/*
* 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.h>
#include <linux/kdebug.h>
#include <linux/uaccess.h>
#include <asm/ptrace.h>
#include <asm/setup.h>
#include <asm/kprobes.h>
#include <asm/unaligned.h>
#include <asm/kgdb.h>
void __init trap_init(void)
{
return;
}
void die(const char *str, struct pt_regs *regs, unsigned long address,
unsigned long cause_reg)
{
show_kernel_fault_diag(str, regs, address, cause_reg);
/* 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 handle_exception(unsigned long cause, 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;
tsk->thread.cause_code = cause;
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, cause);
}
return 1;
}
#define DO_ERROR_INFO(signr, str, name, sicode) \
int name(unsigned long cause, unsigned long address, struct pt_regs *regs) \
{ \
siginfo_t info = { \
.si_signo = signr, \
.si_errno = 0, \
.si_code = sicode, \
.si_addr = (void __user *)address, \
}; \
return handle_exception(cause, 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", do_memory_error, BUS_ADRERR)
DO_ERROR_INFO(SIGTRAP, "Breakpoint Set", trap_is_brkpt, TRAP_BRKPT)
#ifdef CONFIG_ARC_MISALIGN_ACCESS
/*
* Entry Point for Misaligned Data access Exception, for emulating in software
*/
int do_misaligned_access(unsigned long cause, unsigned long address,
struct pt_regs *regs, struct callee_regs *cregs)
{
if (misaligned_fixup(address, regs, cause, cregs) != 0) {
siginfo_t info;
info.si_signo = SIGBUS;
info.si_errno = 0;
info.si_code = BUS_ADRALN;
info.si_addr = (void __user *)address;
return handle_exception(cause, "Misaligned Access", regs,
&info);
}
return 0;
}
#else
DO_ERROR_INFO(SIGSEGV, "Misaligned Access", do_misaligned_access, SEGV_ACCERR)
#endif
/*
* Entry point for miscll errors such as Nested Exceptions
* -Duplicate TLB entry is handled seperately though
*/
void do_machine_check_fault(unsigned long cause, unsigned long address,
struct pt_regs *regs)
{
die("Machine Check Exception", regs, address, cause);
}
/*
* 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
*/
void do_non_swi_trap(unsigned long cause, unsigned long address,
struct pt_regs *regs)
{
unsigned int param = cause & 0xff;
switch (param) {
case 1:
trap_is_brkpt(cause, address, regs);
break;
case 2:
trap_is_kprobe(param, address, regs);
break;
case 3:
case 4:
kgdb_trap(regs, param);
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 cause,
unsigned long address,
struct pt_regs *regs)
{
/* Check if this exception is caused by kprobes */
if (notify_die(DIE_IERR, "kprobe_ierr", regs, address,
cause, SIGILL) == NOTIFY_STOP)
return;
insterror_is_error(cause, address, regs);
}
