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054419ed VG |
1 | /* |
2 | * Traps/Non-MMU Exception handling for ARC | |
3 | * | |
4 | * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
2e651ea1 VG |
10 | * vineetg: May 2011 |
11 | * -user-space unaligned access emulation | |
12 | * | |
054419ed VG |
13 | * Rahul Trivedi: Codito Technologies 2004 |
14 | */ | |
15 | ||
16 | #include <linux/sched.h> | |
17 | #include <linux/kdebug.h> | |
18 | #include <linux/uaccess.h> | |
1ec9db10 SK |
19 | #include <linux/ptrace.h> |
20 | #include <linux/kprobes.h> | |
21 | #include <linux/kgdb.h> | |
054419ed | 22 | #include <asm/setup.h> |
2e651ea1 | 23 | #include <asm/unaligned.h> |
5b00029e | 24 | #include <asm/kprobes.h> |
054419ed VG |
25 | |
26 | void __init trap_init(void) | |
27 | { | |
28 | return; | |
29 | } | |
30 | ||
38a9ff6d | 31 | void die(const char *str, struct pt_regs *regs, unsigned long address) |
054419ed | 32 | { |
38a9ff6d | 33 | show_kernel_fault_diag(str, regs, address); |
054419ed VG |
34 | |
35 | /* DEAD END */ | |
36 | __asm__("flag 1"); | |
37 | } | |
38 | ||
39 | /* | |
40 | * Helper called for bulk of exceptions NOT needing specific handling | |
41 | * -for user faults enqueues requested signal | |
42 | * -for kernel, chk if due to copy_(to|from)_user, otherwise die() | |
43 | */ | |
38a9ff6d VG |
44 | static noinline int |
45 | handle_exception(const char *str, struct pt_regs *regs, siginfo_t *info) | |
054419ed VG |
46 | { |
47 | if (user_mode(regs)) { | |
48 | struct task_struct *tsk = current; | |
49 | ||
50 | tsk->thread.fault_address = (__force unsigned int)info->si_addr; | |
054419ed VG |
51 | |
52 | force_sig_info(info->si_signo, info, tsk); | |
53 | ||
54 | } else { | |
55 | /* If not due to copy_(to|from)_user, we are doomed */ | |
56 | if (fixup_exception(regs)) | |
57 | return 0; | |
58 | ||
38a9ff6d | 59 | die(str, regs, (unsigned long)info->si_addr); |
054419ed VG |
60 | } |
61 | ||
62 | return 1; | |
63 | } | |
64 | ||
65 | #define DO_ERROR_INFO(signr, str, name, sicode) \ | |
38a9ff6d | 66 | int name(unsigned long address, struct pt_regs *regs) \ |
054419ed VG |
67 | { \ |
68 | siginfo_t info = { \ | |
69 | .si_signo = signr, \ | |
70 | .si_errno = 0, \ | |
71 | .si_code = sicode, \ | |
72 | .si_addr = (void __user *)address, \ | |
73 | }; \ | |
38a9ff6d | 74 | return handle_exception(str, regs, &info);\ |
054419ed VG |
75 | } |
76 | ||
77 | /* | |
78 | * Entry points for exceptions NOT needing specific handling | |
79 | */ | |
80 | DO_ERROR_INFO(SIGILL, "Priv Op/Disabled Extn", do_privilege_fault, ILL_PRVOPC) | |
81 | DO_ERROR_INFO(SIGILL, "Invalid Extn Insn", do_extension_fault, ILL_ILLOPC) | |
82 | DO_ERROR_INFO(SIGILL, "Illegal Insn (or Seq)", insterror_is_error, ILL_ILLOPC) | |
83 | DO_ERROR_INFO(SIGBUS, "Invalid Mem Access", do_memory_error, BUS_ADRERR) | |
84 | DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT) | |
c723ea46 | 85 | DO_ERROR_INFO(SIGBUS, "Misaligned Access", do_misaligned_error, BUS_ADRALN) |
054419ed | 86 | |
2e651ea1 VG |
87 | /* |
88 | * Entry Point for Misaligned Data access Exception, for emulating in software | |
89 | */ | |
38a9ff6d VG |
90 | int do_misaligned_access(unsigned long address, struct pt_regs *regs, |
91 | struct callee_regs *cregs) | |
2e651ea1 | 92 | { |
07ba69a4 | 93 | /* If emulation not enabled, or failed, kill the task */ |
38a9ff6d VG |
94 | if (misaligned_fixup(address, regs, cregs) != 0) |
95 | return do_misaligned_error(address, regs); | |
c723ea46 | 96 | |
2e651ea1 VG |
97 | return 0; |
98 | } | |
054419ed VG |
99 | |
100 | /* | |
101 | * Entry point for miscll errors such as Nested Exceptions | |
102 | * -Duplicate TLB entry is handled seperately though | |
103 | */ | |
38a9ff6d | 104 | void do_machine_check_fault(unsigned long address, struct pt_regs *regs) |
054419ed | 105 | { |
38a9ff6d | 106 | die("Machine Check Exception", regs, address); |
054419ed VG |
107 | } |
108 | ||
4d86dfbb | 109 | |
054419ed VG |
110 | /* |
111 | * Entry point for traps induced by ARCompact TRAP_S <n> insn | |
112 | * This is same family as TRAP0/SWI insn (use the same vector). | |
113 | * The only difference being SWI insn take no operand, while TRAP_S does | |
114 | * which reflects in ECR Reg as 8 bit param. | |
115 | * Thus TRAP_S <n> can be used for specific purpose | |
116 | * -1 used for software breakpointing (gdb) | |
117 | * -2 used by kprobes | |
118 | */ | |
38a9ff6d | 119 | void do_non_swi_trap(unsigned long address, struct pt_regs *regs) |
054419ed | 120 | { |
38a9ff6d | 121 | unsigned int param = regs->ecr_param; |
054419ed VG |
122 | |
123 | switch (param) { | |
124 | case 1: | |
38a9ff6d | 125 | trap_is_brkpt(address, regs); |
054419ed VG |
126 | break; |
127 | ||
4d86dfbb | 128 | case 2: |
38a9ff6d | 129 | trap_is_kprobe(address, regs); |
4d86dfbb VG |
130 | break; |
131 | ||
f46121bd MJ |
132 | case 3: |
133 | case 4: | |
38a9ff6d | 134 | kgdb_trap(regs); |
f46121bd MJ |
135 | break; |
136 | ||
054419ed VG |
137 | default: |
138 | break; | |
139 | } | |
140 | } | |
141 | ||
142 | /* | |
143 | * Entry point for Instruction Error Exception | |
4d86dfbb VG |
144 | * -For a corner case, ARC kprobes implementation resorts to using |
145 | * this exception, hence the check | |
054419ed | 146 | */ |
38a9ff6d | 147 | void do_insterror_or_kprobe(unsigned long address, struct pt_regs *regs) |
054419ed | 148 | { |
38a9ff6d VG |
149 | int rc; |
150 | ||
4d86dfbb | 151 | /* Check if this exception is caused by kprobes */ |
38a9ff6d VG |
152 | rc = notify_die(DIE_IERR, "kprobe_ierr", regs, address, 0, SIGILL); |
153 | if (rc == NOTIFY_STOP) | |
4d86dfbb VG |
154 | return; |
155 | ||
38a9ff6d | 156 | insterror_is_error(address, regs); |
054419ed | 157 | } |