sparc: implement watchdog_nmi_enable and watchdog_nmi_disable
Implement functions watchdog_nmi_enable and watchdog_nmi_disable to enable/disable nmi watchdog. Sparc uses arch specific nmi watchdog handler. Currently, we do not have a way to enable/disable nmi watchdog dynamically. With these patches we can enable or disable arch specific nmi watchdogs using proc or sysctl interface. Example commands. To enable: echo 1 > /proc/sys/kernel/nmi_watchdog To disable: echo 0 > /proc/sys/kernel/nmi_watchdog It can also achieved using the sysctl parameter kernel.nmi_watchdog Link: http://lkml.kernel.org/r/1478034826-43888-4-git-send-email-babu.moger@oracle.com Signed-off-by: Babu Moger <babu.moger@oracle.com> Acked-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Andi Kleen <andi@firstfloor.org> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: Josh Hunt <johunt@akamai.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -42,7 +42,7 @@ static int panic_on_timeout;
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*/
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*/
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atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
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atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
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EXPORT_SYMBOL(nmi_active);
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EXPORT_SYMBOL(nmi_active);
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static int nmi_init_done;
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static unsigned int nmi_hz = HZ;
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static unsigned int nmi_hz = HZ;
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static DEFINE_PER_CPU(short, wd_enabled);
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static DEFINE_PER_CPU(short, wd_enabled);
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static int endflag __initdata;
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static int endflag __initdata;
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@ -153,6 +153,8 @@ static void report_broken_nmi(int cpu, int *prev_nmi_count)
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void stop_nmi_watchdog(void *unused)
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void stop_nmi_watchdog(void *unused)
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{
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{
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if (!__this_cpu_read(wd_enabled))
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return;
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pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable);
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pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable);
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__this_cpu_write(wd_enabled, 0);
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__this_cpu_write(wd_enabled, 0);
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atomic_dec(&nmi_active);
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atomic_dec(&nmi_active);
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@ -207,6 +209,9 @@ error:
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void start_nmi_watchdog(void *unused)
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void start_nmi_watchdog(void *unused)
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{
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{
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if (__this_cpu_read(wd_enabled))
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return;
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__this_cpu_write(wd_enabled, 1);
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__this_cpu_write(wd_enabled, 1);
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atomic_inc(&nmi_active);
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atomic_inc(&nmi_active);
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@ -259,6 +264,8 @@ int __init nmi_init(void)
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}
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}
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}
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}
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nmi_init_done = 1;
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return err;
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return err;
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}
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}
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@ -270,3 +277,38 @@ static int __init setup_nmi_watchdog(char *str)
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return 0;
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return 0;
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}
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}
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__setup("nmi_watchdog=", setup_nmi_watchdog);
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__setup("nmi_watchdog=", setup_nmi_watchdog);
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/*
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* sparc specific NMI watchdog enable function.
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* Enables watchdog if it is not enabled already.
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*/
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int watchdog_nmi_enable(unsigned int cpu)
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{
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if (atomic_read(&nmi_active) == -1) {
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pr_warn("NMI watchdog cannot be enabled or disabled\n");
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return -1;
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}
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/*
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* watchdog thread could start even before nmi_init is called.
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* Just Return in that case. Let nmi_init finish the init
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* process first.
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*/
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if (!nmi_init_done)
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return 0;
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smp_call_function_single(cpu, start_nmi_watchdog, NULL, 1);
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return 0;
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}
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/*
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* sparc specific NMI watchdog disable function.
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* Disables watchdog if it is not disabled already.
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*/
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void watchdog_nmi_disable(unsigned int cpu)
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{
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if (atomic_read(&nmi_active) == -1)
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pr_warn_once("NMI watchdog cannot be enabled or disabled\n");
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else
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smp_call_function_single(cpu, stop_nmi_watchdog, NULL, 1);
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}
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