159 lines
4.1 KiB
C
159 lines
4.1 KiB
C
// 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/entry.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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switch (regs->ecr.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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