x\n", psw->ri, psw->eaba);
172	printk("%s GPRS: %016lx %016lx %016lx %016lx\n", mode,
173	       regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
174	printk("           %016lx %016lx %016lx %016lx\n",
175	       regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
176	printk("           %016lx %016lx %016lx %016lx\n",
177	       regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
178	printk("           %016lx %016lx %016lx %016lx\n",
179	       regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
180	show_code(regs);
181}
182
183void show_regs(struct pt_regs *regs)
184{
185	show_regs_print_info(KERN_DEFAULT);
186	show_registers(regs);
187	/* Show stack backtrace if pt_regs is from kernel mode */
188	if (!user_mode(regs))
189		show_stack(NULL, (unsigned long *) regs->gprs[15], KERN_DEFAULT);
190	show_last_breaking_event(regs);
191}
192
193static DEFINE_SPINLOCK(die_lock);
194
195void __noreturn die(struct pt_regs *regs, const char *str)
196{
197	static int die_counter;
198
199	oops_enter();
200	lgr_info_log();
201	debug_stop_all();
202	console_verbose();
203	spin_lock_irq(&die_lock);
204	bust_spinlocks(1);
205	printk("%s: %04x ilc:%d [#%d] ", str, regs->int_code & 0xffff,
206	       regs->int_code >> 17, ++die_counter);
207#ifdef CONFIG_PREEMPT
208	pr_cont("PREEMPT ");
209#elif defined(CONFIG_PREEMPT_RT)
210	pr_cont("PREEMPT_RT ");
211#endif
212	pr_cont("SMP ");
213	if (debug_pagealloc_enabled())
214		pr_cont("DEBUG_PAGEALLOC");
215	pr_cont("\n");
216	notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
217	print_modules();
218	show_regs(regs);
219	bust_spinlocks(0);
220	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
221	spin_unlock_irq(&die_lock);
222	if (in_interrupt())
223		panic("Fatal exception in interrupt");
224	if (panic_on_oops)
225		panic("Fatal exception: panic_on_oops");
226	oops_exit();
227	make_task_dead(SIGSEGV);
228}