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kernel/debug/debug_core.c
24.8 KB
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/* |
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* Kernel Debug Core |
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* * 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> |
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* Copyright (C) 2004 Pavel Machek <pavel@ucw.cz> |
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* Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org> * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd. |
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* Copyright (C) 2005-2009 Wind River Systems, Inc. |
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* 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> |
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#include <linux/clocksource.h> |
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#include <linux/serial_core.h> |
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#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> |
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#include <linux/string.h> #include <linux/delay.h> #include <linux/sched.h> #include <linux/sysrq.h> |
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#include <linux/reboot.h> |
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#include <linux/init.h> #include <linux/kgdb.h> |
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#include <linux/kdb.h> |
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#include <linux/pid.h> #include <linux/smp.h> #include <linux/mm.h> |
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#include <linux/vmacache.h> |
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#include <linux/rcupdate.h> |
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#include <asm/cacheflush.h> #include <asm/byteorder.h> |
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#include <linux/atomic.h> |
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#include "debug_core.h" |
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static int kgdb_break_asap; |
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struct debuggerinfo_struct kgdb_info[NR_CPUS]; |
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/** * kgdb_connected - Is a host GDB connected to us? */ int kgdb_connected; EXPORT_SYMBOL_GPL(kgdb_connected); /* All the KGDB handlers are installed */ |
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int kgdb_io_module_registered; |
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/* Guard for recursive entry */ static int exception_level; |
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struct kgdb_io *dbg_io_ops; |
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static DEFINE_SPINLOCK(kgdb_registration_lock); |
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/* Action for the reboot notifiter, a global allow kdb to change it */ static int kgdbreboot; |
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/* kgdb console driver is loaded */ static int kgdb_con_registered; /* determine if kgdb console output should be used */ static int kgdb_use_con; |
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/* Flag for alternate operations for early debugging */ bool dbg_is_early = true; |
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/* Next cpu to become the master debug core */ int dbg_switch_cpu; /* Use kdb or gdbserver mode */ |
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int dbg_kdb_mode = 1; |
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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); |
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module_param(kgdbreboot, int, 0644); |
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/* * 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); |
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EXPORT_SYMBOL_GPL(kgdb_active); |
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static DEFINE_RAW_SPINLOCK(dbg_master_lock); static DEFINE_RAW_SPINLOCK(dbg_slave_lock); |
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/* * We use NR_CPUs not PERCPU, in case kgdb is used to debug early * bootup code (which might not have percpu set up yet): */ |
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static atomic_t masters_in_kgdb; static atomic_t slaves_in_kgdb; |
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static atomic_t kgdb_break_tasklet_var; |
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atomic_t kgdb_setting_breakpoint; struct task_struct *kgdb_usethread; struct task_struct *kgdb_contthread; int kgdb_single_step; |
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static pid_t kgdb_sstep_pid; |
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/* 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: */ |
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static int kgdb_do_roundup = 1; |
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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: */ |
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int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) |
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{ int err; |
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err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); |
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if (err) return err; |
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err = probe_kernel_write((char *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); return err; |
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} |
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int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) |
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{ |
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return probe_kernel_write((char *)bpt->bpt_addr, (char *)bpt->saved_instr, BREAK_INSTR_SIZE); |
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} |
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int __weak kgdb_validate_break_address(unsigned long addr) { |
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struct kgdb_bkpt tmp; |
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int err; |
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/* Validate setting the breakpoint and then removing it. If the |
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* 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. */ |
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tmp.bpt_addr = addr; err = kgdb_arch_set_breakpoint(&tmp); |
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if (err) return err; |
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err = kgdb_arch_remove_breakpoint(&tmp); |
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if (err) printk(KERN_ERR "KGDB: Critical breakpoint error, kernel " "memory destroyed at: %lx", addr); return err; } |
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unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) { return instruction_pointer(regs); } int __weak kgdb_arch_init(void) { return 0; } |
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int __weak kgdb_skipexception(int exception, struct pt_regs *regs) { return 0; } |
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/* |
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* 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; |
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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); } |
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} |
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/* Force flush instruction cache if it was outside the mm */ flush_icache_range(addr, addr + BREAK_INSTR_SIZE); |
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} /* * SW breakpoint management: */ |
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int dbg_activate_sw_breakpoints(void) |
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{ |
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int error; int ret = 0; |
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int i; for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { if (kgdb_break[i].state != BP_SET) continue; |
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error = kgdb_arch_set_breakpoint(&kgdb_break[i]); |
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if (error) { ret = error; |
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printk(KERN_INFO "KGDB: BP install failed: %lx", kgdb_break[i].bpt_addr); |
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continue; } |
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kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
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kgdb_break[i].state = BP_ACTIVE; } |
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return ret; |
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} |
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int dbg_set_sw_break(unsigned long addr) |
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{ 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; } |
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int dbg_deactivate_sw_breakpoints(void) |
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{ |
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int error; int ret = 0; |
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int i; for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { if (kgdb_break[i].state != BP_ACTIVE) continue; |
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error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
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if (error) { |
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printk(KERN_INFO "KGDB: BP remove failed: %lx ", kgdb_break[i].bpt_addr); |
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ret = error; } |
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kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr); |
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kgdb_break[i].state = BP_SET; } |
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return ret; |
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} |
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int dbg_remove_sw_break(unsigned long addr) |
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{ 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; } |
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int dbg_remove_all_break(void) |
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{ |
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int error; int i; /* Clear memory breakpoints. */ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
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if (kgdb_break[i].state != BP_ACTIVE) goto setundefined; |
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error = kgdb_arch_remove_breakpoint(&kgdb_break[i]); |
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if (error) |
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printk(KERN_ERR "KGDB: breakpoint remove failed: %lx ", |
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kgdb_break[i].bpt_addr); |
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setundefined: kgdb_break[i].state = BP_UNDEFINED; |
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} /* Clear hardware breakpoints. */ if (arch_kgdb_ops.remove_all_hw_break) arch_kgdb_ops.remove_all_hw_break(); return 0; } /* |
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* 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) { |
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if (!dbg_io_ops) |
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return 0; if (kgdb_connected) return 1; if (atomic_read(&kgdb_setting_breakpoint)) return 1; |
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if (print_wait) { #ifdef CONFIG_KGDB_KDB if (!dbg_kdb_mode) printk(KERN_CRIT "KGDB: waiting... or $3#33 for KDB "); #else |
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printk(KERN_CRIT "KGDB: Waiting for remote debugger "); |
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#endif } |
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return 1; } |
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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); |
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dbg_deactivate_sw_breakpoints(); |
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/* * 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. */ |
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if (dbg_remove_sw_break(addr) == 0) { |
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exception_level = 0; kgdb_skipexception(ks->ex_vector, ks->linux_regs); |
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dbg_activate_sw_breakpoints(); |
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printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx ", addr); |
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WARN_ON_ONCE(1); return 1; } |
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dbg_remove_all_break(); |
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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 "); |
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#ifdef CONFIG_KGDB_KDB /* Allow kdb to debug itself one level */ return 0; #endif |
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dump_stack(); panic("Recursive entry to debugger"); return 1; } |
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static void dbg_touch_watchdogs(void) { touch_softlockup_watchdog_sync(); clocksource_touch_watchdog(); |
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rcu_cpu_stall_reset(); |
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} |
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static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs, int exception_state) |
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{ |
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unsigned long flags; |
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int sstep_tries = 100; |
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int error; |
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int cpu; |
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int trace_on = 0; |
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int online_cpus = num_online_cpus(); |
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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); |
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if (arch_kgdb_ops.disable_hw_break) arch_kgdb_ops.disable_hw_break(regs); |
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acquirelock: /* * Interrupts will be restored by the 'trap return' code, except when * single stepping. */ local_irq_save(flags); |
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cpu = ks->cpu; kgdb_info[cpu].debuggerinfo = regs; kgdb_info[cpu].task = current; |
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kgdb_info[cpu].ret_state = 0; kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT; |
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/* 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); |
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goto cpu_master_loop; |
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} |
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/* |
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* CPU will loop if it is a slave or request to become a kgdb * master cpu and acquire the kgdb_active lock: |
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*/ |
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while (1) { |
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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) { |
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if (raw_spin_trylock(&dbg_master_lock)) { atomic_xchg(&kgdb_active, cpu); |
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break; |
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} |
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} else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) { |
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if (!raw_spin_is_locked(&dbg_slave_lock)) |
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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(); |
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if (trace_on) tracing_on(); |
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kgdb_info[cpu].exception_state &= ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); kgdb_info[cpu].enter_kgdb--; |
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smp_mb__before_atomic(); |
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atomic_dec(&slaves_in_kgdb); |
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dbg_touch_watchdogs(); |
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local_irq_restore(flags); return 0; } |
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cpu_relax(); |
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} |
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/* |
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* For single stepping, try to only enter on the processor |
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* that was single stepping. To guard against a deadlock, the |
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* kernel will only try for the value of sstep_tries before * giving up and continuing on. |
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*/ if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && |
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(kgdb_info[cpu].task && kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) { |
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atomic_set(&kgdb_active, -1); |
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raw_spin_unlock(&dbg_master_lock); |
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dbg_touch_watchdogs(); |
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local_irq_restore(flags); goto acquirelock; } if (!kgdb_io_ready(1)) { |
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kgdb_info[cpu].ret_state = 1; |
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goto kgdb_restore; /* No I/O connection, resume the system */ |
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|
554 555 556 557 558 559 560 561 562 |
} /* * 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 */ |
53197fc49
|
563 564 |
if (dbg_io_ops->pre_exception) dbg_io_ops->pre_exception(); |
dc7d55270
|
565 |
|
dc7d55270
|
566 567 568 569 |
/* * Get the passive CPU lock which will hold all the non-primary * CPU in a spin state while the debugger is active */ |
dfee3a7b9
|
570 571 |
if (!kgdb_single_step) raw_spin_lock(&dbg_slave_lock); |
dc7d55270
|
572 |
|
56fb70932
|
573 |
#ifdef CONFIG_SMP |
8daaa5f82
|
574 575 576 |
/* If send_ready set, slaves are already waiting */ if (ks->send_ready) atomic_set(ks->send_ready, 1); |
56fb70932
|
577 |
/* Signal the other CPUs to enter kgdb_wait() */ |
8daaa5f82
|
578 |
else if ((!kgdb_single_step) && kgdb_do_roundup) |
56fb70932
|
579 580 |
kgdb_roundup_cpus(flags); #endif |
dc7d55270
|
581 582 583 |
/* * Wait for the other CPUs to be notified and be waiting for us: */ |
dfee3a7b9
|
584 585 586 |
while (kgdb_do_roundup && (atomic_read(&masters_in_kgdb) + atomic_read(&slaves_in_kgdb)) != online_cpus) cpu_relax(); |
dc7d55270
|
587 588 589 590 591 |
/* * At this point the primary processor is completely * in the debugger and all secondary CPUs are quiescent */ |
dcc787112
|
592 |
dbg_deactivate_sw_breakpoints(); |
dc7d55270
|
593 |
kgdb_single_step = 0; |
d7161a653
|
594 |
kgdb_contthread = current; |
dc7d55270
|
595 |
exception_level = 0; |
4da75b9ce
|
596 597 598 |
trace_on = tracing_is_on(); if (trace_on) tracing_off(); |
dc7d55270
|
599 |
|
dcc787112
|
600 601 602 603 604 |
while (1) { cpu_master_loop: if (dbg_kdb_mode) { kgdb_connected = 1; error = kdb_stub(ks); |
3fa43aba0
|
605 606 |
if (error == -1) continue; |
b0679c63d
|
607 |
kgdb_connected = 0; |
dcc787112
|
608 609 610 611 612 613 |
} else { error = gdb_serial_stub(ks); } if (error == DBG_PASS_EVENT) { dbg_kdb_mode = !dbg_kdb_mode; |
dcc787112
|
614 |
} else if (error == DBG_SWITCH_CPU_EVENT) { |
495363d38
|
615 616 |
kgdb_info[dbg_switch_cpu].exception_state |= DCPU_NEXT_MASTER; |
dcc787112
|
617 618 619 620 621 622 |
goto cpu_loop; } else { kgdb_info[cpu].ret_state = error; break; } } |
dc7d55270
|
623 624 |
/* Call the I/O driver's post_exception routine */ |
53197fc49
|
625 626 |
if (dbg_io_ops->post_exception) dbg_io_ops->post_exception(); |
dc7d55270
|
627 |
|
d7161a653
|
628 |
if (!kgdb_single_step) { |
dfee3a7b9
|
629 630 631 632 |
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(); |
dc7d55270
|
633 634 635 |
} kgdb_restore: |
028e7b175
|
636 637 638 639 640 641 642 |
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; } |
c1bb9a9c1
|
643 644 |
if (arch_kgdb_ops.correct_hw_break) arch_kgdb_ops.correct_hw_break(); |
4da75b9ce
|
645 646 |
if (trace_on) tracing_on(); |
dfee3a7b9
|
647 648 649 650 |
kgdb_info[cpu].exception_state &= ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); kgdb_info[cpu].enter_kgdb--; |
4e857c58e
|
651 |
smp_mb__before_atomic(); |
dfee3a7b9
|
652 |
atomic_dec(&masters_in_kgdb); |
dc7d55270
|
653 654 |
/* Free kgdb_active */ atomic_set(&kgdb_active, -1); |
dfee3a7b9
|
655 |
raw_spin_unlock(&dbg_master_lock); |
16cdc628c
|
656 |
dbg_touch_watchdogs(); |
dc7d55270
|
657 |
local_irq_restore(flags); |
dcc787112
|
658 |
return kgdb_info[cpu].ret_state; |
dc7d55270
|
659 |
} |
62fae3121
|
660 661 662 663 664 665 666 667 668 669 670 671 |
/* * 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; |
5a14fead0
|
672 673 674 675 |
int ret = 0; if (arch_kgdb_ops.enable_nmi) arch_kgdb_ops.enable_nmi(0); |
62fae3121
|
676 |
|
8daaa5f82
|
677 |
memset(ks, 0, sizeof(struct kgdb_state)); |
62fae3121
|
678 679 680 |
ks->cpu = raw_smp_processor_id(); ks->ex_vector = evector; ks->signo = signo; |
62fae3121
|
681 |
ks->err_code = ecode; |
62fae3121
|
682 683 684 |
ks->linux_regs = regs; if (kgdb_reenter_check(ks)) |
5a14fead0
|
685 |
goto out; /* Ouch, double exception ! */ |
dfee3a7b9
|
686 |
if (kgdb_info[ks->cpu].enter_kgdb != 0) |
5a14fead0
|
687 |
goto out; |
dfee3a7b9
|
688 |
|
5a14fead0
|
689 690 691 692 693 |
ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); out: if (arch_kgdb_ops.enable_nmi) arch_kgdb_ops.enable_nmi(1); return ret; |
62fae3121
|
694 |
} |
f30fed10c
|
695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 |
/* * 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, }; |
dc7d55270
|
710 711 712 |
int kgdb_nmicallback(int cpu, void *regs) { #ifdef CONFIG_SMP |
62fae3121
|
713 714 715 716 717 718 |
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; |
dfee3a7b9
|
719 720 721 |
if (kgdb_info[ks->cpu].enter_kgdb == 0 && raw_spin_is_locked(&dbg_master_lock)) { kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE); |
dc7d55270
|
722 723 724 725 726 |
return 0; } #endif return 1; } |
fc8b13740
|
727 728 |
int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code, atomic_t *send_ready) |
8daaa5f82
|
729 730 731 732 733 734 735 736 737 738 739 740 741 |
{ #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; |
fc8b13740
|
742 |
ks->err_code = err_code; |
8daaa5f82
|
743 744 745 746 747 748 749 750 |
ks->linux_regs = regs; ks->send_ready = send_ready; kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); return 0; } #endif return 1; } |
aabdc3b8c
|
751 752 |
static void kgdb_console_write(struct console *co, const char *s, unsigned count) |
dc7d55270
|
753 754 755 756 757 |
{ unsigned long flags; /* If we're debugging, or KGDB has not connected, don't try * and print. */ |
dcc787112
|
758 |
if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode) |
dc7d55270
|
759 760 761 |
return; local_irq_save(flags); |
53197fc49
|
762 |
gdbstub_msg_write(s, count); |
dc7d55270
|
763 764 765 766 767 768 769 770 771 772 773 |
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 |
1495cc9df
|
774 |
static void sysrq_handle_dbg(int key) |
dc7d55270
|
775 |
{ |
53197fc49
|
776 |
if (!dbg_io_ops) { |
dc7d55270
|
777 778 779 780 |
printk(KERN_CRIT "ERROR: No KGDB I/O module available "); return; } |
dcc787112
|
781 782 783 784 785 786 |
if (!kgdb_connected) { #ifdef CONFIG_KGDB_KDB if (!dbg_kdb_mode) printk(KERN_CRIT "KGDB or $3#33 for KDB "); #else |
dc7d55270
|
787 788 |
printk(KERN_CRIT "Entering KGDB "); |
dcc787112
|
789 790 |
#endif } |
dc7d55270
|
791 792 793 |
kgdb_breakpoint(); } |
53197fc49
|
794 795 |
static struct sysrq_key_op sysrq_dbg_op = { .handler = sysrq_handle_dbg, |
f34565096
|
796 |
.help_msg = "debug(g)", |
364b5b7b1
|
797 |
.action_msg = "DEBUG", |
dc7d55270
|
798 799 |
}; #endif |
4402c153c
|
800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 |
static int kgdb_panic_event(struct notifier_block *self, unsigned long val, void *data) { if (dbg_kdb_mode) kdb_printf("PANIC: %s ", (char *)data); kgdb_breakpoint(); return NOTIFY_DONE; } static struct notifier_block kgdb_panic_event_nb = { .notifier_call = kgdb_panic_event, .priority = INT_MAX, }; |
0b4b3827d
|
815 816 817 818 819 820 821 822 823 824 825 |
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); } |
2366e0478
|
826 827 828 |
static int dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x) { |
bec4d62ea
|
829 830 831 832 833 834 835 836 837 838 839 840 |
/* * 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; } |
2366e0478
|
841 842 |
if (!dbg_kdb_mode) gdbstub_exit(code); |
bec4d62ea
|
843 |
done: |
2366e0478
|
844 845 846 847 848 849 850 851 |
return NOTIFY_DONE; } static struct notifier_block dbg_reboot_notifier = { .notifier_call = dbg_notify_reboot, .next = NULL, .priority = INT_MAX, }; |
dc7d55270
|
852 853 854 855 856 |
static void kgdb_register_callbacks(void) { if (!kgdb_io_module_registered) { kgdb_io_module_registered = 1; kgdb_arch_init(); |
0b4b3827d
|
857 858 |
if (!dbg_is_early) kgdb_arch_late(); |
f30fed10c
|
859 |
register_module_notifier(&dbg_module_load_nb); |
2366e0478
|
860 |
register_reboot_notifier(&dbg_reboot_notifier); |
4402c153c
|
861 862 |
atomic_notifier_chain_register(&panic_notifier_list, &kgdb_panic_event_nb); |
dc7d55270
|
863 |
#ifdef CONFIG_MAGIC_SYSRQ |
53197fc49
|
864 |
register_sysrq_key('g', &sysrq_dbg_op); |
dc7d55270
|
865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 |
#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; |
2366e0478
|
882 |
unregister_reboot_notifier(&dbg_reboot_notifier); |
f30fed10c
|
883 |
unregister_module_notifier(&dbg_module_load_nb); |
4402c153c
|
884 885 |
atomic_notifier_chain_unregister(&panic_notifier_list, &kgdb_panic_event_nb); |
dc7d55270
|
886 887 |
kgdb_arch_exit(); #ifdef CONFIG_MAGIC_SYSRQ |
53197fc49
|
888 |
unregister_sysrq_key('g', &sysrq_dbg_op); |
dc7d55270
|
889 890 891 892 893 894 895 |
#endif if (kgdb_con_registered) { unregister_console(&kgdbcons); kgdb_con_registered = 0; } } } |
1cee5e35f
|
896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 |
/* * 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); |
dc7d55270
|
920 921 922 923 924 925 926 927 928 929 |
static void kgdb_initial_breakpoint(void) { kgdb_break_asap = 0; printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb... "); kgdb_breakpoint(); } /** |
737a460f2
|
930 |
* kgdb_register_io_module - register KGDB IO module |
53197fc49
|
931 |
* @new_dbg_io_ops: the io ops vector |
dc7d55270
|
932 933 934 |
* * Register it with the KGDB core. */ |
53197fc49
|
935 |
int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops) |
dc7d55270
|
936 937 938 939 |
{ int err; spin_lock(&kgdb_registration_lock); |
53197fc49
|
940 |
if (dbg_io_ops) { |
dc7d55270
|
941 942 943 944 945 946 947 |
spin_unlock(&kgdb_registration_lock); printk(KERN_ERR "kgdb: Another I/O driver is already " "registered with KGDB. "); return -EBUSY; } |
53197fc49
|
948 949 |
if (new_dbg_io_ops->init) { err = new_dbg_io_ops->init(); |
dc7d55270
|
950 951 952 953 954 |
if (err) { spin_unlock(&kgdb_registration_lock); return err; } } |
53197fc49
|
955 |
dbg_io_ops = new_dbg_io_ops; |
dc7d55270
|
956 957 958 959 960 |
spin_unlock(&kgdb_registration_lock); printk(KERN_INFO "kgdb: Registered I/O driver %s. ", |
53197fc49
|
961 |
new_dbg_io_ops->name); |
dc7d55270
|
962 963 964 965 966 967 968 969 970 971 972 973 974 |
/* 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 |
53197fc49
|
975 |
* @old_dbg_io_ops: the io ops vector |
dc7d55270
|
976 977 978 |
* * Unregister it with the KGDB core. */ |
53197fc49
|
979 |
void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops) |
dc7d55270
|
980 981 982 983 984 985 986 987 988 989 |
{ 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); |
53197fc49
|
990 991 |
WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops); dbg_io_ops = NULL; |
dc7d55270
|
992 993 994 995 996 997 |
spin_unlock(&kgdb_registration_lock); printk(KERN_INFO "kgdb: Unregistered I/O driver %s, debugger disabled. ", |
53197fc49
|
998 |
old_dbg_io_ops->name); |
dc7d55270
|
999 1000 |
} EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); |
dcc787112
|
1001 1002 1003 |
int dbg_io_get_char(void) { int ret = dbg_io_ops->read_char(); |
f5316b4ae
|
1004 1005 |
if (ret == NO_POLL_CHAR) return -1; |
dcc787112
|
1006 1007 1008 1009 1010 1011 |
if (!dbg_kdb_mode) return ret; if (ret == 127) return 8; return ret; } |
dc7d55270
|
1012 1013 1014 1015 1016 1017 1018 1019 |
/** * 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. */ |
d498d4b47
|
1020 |
noinline void kgdb_breakpoint(void) |
dc7d55270
|
1021 |
{ |
ae6bf53e0
|
1022 |
atomic_inc(&kgdb_setting_breakpoint); |
dc7d55270
|
1023 1024 1025 |
wmb(); /* Sync point before breakpoint */ arch_kgdb_breakpoint(); wmb(); /* Sync point after breakpoint */ |
ae6bf53e0
|
1026 |
atomic_dec(&kgdb_setting_breakpoint); |
dc7d55270
|
1027 1028 1029 1030 1031 1032 |
} EXPORT_SYMBOL_GPL(kgdb_breakpoint); static int __init opt_kgdb_wait(char *str) { kgdb_break_asap = 1; |
dcc787112
|
1033 |
kdb_init(KDB_INIT_EARLY); |
dc7d55270
|
1034 1035 1036 1037 1038 1039 1040 |
if (kgdb_io_module_registered) kgdb_initial_breakpoint(); return 0; } early_param("kgdbwait", opt_kgdb_wait); |