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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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ba58d1020a
Power management suspend/resume tracing (ab)uses the RTC to store
suspend/resume information persistently. As a consequence the RTC value is
clobbered when timekeeping is resumed and tries to inject the sleep time.
Commit a4f8f6667f ("timekeeping: Cap array access in timekeeping_debug")
plugged a out of bounds array access in the timekeeping debug code which
was caused by the clobbered RTC value, but we still use the clobbered RTC
value for sleep time injection into kernel timekeeping, which will result
in random adjustments depending on the stored "hash" value.
To prevent this keep track of the RTC clobbering and ignore the invalid RTC
timestamp at resume. If the system resumed successfully clear the flag,
which marks the RTC as unusable, warn the user about the RTC clobber and
recommend to adjust the RTC with 'ntpdate' or 'rdate'.
[jstultz: Fixed up pr_warn formating, and implemented suggestions from Ingo]
[ tglx: Rewrote changelog ]
Originally-from: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Xunlei Pang <xlpang@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/1480372524-15181-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
43 lines
901 B
C
43 lines
901 B
C
#ifndef PM_TRACE_H
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#define PM_TRACE_H
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#include <linux/types.h>
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#ifdef CONFIG_PM_TRACE
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#include <asm/pm-trace.h>
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extern int pm_trace_enabled;
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extern bool pm_trace_rtc_abused;
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static inline bool pm_trace_rtc_valid(void)
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{
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return !pm_trace_rtc_abused;
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}
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static inline int pm_trace_is_enabled(void)
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{
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return pm_trace_enabled;
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}
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struct device;
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extern void set_trace_device(struct device *);
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extern void generate_pm_trace(const void *tracedata, unsigned int user);
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extern int show_trace_dev_match(char *buf, size_t size);
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#define TRACE_DEVICE(dev) do { \
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if (pm_trace_enabled) \
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set_trace_device(dev); \
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} while(0)
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#else
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static inline bool pm_trace_rtc_valid(void) { return true; }
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static inline int pm_trace_is_enabled(void) { return 0; }
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#define TRACE_DEVICE(dev) do { } while (0)
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#define TRACE_RESUME(dev) do { } while (0)
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#define TRACE_SUSPEND(dev) do { } while (0)
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#endif
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#endif
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