1/*
2 * HW exception handling
3 *
4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
5 * Copyright (C) 2008 PetaLogix
6 *
7 * This file is subject to the terms and conditions of the GNU General
8 * Public License.  See the file COPYING in the main directory of this
9 * archive for more details.
10 */
11
12/*
13 * This file handles the architecture-dependent parts of hardware exceptions
14 */
15
16#include <linux/export.h>
17#include <linux/kernel.h>
18#include <linux/signal.h>
19#include <linux/sched.h>
20#include <linux/sched/debug.h>
21#include <linux/kallsyms.h>
22
23#include <asm/exceptions.h>
24#include <asm/entry.h>		/* For KM CPU var */
25#include <linux/uaccess.h>
26#include <linux/errno.h>
27#include <linux/ptrace.h>
28#include <asm/current.h>
29#include <asm/cacheflush.h>
30
31#define MICROBLAZE_ILL_OPCODE_EXCEPTION	0x02
32#define MICROBLAZE_IBUS_EXCEPTION	0x03
33#define MICROBLAZE_DBUS_EXCEPTION	0x04
34#define MICROBLAZE_DIV_ZERO_EXCEPTION	0x05
35#define MICROBLAZE_FPU_EXCEPTION	0x06
36#define MICROBLAZE_PRIVILEGED_EXCEPTION	0x07
37
38static DEFINE_SPINLOCK(die_lock);
39
40void die(const char *str, struct pt_regs *fp, long err)
41{
42	console_verbose();
43	spin_lock_irq(&die_lock);
44	pr_warn("Oops: %s, sig: %ld\n", str, err);
45	show_regs(fp);
46	spin_unlock_irq(&die_lock);
47	/* make_task_dead() should take care of panic'ing from an interrupt
48	 * context so we don't handle it here
49	 */
50	make_task_dead(err);
51}
52
53/* for user application debugging */
54asmlinkage void sw_exception(struct pt_regs *regs)
55{
56	_exception(SIGTRAP, regs, TRAP_BRKPT, regs->r16);
57	flush_dcache_range(regs->r16, regs->r16 + 0x4);
58	flush_icache_range(regs->r16, regs->r16 + 0x4);
59}
60
61void _exception(int signr, struct pt_regs *regs, int code, unsigned long addr)
62{
63	if (kernel_mode(regs))
64		die("Exception in kernel mode", regs, signr);
65
66	force_sig_fault(signr, code, (void __user *)addr);
67}
68
69asmlinkage void full_exception(struct pt_regs *regs, unsigned int type,
70							int fsr, int addr)
71{
72	addr = regs->pc;
73
74#if 0
75	pr_warn("Exception %02x in %s mode, FSR=%08x PC=%08x ESR=%08x\n",
76			type, user_mode(regs) ? "user" : "kernel", fsr,
77			(unsigned int) regs->pc, (unsigned int) regs->esr);
78#endif
79
80	switch (type & 0x1F) {
81	case MICROBLAZE_ILL_OPCODE_EXCEPTION:
82		if (user_mode(regs)) {
83			pr_debug("Illegal opcode exception in user mode\n");
84			_exception(SIGILL, regs, ILL_ILLOPC, addr);
85			return;
86		}
87		pr_warn("Illegal opcode exception in kernel mode.\n");
88		die("opcode exception", regs, SIGBUS);
89		break;
90	case MICROBLAZE_IBUS_EXCEPTION:
91		if (user_mode(regs)) {
92			pr_debug("Instruction bus error exception in user mode\n");
93			_exception(SIGBUS, regs, BUS_ADRERR, addr);
94			return;
95		}
96		pr_warn("Instruction bus error exception in kernel mode.\n");
97		die("bus exception", regs, SIGBUS);
98		break;
99	case MICROBLAZE_DBUS_EXCEPTION:
100		if (user_mode(regs)) {
101			pr_debug("Data bus error exception in user mode\n");
102			_exception(SIGBUS, regs, BUS_ADRERR, addr);
103			return;
104		}
105		pr_warn("Data bus error exception in kernel mode.\n");
106		die("bus exception", regs, SIGBUS);
107		break;
108	case MICROBLAZE_DIV_ZERO_EXCEPTION:
109		if (user_mode(regs)) {
110			pr_debug("Divide by zero exception in user mode\n");
111			_exception(SIGFPE, regs, FPE_INTDIV, addr);
112			return;
113		}
114		pr_warn("Divide by zero exception in kernel mode.\n");
115		die("Divide by zero exception", regs, SIGBUS);
116		break;
117	case MICROBLAZE_FPU_EXCEPTION:
118		pr_debug("FPU exception\n");
119		/* IEEE FP exception */
120		/* I removed fsr variable and use code var for storing fsr */
121		if (fsr & FSR_IO)
122			fsr = FPE_FLTINV;
123		else if (fsr & FSR_OF)
124			fsr = FPE_FLTOVF;
125		else if (fsr & FSR_UF)
126			fsr = FPE_FLTUND;
127		else if (fsr & FSR_DZ)
128			fsr = FPE_FLTDIV;
129		else if (fsr & FSR_DO)
130			fsr = FPE_FLTRES;
131		_exception(SIGFPE, regs, fsr, addr);
132		break;
133	case MICROBLAZE_PRIVILEGED_EXCEPTION:
134		pr_debug("Privileged exception\n");
135		_exception(SIGILL, regs, ILL_PRVOPC, addr);
136		break;
137	default:
138	/* FIXME what to do in unexpected exception */
139		pr_warn("Unexpected exception %02x PC=%08x in %s mode\n",
140			type, (unsigned int) addr,
141			kernel_mode(regs) ? "kernel" : "user");
142	}
143	return;
144}
145