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 
38 static DEFINE_SPINLOCK(die_lock);
39 
40 void 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 	/* do_exit() should take care of panic'ing from an interrupt
48 	 * context so we don't handle it here
49 	 */
50 	do_exit(err);
51 }
52 
53 /* for user application debugging */
54 asmlinkage 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 
61 void _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, current);
67 }
68 
69 asmlinkage void full_exception(struct pt_regs *regs, unsigned int type,
70 							int fsr, int addr)
71 {
72 #ifdef CONFIG_MMU
73 	addr = regs->pc;
74 #endif
75 
76 #if 0
77 	pr_warn("Exception %02x in %s mode, FSR=%08x PC=%08x ESR=%08x\n",
78 			type, user_mode(regs) ? "user" : "kernel", fsr,
79 			(unsigned int) regs->pc, (unsigned int) regs->esr);
80 #endif
81 
82 	switch (type & 0x1F) {
83 	case MICROBLAZE_ILL_OPCODE_EXCEPTION:
84 		if (user_mode(regs)) {
85 			pr_debug("Illegal opcode exception in user mode\n");
86 			_exception(SIGILL, regs, ILL_ILLOPC, addr);
87 			return;
88 		}
89 		pr_warn("Illegal opcode exception in kernel mode.\n");
90 		die("opcode exception", regs, SIGBUS);
91 		break;
92 	case MICROBLAZE_IBUS_EXCEPTION:
93 		if (user_mode(regs)) {
94 			pr_debug("Instruction bus error exception in user mode\n");
95 			_exception(SIGBUS, regs, BUS_ADRERR, addr);
96 			return;
97 		}
98 		pr_warn("Instruction bus error exception in kernel mode.\n");
99 		die("bus exception", regs, SIGBUS);
100 		break;
101 	case MICROBLAZE_DBUS_EXCEPTION:
102 		if (user_mode(regs)) {
103 			pr_debug("Data bus error exception in user mode\n");
104 			_exception(SIGBUS, regs, BUS_ADRERR, addr);
105 			return;
106 		}
107 		pr_warn("Data bus error exception in kernel mode.\n");
108 		die("bus exception", regs, SIGBUS);
109 		break;
110 	case MICROBLAZE_DIV_ZERO_EXCEPTION:
111 		if (user_mode(regs)) {
112 			pr_debug("Divide by zero exception in user mode\n");
113 			_exception(SIGFPE, regs, FPE_INTDIV, addr);
114 			return;
115 		}
116 		pr_warn("Divide by zero exception in kernel mode.\n");
117 		die("Divide by zero exception", regs, SIGBUS);
118 		break;
119 	case MICROBLAZE_FPU_EXCEPTION:
120 		pr_debug("FPU exception\n");
121 		/* IEEE FP exception */
122 		/* I removed fsr variable and use code var for storing fsr */
123 		if (fsr & FSR_IO)
124 			fsr = FPE_FLTINV;
125 		else if (fsr & FSR_OF)
126 			fsr = FPE_FLTOVF;
127 		else if (fsr & FSR_UF)
128 			fsr = FPE_FLTUND;
129 		else if (fsr & FSR_DZ)
130 			fsr = FPE_FLTDIV;
131 		else if (fsr & FSR_DO)
132 			fsr = FPE_FLTRES;
133 		_exception(SIGFPE, regs, fsr, addr);
134 		break;
135 
136 #ifdef CONFIG_MMU
137 	case MICROBLAZE_PRIVILEGED_EXCEPTION:
138 		pr_debug("Privileged exception\n");
139 		_exception(SIGILL, regs, ILL_PRVOPC, addr);
140 		break;
141 #endif
142 	default:
143 	/* FIXME what to do in unexpected exception */
144 		pr_warn("Unexpected exception %02x PC=%08x in %s mode\n",
145 			type, (unsigned int) addr,
146 			kernel_mode(regs) ? "kernel" : "user");
147 	}
148 	return;
149 }
150