[linux-2.6-block.git] / arch / unicore32 / kernel / traps.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/arch/unicore32/kernel/traps.c
 *
 * Code specific to PKUnity SoC and UniCore ISA
 *
 * Copyright (C) 2001-2010 GUAN Xue-tao
 *
 *  'traps.c' handles hardware exceptions after we have saved some state.
 *  Mostly a debugging aid, but will probably kill the offending process.
 */
#include <linux/module.h>
#include <linux/signal.h>
#include <linux/sched/signal.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
#include <linux/spinlock.h>
#include <linux/personality.h>
#include <linux/kallsyms.h>
#include <linux/kdebug.h>
#include <linux/uaccess.h>
#include <linux/delay.h>
#include <linux/hardirq.h>
#include <linux/init.h>
#include <linux/atomic.h>
#include <linux/unistd.h>

#include <asm/cacheflush.h>
#include <asm/traps.h>

#include "setup.h"

static void dump_mem(const char *, const char *, unsigned long, unsigned long);

void dump_backtrace_entry(unsigned long where,
		unsigned long from, unsigned long frame)
{
#ifdef CONFIG_KALLSYMS
	printk(KERN_DEFAULT "[<%08lx>] (%pS) from [<%08lx>] (%pS)\n",
			where, (void *)where, from, (void *)from);
#else
	printk(KERN_DEFAULT "Function entered at [<%08lx>] from [<%08lx>]\n",
			where, from);
#endif
}

/*
 * Stack pointers should always be within the kernels view of
 * physical memory.  If it is not there, then we can't dump
 * out any information relating to the stack.
 */
static int verify_stack(unsigned long sp)
{
	if (sp < PAGE_OFFSET ||
	    (sp > (unsigned long)high_memory && high_memory != NULL))
		return -EFAULT;

	return 0;
}

/*
 * Dump out the contents of some memory nicely...
 */
static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
		     unsigned long top)
{
	unsigned long first;
	mm_segment_t fs;
	int i;

	/*
	 * We need to switch to kernel mode so that we can use __get_user
	 * to safely read from kernel space.  Note that we now dump the
	 * code first, just in case the backtrace kills us.
	 */
	fs = get_fs();
	set_fs(KERNEL_DS);

	printk(KERN_DEFAULT "%s%s(0x%08lx to 0x%08lx)\n",
			lvl, str, bottom, top);

	for (first = bottom & ~31; first < top; first += 32) {
		unsigned long p;
		char str[sizeof(" 12345678") * 8 + 1];

		memset(str, ' ', sizeof(str));
		str[sizeof(str) - 1] = '\0';

		for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
			if (p >= bottom && p < top) {
				unsigned long val;
				if (__get_user(val, (unsigned long *)p) == 0)
					sprintf(str + i * 9, " %08lx", val);
				else
					sprintf(str + i * 9, " ????????");
			}
		}
		printk(KERN_DEFAULT "%s%04lx:%s\n", lvl, first & 0xffff, str);
	}

	set_fs(fs);
}

static void dump_instr(const char *lvl, struct pt_regs *regs)
{
	unsigned long addr = instruction_pointer(regs);
	const int width = 8;
	mm_segment_t fs;
	char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
	int i;

	/*
	 * We need to switch to kernel mode so that we can use __get_user
	 * to safely read from kernel space.  Note that we now dump the
	 * code first, just in case the backtrace kills us.
	 */
	fs = get_fs();
	set_fs(KERNEL_DS);

	for (i = -4; i < 1; i++) {
		unsigned int val, bad;

		bad = __get_user(val, &((u32 *)addr)[i]);

		if (!bad)
			p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
					width, val);
		else {
			p += sprintf(p, "bad PC value");
			break;
		}
	}
	printk(KERN_DEFAULT "%sCode: %s\n", lvl, str);

	set_fs(fs);
}

static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
{
	unsigned int fp;
	int ok = 1;

	printk(KERN_DEFAULT "Backtrace: ");

	if (!tsk)
		tsk = current;

	if (regs)
		fp = regs->UCreg_fp;
	else if (tsk != current)
		fp = thread_saved_fp(tsk);
	else
		asm("mov %0, fp" : "=r" (fp) : : "cc");

	if (!fp) {
		printk("no frame pointer");
		ok = 0;
	} else if (verify_stack(fp)) {
		printk("invalid frame pointer 0x%08x", fp);
		ok = 0;
	} else if (fp < (unsigned long)end_of_stack(tsk))
		printk("frame pointer underflow");
	printk("\n");

	if (ok)
		c_backtrace(fp);
}

void show_stack(struct task_struct *tsk, unsigned long *sp)
{
	dump_backtrace(NULL, tsk);
	barrier();
}

static int __die(const char *str, int err, struct thread_info *thread,
		struct pt_regs *regs)
{
	struct task_struct *tsk = thread->task;
	static int die_counter;
	int ret;

	printk(KERN_EMERG "Internal error: %s: %x [#%d]\n",
	       str, err, ++die_counter);

	/* trap and error numbers are mostly meaningless on UniCore */
	ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, \
			SIGSEGV);
	if (ret == NOTIFY_STOP)
		return ret;

	print_modules();
	__show_regs(regs);
	printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n",
		TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);

	if (!user_mode(regs) || in_interrupt()) {
		dump_mem(KERN_EMERG, "Stack: ", regs->UCreg_sp,
			 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
		dump_backtrace(regs, tsk);
		dump_instr(KERN_EMERG, regs);
	}

	return ret;
}

DEFINE_SPINLOCK(die_lock);

/*
 * This function is protected against re-entrancy.
 */
void die(const char *str, struct pt_regs *regs, int err)
{
	struct thread_info *thread = current_thread_info();
	int ret;

	oops_enter();

	spin_lock_irq(&die_lock);
	console_verbose();
	bust_spinlocks(1);
	ret = __die(str, err, thread, regs);

	bust_spinlocks(0);
	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
	spin_unlock_irq(&die_lock);
	oops_exit();

	if (in_interrupt())
		panic("Fatal exception in interrupt");
	if (panic_on_oops)
		panic("Fatal exception");
	if (ret != NOTIFY_STOP)
		do_exit(SIGSEGV);
}

void uc32_notify_die(const char *str, struct pt_regs *regs,
		int sig, int code, void __user *addr,
		unsigned long err, unsigned long trap)
{
	if (user_mode(regs)) {
		current->thread.error_code = err;
		current->thread.trap_no = trap;

		force_sig_fault(sig, code, addr);
	} else
		die(str, regs, err);
}

/*
 * bad_mode handles the impossible case in the vectors.  If you see one of
 * these, then it's extremely serious, and could mean you have buggy hardware.
 * It never returns, and never tries to sync.  We hope that we can at least
 * dump out some state information...
 */
asmlinkage void bad_mode(struct pt_regs *regs, unsigned int reason)
{
	console_verbose();

	printk(KERN_CRIT "Bad mode detected with reason 0x%x\n", reason);

	die("Oops - bad mode", regs, 0);
	local_irq_disable();
	panic("bad mode");
}

void __pte_error(const char *file, int line, unsigned long val)
{
	printk(KERN_DEFAULT "%s:%d: bad pte %08lx.\n", file, line, val);
}

void __pmd_error(const char *file, int line, unsigned long val)
{
	printk(KERN_DEFAULT "%s:%d: bad pmd %08lx.\n", file, line, val);
}

void __pgd_error(const char *file, int line, unsigned long val)
{
	printk(KERN_DEFAULT "%s:%d: bad pgd %08lx.\n", file, line, val);
}

asmlinkage void __div0(void)
{
	printk(KERN_DEFAULT "Division by zero in kernel.\n");
	dump_stack();
}
EXPORT_SYMBOL(__div0);

void abort(void)
{
	BUG();

	/* if that doesn't kill us, halt */
	panic("Oops failed to kill thread");
}

void __init trap_init(void)
{
	return;
}

void __init early_trap_init(void)
{
	unsigned long vectors = VECTORS_BASE;

	/*
	 * Copy the vectors, stubs (in entry-unicore.S)
	 * into the vector page, mapped at 0xffff0000, and ensure these
	 * are visible to the instruction stream.
	 */
	memcpy((void *)vectors,
			__vectors_start,
			__vectors_end - __vectors_start);
	memcpy((void *)vectors + 0x200,
			__stubs_start,
			__stubs_end - __stubs_start);

	early_signal_init();

	flush_icache_range(vectors, vectors + PAGE_SIZE);
}
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
141c943f G	2	/*
	3	* linux/arch/unicore32/kernel/traps.c
	4	*
	5	* Code specific to PKUnity SoC and UniCore ISA
	6	*
	7	* Copyright (C) 2001-2010 GUAN Xue-tao
	8	*
141c943f G	9	* 'traps.c' handles hardware exceptions after we have saved some state.
	10	* Mostly a debugging aid, but will probably kill the offending process.
	11	*/
	12	#include <linux/module.h>
	13	#include <linux/signal.h>
3f07c014	14	#include <linux/sched/signal.h>
b17b0153	15	#include <linux/sched/debug.h>
68db0cf1	16	#include <linux/sched/task_stack.h>
141c943f G	17	#include <linux/spinlock.h>
	18	#include <linux/personality.h>
	19	#include <linux/kallsyms.h>
	20	#include <linux/kdebug.h>
	21	#include <linux/uaccess.h>
	22	#include <linux/delay.h>
	23	#include <linux/hardirq.h>
	24	#include <linux/init.h>
141c943f G	25	#include <linux/atomic.h>
	26	#include <linux/unistd.h>
	27
	28	#include <asm/cacheflush.h>
141c943f G	29	#include <asm/traps.h>
	30
	31	#include "setup.h"
	32
	33	static void dump_mem(const char , const char , unsigned long, unsigned long);
	34
	35	void dump_backtrace_entry(unsigned long where,
	36	unsigned long from, unsigned long frame)
	37	{
	38	#ifdef CONFIG_KALLSYMS
	39	printk(KERN_DEFAULT "[<%08lx>] (%pS) from [<%08lx>] (%pS)\n",
	40	where, (void )where, from, (void )from);
	41	#else
	42	printk(KERN_DEFAULT "Function entered at [<%08lx>] from [<%08lx>]\n",
	43	where, from);
	44	#endif
	45	}
	46
	47	/*
	48	* Stack pointers should always be within the kernels view of
	49	* physical memory. If it is not there, then we can't dump
	50	* out any information relating to the stack.
	51	*/
	52	static int verify_stack(unsigned long sp)
	53	{
	54	if (sp < PAGE_OFFSET \|\|
	55	(sp > (unsigned long)high_memory && high_memory != NULL))
	56	return -EFAULT;
	57
	58	return 0;
	59	}
	60
	61	/*
	62	* Dump out the contents of some memory nicely...
	63	*/
	64	static void dump_mem(const char lvl, const char str, unsigned long bottom,
	65	unsigned long top)
	66	{
	67	unsigned long first;
	68	mm_segment_t fs;
	69	int i;
	70
	71	/*
	72	* We need to switch to kernel mode so that we can use __get_user
	73	* to safely read from kernel space. Note that we now dump the
	74	* code first, just in case the backtrace kills us.
	75	*/
	76	fs = get_fs();
	77	set_fs(KERNEL_DS);
	78
	79	printk(KERN_DEFAULT "%s%s(0x%08lx to 0x%08lx)\n",
	80	lvl, str, bottom, top);
	81
	82	for (first = bottom & ~31; first < top; first += 32) {
	83	unsigned long p;
	84	char str[sizeof(" 12345678") * 8 + 1];
	85
	86	memset(str, ' ', sizeof(str));
	87	str[sizeof(str) - 1] = '\0';
	88
	89	for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
	90	if (p >= bottom && p < top) {
	91	unsigned long val;
	92	if (__get_user(val, (unsigned long *)p) == 0)
93	sprintf(str + i * 9, " %08lx", val);
94	else
95	sprintf(str + i * 9, " ????????");
96	}
97	}
98	printk(KERN_DEFAULT "%s%04lx:%s\n", lvl, first & 0xffff, str);
99	}
100
101	set_fs(fs);
102	}
103
104	static void dump_instr(const char lvl, struct pt_regs regs)
105	{
106	unsigned long addr = instruction_pointer(regs);
107	const int width = 8;
108	mm_segment_t fs;
109	char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
110	int i;
111
112	/*
113	* We need to switch to kernel mode so that we can use __get_user
114	* to safely read from kernel space. Note that we now dump the
115	* code first, just in case the backtrace kills us.
116	*/
117	fs = get_fs();
118	set_fs(KERNEL_DS);
119
120	for (i = -4; i < 1; i++) {
121	unsigned int val, bad;
122
123	bad = __get_user(val, &((u32 *)addr)[i]);
124
125	if (!bad)
126	p += sprintf(p, i == 0 ? "(%0x) " : "%0x ",
127	width, val);
128	else {
129	p += sprintf(p, "bad PC value");
130	break;
131	}
132	}
133	printk(KERN_DEFAULT "%sCode: %s\n", lvl, str);
134
135	set_fs(fs);
136	}
137
138	static void dump_backtrace(struct pt_regs regs, struct task_struct tsk)
139	{
ee1e9900	140	unsigned int fp;
141c943f G	141	int ok = 1;
	142
	143	printk(KERN_DEFAULT "Backtrace: ");
	144
	145	if (!tsk)
	146	tsk = current;
	147
ee1e9900	148	if (regs)
141c943f	149	fp = regs->UCreg_fp;
ee1e9900	150	else if (tsk != current)
141c943f	151	fp = thread_saved_fp(tsk);
ee1e9900	152	else
141c943f	153	asm("mov %0, fp" : "=r" (fp) : : "cc");
141c943f G	154
	155	if (!fp) {
	156	printk("no frame pointer");
	157	ok = 0;
	158	} else if (verify_stack(fp)) {
	159	printk("invalid frame pointer 0x%08x", fp);
	160	ok = 0;
	161	} else if (fp < (unsigned long)end_of_stack(tsk))
	162	printk("frame pointer underflow");
	163	printk("\n");
	164
	165	if (ok)
ee1e9900	166	c_backtrace(fp);
141c943f G	167	}
141c943f G	168
141c943f G	169	void show_stack(struct task_struct tsk, unsigned long sp)
	170	{
	171	dump_backtrace(NULL, tsk);
	172	barrier();
	173	}
	174
	175	static int __die(const char str, int err, struct thread_info thread,
	176	struct pt_regs *regs)
	177	{
	178	struct task_struct *tsk = thread->task;
	179	static int die_counter;
	180	int ret;
	181
	182	printk(KERN_EMERG "Internal error: %s: %x [#%d]\n",
	183	str, err, ++die_counter);
141c943f G	184
	185	/* trap and error numbers are mostly meaningless on UniCore */
	186	ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, \
	187	SIGSEGV);
	188	if (ret == NOTIFY_STOP)
	189	return ret;
	190
	191	print_modules();
	192	__show_regs(regs);
	193	printk(KERN_EMERG "Process %.*s (pid: %d, stack limit = 0x%p)\n",
	194	TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1);
	195
	196	if (!user_mode(regs) \|\| in_interrupt()) {
	197	dump_mem(KERN_EMERG, "Stack: ", regs->UCreg_sp,
	198	THREAD_SIZE + (unsigned long)task_stack_page(tsk));
	199	dump_backtrace(regs, tsk);
	200	dump_instr(KERN_EMERG, regs);
	201	}
	202
	203	return ret;
	204	}
	205
	206	DEFINE_SPINLOCK(die_lock);
	207
	208	/*
	209	* This function is protected against re-entrancy.
	210	*/
	211	void die(const char str, struct pt_regs regs, int err)
	212	{
	213	struct thread_info *thread = current_thread_info();
	214	int ret;
	215
	216	oops_enter();
	217
	218	spin_lock_irq(&die_lock);
	219	console_verbose();
	220	bust_spinlocks(1);
	221	ret = __die(str, err, thread, regs);
	222
	223	bust_spinlocks(0);
373d4d09	224	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
141c943f G	225	spin_unlock_irq(&die_lock);
	226	oops_exit();
	227
	228	if (in_interrupt())
	229	panic("Fatal exception in interrupt");
	230	if (panic_on_oops)
	231	panic("Fatal exception");
	232	if (ret != NOTIFY_STOP)
	233	do_exit(SIGSEGV);
	234	}
	235
	236	void uc32_notify_die(const char str, struct pt_regs regs,
ccebcb1f EB	237	int sig, int code, void __user *addr,
ccebcb1f EB	238	unsigned long err, unsigned long trap)
141c943f G	239	{
	240	if (user_mode(regs)) {
	241	current->thread.error_code = err;
	242	current->thread.trap_no = trap;
	243
2e1661d2	244	force_sig_fault(sig, code, addr);
141c943f G	245	} else
	246	die(str, regs, err);
	247	}
	248
	249	/*
	250	* bad_mode handles the impossible case in the vectors. If you see one of
	251	* these, then it's extremely serious, and could mean you have buggy hardware.
	252	* It never returns, and never tries to sync. We hope that we can at least
	253	* dump out some state information...
	254	*/
	255	asmlinkage void bad_mode(struct pt_regs *regs, unsigned int reason)
	256	{
	257	console_verbose();
	258
	259	printk(KERN_CRIT "Bad mode detected with reason 0x%x\n", reason);
	260
	261	die("Oops - bad mode", regs, 0);
	262	local_irq_disable();
	263	panic("bad mode");
	264	}
	265
	266	void __pte_error(const char *file, int line, unsigned long val)
	267	{
	268	printk(KERN_DEFAULT "%s:%d: bad pte %08lx.\n", file, line, val);
	269	}
	270
	271	void __pmd_error(const char *file, int line, unsigned long val)
	272	{
	273	printk(KERN_DEFAULT "%s:%d: bad pmd %08lx.\n", file, line, val);
	274	}
	275
	276	void __pgd_error(const char *file, int line, unsigned long val)
	277	{
	278	printk(KERN_DEFAULT "%s:%d: bad pgd %08lx.\n", file, line, val);
	279	}
	280
	281	asmlinkage void __div0(void)
	282	{
	283	printk(KERN_DEFAULT "Division by zero in kernel.\n");
	284	dump_stack();
	285	}
	286	EXPORT_SYMBOL(__div0);
	287
	288	void abort(void)
	289	{
	290	BUG();
	291
	292	/* if that doesn't kill us, halt */
	293	panic("Oops failed to kill thread");
	294	}
141c943f G	295
	296	void __init trap_init(void)
	297	{
	298	return;
	299	}
	300
	301	void __init early_trap_init(void)
	302	{
	303	unsigned long vectors = VECTORS_BASE;
	304
	305	/*
	306	* Copy the vectors, stubs (in entry-unicore.S)
	307	* into the vector page, mapped at 0xffff0000, and ensure these
	308	* are visible to the instruction stream.
	309	*/
	310	memcpy((void *)vectors,
	311	__vectors_start,
	312	__vectors_end - __vectors_start);
	313	memcpy((void *)vectors + 0x200,
	314	__stubs_start,
	315	__stubs_end - __stubs_start);
	316
	317	early_signal_init();
	318
	319	flush_icache_range(vectors, vectors + PAGE_SIZE);
	320	}