/* * 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. */#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) printk(KERN_ERR "KGDB: Critical breakpoint error, kernel " "memory destroyed at: %lx", 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; printk(KERN_INFO "KGDB: BP install failed: %lx", 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) { printk(KERN_INFO "KGDB: 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) printk(KERN_ERR "KGDB: 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) printk(KERN_CRIT "KGDB: waiting... or $3#33 for KDB\n");#else printk(KERN_CRIT "KGDB: 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(); printk(KERN_CRIT "KGDB: 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"); } printk(KERN_CRIT "KGDB: 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(); 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();Lines 1–500 of 1067. 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/* * 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. */ #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) printk(KERN_ERR "KGDB: Critical breakpoint error, kernel " "memory destroyed at: %lx", 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; printk(KERN_INFO "KGDB: BP install failed: %lx", 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) { printk(KERN_INFO "KGDB: 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) printk(KERN_ERR "KGDB: 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) printk(KERN_CRIT "KGDB: waiting... or $3#33 for KDB\n"); #else printk(KERN_CRIT "KGDB: 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(); printk(KERN_CRIT "KGDB: 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"); } printk(KERN_CRIT "KGDB: 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(); 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();