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159 lines
4.1 KiB
159 lines
4.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Traps/Non-MMU Exception handling for ARC |
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* |
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) |
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* |
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* vineetg: May 2011 |
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* -user-space unaligned access emulation |
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* |
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* Rahul Trivedi: Codito Technologies 2004 |
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*/ |
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#include <linux/sched/signal.h> |
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#include <linux/kdebug.h> |
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#include <linux/uaccess.h> |
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#include <linux/ptrace.h> |
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#include <linux/kprobes.h> |
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#include <linux/kgdb.h> |
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#include <asm/setup.h> |
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#include <asm/unaligned.h> |
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#include <asm/kprobes.h> |
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void die(const char *str, struct pt_regs *regs, unsigned long address) |
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{ |
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show_kernel_fault_diag(str, regs, address); |
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/* DEAD END */ |
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__asm__("flag 1"); |
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} |
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/* |
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* Helper called for bulk of exceptions NOT needing specific handling |
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* -for user faults enqueues requested signal |
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* -for kernel, chk if due to copy_(to|from)_user, otherwise die() |
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*/ |
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static noinline int |
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unhandled_exception(const char *str, struct pt_regs *regs, |
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int signo, int si_code, void __user *addr) |
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{ |
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if (user_mode(regs)) { |
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struct task_struct *tsk = current; |
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tsk->thread.fault_address = (__force unsigned int)addr; |
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force_sig_fault(signo, si_code, addr); |
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} else { |
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/* If not due to copy_(to|from)_user, we are doomed */ |
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if (fixup_exception(regs)) |
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return 0; |
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die(str, regs, (unsigned long)addr); |
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} |
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return 1; |
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} |
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#define DO_ERROR_INFO(signr, str, name, sicode) \ |
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int name(unsigned long address, struct pt_regs *regs) \ |
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{ \ |
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return unhandled_exception(str, regs, signr, sicode, \ |
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(void __user *)address); \ |
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} |
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/* |
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* Entry points for exceptions NOT needing specific handling |
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*/ |
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DO_ERROR_INFO(SIGILL, "Priv Op/Disabled Extn", do_privilege_fault, ILL_PRVOPC) |
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DO_ERROR_INFO(SIGILL, "Invalid Extn Insn", do_extension_fault, ILL_ILLOPC) |
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DO_ERROR_INFO(SIGILL, "Illegal Insn (or Seq)", insterror_is_error, ILL_ILLOPC) |
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DO_ERROR_INFO(SIGBUS, "Invalid Mem Access", __weak do_memory_error, BUS_ADRERR) |
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DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT) |
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DO_ERROR_INFO(SIGBUS, "Misaligned Access", do_misaligned_error, BUS_ADRALN) |
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DO_ERROR_INFO(SIGSEGV, "gcc generated __builtin_trap", do_trap5_error, 0) |
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/* |
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* Entry Point for Misaligned Data access Exception, for emulating in software |
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*/ |
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int do_misaligned_access(unsigned long address, struct pt_regs *regs, |
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struct callee_regs *cregs) |
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{ |
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/* If emulation not enabled, or failed, kill the task */ |
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if (misaligned_fixup(address, regs, cregs) != 0) |
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return do_misaligned_error(address, regs); |
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return 0; |
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} |
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/* |
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* Entry point for miscll errors such as Nested Exceptions |
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* -Duplicate TLB entry is handled seperately though |
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*/ |
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void do_machine_check_fault(unsigned long address, struct pt_regs *regs) |
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{ |
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die("Unhandled Machine Check Exception", regs, address); |
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} |
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/* |
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* Entry point for traps induced by ARCompact TRAP_S <n> insn |
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* This is same family as TRAP0/SWI insn (use the same vector). |
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* The only difference being SWI insn take no operand, while TRAP_S does |
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* which reflects in ECR Reg as 8 bit param. |
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* Thus TRAP_S <n> can be used for specific purpose |
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* -1 used for software breakpointing (gdb) |
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* -2 used by kprobes |
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* -5 __builtin_trap() generated by gcc (2018.03 onwards) for toggle such as |
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* -fno-isolate-erroneous-paths-dereference |
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*/ |
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void do_non_swi_trap(unsigned long address, struct pt_regs *regs) |
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{ |
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unsigned int param = regs->ecr_param; |
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switch (param) { |
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case 1: |
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trap_is_brkpt(address, regs); |
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break; |
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case 2: |
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trap_is_kprobe(address, regs); |
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break; |
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case 3: |
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case 4: |
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kgdb_trap(regs); |
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break; |
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case 5: |
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do_trap5_error(address, regs); |
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break; |
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default: |
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break; |
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} |
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} |
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/* |
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* Entry point for Instruction Error Exception |
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* -For a corner case, ARC kprobes implementation resorts to using |
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* this exception, hence the check |
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*/ |
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void do_insterror_or_kprobe(unsigned long address, struct pt_regs *regs) |
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{ |
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int rc; |
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/* Check if this exception is caused by kprobes */ |
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rc = notify_die(DIE_IERR, "kprobe_ierr", regs, address, 0, SIGILL); |
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if (rc == NOTIFY_STOP) |
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return; |
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insterror_is_error(address, regs); |
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} |
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/* |
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* abort() call generated by older gcc for __builtin_trap() |
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*/ |
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void abort(void) |
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{ |
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__asm__ __volatile__("trap_s 5\n"); |
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}
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