diff options
Diffstat (limited to 'arch/arc/kernel/traps.c')
| -rw-r--r-- | arch/arc/kernel/traps.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c new file mode 100644 index 000000000..b123558bf --- /dev/null +++ b/arch/arc/kernel/traps.c @@ -0,0 +1,173 @@ +/* + * Traps/Non-MMU Exception handling for ARC + * + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * vineetg: May 2011 + * -user-space unaligned access emulation + * + * Rahul Trivedi: Codito Technologies 2004 + */ + +#include <linux/sched/signal.h> +#include <linux/kdebug.h> +#include <linux/uaccess.h> +#include <linux/ptrace.h> +#include <linux/kprobes.h> +#include <linux/kgdb.h> +#include <asm/setup.h> +#include <asm/unaligned.h> +#include <asm/kprobes.h> + +void __init trap_init(void) +{ + return; +} + +void die(const char *str, struct pt_regs *regs, unsigned long address) +{ + show_kernel_fault_diag(str, regs, address); + + /* DEAD END */ + __asm__("flag 1"); +} + +/* + * Helper called for bulk of exceptions NOT needing specific handling + * -for user faults enqueues requested signal + * -for kernel, chk if due to copy_(to|from)_user, otherwise die() + */ +static noinline int +unhandled_exception(const char *str, struct pt_regs *regs, siginfo_t *info) +{ + if (user_mode(regs)) { + struct task_struct *tsk = current; + + tsk->thread.fault_address = (__force unsigned int)info->si_addr; + + force_sig_info(info->si_signo, info, tsk); + + } else { + /* If not due to copy_(to|from)_user, we are doomed */ + if (fixup_exception(regs)) + return 0; + + die(str, regs, (unsigned long)info->si_addr); + } + + return 1; +} + +#define DO_ERROR_INFO(signr, str, name, sicode) \ +int name(unsigned long address, struct pt_regs *regs) \ +{ \ + siginfo_t info; \ + \ + clear_siginfo(&info); \ + info.si_signo = signr; \ + info.si_errno = 0; \ + info.si_code = sicode; \ + info.si_addr = (void __user *)address; \ + \ + return unhandled_exception(str, regs, &info);\ +} + +/* + * Entry points for exceptions NOT needing specific handling + */ +DO_ERROR_INFO(SIGILL, "Priv Op/Disabled Extn", do_privilege_fault, ILL_PRVOPC) +DO_ERROR_INFO(SIGILL, "Invalid Extn Insn", do_extension_fault, ILL_ILLOPC) +DO_ERROR_INFO(SIGILL, "Illegal Insn (or Seq)", insterror_is_error, ILL_ILLOPC) +DO_ERROR_INFO(SIGBUS, "Invalid Mem Access", __weak do_memory_error, BUS_ADRERR) +DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT) +DO_ERROR_INFO(SIGBUS, "Misaligned Access", do_misaligned_error, BUS_ADRALN) +DO_ERROR_INFO(SIGSEGV, "gcc generated __builtin_trap", do_trap5_error, 0) + +/* + * Entry Point for Misaligned Data access Exception, for emulating in software + */ +int do_misaligned_access(unsigned long address, struct pt_regs *regs, + struct callee_regs *cregs) +{ + /* If emulation not enabled, or failed, kill the task */ + if (misaligned_fixup(address, regs, cregs) != 0) + return do_misaligned_error(address, regs); + + return 0; +} + +/* + * Entry point for miscll errors such as Nested Exceptions + * -Duplicate TLB entry is handled seperately though + */ +void do_machine_check_fault(unsigned long address, struct pt_regs *regs) +{ + die("Unhandled Machine Check Exception", regs, address); +} + + +/* + * Entry point for traps induced by ARCompact TRAP_S <n> insn + * This is same family as TRAP0/SWI insn (use the same vector). + * The only difference being SWI insn take no operand, while TRAP_S does + * which reflects in ECR Reg as 8 bit param. + * Thus TRAP_S <n> can be used for specific purpose + * -1 used for software breakpointing (gdb) + * -2 used by kprobes + * -5 __builtin_trap() generated by gcc (2018.03 onwards) for toggle such as + * -fno-isolate-erroneous-paths-dereference + */ +void do_non_swi_trap(unsigned long address, struct pt_regs *regs) +{ + unsigned int param = regs->ecr_param; + + switch (param) { + case 1: + trap_is_brkpt(address, regs); + break; + + case 2: + trap_is_kprobe(address, regs); + break; + + case 3: + case 4: + kgdb_trap(regs); + break; + + case 5: + do_trap5_error(address, regs); + break; + default: + break; + } +} + +/* + * Entry point for Instruction Error Exception + * -For a corner case, ARC kprobes implementation resorts to using + * this exception, hence the check + */ +void do_insterror_or_kprobe(unsigned long address, struct pt_regs *regs) +{ + int rc; + + /* Check if this exception is caused by kprobes */ + rc = notify_die(DIE_IERR, "kprobe_ierr", regs, address, 0, SIGILL); + if (rc == NOTIFY_STOP) + return; + + insterror_is_error(address, regs); +} + +/* + * abort() call generated by older gcc for __builtin_trap() + */ +void abort(void) +{ + __asm__ __volatile__("trap_s 5\n"); +} |