Commit 5e123e5d authored by Linus Torvalds's avatar Linus Torvalds

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

* 'kgdb-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  kgdb: Turn off tracing while in the debugger
  kgdb: use atomic_inc and atomic_dec instead of atomic_set
  kgdb: eliminate kgdb_wait(), all cpus enter the same way
  kgdbts,sh: Add in breakpoint pc offset for superh
  kgdb: have ebin2mem call probe_kernel_write once
parents 24b99d15 4da75b9c
...@@ -295,6 +295,10 @@ static int check_and_rewind_pc(char *put_str, char *arg) ...@@ -295,6 +295,10 @@ static int check_and_rewind_pc(char *put_str, char *arg)
/* On x86 a breakpoint stop requires it to be decremented */ /* On x86 a breakpoint stop requires it to be decremented */
if (addr + 1 == kgdbts_regs.ip) if (addr + 1 == kgdbts_regs.ip)
offset = -1; offset = -1;
#elif defined(CONFIG_SUPERH)
/* On SUPERH a breakpoint stop requires it to be decremented */
if (addr + 2 == kgdbts_regs.pc)
offset = -2;
#endif #endif
if (strcmp(arg, "silent") && if (strcmp(arg, "silent") &&
instruction_pointer(&kgdbts_regs) + offset != addr) { instruction_pointer(&kgdbts_regs) + offset != addr) {
...@@ -305,6 +309,8 @@ static int check_and_rewind_pc(char *put_str, char *arg) ...@@ -305,6 +309,8 @@ static int check_and_rewind_pc(char *put_str, char *arg)
#ifdef CONFIG_X86 #ifdef CONFIG_X86
/* On x86 adjust the instruction pointer if needed */ /* On x86 adjust the instruction pointer if needed */
kgdbts_regs.ip += offset; kgdbts_regs.ip += offset;
#elif defined(CONFIG_SUPERH)
kgdbts_regs.pc += offset;
#endif #endif
return 0; return 0;
} }
......
...@@ -69,9 +69,16 @@ struct kgdb_state { ...@@ -69,9 +69,16 @@ struct kgdb_state {
struct pt_regs *linux_regs; 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 { static struct debuggerinfo_struct {
void *debuggerinfo; void *debuggerinfo;
struct task_struct *task; struct task_struct *task;
int exception_state;
} kgdb_info[NR_CPUS]; } kgdb_info[NR_CPUS];
/** /**
...@@ -391,27 +398,22 @@ int kgdb_mem2hex(char *mem, char *buf, int count) ...@@ -391,27 +398,22 @@ int kgdb_mem2hex(char *mem, char *buf, int count)
/* /*
* Copy the binary array pointed to by buf into mem. Fix $, #, and * Copy the binary array pointed to by buf into mem. Fix $, #, and
* 0x7d escaped with 0x7d. Return a pointer to the character after * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
* the last byte written. * The input buf is overwitten with the result to write to mem.
*/ */
static int kgdb_ebin2mem(char *buf, char *mem, int count) static int kgdb_ebin2mem(char *buf, char *mem, int count)
{ {
int err = 0; int size = 0;
char c; char *c = buf;
while (count-- > 0) { while (count-- > 0) {
c = *buf++; c[size] = *buf++;
if (c == 0x7d) if (c[size] == 0x7d)
c = *buf++ ^ 0x20; c[size] = *buf++ ^ 0x20;
size++;
err = probe_kernel_write(mem, &c, 1);
if (err)
break;
mem++;
} }
return err; return probe_kernel_write(mem, c, size);
} }
/* /*
...@@ -562,49 +564,6 @@ static struct task_struct *getthread(struct pt_regs *regs, int tid) ...@@ -562,49 +564,6 @@ static struct task_struct *getthread(struct pt_regs *regs, int tid)
return find_task_by_pid_ns(tid, &init_pid_ns); return find_task_by_pid_ns(tid, &init_pid_ns);
} }
/*
* 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);
/* Disable any cpu specific hw breakpoints */
kgdb_disable_hw_debug(regs);
/* 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_sync();
clocksource_touch_watchdog();
local_irq_restore(flags);
}
#endif
/* /*
* Some architectures need cache flushes when we set/clear a * Some architectures need cache flushes when we set/clear a
* breakpoint: * breakpoint:
...@@ -1400,34 +1359,13 @@ static int kgdb_reenter_check(struct kgdb_state *ks) ...@@ -1400,34 +1359,13 @@ static int kgdb_reenter_check(struct kgdb_state *ks)
return 1; return 1;
} }
/* static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs)
* 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;
unsigned long flags; unsigned long flags;
int sstep_tries = 100; int sstep_tries = 100;
int error = 0; int error = 0;
int i, cpu; int i, cpu;
int trace_on = 0;
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 ! */
acquirelock: acquirelock:
/* /*
* Interrupts will be restored by the 'trap return' code, except when * Interrupts will be restored by the 'trap return' code, except when
...@@ -1435,13 +1373,43 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) ...@@ -1435,13 +1373,43 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
*/ */
local_irq_save(flags); 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(); cpu_relax();
}
/* /*
* For single stepping, try to only enter on the processor * For single stepping, try to only enter on the processor
...@@ -1475,9 +1443,6 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) ...@@ -1475,9 +1443,6 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
if (kgdb_io_ops->pre_exception) if (kgdb_io_ops->pre_exception)
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); kgdb_disable_hw_debug(ks->linux_regs);
/* /*
...@@ -1486,15 +1451,9 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) ...@@ -1486,15 +1451,9 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
*/ */
if (!kgdb_single_step) { if (!kgdb_single_step) {
for (i = 0; i < NR_CPUS; i++) 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 #ifdef CONFIG_SMP
/* Signal the other CPUs to enter kgdb_wait() */ /* Signal the other CPUs to enter kgdb_wait() */
if ((!kgdb_single_step) && kgdb_do_roundup) if ((!kgdb_single_step) && kgdb_do_roundup)
...@@ -1518,6 +1477,9 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) ...@@ -1518,6 +1477,9 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
kgdb_single_step = 0; kgdb_single_step = 0;
kgdb_contthread = current; kgdb_contthread = current;
exception_level = 0; exception_level = 0;
trace_on = tracing_is_on();
if (trace_on)
tracing_off();
/* Talk to debugger with gdbserial protocol */ /* Talk to debugger with gdbserial protocol */
error = gdb_serial_stub(ks); error = gdb_serial_stub(ks);
...@@ -1526,13 +1488,11 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) ...@@ -1526,13 +1488,11 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
if (kgdb_io_ops->post_exception) if (kgdb_io_ops->post_exception)
kgdb_io_ops->post_exception(); kgdb_io_ops->post_exception();
kgdb_info[ks->cpu].debuggerinfo = NULL; atomic_dec(&cpu_in_kgdb[ks->cpu]);
kgdb_info[ks->cpu].task = NULL;
atomic_set(&cpu_in_kgdb[ks->cpu], 0);
if (!kgdb_single_step) { if (!kgdb_single_step) {
for (i = NR_CPUS-1; i >= 0; i--) 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 * Wait till all the CPUs have quit
* from the debugger. * from the debugger.
...@@ -1551,6 +1511,8 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) ...@@ -1551,6 +1511,8 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
else else
kgdb_sstep_pid = 0; kgdb_sstep_pid = 0;
} }
if (trace_on)
tracing_on();
/* Free kgdb_active */ /* Free kgdb_active */
atomic_set(&kgdb_active, -1); atomic_set(&kgdb_active, -1);
touch_softlockup_watchdog_sync(); touch_softlockup_watchdog_sync();
...@@ -1560,13 +1522,52 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) ...@@ -1560,13 +1522,52 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
return error; 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) int kgdb_nmicallback(int cpu, void *regs)
{ {
#ifdef CONFIG_SMP #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]) && if (!atomic_read(&cpu_in_kgdb[cpu]) &&
atomic_read(&kgdb_active) != cpu && atomic_read(&kgdb_active) != -1 &&
atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)])) { atomic_read(&kgdb_active) != cpu) {
kgdb_wait((struct pt_regs *)regs); kgdb_info[cpu].exception_state |= DCPU_IS_SLAVE;
kgdb_cpu_enter(ks, regs);
kgdb_info[cpu].exception_state &= ~DCPU_IS_SLAVE;
return 0; return 0;
} }
#endif #endif
...@@ -1742,11 +1743,11 @@ EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); ...@@ -1742,11 +1743,11 @@ EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
*/ */
void kgdb_breakpoint(void) void kgdb_breakpoint(void)
{ {
atomic_set(&kgdb_setting_breakpoint, 1); atomic_inc(&kgdb_setting_breakpoint);
wmb(); /* Sync point before breakpoint */ wmb(); /* Sync point before breakpoint */
arch_kgdb_breakpoint(); arch_kgdb_breakpoint();
wmb(); /* Sync point after breakpoint */ wmb(); /* Sync point after breakpoint */
atomic_set(&kgdb_setting_breakpoint, 0); atomic_dec(&kgdb_setting_breakpoint);
} }
EXPORT_SYMBOL_GPL(kgdb_breakpoint); EXPORT_SYMBOL_GPL(kgdb_breakpoint);
......
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