From 0f26d0e0a715556270d85b7946b99546a2f92888 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Mon, 30 Jul 2012 22:44:41 -0500 Subject: kdb: Remove unused KDB_FLAG_ONLY_DO_DUMP This code cleanup was missed in the original kdb merge, and this code is simply not used at all. The code that was previously used to set the KDB_FLAG_ONLY_DO_DUMP was removed prior to the initial kdb merge. Signed-off-by: Jason Wessel --- kernel/debug/kdb/kdb_main.c | 15 +-------------- 1 file changed, 1 insertion(+), 14 deletions(-) (limited to 'kernel/debug') diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 1f91413edb87..31df1706b9a9 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -139,11 +139,10 @@ static const int __nkdb_err = sizeof(kdbmsgs) / sizeof(kdbmsg_t); static char *__env[] = { #if defined(CONFIG_SMP) "PROMPT=[%d]kdb> ", - "MOREPROMPT=[%d]more> ", #else "PROMPT=kdb> ", - "MOREPROMPT=more> ", #endif + "MOREPROMPT=more> ", "RADIX=16", "MDCOUNT=8", /* lines of md output */ KDB_PLATFORM_ENV, @@ -1236,18 +1235,6 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs, *cmdbuf = '\0'; *(cmd_hist[cmd_head]) = '\0'; - if (KDB_FLAG(ONLY_DO_DUMP)) { - /* kdb is off but a catastrophic error requires a dump. - * Take the dump and reboot. - * Turn on logging so the kdb output appears in the log - * buffer in the dump. - */ - const char *setargs[] = { "set", "LOGGING", "1" }; - kdb_set(2, setargs); - kdb_reboot(0, NULL); - /*NOTREACHED*/ - } - do_full_getstr: #if defined(CONFIG_SMP) snprintf(kdb_prompt_str, CMD_BUFLEN, kdbgetenv("PROMPT"), -- cgit v1.2.3 From 07cd27bbd4d07af6c3e24ae479316a69e7935e1e Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Mon, 30 Jul 2012 22:44:41 -0500 Subject: kdb: Remove cpu from the more prompt Having the CPU in the more prompt is completely redundent vs the standard kdb prompt, and it also wastes 32 bytes on the stack. Signed-off-by: Jason Wessel --- kernel/debug/kdb/kdb_io.c | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'kernel/debug') diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index bb9520f0f6ff..0a69d2adc4f3 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -715,9 +715,6 @@ kdb_printit: /* check for having reached the LINES number of printed lines */ if (kdb_nextline == linecount) { char buf1[16] = ""; -#if defined(CONFIG_SMP) - char buf2[32]; -#endif /* Watch out for recursion here. Any routine that calls * kdb_printf will come back through here. And kdb_read @@ -732,14 +729,6 @@ kdb_printit: if (moreprompt == NULL) moreprompt = "more> "; -#if defined(CONFIG_SMP) - if (strchr(moreprompt, '%')) { - sprintf(buf2, moreprompt, get_cpu()); - put_cpu(); - moreprompt = buf2; - } -#endif - kdb_input_flush(); c = console_drivers; -- cgit v1.2.3 From b10d22d6e8f76b9e94871aebe0fc62aab2748200 Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Mon, 30 Jul 2012 04:58:10 -0700 Subject: kernel/debug: Make use of KGDB_REASON_NMI Currently kernel never set KGDB_REASON_NMI. We do now, when we enter KGDB/KDB from an NMI. This is not to be confused with kgdb_nmicallback(), NMI callback is an entry for the slave CPUs during CPUs roundup, but REASON_NMI is the entry for the master CPU. Signed-off-by: Anton Vorontsov Signed-off-by: Jason Wessel --- kernel/debug/kdb/kdb_debugger.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/debug') diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c index 8b68ce78ff17..be7b33b73d30 100644 --- a/kernel/debug/kdb/kdb_debugger.c +++ b/kernel/debug/kdb/kdb_debugger.c @@ -12,6 +12,7 @@ #include #include #include +#include #include "kdb_private.h" #include "../debug_core.h" @@ -52,6 +53,9 @@ int kdb_stub(struct kgdb_state *ks) if (atomic_read(&kgdb_setting_breakpoint)) reason = KDB_REASON_KEYBOARD; + if (in_nmi()) + reason = KDB_REASON_NMI; + for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) { if ((bp->bp_enabled) && (bp->bp_addr == addr)) { reason = KDB_REASON_BREAK; -- cgit v1.2.3 From 5a14fead07bcf4e0acc877a8d9e1d1f40a441153 Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Mon, 24 Sep 2012 14:27:50 -0700 Subject: kernel/debug: Mask KGDB NMI upon entry The new arch callback should manage NMIs that usually cause KGDB to enter. That is, not all NMIs should be enabled/disabled, but only those that issue kgdb_handle_exception(). We must mask it as serial-line interrupt can be used as an NMI, so if the original KGDB-entry cause was say a breakpoint, then every input to KDB console will cause KGDB to reenter, which we don't want. Signed-off-by: Anton Vorontsov Acked-by: Jason Wessel Signed-off-by: Greg Kroah-Hartman --- kernel/debug/debug_core.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'kernel/debug') diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 0557f24c6bca..17e073c309e6 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -672,6 +672,10 @@ 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 = 0; + + if (arch_kgdb_ops.enable_nmi) + arch_kgdb_ops.enable_nmi(0); ks->cpu = raw_smp_processor_id(); ks->ex_vector = evector; @@ -681,11 +685,15 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) ks->linux_regs = regs; if (kgdb_reenter_check(ks)) - return 0; /* Ouch, double exception ! */ + goto out; /* Ouch, double exception ! */ if (kgdb_info[ks->cpu].enter_kgdb != 0) - return 0; + goto out; - return kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); + ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER); +out: + if (arch_kgdb_ops.enable_nmi) + arch_kgdb_ops.enable_nmi(1); + return ret; } int kgdb_nmicallback(int cpu, void *regs) -- cgit v1.2.3 From ad394f66fa57ae66014cb74f337e2820bac4c417 Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Mon, 24 Sep 2012 14:27:51 -0700 Subject: kdb: Implement disable_nmi command This command disables NMI-entry. If NMI source has been previously shared with a serial console ("debug port"), this effectively releases the port from KDB exclusive use, and makes the console available for normal use. Of course, NMI can be reenabled, enable_nmi modparam is used for that: echo 1 > /sys/module/kdb/parameters/enable_nmi Signed-off-by: Anton Vorontsov Acked-by: Jason Wessel Signed-off-by: Greg Kroah-Hartman --- kernel/debug/kdb/kdb_main.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'kernel/debug') diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 31df1706b9a9..1261dc7eaeb9 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -2107,6 +2108,32 @@ static int kdb_dmesg(int argc, const char **argv) return 0; } #endif /* CONFIG_PRINTK */ + +/* Make sure we balance enable/disable calls, must disable first. */ +static atomic_t kdb_nmi_disabled; + +static int kdb_disable_nmi(int argc, const char *argv[]) +{ + if (atomic_read(&kdb_nmi_disabled)) + return 0; + atomic_set(&kdb_nmi_disabled, 1); + arch_kgdb_ops.enable_nmi(0); + return 0; +} + +static int kdb_param_enable_nmi(const char *val, const struct kernel_param *kp) +{ + if (!atomic_add_unless(&kdb_nmi_disabled, -1, 0)) + return -EINVAL; + arch_kgdb_ops.enable_nmi(1); + return 0; +} + +static const struct kernel_param_ops kdb_param_ops_enable_nmi = { + .set = kdb_param_enable_nmi, +}; +module_param_cb(enable_nmi, &kdb_param_ops_enable_nmi, NULL, 0600); + /* * kdb_cpu - This function implements the 'cpu' command. * cpu [] @@ -2851,6 +2878,10 @@ static void __init kdb_inittab(void) kdb_register_repeat("dmesg", kdb_dmesg, "[lines]", "Display syslog buffer", 0, KDB_REPEAT_NONE); #endif + if (arch_kgdb_ops.enable_nmi) { + kdb_register_repeat("disable_nmi", kdb_disable_nmi, "", + "Disable NMI entry to KDB", 0, KDB_REPEAT_NONE); + } kdb_register_repeat("defcmd", kdb_defcmd, "name \"usage\" \"help\"", "Define a set of commands, down to endefcmd", 0, KDB_REPEAT_NONE); kdb_register_repeat("kill", kdb_kill, "<-signal> ", -- cgit v1.2.3