struct pt_regs *linux_regs;
};
+/* Exception state values */
+#define DCPU_WANT_MASTER 0x1 /* Waiting to become a master kgdb cpu */
+#define DCPU_NEXT_MASTER 0x2 /* Transition from one master cpu to another */
+#define DCPU_IS_SLAVE 0x4 /* Slave cpu enter exception */
+#define DCPU_SSTEP 0x8 /* CPU is single stepping */
+
static struct debuggerinfo_struct {
void *debuggerinfo;
struct task_struct *task;
+ int exception_state;
} kgdb_info[NR_CPUS];
/**
struct task_struct *kgdb_contthread;
int kgdb_single_step;
+pid_t kgdb_sstep_pid;
/* Our I/O buffers. */
static char remcom_in_buffer[BUFMAX];
/*
* Copy the binary array pointed to by buf into mem. Fix $, #, and
- * 0x7d escaped with 0x7d. Return a pointer to the character after
- * the last byte written.
+ * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
+ * The input buf is overwitten with the result to write to mem.
*/
static int kgdb_ebin2mem(char *buf, char *mem, int count)
{
- int err = 0;
- char c;
+ int size = 0;
+ char *c = buf;
while (count-- > 0) {
- c = *buf++;
- if (c == 0x7d)
- c = *buf++ ^ 0x20;
-
- err = probe_kernel_write(mem, &c, 1);
- if (err)
- break;
-
- mem++;
+ c[size] = *buf++;
+ if (c[size] == 0x7d)
+ c[size] = *buf++ ^ 0x20;
+ size++;
}
- return err;
+ return probe_kernel_write(mem, c, size);
}
/*
*/
if (tid == 0 || tid == -1)
tid = -atomic_read(&kgdb_active) - 2;
- if (tid < 0) {
+ if (tid < -1 && tid > -NR_CPUS - 2) {
if (kgdb_info[-tid - 2].task)
return kgdb_info[-tid - 2].task;
else
return idle_task(-tid - 2);
}
+ if (tid <= 0) {
+ printk(KERN_ERR "KGDB: Internal thread select error\n");
+ dump_stack();
+ return NULL;
+ }
/*
* find_task_by_pid_ns() does not take the tasklist lock anymore
}
/*
- * CPU debug state control:
- */
-
-#ifdef CONFIG_SMP
-static void kgdb_wait(struct pt_regs *regs)
-{
- unsigned long flags;
- int cpu;
-
- local_irq_save(flags);
- cpu = raw_smp_processor_id();
- kgdb_info[cpu].debuggerinfo = regs;
- kgdb_info[cpu].task = current;
- /*
- * Make sure the above info reaches the primary CPU before
- * our cpu_in_kgdb[] flag setting does:
- */
- smp_wmb();
- atomic_set(&cpu_in_kgdb[cpu], 1);
-
- /* Wait till primary CPU is done with debugging */
- while (atomic_read(&passive_cpu_wait[cpu]))
- cpu_relax();
-
- kgdb_info[cpu].debuggerinfo = NULL;
- kgdb_info[cpu].task = NULL;
-
- /* fix up hardware debug registers on local cpu */
- if (arch_kgdb_ops.correct_hw_break)
- arch_kgdb_ops.correct_hw_break();
-
- /* Signal the primary CPU that we are done: */
- atomic_set(&cpu_in_kgdb[cpu], 0);
- touch_softlockup_watchdog();
- clocksource_touch_watchdog();
- local_irq_restore(flags);
-}
-#endif
-
-/*
* Some architectures need cache flushes when we set/clear a
* breakpoint:
*/
static int kgdb_activate_sw_breakpoints(void)
{
unsigned long addr;
- int error = 0;
+ int error;
+ int ret = 0;
int i;
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
addr = kgdb_break[i].bpt_addr;
error = kgdb_arch_set_breakpoint(addr,
kgdb_break[i].saved_instr);
- if (error)
- return error;
+ if (error) {
+ ret = error;
+ printk(KERN_INFO "KGDB: BP install failed: %lx", addr);
+ continue;
+ }
kgdb_flush_swbreak_addr(addr);
kgdb_break[i].state = BP_ACTIVE;
}
- return 0;
+ return ret;
}
static int kgdb_set_sw_break(unsigned long addr)
static int kgdb_deactivate_sw_breakpoints(void)
{
unsigned long addr;
- int error = 0;
+ int error;
+ int ret = 0;
int i;
for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
addr = kgdb_break[i].bpt_addr;
error = kgdb_arch_remove_breakpoint(addr,
kgdb_break[i].saved_instr);
- if (error)
- return error;
+ if (error) {
+ printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr);
+ ret = error;
+ }
kgdb_flush_swbreak_addr(addr);
kgdb_break[i].state = BP_SET;
}
- return 0;
+ return ret;
}
static int kgdb_remove_sw_break(unsigned long addr)
/*
* All threads that don't have debuggerinfo should be
- * in __schedule() sleeping, since all other CPUs
+ * in schedule() sleeping, since all other CPUs
* are in kgdb_wait, and thus have debuggerinfo.
*/
if (local_debuggerinfo) {
return 1;
} else {
- error_packet(remcom_out_buffer, -EINVAL);
- return 0;
+ kgdb_msg_write("KGDB only knows signal 9 (pass)"
+ " and 15 (pass and disconnect)\n"
+ "Executing a continue without signal passing\n", 0);
+ remcom_in_buffer[0] = 'c';
}
/* Indicate fall through */
return 1;
}
-/*
- * 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)
+static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs)
{
- struct kgdb_state kgdb_var;
- struct kgdb_state *ks = &kgdb_var;
unsigned long flags;
+ int sstep_tries = 100;
int error = 0;
int i, cpu;
-
- ks->cpu = raw_smp_processor_id();
- ks->ex_vector = evector;
- ks->signo = signo;
- ks->ex_vector = evector;
- ks->err_code = ecode;
- ks->kgdb_usethreadid = 0;
- ks->linux_regs = regs;
-
- if (kgdb_reenter_check(ks))
- return 0; /* Ouch, double exception ! */
-
+ int trace_on = 0;
acquirelock:
/*
* Interrupts will be restored by the 'trap return' code, except when
*/
local_irq_save(flags);
- cpu = raw_smp_processor_id();
+ cpu = ks->cpu;
+ kgdb_info[cpu].debuggerinfo = regs;
+ kgdb_info[cpu].task = current;
+ /*
+ * Make sure the above info reaches the primary CPU before
+ * our cpu_in_kgdb[] flag setting does:
+ */
+ atomic_inc(&cpu_in_kgdb[cpu]);
/*
- * Acquire the kgdb_active lock:
+ * CPU will loop if it is a slave or request to become a kgdb
+ * master cpu and acquire the kgdb_active lock:
*/
- while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1)
+ while (1) {
+ 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) {
+ if (!atomic_read(&passive_cpu_wait[cpu]))
+ 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();
+ if (trace_on)
+ tracing_on();
+ atomic_dec(&cpu_in_kgdb[cpu]);
+ touch_softlockup_watchdog_sync();
+ clocksource_touch_watchdog();
+ local_irq_restore(flags);
+ return 0;
+ }
cpu_relax();
+ }
/*
- * Do not start the debugger connection on this CPU if the last
- * instance of the exception handler wanted to come into the
- * debugger on a different CPU via a single step
+ * For single stepping, try to only enter on the processor
+ * that was single stepping. To gaurd against a deadlock, the
+ * kernel will only try for the value of sstep_tries before
+ * giving up and continuing on.
*/
if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
- atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
-
+ (kgdb_info[cpu].task &&
+ kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) {
atomic_set(&kgdb_active, -1);
- touch_softlockup_watchdog();
+ touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
local_irq_restore(flags);
if (kgdb_io_ops->pre_exception)
kgdb_io_ops->pre_exception();
- kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs;
- kgdb_info[ks->cpu].task = current;
-
kgdb_disable_hw_debug(ks->linux_regs);
/*
*/
if (!kgdb_single_step) {
for (i = 0; i < NR_CPUS; i++)
- atomic_set(&passive_cpu_wait[i], 1);
+ atomic_inc(&passive_cpu_wait[i]);
}
- /*
- * spin_lock code is good enough as a barrier so we don't
- * need one here:
- */
- atomic_set(&cpu_in_kgdb[ks->cpu], 1);
-
#ifdef CONFIG_SMP
/* Signal the other CPUs to enter kgdb_wait() */
if ((!kgdb_single_step) && kgdb_do_roundup)
kgdb_single_step = 0;
kgdb_contthread = current;
exception_level = 0;
+ trace_on = tracing_is_on();
+ if (trace_on)
+ tracing_off();
/* Talk to debugger with gdbserial protocol */
error = gdb_serial_stub(ks);
if (kgdb_io_ops->post_exception)
kgdb_io_ops->post_exception();
- kgdb_info[ks->cpu].debuggerinfo = NULL;
- kgdb_info[ks->cpu].task = NULL;
- atomic_set(&cpu_in_kgdb[ks->cpu], 0);
+ atomic_dec(&cpu_in_kgdb[ks->cpu]);
if (!kgdb_single_step) {
for (i = NR_CPUS-1; i >= 0; i--)
- atomic_set(&passive_cpu_wait[i], 0);
+ atomic_dec(&passive_cpu_wait[i]);
/*
* Wait till all the CPUs have quit
* from the debugger.
}
kgdb_restore:
+ 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;
+ }
+ if (trace_on)
+ tracing_on();
/* Free kgdb_active */
atomic_set(&kgdb_active, -1);
- touch_softlockup_watchdog();
+ touch_softlockup_watchdog_sync();
clocksource_touch_watchdog();
local_irq_restore(flags);
return error;
}
+/*
+ * 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;
+ int ret;
+
+ ks->cpu = raw_smp_processor_id();
+ ks->ex_vector = evector;
+ ks->signo = signo;
+ ks->ex_vector = evector;
+ ks->err_code = ecode;
+ ks->kgdb_usethreadid = 0;
+ ks->linux_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;
+ return ret;
+}
+
int kgdb_nmicallback(int cpu, void *regs)
{
#ifdef CONFIG_SMP
+ 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;
+
if (!atomic_read(&cpu_in_kgdb[cpu]) &&
- atomic_read(&kgdb_active) != cpu &&
- atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)])) {
- kgdb_wait((struct pt_regs *)regs);
+ 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;
return 0;
}
#endif
static struct sysrq_key_op sysrq_gdb_op = {
.handler = sysrq_handle_gdb,
- .help_msg = "Gdb",
- .action_msg = "GDB",
+ .help_msg = "debug(G)",
+ .action_msg = "DEBUG",
};
#endif
*/
void kgdb_breakpoint(void)
{
- atomic_set(&kgdb_setting_breakpoint, 1);
+ atomic_inc(&kgdb_setting_breakpoint);
wmb(); /* Sync point before breakpoint */
arch_kgdb_breakpoint();
wmb(); /* Sync point after breakpoint */
- atomic_set(&kgdb_setting_breakpoint, 0);
+ atomic_dec(&kgdb_setting_breakpoint);
}
EXPORT_SYMBOL_GPL(kgdb_breakpoint);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff