diff options
Diffstat (limited to 'arch/mips/kernel/gdb-stub.c')
| -rw-r--r-- | arch/mips/kernel/gdb-stub.c | 61 |
1 files changed, 60 insertions, 1 deletions
diff --git a/arch/mips/kernel/gdb-stub.c b/arch/mips/kernel/gdb-stub.c index d4f88e0af24..6ecbdc1fefd 100644 --- a/arch/mips/kernel/gdb-stub.c +++ b/arch/mips/kernel/gdb-stub.c @@ -140,6 +140,7 @@ #include <asm/system.h> #include <asm/gdb-stub.h> #include <asm/inst.h> +#include <asm/smp.h> /* * external low-level support routines @@ -669,6 +670,64 @@ static void kgdb_wait(void *arg) local_irq_restore(flags); } +/* + * GDB stub needs to call kgdb_wait on all processor with interrupts + * disabled, so it uses it's own special variant. + */ +static int kgdb_smp_call_kgdb_wait(void) +{ +#ifdef CONFIG_SMP + struct call_data_struct data; + int i, cpus = num_online_cpus() - 1; + int cpu = smp_processor_id(); + + /* + * Can die spectacularly if this CPU isn't yet marked online + */ + BUG_ON(!cpu_online(cpu)); + + if (!cpus) + return 0; + + if (spin_is_locked(&smp_call_lock)) { + /* + * Some other processor is trying to make us do something + * but we're not going to respond... give up + */ + return -1; + } + + /* + * We will continue here, accepting the fact that + * the kernel may deadlock if another CPU attempts + * to call smp_call_function now... + */ + + data.func = kgdb_wait; + data.info = NULL; + atomic_set(&data.started, 0); + data.wait = 0; + + spin_lock(&smp_call_lock); + call_data = &data; + mb(); + + /* Send a message to all other CPUs and wait for them to respond */ + for (i = 0; i < NR_CPUS; i++) + if (cpu_online(i) && i != cpu) + core_send_ipi(i, SMP_CALL_FUNCTION); + + /* Wait for response */ + /* FIXME: lock-up detection, backtrace on lock-up */ + while (atomic_read(&data.started) != cpus) + barrier(); + + call_data = NULL; + spin_unlock(&smp_call_lock); +#endif + + return 0; +} /* * This function does all command processing for interfacing to gdb. It @@ -718,7 +777,7 @@ void handle_exception (struct gdb_regs *regs) /* * force other cpus to enter kgdb */ - smp_call_function(kgdb_wait, NULL, 0, 0); + kgdb_smp_call_kgdb_wait(); /* * If we're in breakpoint() increment the PC |