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Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb

Browse Source 
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  kdb,debug_core: adjust master cpu switch logic against new debug_core locking
  debug_core: refactor locking for master/slave cpus
  x86,kgdb: remove unnecessary call to kgdb_correct_hw_break()
  debug_core: disable hw_breakpoints on all cores in kgdb_cpu_enter()
  kdb,kgdb: fix sparse fixups
  kdb: Fix oops in kdb_unregister
  kdb,ftdump: Remove reference to internal kdb include
  kdb: Allow kernel loadable modules to add kdb shell functions
  debug_core: stop rcu warnings on kernel resume
  debug_core: move all watch dog syncs to a single function
  x86,kgdb: fix debugger hw breakpoint test regression in 2.6.35
This commit is contained in:
Linus Torvalds 2010-10-22 20:35:12 -07:00
commit 8814011679
10 changed files with 144 additions and 132 deletions
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11
arch/x86/kernel/kgdb.c
View File

@ -477,8 +477,6 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
raw_smp_processor_id());
}
kgdb_correct_hw_break();
return 0;
}
@ -621,7 +619,12 @@ int kgdb_arch_init(void)
static void kgdb_hw_overflow_handler(struct perf_event *event, int nmi,
struct perf_sample_data *data, struct pt_regs *regs)
{
kgdb_ll_trap(DIE_DEBUG, "debug", regs, 0, 0, SIGTRAP);
struct task_struct *tsk = current;
int i;
for (i = 0; i < 4; i++)
if (breakinfo[i].enabled)
tsk->thread.debugreg6 |= (DR_TRAP0 << i);
}
void kgdb_arch_late(void)
@ -644,7 +647,7 @@ void kgdb_arch_late(void)
if (breakinfo[i].pev)
continue;
breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL);
if (IS_ERR(breakinfo[i].pev)) {
if (IS_ERR((void * __force)breakinfo[i].pev)) {
printk(KERN_ERR "kgdb: Could not allocate hw"
"breakpoints\nDisabling the kernel debugger\n");
breakinfo[i].pev = NULL;

2
drivers/serial/kgdboc.c
View File

@ -243,7 +243,7 @@ static struct kgdb_io kgdboc_io_ops = {
#ifdef CONFIG_KGDB_SERIAL_CONSOLE
/* This is only available if kgdboc is a built in for early debugging */
int __init kgdboc_early_init(char *opt)
static int __init kgdboc_early_init(char *opt)
{
/* save the first character of the config string because the
* init routine can destroy it.

51
include/linux/kdb.h
View File

@ -28,6 +28,41 @@ extern int kdb_poll_idx;
extern int kdb_initial_cpu;
extern atomic_t kdb_event;
/* Types and messages used for dynamically added kdb shell commands */
#define KDB_MAXARGS 16 /* Maximum number of arguments to a function */
typedef enum {
KDB_REPEAT_NONE = 0, /* Do not repeat this command */
KDB_REPEAT_NO_ARGS, /* Repeat the command without arguments */
KDB_REPEAT_WITH_ARGS, /* Repeat the command including its arguments */
} kdb_repeat_t;
typedef int (*kdb_func_t)(int, const char **);
/* KDB return codes from a command or internal kdb function */
#define KDB_NOTFOUND (-1)
#define KDB_ARGCOUNT (-2)
#define KDB_BADWIDTH (-3)
#define KDB_BADRADIX (-4)
#define KDB_NOTENV (-5)
#define KDB_NOENVVALUE (-6)
#define KDB_NOTIMP (-7)
#define KDB_ENVFULL (-8)
#define KDB_ENVBUFFULL (-9)
#define KDB_TOOMANYBPT (-10)
#define KDB_TOOMANYDBREGS (-11)
#define KDB_DUPBPT (-12)
#define KDB_BPTNOTFOUND (-13)
#define KDB_BADMODE (-14)
#define KDB_BADINT (-15)
#define KDB_INVADDRFMT (-16)
#define KDB_BADREG (-17)
#define KDB_BADCPUNUM (-18)
#define KDB_BADLENGTH (-19)
#define KDB_NOBP (-20)
#define KDB_BADADDR (-21)
/*
* kdb_diemsg
*
@ -104,10 +139,26 @@ int kdb_process_cpu(const struct task_struct *p)
/* kdb access to register set for stack dumping */
extern struct pt_regs *kdb_current_regs;
#ifdef CONFIG_KALLSYMS
extern const char *kdb_walk_kallsyms(loff_t *pos);
#else /* ! CONFIG_KALLSYMS */
static inline const char *kdb_walk_kallsyms(loff_t *pos)
{
return NULL;
}
#endif /* ! CONFIG_KALLSYMS */
/* Dynamic kdb shell command registration */
extern int kdb_register(char *, kdb_func_t, char *, char *, short);
extern int kdb_register_repeat(char *, kdb_func_t, char *, char *,
short, kdb_repeat_t);
extern int kdb_unregister(char *);
#else /* ! CONFIG_KGDB_KDB */
#define kdb_printf(...)
#define kdb_init(x)
#define kdb_register(...)
#define kdb_register_repeat(...)
#define kdb_uregister(x)
#endif /* CONFIG_KGDB_KDB */
enum {
KDB_NOT_INITIALIZED,

139
kernel/debug/debug_core.c
View File

@ -47,6 +47,7 @@
#include <linux/pid.h>
#include <linux/smp.h>
#include <linux/mm.h>
#include <linux/rcupdate.h>
#include <asm/cacheflush.h>
#include <asm/byteorder.h>
@ -109,13 +110,15 @@ static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
*/
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 passive_cpu_wait[NR_CPUS];
static atomic_t cpu_in_kgdb[NR_CPUS];
static atomic_t masters_in_kgdb;
static atomic_t slaves_in_kgdb;
static atomic_t kgdb_break_tasklet_var;
atomic_t kgdb_setting_breakpoint;
@ -457,26 +460,32 @@ static int kgdb_reenter_check(struct kgdb_state *ks)
return 1;
}
static void dbg_cpu_switch(int cpu, int next_cpu)
static void dbg_touch_watchdogs(void)
{
/* 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;
touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
rcu_cpu_stall_reset();
}
static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs)
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 i, cpu;
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);
kgdb_disable_hw_debug(ks->linux_regs);
acquirelock:
/*
* Interrupts will be restored by the 'trap return' code, except when
@ -489,14 +498,15 @@ acquirelock:
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:
*/
atomic_inc(&cpu_in_kgdb[cpu]);
if (exception_level == 1)
/* 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
@ -508,10 +518,12 @@ cpu_loop:
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)
if (raw_spin_trylock(&dbg_master_lock)) {
atomic_xchg(&kgdb_active, cpu);
break;
}
} else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) {
if (!atomic_read(&passive_cpu_wait[cpu]))
if (!raw_spin_is_locked(&dbg_slave_lock))
goto return_normal;
} else {
return_normal:
@ -522,9 +534,12 @@ return_normal:
arch_kgdb_ops.correct_hw_break();
if (trace_on)
tracing_on();
atomic_dec(&cpu_in_kgdb[cpu]);
touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
kgdb_info[cpu].exception_state &=
~(DCPU_WANT_MASTER | DCPU_IS_SLAVE);
kgdb_info[cpu].enter_kgdb--;
smp_mb__before_atomic_dec();
atomic_dec(&slaves_in_kgdb);
dbg_touch_watchdogs();
local_irq_restore(flags);
return 0;
}
@ -541,8 +556,8 @@ return_normal:
(kgdb_info[cpu].task &&
kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) {
atomic_set(&kgdb_active, -1);
touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
raw_spin_unlock(&dbg_master_lock);
dbg_touch_watchdogs();
local_irq_restore(flags);
goto acquirelock;
@ -563,16 +578,12 @@ return_normal:
if (dbg_io_ops->pre_exception)
dbg_io_ops->pre_exception();
kgdb_disable_hw_debug(ks->linux_regs);
/*
* 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) {
for (i = 0; i < NR_CPUS; i++)
atomic_inc(&passive_cpu_wait[i]);
}
if (!kgdb_single_step)
raw_spin_lock(&dbg_slave_lock);
#ifdef CONFIG_SMP
/* Signal the other CPUs to enter kgdb_wait() */
@ -583,10 +594,9 @@ return_normal:
/*
* Wait for the other CPUs to be notified and be waiting for us:
*/
for_each_online_cpu(i) {
while (kgdb_do_roundup && !atomic_read(&cpu_in_kgdb[i]))
cpu_relax();
}
while (kgdb_do_roundup && (atomic_read(&masters_in_kgdb) +
atomic_read(&slaves_in_kgdb)) != online_cpus)
cpu_relax();
/*
* At this point the primary processor is completely
@ -615,7 +625,8 @@ cpu_master_loop:
if (error == DBG_PASS_EVENT) {
dbg_kdb_mode = !dbg_kdb_mode;
} else if (error == DBG_SWITCH_CPU_EVENT) {
dbg_cpu_switch(cpu, dbg_switch_cpu);
kgdb_info[dbg_switch_cpu].exception_state |=
DCPU_NEXT_MASTER;
goto cpu_loop;
} else {
kgdb_info[cpu].ret_state = error;
@ -627,24 +638,11 @@ cpu_master_loop:
if (dbg_io_ops->post_exception)
dbg_io_ops->post_exception();
atomic_dec(&cpu_in_kgdb[ks->cpu]);
if (!kgdb_single_step) {
for (i = NR_CPUS-1; i >= 0; i--)
atomic_dec(&passive_cpu_wait[i]);
/*
* 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 (kgdb_do_roundup &&
atomic_read(&cpu_in_kgdb[i]) &&
!(kgdb_info[i].exception_state &
DCPU_WANT_MASTER))
cpu_relax();
}
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:
@ -655,12 +653,20 @@ kgdb_restore:
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_dec();
atomic_dec(&masters_in_kgdb);
/* Free kgdb_active */
atomic_set(&kgdb_active, -1);
touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
raw_spin_unlock(&dbg_master_lock);
dbg_touch_watchdogs();
local_irq_restore(flags);
return kgdb_info[cpu].ret_state;
@ -678,7 +684,6 @@ 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;
ks->cpu = raw_smp_processor_id();
ks->ex_vector = evector;
@ -689,11 +694,10 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
if (kgdb_reenter_check(ks))
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 |
DCPU_IS_SLAVE);
return ret;
if (kgdb_info[ks->cpu].enter_kgdb != 0)
return 0;
return kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
}
int kgdb_nmicallback(int cpu, void *regs)
@ -706,12 +710,9 @@ int kgdb_nmicallback(int cpu, void *regs)
ks->cpu = cpu;
ks->linux_regs = regs;
if (!atomic_read(&cpu_in_kgdb[cpu]) &&
atomic_read(&kgdb_active) != -1 &&
atomic_read(&kgdb_active) != cpu) {
kgdb_info[cpu].exception_state |= DCPU_IS_SLAVE;
kgdb_cpu_enter(ks, regs);
kgdb_info[cpu].exception_state &= ~DCPU_IS_SLAVE;
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

1
kernel/debug/debug_core.h
View File

@ -40,6 +40,7 @@ struct debuggerinfo_struct {
int exception_state;
int ret_state;
int irq_depth;
int enter_kgdb;
};
extern struct debuggerinfo_struct kgdb_info[];

3
kernel/debug/kdb/kdb_debugger.c
View File

@ -86,7 +86,7 @@ int kdb_stub(struct kgdb_state *ks)
}
/* Set initial kdb state variables */
KDB_STATE_CLEAR(KGDB_TRANS);
kdb_initial_cpu = ks->cpu;
kdb_initial_cpu = atomic_read(&kgdb_active);
kdb_current_task = kgdb_info[ks->cpu].task;
kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
/* Remove any breakpoints as needed by kdb and clear single step */
@ -105,7 +105,6 @@ int kdb_stub(struct kgdb_state *ks)
ks->pass_exception = 1;
KDB_FLAG_SET(CATASTROPHIC);
}
kdb_initial_cpu = ks->cpu;
if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
KDB_STATE_CLEAR(SSBPT);
KDB_STATE_CLEAR(DOING_SS);

2
kernel/debug/kdb/kdb_io.c
View File

@ -823,4 +823,4 @@ int kdb_printf(const char *fmt, ...)
return r;
}
EXPORT_SYMBOL_GPL(kdb_printf);

18
kernel/debug/kdb/kdb_main.c
View File

@ -1749,13 +1749,13 @@ static int kdb_go(int argc, const char **argv)
int nextarg;
long offset;
if (raw_smp_processor_id() != kdb_initial_cpu) {
kdb_printf("go must execute on the entry cpu, "
"please use \"cpu %d\" and then execute go\n",
kdb_initial_cpu);
return KDB_BADCPUNUM;
}
if (argc == 1) {
if (raw_smp_processor_id() != kdb_initial_cpu) {
kdb_printf("go <address> must be issued from the "
"initial cpu, do cpu %d first\n",
kdb_initial_cpu);
return KDB_ARGCOUNT;
}
nextarg = 1;
diag = kdbgetaddrarg(argc, argv, &nextarg,
&addr, &offset, NULL);
@ -2783,6 +2783,8 @@ int kdb_register_repeat(char *cmd,
return 0;
}
EXPORT_SYMBOL_GPL(kdb_register_repeat);
/*
* kdb_register - Compatibility register function for commands that do
@ -2805,6 +2807,7 @@ int kdb_register(char *cmd,
return kdb_register_repeat(cmd, func, usage, help, minlen,
KDB_REPEAT_NONE);
}
EXPORT_SYMBOL_GPL(kdb_register);
/*
* kdb_unregister - This function is used to unregister a kernel
@ -2823,7 +2826,7 @@ int kdb_unregister(char *cmd)
/*
* find the command.
*/
for (i = 0, kp = kdb_commands; i < kdb_max_commands; i++, kp++) {
for_each_kdbcmd(kp, i) {
if (kp->cmd_name && (strcmp(kp->cmd_name, cmd) == 0)) {
kp->cmd_name = NULL;
return 0;
@ -2833,6 +2836,7 @@ int kdb_unregister(char *cmd)
/* Couldn't find it. */
return 1;
}
EXPORT_SYMBOL_GPL(kdb_unregister);
/* Initialize the kdb command table. */
static void __init kdb_inittab(void)

48
kernel/debug/kdb/kdb_private.h
View File

@ -15,29 +15,6 @@
#include <linux/kgdb.h>
#include "../debug_core.h"
/* Kernel Debugger Error codes. Must not overlap with command codes. */
#define KDB_NOTFOUND (-1)
#define KDB_ARGCOUNT (-2)
#define KDB_BADWIDTH (-3)
#define KDB_BADRADIX (-4)
#define KDB_NOTENV (-5)
#define KDB_NOENVVALUE (-6)
#define KDB_NOTIMP (-7)
#define KDB_ENVFULL (-8)
#define KDB_ENVBUFFULL (-9)
#define KDB_TOOMANYBPT (-10)
#define KDB_TOOMANYDBREGS (-11)
#define KDB_DUPBPT (-12)
#define KDB_BPTNOTFOUND (-13)
#define KDB_BADMODE (-14)
#define KDB_BADINT (-15)
#define KDB_INVADDRFMT (-16)
#define KDB_BADREG (-17)
#define KDB_BADCPUNUM (-18)
#define KDB_BADLENGTH (-19)
#define KDB_NOBP (-20)
#define KDB_BADADDR (-21)
/* Kernel Debugger Command codes. Must not overlap with error codes. */
#define KDB_CMD_GO (-1001)
#define KDB_CMD_CPU (-1002)
@ -93,17 +70,6 @@
*/
#define KDB_MAXBPT 16
/* Maximum number of arguments to a function */
#define KDB_MAXARGS 16
typedef enum {
KDB_REPEAT_NONE = 0, /* Do not repeat this command */
KDB_REPEAT_NO_ARGS, /* Repeat the command without arguments */
KDB_REPEAT_WITH_ARGS, /* Repeat the command including its arguments */
} kdb_repeat_t;
typedef int (*kdb_func_t)(int, const char **);
/* Symbol table format returned by kallsyms. */
typedef struct __ksymtab {
unsigned long value; /* Address of symbol */
@ -123,11 +89,6 @@ extern int kallsyms_symbol_next(char *prefix_name, int flag);
extern int kallsyms_symbol_complete(char *prefix_name, int max_len);
/* Exported Symbols for kernel loadable modules to use. */
extern int kdb_register(char *, kdb_func_t, char *, char *, short);
extern int kdb_register_repeat(char *, kdb_func_t, char *, char *,
short, kdb_repeat_t);
extern int kdb_unregister(char *);
extern int kdb_getarea_size(void *, unsigned long, size_t);
extern int kdb_putarea_size(unsigned long, void *, size_t);
@ -144,6 +105,7 @@ extern int kdb_getword(unsigned long *, unsigned long, size_t);
extern int kdb_putword(unsigned long, unsigned long, size_t);
extern int kdbgetularg(const char *, unsigned long *);
extern int kdbgetu64arg(const char *, u64 *);
extern char *kdbgetenv(const char *);
extern int kdbgetaddrarg(int, const char **, int*, unsigned long *,
long *, char **);
@ -255,14 +217,6 @@ extern void kdb_ps1(const struct task_struct *p);
extern void kdb_print_nameval(const char *name, unsigned long val);
extern void kdb_send_sig_info(struct task_struct *p, struct siginfo *info);
extern void kdb_meminfo_proc_show(void);
#ifdef CONFIG_KALLSYMS
extern const char *kdb_walk_kallsyms(loff_t *pos);
#else /* ! CONFIG_KALLSYMS */
static inline const char *kdb_walk_kallsyms(loff_t *pos)
{
return NULL;
}
#endif /* ! CONFIG_KALLSYMS */
extern char *kdb_getstr(char *, size_t, char *);
/* Defines for kdb_symbol_print */

1
kernel/trace/trace_kdb.c
View File

@ -13,7 +13,6 @@
#include <linux/kdb.h>
#include <linux/ftrace.h>
#include "../debug/kdb/kdb_private.h"
#include "trace.h"
#include "trace_output.h"