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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Traps/Non-MMU Exception handling for ARC
4 *
5 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
6 *
7 * vineetg: May 2011
8 * -user-space unaligned access emulation
9 *
10 * Rahul Trivedi: Codito Technologies 2004
11 */
12
13#include <linux/sched/signal.h>
14#include <linux/kdebug.h>
15#include <linux/uaccess.h>
16#include <linux/ptrace.h>
17#include <linux/kprobes.h>
18#include <linux/kgdb.h>
19#include <asm/setup.h>
20#include <asm/unaligned.h>
21#include <asm/kprobes.h>
22
23void __init trap_init(void)
24{
25 return;
26}
27
28void die(const char *str, struct pt_regs *regs, unsigned long address)
29{
30 show_kernel_fault_diag(str, regs, address);
31
32 /* DEAD END */
33 __asm__("flag 1");
34}
35
36/*
37 * Helper called for bulk of exceptions NOT needing specific handling
38 * -for user faults enqueues requested signal
39 * -for kernel, chk if due to copy_(to|from)_user, otherwise die()
40 */
41static noinline int
42unhandled_exception(const char *str, struct pt_regs *regs,
43 int signo, int si_code, void __user *addr)
44{
45 if (user_mode(regs)) {
46 struct task_struct *tsk = current;
47
48 tsk->thread.fault_address = (__force unsigned int)addr;
49
50 force_sig_fault(signo, si_code, addr);
51
52 } else {
53 /* If not due to copy_(to|from)_user, we are doomed */
54 if (fixup_exception(regs))
55 return 0;
56
57 die(str, regs, (unsigned long)addr);
58 }
59
60 return 1;
61}
62
63#define DO_ERROR_INFO(signr, str, name, sicode) \
64int name(unsigned long address, struct pt_regs *regs) \
65{ \
66 return unhandled_exception(str, regs, signr, sicode, \
67 (void __user *)address); \
68}
69
70/*
71 * Entry points for exceptions NOT needing specific handling
72 */
73DO_ERROR_INFO(SIGILL, "Priv Op/Disabled Extn", do_privilege_fault, ILL_PRVOPC)
74DO_ERROR_INFO(SIGILL, "Invalid Extn Insn", do_extension_fault, ILL_ILLOPC)
75DO_ERROR_INFO(SIGILL, "Illegal Insn (or Seq)", insterror_is_error, ILL_ILLOPC)
76DO_ERROR_INFO(SIGBUS, "Invalid Mem Access", __weak do_memory_error, BUS_ADRERR)
77DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT)
78DO_ERROR_INFO(SIGBUS, "Misaligned Access", do_misaligned_error, BUS_ADRALN)
79DO_ERROR_INFO(SIGSEGV, "gcc generated __builtin_trap", do_trap5_error, 0)
80
81/*
82 * Entry Point for Misaligned Data access Exception, for emulating in software
83 */
84int do_misaligned_access(unsigned long address, struct pt_regs *regs,
85 struct callee_regs *cregs)
86{
87 /* If emulation not enabled, or failed, kill the task */
88 if (misaligned_fixup(address, regs, cregs) != 0)
89 return do_misaligned_error(address, regs);
90
91 return 0;
92}
93
94/*
95 * Entry point for miscll errors such as Nested Exceptions
96 * -Duplicate TLB entry is handled seperately though
97 */
98void do_machine_check_fault(unsigned long address, struct pt_regs *regs)
99{
100 die("Unhandled Machine Check Exception", regs, address);
101}
102
103
104/*
105 * Entry point for traps induced by ARCompact TRAP_S <n> insn
106 * This is same family as TRAP0/SWI insn (use the same vector).
107 * The only difference being SWI insn take no operand, while TRAP_S does
108 * which reflects in ECR Reg as 8 bit param.
109 * Thus TRAP_S <n> can be used for specific purpose
110 * -1 used for software breakpointing (gdb)
111 * -2 used by kprobes
112 * -5 __builtin_trap() generated by gcc (2018.03 onwards) for toggle such as
113 * -fno-isolate-erroneous-paths-dereference
114 */
115void do_non_swi_trap(unsigned long address, struct pt_regs *regs)
116{
117 unsigned int param = regs->ecr_param;
118
119 switch (param) {
120 case 1:
121 trap_is_brkpt(address, regs);
122 break;
123
124 case 2:
125 trap_is_kprobe(address, regs);
126 break;
127
128 case 3:
129 case 4:
130 kgdb_trap(regs);
131 break;
132
133 case 5:
134 do_trap5_error(address, regs);
135 break;
136 default:
137 break;
138 }
139}
140
141/*
142 * Entry point for Instruction Error Exception
143 * -For a corner case, ARC kprobes implementation resorts to using
144 * this exception, hence the check
145 */
146void do_insterror_or_kprobe(unsigned long address, struct pt_regs *regs)
147{
148 int rc;
149
150 /* Check if this exception is caused by kprobes */
151 rc = notify_die(DIE_IERR, "kprobe_ierr", regs, address, 0, SIGILL);
152 if (rc == NOTIFY_STOP)
153 return;
154
155 insterror_is_error(address, regs);
156}
157
158/*
159 * abort() call generated by older gcc for __builtin_trap()
160 */
161void abort(void)
162{
163 __asm__ __volatile__("trap_s 5\n");
164}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Traps/Non-MMU Exception handling for ARC
4 *
5 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
6 *
7 * vineetg: May 2011
8 * -user-space unaligned access emulation
9 *
10 * Rahul Trivedi: Codito Technologies 2004
11 */
12
13#include <linux/sched/signal.h>
14#include <linux/kdebug.h>
15#include <linux/uaccess.h>
16#include <linux/ptrace.h>
17#include <linux/kprobes.h>
18#include <linux/kgdb.h>
19#include <asm/setup.h>
20#include <asm/unaligned.h>
21#include <asm/kprobes.h>
22
23void __init trap_init(void)
24{
25 return;
26}
27
28void die(const char *str, struct pt_regs *regs, unsigned long address)
29{
30 show_kernel_fault_diag(str, regs, address);
31
32 /* DEAD END */
33 __asm__("flag 1");
34}
35
36/*
37 * Helper called for bulk of exceptions NOT needing specific handling
38 * -for user faults enqueues requested signal
39 * -for kernel, chk if due to copy_(to|from)_user, otherwise die()
40 */
41static noinline int
42unhandled_exception(const char *str, struct pt_regs *regs,
43 int signo, int si_code, void __user *addr)
44{
45 if (user_mode(regs)) {
46 struct task_struct *tsk = current;
47
48 tsk->thread.fault_address = (__force unsigned int)addr;
49
50 force_sig_fault(signo, si_code, addr);
51
52 } else {
53 /* If not due to copy_(to|from)_user, we are doomed */
54 if (fixup_exception(regs))
55 return 0;
56
57 die(str, regs, (unsigned long)addr);
58 }
59
60 return 1;
61}
62
63#define DO_ERROR_INFO(signr, str, name, sicode) \
64int name(unsigned long address, struct pt_regs *regs) \
65{ \
66 return unhandled_exception(str, regs, signr, sicode, \
67 (void __user *)address); \
68}
69
70/*
71 * Entry points for exceptions NOT needing specific handling
72 */
73DO_ERROR_INFO(SIGILL, "Priv Op/Disabled Extn", do_privilege_fault, ILL_PRVOPC)
74DO_ERROR_INFO(SIGILL, "Invalid Extn Insn", do_extension_fault, ILL_ILLOPC)
75DO_ERROR_INFO(SIGILL, "Illegal Insn (or Seq)", insterror_is_error, ILL_ILLOPC)
76DO_ERROR_INFO(SIGBUS, "Invalid Mem Access", __weak do_memory_error, BUS_ADRERR)
77DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT)
78DO_ERROR_INFO(SIGBUS, "Misaligned Access", do_misaligned_error, BUS_ADRALN)
79DO_ERROR_INFO(SIGSEGV, "gcc generated __builtin_trap", do_trap5_error, 0)
80
81/*
82 * Entry Point for Misaligned Data access Exception, for emulating in software
83 */
84int do_misaligned_access(unsigned long address, struct pt_regs *regs,
85 struct callee_regs *cregs)
86{
87 /* If emulation not enabled, or failed, kill the task */
88 if (misaligned_fixup(address, regs, cregs) != 0)
89 return do_misaligned_error(address, regs);
90
91 return 0;
92}
93
94/*
95 * Entry point for miscll errors such as Nested Exceptions
96 * -Duplicate TLB entry is handled seperately though
97 */
98void do_machine_check_fault(unsigned long address, struct pt_regs *regs)
99{
100 die("Unhandled Machine Check Exception", regs, address);
101}
102
103
104/*
105 * Entry point for traps induced by ARCompact TRAP_S <n> insn
106 * This is same family as TRAP0/SWI insn (use the same vector).
107 * The only difference being SWI insn take no operand, while TRAP_S does
108 * which reflects in ECR Reg as 8 bit param.
109 * Thus TRAP_S <n> can be used for specific purpose
110 * -1 used for software breakpointing (gdb)
111 * -2 used by kprobes
112 * -5 __builtin_trap() generated by gcc (2018.03 onwards) for toggle such as
113 * -fno-isolate-erroneous-paths-dereference
114 */
115void do_non_swi_trap(unsigned long address, struct pt_regs *regs)
116{
117 unsigned int param = regs->ecr_param;
118
119 switch (param) {
120 case 1:
121 trap_is_brkpt(address, regs);
122 break;
123
124 case 2:
125 trap_is_kprobe(address, regs);
126 break;
127
128 case 3:
129 case 4:
130 kgdb_trap(regs);
131 break;
132
133 case 5:
134 do_trap5_error(address, regs);
135 break;
136 default:
137 break;
138 }
139}
140
141/*
142 * Entry point for Instruction Error Exception
143 * -For a corner case, ARC kprobes implementation resorts to using
144 * this exception, hence the check
145 */
146void do_insterror_or_kprobe(unsigned long address, struct pt_regs *regs)
147{
148 int rc;
149
150 /* Check if this exception is caused by kprobes */
151 rc = notify_die(DIE_IERR, "kprobe_ierr", regs, address, 0, SIGILL);
152 if (rc == NOTIFY_STOP)
153 return;
154
155 insterror_is_error(address, regs);
156}
157
158/*
159 * abort() call generated by older gcc for __builtin_trap()
160 */
161void abort(void)
162{
163 __asm__ __volatile__("trap_s 5\n");
164}