diff options
| -rw-r--r-- | arch/arm/kernel/kgdb.c | 5 | ||||
| -rw-r--r-- | arch/mips/kernel/kgdb.c | 5 | ||||
| -rw-r--r-- | arch/powerpc/kernel/kgdb.c | 5 | ||||
| -rw-r--r-- | arch/x86/kernel/kgdb.c | 5 | ||||
| -rw-r--r-- | include/linux/kgdb.h | 11 | ||||
| -rw-r--r-- | kernel/debug/debug_core.c | 107 | ||||
| -rw-r--r-- | kernel/debug/debug_core.h | 24 | ||||
| -rw-r--r-- | kernel/debug/gdbstub.c | 36 | ||||
| -rw-r--r-- | lib/Kconfig.kgdb | 8 |
9 files changed, 186 insertions, 20 deletions
diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c index a5b846b..c868a88 100644 --- a/arch/arm/kernel/kgdb.c +++ b/arch/arm/kernel/kgdb.c @@ -98,6 +98,11 @@ sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task) gdb_regs[_CPSR] = thread_regs->ARM_cpsr; } +void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) +{ + regs->ARM_pc = pc; +} + static int compiled_break; int kgdb_arch_handle_exception(int exception_vector, int signo, diff --git a/arch/mips/kernel/kgdb.c b/arch/mips/kernel/kgdb.c index 50c9bb8..6ed4c83 100644 --- a/arch/mips/kernel/kgdb.c +++ b/arch/mips/kernel/kgdb.c @@ -180,6 +180,11 @@ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) *(ptr++) = regs->cp0_epc; } +void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) +{ + regs->cp0_epc = pc; +} + /* * Calls linux_debug_hook before the kernel dies. If KGDB is enabled, * then try to fall into the debugger diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index 41bada0..c81e3de 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -309,6 +309,11 @@ void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) (unsigned long)(((void *)gdb_regs) + NUMREGBYTES)); } +void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) +{ + regs->nip = pc; +} + /* * This function does PowerPC specific procesing for interfacing to gdb. */ diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index b2258ca..f95a2c0 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -690,6 +690,11 @@ unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) return instruction_pointer(regs); } +void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) +{ + regs->ip = ip; +} + struct kgdb_arch arch_kgdb_ops = { /* Breakpoint instruction: */ .gdb_bpt_instr = { 0xcc }, diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h index 4830142..5b37df0 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -16,10 +16,12 @@ #include <linux/serial_8250.h> #include <linux/linkage.h> #include <linux/init.h> - #include <asm/atomic.h> +#ifdef CONFIG_HAVE_ARCH_KGDB #include <asm/kgdb.h> +#endif +#ifdef CONFIG_KGDB struct pt_regs; /** @@ -262,6 +264,7 @@ extern struct kgdb_arch arch_kgdb_ops; extern unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs); +extern void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc); extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops); extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops); extern struct kgdb_io *dbg_io_ops; @@ -279,5 +282,9 @@ extern int kgdb_nmicallback(int cpu, void *regs); extern int kgdb_single_step; extern atomic_t kgdb_active; - +#define in_dbg_master() \ + (raw_smp_processor_id() == atomic_read(&kgdb_active)) +#else /* ! CONFIG_KGDB */ +#define in_dbg_master() (0) +#endif /* ! CONFIG_KGDB */ #endif /* _KGDB_H_ */ diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 7e03969..6e1fa82 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -43,6 +43,7 @@ #include <linux/sysrq.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> @@ -77,6 +78,11 @@ static DEFINE_SPINLOCK(kgdb_registration_lock); static int kgdb_con_registered; /* determine if kgdb console output should be used */ static int kgdb_use_con; +/* Next cpu to become the master debug core */ +int dbg_switch_cpu; + +/* Use kdb or gdbserver mode */ +static int dbg_kdb_mode = 1; static int __init opt_kgdb_con(char *str) { @@ -100,6 +106,7 @@ static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { * The CPU# of the active CPU, or -1 if none: */ atomic_t kgdb_active = ATOMIC_INIT(-1); +EXPORT_SYMBOL_GPL(kgdb_active); /* * We use NR_CPUs not PERCPU, in case kgdb is used to debug early @@ -301,7 +308,7 @@ int dbg_set_sw_break(unsigned long addr) return 0; } -static int kgdb_deactivate_sw_breakpoints(void) +int dbg_deactivate_sw_breakpoints(void) { unsigned long addr; int error; @@ -395,8 +402,14 @@ static int kgdb_io_ready(int print_wait) return 1; if (atomic_read(&kgdb_setting_breakpoint)) return 1; - if (print_wait) + 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; } @@ -410,7 +423,7 @@ static int kgdb_reenter_check(struct kgdb_state *ks) /* Panic on recursive debugger calls: */ exception_level++; addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs); - kgdb_deactivate_sw_breakpoints(); + dbg_deactivate_sw_breakpoints(); /* * If the break point removed ok at the place exception @@ -443,11 +456,24 @@ static int kgdb_reenter_check(struct kgdb_state *ks) return 1; } +static void dbg_cpu_switch(int cpu, int next_cpu) +{ + /* Mark the cpu we are switching away from as a slave when it + * holds the kgdb_active token. This must be done so that the + * that all the cpus wait in for the debug core will not enter + * again as the master. */ + if (cpu == atomic_read(&kgdb_active)) { + kgdb_info[cpu].exception_state |= DCPU_IS_SLAVE; + kgdb_info[cpu].exception_state &= ~DCPU_WANT_MASTER; + } + kgdb_info[next_cpu].exception_state |= DCPU_NEXT_MASTER; +} + static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs) { unsigned long flags; int sstep_tries = 100; - int error = 0; + int error; int i, cpu; int trace_on = 0; acquirelock: @@ -460,6 +486,8 @@ acquirelock: 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 before * our cpu_in_kgdb[] flag setting does: @@ -471,7 +499,11 @@ acquirelock: * master cpu and acquire the kgdb_active lock: */ while (1) { - if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) { +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 (atomic_cmpxchg(&kgdb_active, -1, cpu) == cpu) break; } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) { @@ -513,7 +545,7 @@ return_normal: } if (!kgdb_io_ready(1)) { - error = 1; + kgdb_info[cpu].ret_state = 1; goto kgdb_restore; /* No I/O connection, resume the system */ } @@ -548,7 +580,7 @@ return_normal: * Wait for the other CPUs to be notified and be waiting for us: */ for_each_online_cpu(i) { - while (!atomic_read(&cpu_in_kgdb[i])) + while (kgdb_do_roundup && !atomic_read(&cpu_in_kgdb[i])) cpu_relax(); } @@ -557,7 +589,7 @@ return_normal: * in the debugger and all secondary CPUs are quiescent */ kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code); - kgdb_deactivate_sw_breakpoints(); + dbg_deactivate_sw_breakpoints(); kgdb_single_step = 0; kgdb_contthread = current; exception_level = 0; @@ -565,8 +597,26 @@ return_normal: if (trace_on) tracing_off(); - /* Talk to debugger with gdbserial protocol */ - error = gdb_serial_stub(ks); + while (1) { +cpu_master_loop: + if (dbg_kdb_mode) { + kgdb_connected = 1; + error = kdb_stub(ks); + } else { + error = gdb_serial_stub(ks); + } + + if (error == DBG_PASS_EVENT) { + dbg_kdb_mode = !dbg_kdb_mode; + kgdb_connected = 0; + } else if (error == DBG_SWITCH_CPU_EVENT) { + dbg_cpu_switch(cpu, dbg_switch_cpu); + 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) @@ -578,11 +628,16 @@ return_normal: for (i = NR_CPUS-1; i >= 0; i--) atomic_dec(&passive_cpu_wait[i]); /* - * Wait till all the CPUs have quit - * from the debugger. + * Wait till all the CPUs have quit from the debugger, + * but allow a CPU that hit an exception and is + * waiting to become the master to remain in the debug + * core. */ for_each_online_cpu(i) { - while (atomic_read(&cpu_in_kgdb[i])) + while (kgdb_do_roundup && + atomic_read(&cpu_in_kgdb[i]) && + !(kgdb_info[i].exception_state & + DCPU_WANT_MASTER)) cpu_relax(); } } @@ -603,7 +658,7 @@ kgdb_restore: clocksource_touch_watchdog(); local_irq_restore(flags); - return error; + return kgdb_info[cpu].ret_state; } /* @@ -632,7 +687,8 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) return 0; /* Ouch, double exception ! */ kgdb_info[ks->cpu].exception_state |= DCPU_WANT_MASTER; ret = kgdb_cpu_enter(ks, regs); - kgdb_info[ks->cpu].exception_state &= ~DCPU_WANT_MASTER; + kgdb_info[ks->cpu].exception_state &= ~(DCPU_WANT_MASTER | + DCPU_IS_SLAVE); return ret; } @@ -665,7 +721,7 @@ static void kgdb_console_write(struct console *co, const char *s, /* If we're debugging, or KGDB has not connected, don't try * and print. */ - if (!kgdb_connected || atomic_read(&kgdb_active) != -1) + if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode) return; local_irq_save(flags); @@ -687,8 +743,14 @@ static void sysrq_handle_dbg(int key, struct tty_struct *tty) printk(KERN_CRIT "ERROR: No KGDB I/O module available\n"); return; } - if (!kgdb_connected) + if (!kgdb_connected) { +#ifdef CONFIG_KGDB_KDB + if (!dbg_kdb_mode) + printk(KERN_CRIT "KGDB or $3#33 for KDB\n"); +#else printk(KERN_CRIT "Entering KGDB\n"); +#endif + } kgdb_breakpoint(); } @@ -817,6 +879,16 @@ void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops) } EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); +int dbg_io_get_char(void) +{ + int ret = dbg_io_ops->read_char(); + if (!dbg_kdb_mode) + return ret; + if (ret == 127) + return 8; + return ret; +} + /** * kgdb_breakpoint - generate breakpoint exception * @@ -839,6 +911,7 @@ 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(); diff --git a/kernel/debug/debug_core.h b/kernel/debug/debug_core.h index db554f9..44cf3de 100644 --- a/kernel/debug/debug_core.h +++ b/kernel/debug/debug_core.h @@ -38,6 +38,8 @@ struct debuggerinfo_struct { void *debuggerinfo; struct task_struct *task; int exception_state; + int ret_state; + int irq_depth; }; extern struct debuggerinfo_struct kgdb_info[]; @@ -47,9 +49,31 @@ extern int dbg_remove_all_break(void); extern int dbg_set_sw_break(unsigned long addr); extern int dbg_remove_sw_break(unsigned long addr); extern int dbg_activate_sw_breakpoints(void); +extern int dbg_deactivate_sw_breakpoints(void); + +/* polled character access to i/o module */ +extern int dbg_io_get_char(void); + +/* stub return value for switching between the gdbstub and kdb */ +#define DBG_PASS_EVENT -12345 +/* Switch from one cpu to another */ +#define DBG_SWITCH_CPU_EVENT -123456 +extern int dbg_switch_cpu; /* gdbstub interface functions */ extern int gdb_serial_stub(struct kgdb_state *ks); extern void gdbstub_msg_write(const char *s, int len); +/* gdbstub functions used for kdb <-> gdbstub transition */ +extern int gdbstub_state(struct kgdb_state *ks, char *cmd); + +#ifdef CONFIG_KGDB_KDB +extern int kdb_stub(struct kgdb_state *ks); +#else /* ! CONFIG_KGDB_KDB */ +static inline int kdb_stub(struct kgdb_state *ks) +{ + return DBG_PASS_EVENT; +} +#endif /* CONFIG_KGDB_KDB */ + #endif /* _DEBUG_CORE_H_ */ diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c index ccdf092..188203a 100644 --- a/kernel/debug/gdbstub.c +++ b/kernel/debug/gdbstub.c @@ -887,6 +887,13 @@ int gdb_serial_stub(struct kgdb_state *ks) case 'Z': /* Break point set */ gdb_cmd_break(ks); break; +#ifdef CONFIG_KGDB_KDB + case '3': /* Escape into back into kdb */ + if (remcom_in_buffer[1] == '\0') { + gdb_cmd_detachkill(ks); + return DBG_PASS_EVENT; + } +#endif case 'C': /* Exception passing */ tmp = gdb_cmd_exception_pass(ks); if (tmp > 0) @@ -932,3 +939,32 @@ kgdb_exit: error = 1; return error; } + +int gdbstub_state(struct kgdb_state *ks, char *cmd) +{ + int error; + + switch (cmd[0]) { + case 'e': + error = kgdb_arch_handle_exception(ks->ex_vector, + ks->signo, + ks->err_code, + remcom_in_buffer, + remcom_out_buffer, + ks->linux_regs); + return error; + case 's': + case 'c': + strcpy(remcom_in_buffer, cmd); + return 0; + case '?': + gdb_cmd_status(ks); + break; + case '\0': + strcpy(remcom_out_buffer, ""); + break; + } + dbg_io_ops->write_char('+'); + put_packet(remcom_out_buffer); + return 0; +} diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb index 9b5d1d7..78de43a 100644 --- a/lib/Kconfig.kgdb +++ b/lib/Kconfig.kgdb @@ -3,7 +3,7 @@ config HAVE_ARCH_KGDB bool menuconfig KGDB - bool "KGDB: kernel debugging with remote gdb" + bool "KGDB: kernel debugger" depends on HAVE_ARCH_KGDB depends on DEBUG_KERNEL && EXPERIMENTAL help @@ -57,4 +57,10 @@ config KGDB_TESTS_BOOT_STRING information about other strings you could use beyond the default of V1F100. +config KGDB_KDB + bool "KGDB_KDB: include kdb frontend for kgdb" + default n + help + KDB frontend for kernel + endif # KGDB |