[MIPS] kgdb: add arch support for the kernel's kgdb core
The new kgdb architecture specific handler registers and unregisters dynamically for exceptions depending on when you configure a kgdb I/O driver. Aside from initializing the exceptions earlier in the boot process, kgdb should have no impact on a device when it is compiled in so long as an I/O module is not configured for use. There have been quite a number of contributors during the existence of this patch (see arch/mips/kernel/kgdb.c). Most recently Jason re-wrote the mips kgdb logic to use the die notification handlers. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Jason Wessel
committed by
Ralf Baechle
Ralf Baechle
parent
8d60a903d9
commit
8854700115
281
arch/mips/kernel/kgdb.c
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281
arch/mips/kernel/kgdb.c
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/*
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* Originally written by Glenn Engel, Lake Stevens Instrument Division
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*
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* Contributed by HP Systems
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*
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* Modified for Linux/MIPS (and MIPS in general) by Andreas Busse
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* Send complaints, suggestions etc. to <andy@waldorf-gmbh.de>
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*
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* Copyright (C) 1995 Andreas Busse
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*
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* Copyright (C) 2003 MontaVista Software Inc.
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* Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
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*
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* Copyright (C) 2004-2005 MontaVista Software Inc.
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* Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
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*
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* Copyright (C) 2007-2008 Wind River Systems, Inc.
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* Author/Maintainer: Jason Wessel, jason.wessel@windriver.com
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*
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* This file is licensed under the terms of the GNU General Public License
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* version 2. This program is licensed "as is" without any warranty of any
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* kind, whether express or implied.
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*/
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#include <linux/ptrace.h> /* for linux pt_regs struct */
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#include <linux/kgdb.h>
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#include <linux/kdebug.h>
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#include <linux/sched.h>
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#include <asm/inst.h>
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#include <asm/fpu.h>
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#include <asm/cacheflush.h>
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#include <asm/processor.h>
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#include <asm/sigcontext.h>
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static struct hard_trap_info {
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unsigned char tt; /* Trap type code for MIPS R3xxx and R4xxx */
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unsigned char signo; /* Signal that we map this trap into */
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} hard_trap_info[] = {
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{ 6, SIGBUS }, /* instruction bus error */
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{ 7, SIGBUS }, /* data bus error */
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{ 9, SIGTRAP }, /* break */
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/* { 11, SIGILL }, */ /* CPU unusable */
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{ 12, SIGFPE }, /* overflow */
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{ 13, SIGTRAP }, /* trap */
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{ 14, SIGSEGV }, /* virtual instruction cache coherency */
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{ 15, SIGFPE }, /* floating point exception */
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{ 23, SIGSEGV }, /* watch */
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{ 31, SIGSEGV }, /* virtual data cache coherency */
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{ 0, 0} /* Must be last */
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};
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void arch_kgdb_breakpoint(void)
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{
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__asm__ __volatile__(
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".globl breakinst\n\t"
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".set\tnoreorder\n\t"
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"nop\n"
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"breakinst:\tbreak\n\t"
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"nop\n\t"
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".set\treorder");
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}
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static void kgdb_call_nmi_hook(void *ignored)
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{
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kgdb_nmicallback(raw_smp_processor_id(), (void *)0);
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}
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void kgdb_roundup_cpus(unsigned long flags)
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{
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local_irq_enable();
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smp_call_function(kgdb_call_nmi_hook, NULL, NULL);
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local_irq_disable();
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}
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static int compute_signal(int tt)
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{
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struct hard_trap_info *ht;
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for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
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if (ht->tt == tt)
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return ht->signo;
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return SIGHUP; /* default for things we don't know about */
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}
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void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
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{
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int reg;
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#if (KGDB_GDB_REG_SIZE == 32)
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u32 *ptr = (u32 *)gdb_regs;
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#else
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u64 *ptr = (u64 *)gdb_regs;
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#endif
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for (reg = 0; reg < 32; reg++)
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*(ptr++) = regs->regs[reg];
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*(ptr++) = regs->cp0_status;
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*(ptr++) = regs->lo;
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*(ptr++) = regs->hi;
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*(ptr++) = regs->cp0_badvaddr;
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*(ptr++) = regs->cp0_cause;
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*(ptr++) = regs->cp0_epc;
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/* FP REGS */
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if (!(current && (regs->cp0_status & ST0_CU1)))
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return;
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save_fp(current);
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for (reg = 0; reg < 32; reg++)
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*(ptr++) = current->thread.fpu.fpr[reg];
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}
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void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
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{
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int reg;
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#if (KGDB_GDB_REG_SIZE == 32)
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const u32 *ptr = (u32 *)gdb_regs;
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#else
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const u64 *ptr = (u64 *)gdb_regs;
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#endif
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for (reg = 0; reg < 32; reg++)
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regs->regs[reg] = *(ptr++);
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regs->cp0_status = *(ptr++);
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regs->lo = *(ptr++);
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regs->hi = *(ptr++);
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regs->cp0_badvaddr = *(ptr++);
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regs->cp0_cause = *(ptr++);
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regs->cp0_epc = *(ptr++);
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/* FP REGS from current */
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if (!(current && (regs->cp0_status & ST0_CU1)))
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return;
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for (reg = 0; reg < 32; reg++)
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current->thread.fpu.fpr[reg] = *(ptr++);
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restore_fp(current);
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}
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/*
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* Similar to regs_to_gdb_regs() except that process is sleeping and so
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* we may not be able to get all the info.
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*/
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void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
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{
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int reg;
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struct thread_info *ti = task_thread_info(p);
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unsigned long ksp = (unsigned long)ti + THREAD_SIZE - 32;
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struct pt_regs *regs = (struct pt_regs *)ksp - 1;
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#if (KGDB_GDB_REG_SIZE == 32)
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u32 *ptr = (u32 *)gdb_regs;
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#else
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u64 *ptr = (u64 *)gdb_regs;
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#endif
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for (reg = 0; reg < 16; reg++)
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*(ptr++) = regs->regs[reg];
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/* S0 - S7 */
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for (reg = 16; reg < 24; reg++)
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*(ptr++) = regs->regs[reg];
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for (reg = 24; reg < 28; reg++)
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*(ptr++) = 0;
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/* GP, SP, FP, RA */
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for (reg = 28; reg < 32; reg++)
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*(ptr++) = regs->regs[reg];
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*(ptr++) = regs->cp0_status;
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*(ptr++) = regs->lo;
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*(ptr++) = regs->hi;
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*(ptr++) = regs->cp0_badvaddr;
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*(ptr++) = regs->cp0_cause;
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*(ptr++) = regs->cp0_epc;
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}
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/*
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* Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
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* then try to fall into the debugger
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*/
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static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
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void *ptr)
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{
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struct die_args *args = (struct die_args *)ptr;
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struct pt_regs *regs = args->regs;
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int trap = (regs->cp0_cause & 0x7c) >> 2;
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if (fixup_exception(regs))
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return NOTIFY_DONE;
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/* Userpace events, ignore. */
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if (user_mode(regs))
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return NOTIFY_DONE;
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if (atomic_read(&kgdb_active) != -1)
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kgdb_nmicallback(smp_processor_id(), regs);
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if (kgdb_handle_exception(trap, compute_signal(trap), 0, regs))
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return NOTIFY_DONE;
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if (atomic_read(&kgdb_setting_breakpoint))
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if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
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regs->cp0_epc += 4;
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/* In SMP mode, __flush_cache_all does IPI */
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local_irq_enable();
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__flush_cache_all();
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return NOTIFY_STOP;
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}
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static struct notifier_block kgdb_notifier = {
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.notifier_call = kgdb_mips_notify,
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};
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/*
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* Handle the 's' and 'c' commands
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*/
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int kgdb_arch_handle_exception(int vector, int signo, int err_code,
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char *remcom_in_buffer, char *remcom_out_buffer,
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struct pt_regs *regs)
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{
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char *ptr;
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unsigned long address;
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int cpu = smp_processor_id();
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switch (remcom_in_buffer[0]) {
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case 's':
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case 'c':
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/* handle the optional parameter */
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ptr = &remcom_in_buffer[1];
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if (kgdb_hex2long(&ptr, &address))
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regs->cp0_epc = address;
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atomic_set(&kgdb_cpu_doing_single_step, -1);
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if (remcom_in_buffer[0] == 's')
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if (kgdb_contthread)
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atomic_set(&kgdb_cpu_doing_single_step, cpu);
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return 0;
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}
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return -1;
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}
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struct kgdb_arch arch_kgdb_ops;
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/*
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* We use kgdb_early_setup so that functions we need to call now don't
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* cause trouble when called again later.
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*/
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int kgdb_arch_init(void)
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{
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union mips_instruction insn = {
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.r_format = {
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.opcode = spec_op,
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.func = break_op,
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}
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};
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memcpy(arch_kgdb_ops.gdb_bpt_instr, insn.byte, BREAK_INSTR_SIZE);
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register_die_notifier(&kgdb_notifier);
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return 0;
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}
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/*
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* kgdb_arch_exit - Perform any architecture specific uninitalization.
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*
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* This function will handle the uninitalization of any architecture
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* specific callbacks, for dynamic registration and unregistration.
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*/
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void kgdb_arch_exit(void)
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{
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unregister_die_notifier(&kgdb_notifier);
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}
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