--- /dev/null
+/*
+ * Kernel Debug Core
+ *
+ * Maintainer: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002-2004 Timesys Corporation
+ * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com>
+ * Copyright (C) 2004 Pavel Machek <pavel@ucw.cz>
+ * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
+ * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
+ * Copyright (C) 2005-2009 Wind River Systems, Inc.
+ * Copyright (C) 2007 MontaVista Software, Inc.
+ * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *
+ * Contributors at various stages not listed above:
+ * Jason Wessel ( jason.wessel@windriver.com )
+ * George Anzinger <george@mvista.com>
+ * Anurekh Saxena (anurekh.saxena@timesys.com)
+ * Lake Stevens Instrument Division (Glenn Engel)
+ * Jim Kingdon, Cygnus Support.
+ *
+ * Original KGDB stub: David Grothe <dave@gcom.com>,
+ * Tigran Aivazian <tigran@sco.com>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#define pr_fmt(fmt) "KGDB: " fmt
+
+#include <linux/pid_namespace.h>
+#include <linux/clocksource.h>
+#include <linux/serial_core.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/console.h>
+#include <linux/threads.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/sysrq.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/pid.h>
+#include <linux/smp.h>
+#include <linux/mm.h>
+#include <linux/vmacache.h>
+#include <linux/rcupdate.h>
+
+#include <asm/cacheflush.h>
+#include <asm/byteorder.h>
+#include <linux/atomic.h>
+
+#include "debug_core.h"
+
+static int kgdb_break_asap;
+
+struct debuggerinfo_struct kgdb_info[NR_CPUS];
+
+/**
+ * kgdb_connected - Is a host GDB connected to us?
+ */
+int kgdb_connected;
+EXPORT_SYMBOL_GPL(kgdb_connected);
+
+/* All the KGDB handlers are installed */
+int kgdb_io_module_registered;
+
+/* Guard for recursive entry */
+static int exception_level;
+
+struct kgdb_io *dbg_io_ops;
+static DEFINE_SPINLOCK(kgdb_registration_lock);
+
+/* Action for the reboot notifiter, a global allow kdb to change it */
+static int kgdbreboot;
+/* kgdb console driver is loaded */
+static int kgdb_con_registered;
+/* determine if kgdb console output should be used */
+static int kgdb_use_con;
+/* Flag for alternate operations for early debugging */
+bool dbg_is_early = true;
+/* Next cpu to become the master debug core */
+int dbg_switch_cpu;
+
+/* Use kdb or gdbserver mode */
+int dbg_kdb_mode = 1;
+
+static int __init opt_kgdb_con(char *str)
+{
+ kgdb_use_con = 1;
+ return 0;
+}
+
+early_param("kgdbcon", opt_kgdb_con);
+
+module_param(kgdb_use_con, int, 0644);
+module_param(kgdbreboot, int, 0644);
+
+/*
+ * Holds information about breakpoints in a kernel. These breakpoints are
+ * added and removed by gdb.
+ */
+static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
+ [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
+};
+
+/*
+ * The CPU# of the active CPU, or -1 if none:
+ */
+atomic_t kgdb_active = ATOMIC_INIT(-1);
+EXPORT_SYMBOL_GPL(kgdb_active);
+static DEFINE_RAW_SPINLOCK(dbg_master_lock);
+static DEFINE_RAW_SPINLOCK(dbg_slave_lock);
+
+/*
+ * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
+ * bootup code (which might not have percpu set up yet):
+ */
+static atomic_t masters_in_kgdb;
+static atomic_t slaves_in_kgdb;
+static atomic_t kgdb_break_tasklet_var;
+atomic_t kgdb_setting_breakpoint;
+
+struct task_struct *kgdb_usethread;
+struct task_struct *kgdb_contthread;
+
+int kgdb_single_step;
+static pid_t kgdb_sstep_pid;
+
+/* to keep track of the CPU which is doing the single stepping*/
+atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
+
+/*
+ * If you are debugging a problem where roundup (the collection of
+ * all other CPUs) is a problem [this should be extremely rare],
+ * then use the nokgdbroundup option to avoid roundup. In that case
+ * the other CPUs might interfere with your debugging context, so
+ * use this with care:
+ */
+static int kgdb_do_roundup = 1;
+
+static int __init opt_nokgdbroundup(char *str)
+{
+ kgdb_do_roundup = 0;
+
+ return 0;
+}
+
+early_param("nokgdbroundup", opt_nokgdbroundup);
+
+/*
+ * Finally, some KGDB code :-)
+ */
+
+/*
+ * Weak aliases for breakpoint management,
+ * can be overriden by architectures when needed:
+ */
+int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+ int err;
+
+ err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
+ BREAK_INSTR_SIZE);
+ if (err)
+ return err;
+ err = probe_kernel_write((char *)bpt->bpt_addr,
+ arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
+ return err;
+}
+
+int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
+{
+ return probe_kernel_write((char *)bpt->bpt_addr,
+ (char *)bpt->saved_instr, BREAK_INSTR_SIZE);
+}
+
+int __weak kgdb_validate_break_address(unsigned long addr)
+{
+ struct kgdb_bkpt tmp;
+ int err;
+ /* Validate setting the breakpoint and then removing it. If the
+ * remove fails, the kernel needs to emit a bad message because we
+ * are deep trouble not being able to put things back the way we
+ * found them.
+ */
+ tmp.bpt_addr = addr;
+ err = kgdb_arch_set_breakpoint(&tmp);
+ if (err)
+ return err;
+ err = kgdb_arch_remove_breakpoint(&tmp);
+ if (err)
+ pr_err("Critical breakpoint error, kernel memory destroyed at: %lx\n",
+ addr);
+ return err;
+}
+
+unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+ return instruction_pointer(regs);
+}
+
+int __weak kgdb_arch_init(void)
+{
+ return 0;
+}
+
+int __weak kgdb_skipexception(int exception, struct pt_regs *regs)
+{
+ return 0;
+}
+
+/*
+ * Some architectures need cache flushes when we set/clear a
+ * breakpoint:
+ */
+static void kgdb_flush_swbreak_addr(unsigned long addr)
+{
+ if (!CACHE_FLUSH_IS_SAFE)
+ return;
+
+ if (current->mm) {
+ int i;
+
+ for (i = 0; i < VMACACHE_SIZE; i++) {
+ if (!current->vmacache[i])
+ continue;
+ flush_cache_range(current->vmacache[i],
+ addr, addr + BREAK_INSTR_SIZE);
+ }
+ }
+
+ /* Force flush instruction cache if it was outside the mm */
+ flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
+}
+
+/*
+ * SW breakpoint management:
+ */
+int dbg_activate_sw_breakpoints(void)
+{
+ int error;
+ int ret = 0;
+ int i;
+
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (kgdb_break[i].state != BP_SET)
+ continue;
+
+ error = kgdb_arch_set_breakpoint(&kgdb_break[i]);
+ if (error) {
+ ret = error;
+ pr_info("BP install failed: %lx\n",
+ kgdb_break[i].bpt_addr);
+ continue;
+ }
+
+ kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
+ kgdb_break[i].state = BP_ACTIVE;
+ }
+ return ret;
+}
+
+int dbg_set_sw_break(unsigned long addr)
+{
+ int err = kgdb_validate_break_address(addr);
+ int breakno = -1;
+ int i;
+
+ if (err)
+ return err;
+
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if ((kgdb_break[i].state == BP_SET) &&
+ (kgdb_break[i].bpt_addr == addr))
+ return -EEXIST;
+ }
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (kgdb_break[i].state == BP_REMOVED &&
+ kgdb_break[i].bpt_addr == addr) {
+ breakno = i;
+ break;
+ }
+ }
+
+ if (breakno == -1) {
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (kgdb_break[i].state == BP_UNDEFINED) {
+ breakno = i;
+ break;
+ }
+ }
+ }
+
+ if (breakno == -1)
+ return -E2BIG;
+
+ kgdb_break[breakno].state = BP_SET;
+ kgdb_break[breakno].type = BP_BREAKPOINT;
+ kgdb_break[breakno].bpt_addr = addr;
+
+ return 0;
+}
+
+int dbg_deactivate_sw_breakpoints(void)
+{
+ int error;
+ int ret = 0;
+ int i;
+
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (kgdb_break[i].state != BP_ACTIVE)
+ continue;
+ error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
+ if (error) {
+ pr_info("BP remove failed: %lx\n",
+ kgdb_break[i].bpt_addr);
+ ret = error;
+ }
+
+ kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
+ kgdb_break[i].state = BP_SET;
+ }
+ return ret;
+}
+
+int dbg_remove_sw_break(unsigned long addr)
+{
+ int i;
+
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if ((kgdb_break[i].state == BP_SET) &&
+ (kgdb_break[i].bpt_addr == addr)) {
+ kgdb_break[i].state = BP_REMOVED;
+ return 0;
+ }
+ }
+ return -ENOENT;
+}
+
+int kgdb_isremovedbreak(unsigned long addr)
+{
+ int i;
+
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if ((kgdb_break[i].state == BP_REMOVED) &&
+ (kgdb_break[i].bpt_addr == addr))
+ return 1;
+ }
+ return 0;
+}
+
+int dbg_remove_all_break(void)
+{
+ int error;
+ int i;
+
+ /* Clear memory breakpoints. */
+ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+ if (kgdb_break[i].state != BP_ACTIVE)
+ goto setundefined;
+ error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
+ if (error)
+ pr_err("breakpoint remove failed: %lx\n",
+ kgdb_break[i].bpt_addr);
+setundefined:
+ kgdb_break[i].state = BP_UNDEFINED;
+ }
+
+ /* Clear hardware breakpoints. */
+ if (arch_kgdb_ops.remove_all_hw_break)
+ arch_kgdb_ops.remove_all_hw_break();
+
+ return 0;
+}
+
+/*
+ * Return true if there is a valid kgdb I/O module. Also if no
+ * debugger is attached a message can be printed to the console about
+ * waiting for the debugger to attach.
+ *
+ * The print_wait argument is only to be true when called from inside
+ * the core kgdb_handle_exception, because it will wait for the
+ * debugger to attach.
+ */
+static int kgdb_io_ready(int print_wait)
+{
+ if (!dbg_io_ops)
+ return 0;
+ if (kgdb_connected)
+ return 1;
+ if (atomic_read(&kgdb_setting_breakpoint))
+ return 1;
+ if (print_wait) {
+#ifdef CONFIG_KGDB_KDB
+ if (!dbg_kdb_mode)
+ pr_crit("waiting... or $3#33 for KDB\n");
+#else
+ pr_crit("Waiting for remote debugger\n");
+#endif
+ }
+ return 1;
+}
+
+static int kgdb_reenter_check(struct kgdb_state *ks)
+{
+ unsigned long addr;
+
+ if (atomic_read(&kgdb_active) != raw_smp_processor_id())
+ return 0;
+
+ /* Panic on recursive debugger calls: */
+ exception_level++;
+ addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
+ dbg_deactivate_sw_breakpoints();
+
+ /*
+ * If the break point removed ok at the place exception
+ * occurred, try to recover and print a warning to the end
+ * user because the user planted a breakpoint in a place that
+ * KGDB needs in order to function.
+ */
+ if (dbg_remove_sw_break(addr) == 0) {
+ exception_level = 0;
+ kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+ dbg_activate_sw_breakpoints();
+ pr_crit("re-enter error: breakpoint removed %lx\n", addr);
+ WARN_ON_ONCE(1);
+
+ return 1;
+ }
+ dbg_remove_all_break();
+ kgdb_skipexception(ks->ex_vector, ks->linux_regs);
+
+ if (exception_level > 1) {
+ dump_stack();
+ panic("Recursive entry to debugger");
+ }
+
+ pr_crit("re-enter exception: ALL breakpoints killed\n");
+#ifdef CONFIG_KGDB_KDB
+ /* Allow kdb to debug itself one level */
+ return 0;
+#endif
+ dump_stack();
+ panic("Recursive entry to debugger");
+
+ return 1;
+}
+
+static void dbg_touch_watchdogs(void)
+{
+ touch_softlockup_watchdog_sync();
+ clocksource_touch_watchdog();
+ rcu_cpu_stall_reset();
+}
+
+static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs,
+ int exception_state)
+{
+ unsigned long flags;
+ int sstep_tries = 100;
+ int error;
+ int cpu;
+ int trace_on = 0;
+ int online_cpus = num_online_cpus();
+ u64 time_left;
+
+ kgdb_info[ks->cpu].enter_kgdb++;
+ kgdb_info[ks->cpu].exception_state |= exception_state;
+
+ if (exception_state == DCPU_WANT_MASTER)
+ atomic_inc(&masters_in_kgdb);
+ else
+ atomic_inc(&slaves_in_kgdb);
+
+ if (arch_kgdb_ops.disable_hw_break)
+ arch_kgdb_ops.disable_hw_break(regs);
+
+acquirelock:
+ /*
+ * Interrupts will be restored by the 'trap return' code, except when
+ * single stepping.
+ */
+ local_irq_save(flags);
+
+ cpu = ks->cpu;
+ kgdb_info[cpu].debuggerinfo = regs;
+ kgdb_info[cpu].task = current;
+ kgdb_info[cpu].ret_state = 0;
+ kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT;
+
+ /* Make sure the above info reaches the primary CPU */
+ smp_mb();
+
+ if (exception_level == 1) {
+ if (raw_spin_trylock(&dbg_master_lock))
+ atomic_xchg(&kgdb_active, cpu);
+ goto cpu_master_loop;
+ }
+
+ /*
+ * CPU will loop if it is a slave or request to become a kgdb
+ * master cpu and acquire the kgdb_active lock:
+ */
+ while (1) {
+cpu_loop:
+ if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) {
+ kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER;
+ goto cpu_master_loop;
+ } else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) {
+ if (raw_spin_trylock(&dbg_master_lock)) {
+ atomic_xchg(&kgdb_active, cpu);
+ break;
+ }
+ } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) {
+ if (!raw_spin_is_locked(&dbg_slave_lock))
+ goto return_normal;
+ } else {
+return_normal:
+ /* Return to normal operation by executing any
+ * hw breakpoint fixup.
+ */
+ if (arch_kgdb_ops.correct_hw_break)
+ arch_kgdb_ops.correct_hw_break();
+ if (trace_on)
+ tracing_on();
+ kgdb_info[cpu].exception_state &=
+ ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE);
+ kgdb_info[cpu].enter_kgdb--;
+ smp_mb__before_atomic();
+ atomic_dec(&slaves_in_kgdb);
+ dbg_touch_watchdogs();
+ local_irq_restore(flags);
+ return 0;
+ }
+ cpu_relax();
+ }
+
+ /*
+ * For single stepping, try to only enter on the processor
+ * that was single stepping. To guard against a deadlock, the
+ * kernel will only try for the value of sstep_tries before
+ * giving up and continuing on.
+ */
+ if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
+ (kgdb_info[cpu].task &&
+ kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) {
+ atomic_set(&kgdb_active, -1);
+ raw_spin_unlock(&dbg_master_lock);
+ dbg_touch_watchdogs();
+ local_irq_restore(flags);
+
+ goto acquirelock;
+ }
+
+ if (!kgdb_io_ready(1)) {
+ kgdb_info[cpu].ret_state = 1;
+ goto kgdb_restore; /* No I/O connection, resume the system */
+ }
+
+ /*
+ * Don't enter if we have hit a removed breakpoint.
+ */
+ if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
+ goto kgdb_restore;
+
+ /* Call the I/O driver's pre_exception routine */
+ if (dbg_io_ops->pre_exception)
+ dbg_io_ops->pre_exception();
+
+ /*
+ * Get the passive CPU lock which will hold all the non-primary
+ * CPU in a spin state while the debugger is active
+ */
+ if (!kgdb_single_step)
+ raw_spin_lock(&dbg_slave_lock);
+
+#ifdef CONFIG_SMP
+ /* If send_ready set, slaves are already waiting */
+ if (ks->send_ready)
+ atomic_set(ks->send_ready, 1);
+
+ /* Signal the other CPUs to enter kgdb_wait() */
+ else if ((!kgdb_single_step) && kgdb_do_roundup)
+ kgdb_roundup_cpus(flags);
+#endif
+
+ /*
+ * Wait for the other CPUs to be notified and be waiting for us:
+ */
+ time_left = loops_per_jiffy * HZ;
+ while (kgdb_do_roundup && --time_left &&
+ (atomic_read(&masters_in_kgdb) + atomic_read(&slaves_in_kgdb)) !=
+ online_cpus)
+ cpu_relax();
+ if (!time_left)
+ pr_crit("Timed out waiting for secondary CPUs.\n");
+
+ /*
+ * At this point the primary processor is completely
+ * in the debugger and all secondary CPUs are quiescent
+ */
+ dbg_deactivate_sw_breakpoints();
+ kgdb_single_step = 0;
+ kgdb_contthread = current;
+ exception_level = 0;
+ trace_on = tracing_is_on();
+ if (trace_on)
+ tracing_off();
+
+ while (1) {
+cpu_master_loop:
+ if (dbg_kdb_mode) {
+ kgdb_connected = 1;
+ error = kdb_stub(ks);
+ if (error == -1)
+ continue;
+ kgdb_connected = 0;
+ } else {
+ error = gdb_serial_stub(ks);
+ }
+
+ if (error == DBG_PASS_EVENT) {
+ dbg_kdb_mode = !dbg_kdb_mode;
+ } else if (error == DBG_SWITCH_CPU_EVENT) {
+ kgdb_info[dbg_switch_cpu].exception_state |=
+ DCPU_NEXT_MASTER;
+ goto cpu_loop;
+ } else {
+ kgdb_info[cpu].ret_state = error;
+ break;
+ }
+ }
+
+ /* Call the I/O driver's post_exception routine */
+ if (dbg_io_ops->post_exception)
+ dbg_io_ops->post_exception();
+
+ if (!kgdb_single_step) {
+ raw_spin_unlock(&dbg_slave_lock);
+ /* Wait till all the CPUs have quit from the debugger. */
+ while (kgdb_do_roundup && atomic_read(&slaves_in_kgdb))
+ cpu_relax();
+ }
+
+kgdb_restore:
+ if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
+ int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step);
+ if (kgdb_info[sstep_cpu].task)
+ kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid;
+ else
+ kgdb_sstep_pid = 0;
+ }
+ if (arch_kgdb_ops.correct_hw_break)
+ arch_kgdb_ops.correct_hw_break();
+ if (trace_on)
+ tracing_on();
+
+ kgdb_info[cpu].exception_state &=
+ ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE);
+ kgdb_info[cpu].enter_kgdb--;
+ smp_mb__before_atomic();
+ atomic_dec(&masters_in_kgdb);
+ /* Free kgdb_active */
+ atomic_set(&kgdb_active, -1);
+ raw_spin_unlock(&dbg_master_lock);
+ dbg_touch_watchdogs();
+ local_irq_restore(flags);
+
+ return kgdb_info[cpu].ret_state;
+}
+
+/*
+ * kgdb_handle_exception() - main entry point from a kernel exception
+ *
+ * Locking hierarchy:
+ * interface locks, if any (begin_session)
+ * kgdb lock (kgdb_active)
+ */
+int
+kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
+{
+ struct kgdb_state kgdb_var;
+ struct kgdb_state *ks = &kgdb_var;
+ int ret = 0;
+
+ if (arch_kgdb_ops.enable_nmi)
+ arch_kgdb_ops.enable_nmi(0);
+ /*
+ * Avoid entering the debugger if we were triggered due to an oops
+ * but panic_timeout indicates the system should automatically
+ * reboot on panic. We don't want to get stuck waiting for input
+ * on such systems, especially if its "just" an oops.
+ */
+ if (signo != SIGTRAP && panic_timeout)
+ return 1;
+
+ memset(ks, 0, sizeof(struct kgdb_state));
+ ks->cpu = raw_smp_processor_id();
+ ks->ex_vector = evector;
+ ks->signo = signo;
+ ks->err_code = ecode;
+ ks->linux_regs = regs;
+
+ if (kgdb_reenter_check(ks))
+ goto out; /* Ouch, double exception ! */
+ if (kgdb_info[ks->cpu].enter_kgdb != 0)
+ goto out;
+
+ ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
+out:
+ if (arch_kgdb_ops.enable_nmi)
+ arch_kgdb_ops.enable_nmi(1);
+ return ret;
+}
+
+/*
+ * GDB places a breakpoint at this function to know dynamically
+ * loaded objects. It's not defined static so that only one instance with this
+ * name exists in the kernel.
+ */
+
+static int module_event(struct notifier_block *self, unsigned long val,
+ void *data)
+{
+ return 0;
+}
+
+static struct notifier_block dbg_module_load_nb = {
+ .notifier_call = module_event,
+};
+
+int kgdb_nmicallback(int cpu, void *regs)
+{
+#ifdef CONFIG_SMP
+ struct kgdb_state kgdb_var;
+ struct kgdb_state *ks = &kgdb_var;
+
+ memset(ks, 0, sizeof(struct kgdb_state));
+ ks->cpu = cpu;
+ ks->linux_regs = regs;
+
+ if (kgdb_info[ks->cpu].enter_kgdb == 0 &&
+ raw_spin_is_locked(&dbg_master_lock)) {
+ kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE);
+ return 0;
+ }
+#endif
+ return 1;
+}
+
+int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code,
+ atomic_t *send_ready)
+{
+#ifdef CONFIG_SMP
+ if (!kgdb_io_ready(0) || !send_ready)
+ return 1;
+
+ if (kgdb_info[cpu].enter_kgdb == 0) {
+ struct kgdb_state kgdb_var;
+ struct kgdb_state *ks = &kgdb_var;
+
+ memset(ks, 0, sizeof(struct kgdb_state));
+ ks->cpu = cpu;
+ ks->ex_vector = trapnr;
+ ks->signo = SIGTRAP;
+ ks->err_code = err_code;
+ ks->linux_regs = regs;
+ ks->send_ready = send_ready;
+ kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
+ return 0;
+ }
+#endif
+ return 1;
+}
+
+static void kgdb_console_write(struct console *co, const char *s,
+ unsigned count)
+{
+ unsigned long flags;
+
+ /* If we're debugging, or KGDB has not connected, don't try
+ * and print. */
+ if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode)
+ return;
+
+ local_irq_save(flags);
+ gdbstub_msg_write(s, count);
+ local_irq_restore(flags);
+}
+
+static struct console kgdbcons = {
+ .name = "kgdb",
+ .write = kgdb_console_write,
+ .flags = CON_PRINTBUFFER | CON_ENABLED,
+ .index = -1,
+};
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static void sysrq_handle_dbg(int key)
+{
+ if (!dbg_io_ops) {
+ pr_crit("ERROR: No KGDB I/O module available\n");
+ return;
+ }
+ if (!kgdb_connected) {
+#ifdef CONFIG_KGDB_KDB
+ if (!dbg_kdb_mode)
+ pr_crit("KGDB or $3#33 for KDB\n");
+#else
+ pr_crit("Entering KGDB\n");
+#endif
+ }
+
+ kgdb_breakpoint();
+}
+
+static struct sysrq_key_op sysrq_dbg_op = {
+ .handler = sysrq_handle_dbg,
+ .help_msg = "debug(g)",
+ .action_msg = "DEBUG",
+};
+#endif
+
+static int kgdb_panic_event(struct notifier_block *self,
+ unsigned long val,
+ void *data)
+{
+ /*
+ * Avoid entering the debugger if we were triggered due to a panic
+ * We don't want to get stuck waiting for input from user in such case.
+ * panic_timeout indicates the system should automatically
+ * reboot on panic.
+ */
+ if (panic_timeout)
+ return NOTIFY_DONE;
+
+ if (dbg_kdb_mode)
+ kdb_printf("PANIC: %s\n", (char *)data);
+ kgdb_breakpoint();
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block kgdb_panic_event_nb = {
+ .notifier_call = kgdb_panic_event,
+ .priority = INT_MAX,
+};
+
+void __weak kgdb_arch_late(void)
+{
+}
+
+void __init dbg_late_init(void)
+{
+ dbg_is_early = false;
+ if (kgdb_io_module_registered)
+ kgdb_arch_late();
+ kdb_init(KDB_INIT_FULL);
+}
+
+static int
+dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x)
+{
+ /*
+ * Take the following action on reboot notify depending on value:
+ * 1 == Enter debugger
+ * 0 == [the default] detatch debug client
+ * -1 == Do nothing... and use this until the board resets
+ */
+ switch (kgdbreboot) {
+ case 1:
+ kgdb_breakpoint();
+ case -1:
+ goto done;
+ }
+ if (!dbg_kdb_mode)
+ gdbstub_exit(code);
+done:
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block dbg_reboot_notifier = {
+ .notifier_call = dbg_notify_reboot,
+ .next = NULL,
+ .priority = INT_MAX,
+};
+
+static void kgdb_register_callbacks(void)
+{
+ if (!kgdb_io_module_registered) {
+ kgdb_io_module_registered = 1;
+ kgdb_arch_init();
+ if (!dbg_is_early)
+ kgdb_arch_late();
+ register_module_notifier(&dbg_module_load_nb);
+ register_reboot_notifier(&dbg_reboot_notifier);
+ atomic_notifier_chain_register(&panic_notifier_list,
+ &kgdb_panic_event_nb);
+#ifdef CONFIG_MAGIC_SYSRQ
+ register_sysrq_key('g', &sysrq_dbg_op);
+#endif
+ if (kgdb_use_con && !kgdb_con_registered) {
+ register_console(&kgdbcons);
+ kgdb_con_registered = 1;
+ }
+ }
+}
+
+static void kgdb_unregister_callbacks(void)
+{
+ /*
+ * When this routine is called KGDB should unregister from the
+ * panic handler and clean up, making sure it is not handling any
+ * break exceptions at the time.
+ */
+ if (kgdb_io_module_registered) {
+ kgdb_io_module_registered = 0;
+ unregister_reboot_notifier(&dbg_reboot_notifier);
+ unregister_module_notifier(&dbg_module_load_nb);
+ atomic_notifier_chain_unregister(&panic_notifier_list,
+ &kgdb_panic_event_nb);
+ kgdb_arch_exit();
+#ifdef CONFIG_MAGIC_SYSRQ
+ unregister_sysrq_key('g', &sysrq_dbg_op);
+#endif
+ if (kgdb_con_registered) {
+ unregister_console(&kgdbcons);
+ kgdb_con_registered = 0;
+ }
+ }
+}
+
+/*
+ * There are times a tasklet needs to be used vs a compiled in
+ * break point so as to cause an exception outside a kgdb I/O module,
+ * such as is the case with kgdboe, where calling a breakpoint in the
+ * I/O driver itself would be fatal.
+ */
+static void kgdb_tasklet_bpt(unsigned long ing)
+{
+ kgdb_breakpoint();
+ atomic_set(&kgdb_break_tasklet_var, 0);
+}
+
+static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0);
+
+void kgdb_schedule_breakpoint(void)
+{
+ if (atomic_read(&kgdb_break_tasklet_var) ||
+ atomic_read(&kgdb_active) != -1 ||
+ atomic_read(&kgdb_setting_breakpoint))
+ return;
+ atomic_inc(&kgdb_break_tasklet_var);
+ tasklet_schedule(&kgdb_tasklet_breakpoint);
+}
+EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint);
+
+static void kgdb_initial_breakpoint(void)
+{
+ kgdb_break_asap = 0;
+
+ pr_crit("Waiting for connection from remote gdb...\n");
+ kgdb_breakpoint();
+}
+
+/**
+ * kgdb_register_io_module - register KGDB IO module
+ * @new_dbg_io_ops: the io ops vector
+ *
+ * Register it with the KGDB core.
+ */
+int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops)
+{
+ int err;
+
+ spin_lock(&kgdb_registration_lock);
+
+ if (dbg_io_ops) {
+ spin_unlock(&kgdb_registration_lock);
+
+ pr_err("Another I/O driver is already registered with KGDB\n");
+ return -EBUSY;
+ }
+
+ if (new_dbg_io_ops->init) {
+ err = new_dbg_io_ops->init();
+ if (err) {
+ spin_unlock(&kgdb_registration_lock);
+ return err;
+ }
+ }
+
+ dbg_io_ops = new_dbg_io_ops;
+
+ spin_unlock(&kgdb_registration_lock);
+
+ pr_info("Registered I/O driver %s\n", new_dbg_io_ops->name);
+
+ /* Arm KGDB now. */
+ kgdb_register_callbacks();
+
+ if (kgdb_break_asap)
+ kgdb_initial_breakpoint();
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kgdb_register_io_module);
+
+/**
+ * kkgdb_unregister_io_module - unregister KGDB IO module
+ * @old_dbg_io_ops: the io ops vector
+ *
+ * Unregister it with the KGDB core.
+ */
+void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops)
+{
+ BUG_ON(kgdb_connected);
+
+ /*
+ * KGDB is no longer able to communicate out, so
+ * unregister our callbacks and reset state.
+ */
+ kgdb_unregister_callbacks();
+
+ spin_lock(&kgdb_registration_lock);
+
+ WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops);
+ dbg_io_ops = NULL;
+
+ spin_unlock(&kgdb_registration_lock);
+
+ pr_info("Unregistered I/O driver %s, debugger disabled\n",
+ old_dbg_io_ops->name);
+}
+EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
+
+int dbg_io_get_char(void)
+{
+ int ret = dbg_io_ops->read_char();
+ if (ret == NO_POLL_CHAR)
+ return -1;
+ if (!dbg_kdb_mode)
+ return ret;
+ if (ret == 127)
+ return 8;
+ return ret;
+}
+
+/**
+ * kgdb_breakpoint - generate breakpoint exception
+ *
+ * This function will generate a breakpoint exception. It is used at the
+ * beginning of a program to sync up with a debugger and can be used
+ * otherwise as a quick means to stop program execution and "break" into
+ * the debugger.
+ */
+noinline void kgdb_breakpoint(void)
+{
+ atomic_inc(&kgdb_setting_breakpoint);
+ wmb(); /* Sync point before breakpoint */
+ arch_kgdb_breakpoint();
+ wmb(); /* Sync point after breakpoint */
+ atomic_dec(&kgdb_setting_breakpoint);
+}
+EXPORT_SYMBOL_GPL(kgdb_breakpoint);
+
+static int __init opt_kgdb_wait(char *str)
+{
+ kgdb_break_asap = 1;
+
+ kdb_init(KDB_INIT_EARLY);
+ if (kgdb_io_module_registered)
+ kgdb_initial_breakpoint();
+
+ return 0;
+}
+
+early_param("kgdbwait", opt_kgdb_wait);
Code Review / kvmfornfv.git / blobdiff