1 // SPDX-License-Identifier: GPL-2.0-only
3 * Traps/Non-MMU Exception handling for ARC
5 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
8 * -user-space unaligned access emulation
10 * Rahul Trivedi: Codito Technologies 2004
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>
23 void die(const char *str, struct pt_regs *regs, unsigned long address)
25 show_kernel_fault_diag(str, regs, address);
32 * Helper called for bulk of exceptions NOT needing specific handling
33 * -for user faults enqueues requested signal
34 * -for kernel, chk if due to copy_(to|from)_user, otherwise die()
37 unhandled_exception(const char *str, struct pt_regs *regs,
38 int signo, int si_code, void __user *addr)
40 if (user_mode(regs)) {
41 struct task_struct *tsk = current;
43 tsk->thread.fault_address = (__force unsigned int)addr;
45 force_sig_fault(signo, si_code, addr);
48 /* If not due to copy_(to|from)_user, we are doomed */
49 if (fixup_exception(regs))
52 die(str, regs, (unsigned long)addr);
58 #define DO_ERROR_INFO(signr, str, name, sicode) \
59 int name(unsigned long address, struct pt_regs *regs) \
61 return unhandled_exception(str, regs, signr, sicode, \
62 (void __user *)address); \
66 * Entry points for exceptions NOT needing specific handling
68 DO_ERROR_INFO(SIGILL, "Priv Op/Disabled Extn", do_privilege_fault, ILL_PRVOPC)
69 DO_ERROR_INFO(SIGILL, "Invalid Extn Insn", do_extension_fault, ILL_ILLOPC)
70 DO_ERROR_INFO(SIGILL, "Illegal Insn (or Seq)", insterror_is_error, ILL_ILLOPC)
71 DO_ERROR_INFO(SIGBUS, "Invalid Mem Access", __weak do_memory_error, BUS_ADRERR)
72 DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT)
73 DO_ERROR_INFO(SIGBUS, "Misaligned Access", do_misaligned_error, BUS_ADRALN)
74 DO_ERROR_INFO(SIGSEGV, "gcc generated __builtin_trap", do_trap5_error, 0)
77 * Entry Point for Misaligned Data access Exception, for emulating in software
79 int do_misaligned_access(unsigned long address, struct pt_regs *regs,
80 struct callee_regs *cregs)
82 /* If emulation not enabled, or failed, kill the task */
83 if (misaligned_fixup(address, regs, cregs) != 0)
84 return do_misaligned_error(address, regs);
90 * Entry point for miscll errors such as Nested Exceptions
91 * -Duplicate TLB entry is handled seperately though
93 void do_machine_check_fault(unsigned long address, struct pt_regs *regs)
95 die("Unhandled Machine Check Exception", regs, address);
100 * Entry point for traps induced by ARCompact TRAP_S <n> insn
101 * This is same family as TRAP0/SWI insn (use the same vector).
102 * The only difference being SWI insn take no operand, while TRAP_S does
103 * which reflects in ECR Reg as 8 bit param.
104 * Thus TRAP_S <n> can be used for specific purpose
105 * -1 used for software breakpointing (gdb)
107 * -5 __builtin_trap() generated by gcc (2018.03 onwards) for toggle such as
108 * -fno-isolate-erroneous-paths-dereference
110 void do_non_swi_trap(unsigned long address, struct pt_regs *regs)
112 unsigned int param = regs->ecr_param;
116 trap_is_brkpt(address, regs);
120 trap_is_kprobe(address, regs);
129 do_trap5_error(address, regs);
137 * Entry point for Instruction Error Exception
138 * -For a corner case, ARC kprobes implementation resorts to using
139 * this exception, hence the check
141 void do_insterror_or_kprobe(unsigned long address, struct pt_regs *regs)
145 /* Check if this exception is caused by kprobes */
146 rc = notify_die(DIE_IERR, "kprobe_ierr", regs, address, 0, SIGILL);
147 if (rc == NOTIFY_STOP)
150 insterror_is_error(address, regs);
154 * abort() call generated by older gcc for __builtin_trap()
158 __asm__ __volatile__("trap_s 5\n");