2 * Traps/Non-MMU Exception handling for ARC
4 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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.
11 * -user-space unaligned access emulation
13 * Rahul Trivedi: Codito Technologies 2004
16 #include <linux/sched/signal.h>
17 #include <linux/kdebug.h>
18 #include <linux/uaccess.h>
19 #include <linux/ptrace.h>
20 #include <linux/kprobes.h>
21 #include <linux/kgdb.h>
22 #include <asm/setup.h>
23 #include <asm/unaligned.h>
24 #include <asm/kprobes.h>
26 void __init trap_init(void)
31 void die(const char *str, struct pt_regs *regs, unsigned long address)
33 show_kernel_fault_diag(str, regs, address);
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()
45 unhandled_exception(const char *str, struct pt_regs *regs,
46 int signo, int si_code, void __user *addr)
48 if (user_mode(regs)) {
49 struct task_struct *tsk = current;
51 tsk->thread.fault_address = (__force unsigned int)addr;
53 force_sig_fault(signo, si_code, addr, tsk);
56 /* If not due to copy_(to|from)_user, we are doomed */
57 if (fixup_exception(regs))
60 die(str, regs, (unsigned long)addr);
66 #define DO_ERROR_INFO(signr, str, name, sicode) \
67 int name(unsigned long address, struct pt_regs *regs) \
69 return unhandled_exception(str, regs, signr, sicode, \
70 (void __user *)address); \
74 * Entry points for exceptions NOT needing specific handling
76 DO_ERROR_INFO(SIGILL, "Priv Op/Disabled Extn", do_privilege_fault, ILL_PRVOPC)
77 DO_ERROR_INFO(SIGILL, "Invalid Extn Insn", do_extension_fault, ILL_ILLOPC)
78 DO_ERROR_INFO(SIGILL, "Illegal Insn (or Seq)", insterror_is_error, ILL_ILLOPC)
79 DO_ERROR_INFO(SIGBUS, "Invalid Mem Access", __weak do_memory_error, BUS_ADRERR)
80 DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT)
81 DO_ERROR_INFO(SIGBUS, "Misaligned Access", do_misaligned_error, BUS_ADRALN)
82 DO_ERROR_INFO(SIGSEGV, "gcc generated __builtin_trap", do_trap5_error, 0)
85 * Entry Point for Misaligned Data access Exception, for emulating in software
87 int do_misaligned_access(unsigned long address, struct pt_regs *regs,
88 struct callee_regs *cregs)
90 /* If emulation not enabled, or failed, kill the task */
91 if (misaligned_fixup(address, regs, cregs) != 0)
92 return do_misaligned_error(address, regs);
98 * Entry point for miscll errors such as Nested Exceptions
99 * -Duplicate TLB entry is handled seperately though
101 void do_machine_check_fault(unsigned long address, struct pt_regs *regs)
103 die("Unhandled Machine Check Exception", regs, address);
108 * Entry point for traps induced by ARCompact TRAP_S <n> insn
109 * This is same family as TRAP0/SWI insn (use the same vector).
110 * The only difference being SWI insn take no operand, while TRAP_S does
111 * which reflects in ECR Reg as 8 bit param.
112 * Thus TRAP_S <n> can be used for specific purpose
113 * -1 used for software breakpointing (gdb)
115 * -5 __builtin_trap() generated by gcc (2018.03 onwards) for toggle such as
116 * -fno-isolate-erroneous-paths-dereference
118 void do_non_swi_trap(unsigned long address, struct pt_regs *regs)
120 unsigned int param = regs->ecr_param;
124 trap_is_brkpt(address, regs);
128 trap_is_kprobe(address, regs);
137 do_trap5_error(address, regs);
145 * Entry point for Instruction Error Exception
146 * -For a corner case, ARC kprobes implementation resorts to using
147 * this exception, hence the check
149 void do_insterror_or_kprobe(unsigned long address, struct pt_regs *regs)
153 /* Check if this exception is caused by kprobes */
154 rc = notify_die(DIE_IERR, "kprobe_ierr", regs, address, 0, SIGILL);
155 if (rc == NOTIFY_STOP)
158 insterror_is_error(address, regs);
162 * abort() call generated by older gcc for __builtin_trap()
166 __asm__ __volatile__("trap_s 5\n");