This patch adds a kgdb_nmicallin() interface that can be used by external NMI handlers to call the KGDB/KDB handler. The primary need for this is for those types of NMI interrupts where all the CPUs have already received the NMI signal. Therefore no send_IPI(NMI) is required, and in fact it will cause a 2nd unhandled NMI to occur. This generates the "Dazed and Confuzed" messages. Since all the CPUs are getting the NMI at roughly the same time, it's not guaranteed that the first CPU that hits the NMI handler will manage to enter KGDB and set the dbg_master_lock before the slaves start entering. The new argument "send_ready" was added for KGDB to signal the NMI handler to release the slave CPUs for entry into KGDB. Signed-off-by: Mike Travis Reviewed-by: Dimitri Sivanich Reviewed-by: Hedi Berriche --- include/linux/kgdb.h | 1 + kernel/debug/debug_core.c | 41 +++++++++++++++++++++++++++++++++++++++++ kernel/debug/debug_core.h | 1 + 3 files changed, 43 insertions(+) --- linux.orig/include/linux/kgdb.h +++ linux/include/linux/kgdb.h @@ -310,6 +310,7 @@ extern int kgdb_handle_exception(int ex_vector, int signo, int err_code, struct pt_regs *regs); extern int kgdb_nmicallback(int cpu, void *regs); +extern int kgdb_nmicallin(int cpu, int trapnr, void *regs, atomic_t *snd_rdy); extern void gdbstub_exit(int status); extern int kgdb_single_step; --- linux.orig/kernel/debug/debug_core.c +++ linux/kernel/debug/debug_core.c @@ -578,6 +578,10 @@ return_normal: /* Signal the other CPUs to enter kgdb_wait() */ if ((!kgdb_single_step) && kgdb_do_roundup) kgdb_roundup_cpus(flags); + + /* If optional send ready pointer, signal CPUs to proceed */ + if (kgdb_info[cpu].send_ready) + atomic_set(kgdb_info[cpu].send_ready, 1); #endif /* @@ -729,6 +733,43 @@ int kgdb_nmicallback(int cpu, void *regs return 0; } #endif + return 1; +} + +int kgdb_nmicallin(int cpu, int trapnr, void *regs, atomic_t *send_ready) +{ +#ifdef CONFIG_SMP + if (!kgdb_io_ready(0)) + return 1; + + if (kgdb_info[cpu].enter_kgdb == 0) { + struct kgdb_state kgdb_var; + struct kgdb_state *ks = &kgdb_var; + int save_kgdb_do_roundup = kgdb_do_roundup; + + memset(ks, 0, sizeof(struct kgdb_state)); + ks->cpu = cpu; + ks->ex_vector = trapnr; + ks->signo = SIGTRAP; + ks->err_code = 0; + ks->kgdb_usethreadid = 0; + ks->linux_regs = regs; + + /* Do not broadcast NMI */ + kgdb_do_roundup = 0; + + /* Indicate there are slaves waiting */ + kgdb_info[cpu].send_ready = send_ready; + kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); + kgdb_do_roundup = save_kgdb_do_roundup; + kgdb_info[cpu].send_ready = NULL; + + /* Wait till all the CPUs have quit from the debugger. */ + while (atomic_read(&slaves_in_kgdb)) + cpu_relax(); + return 0; + } +#endif return 1; } --- linux.orig/kernel/debug/debug_core.h +++ linux/kernel/debug/debug_core.h @@ -37,6 +37,7 @@ struct kgdb_state { struct debuggerinfo_struct { void *debuggerinfo; struct task_struct *task; + atomic_t *send_ready; int exception_state; int ret_state; int irq_depth; -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/