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-rw-r--r--arch/arc/kernel/traps.c170
1 files changed, 170 insertions, 0 deletions
diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c
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+++ b/arch/arc/kernel/traps.c
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+/*
+ * 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);
+}