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

* '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

7 files changed, 85 insertions, 127 deletions

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index de407c78178d..fec596da9bd0 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -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
diff --git a/kernel/debug/debug_core.h b/kernel/debug/debug_core.h
index c5d753d80f67..3494c28a7e7a 100644
--- a/kernel/debug/debug_core.h
+++ b/kernel/debug/debug_core.h
@@ -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[];
diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c
index bf6e8270e957..dd0b1b7dd02c 100644
--- a/kernel/debug/kdb/kdb_debugger.c
+++ b/kernel/debug/kdb/kdb_debugger.c
@@ -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);
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index c9b7f4f90bba..96fdaac46a80 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -823,4 +823,4 @@ int kdb_printf(const char *fmt, ...)
 
         return r;
 }
-
+EXPORT_SYMBOL_GPL(kdb_printf);
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index caf057a3de0e..d7bda21a106b 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -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)
diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
index be775f7e81e0..35d69ed1dfb5 100644
--- a/kernel/debug/kdb/kdb_private.h
+++ b/kernel/debug/kdb/kdb_private.h
@@ -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 */
diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c
index 7b8ecd751d93..3c5c5dfea0b3 100644
--- a/kernel/trace/trace_kdb.c
+++ b/kernel/trace/trace_kdb.c
@@ -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"