From ea417aa8a38bc7db929281d6dc4b671e75f51844 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Wed, 16 Nov 2016 09:48:41 +0100 Subject: [PATCH] s390/debug: make debug event time stamps relative to the boot TOD clock The debug features currently uses absolute TOD time stamps for the debug events. Given that the TOD clock can jump forward and backward due to STP sync checks the order of debug events can get obfuscated. Replace the absolute TOD time stamps with a delta to the IPL time stamp. On a STP sync check the TOD clock correction is added to the IPL time stamp as well to make the deltas unaffected by STP sync check. The readout of the debug feature entries will convert the deltas back to absolute time stamps based on the Unix epoch. Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/timex.h | 8 -------- arch/s390/kernel/debug.c | 13 +++++++------ arch/s390/kernel/time.c | 3 +-- 3 files changed, 8 insertions(+), 16 deletions(-) diff --git a/arch/s390/include/asm/timex.h b/arch/s390/include/asm/timex.h index de82988..354344d 100644 --- a/arch/s390/include/asm/timex.h +++ b/arch/s390/include/asm/timex.h @@ -178,14 +178,6 @@ int get_phys_clock(unsigned long long *clock); void init_cpu_timer(void); unsigned long long monotonic_clock(void); -void tod_to_timeval(__u64 todval, struct timespec64 *xt); - -static inline -void stck_to_timespec64(unsigned long long stck, struct timespec64 *ts) -{ - tod_to_timeval(stck - TOD_UNIX_EPOCH, ts); -} - extern u64 sched_clock_base_cc; /** diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c index 79f8ae9..20a5a42 100644 --- a/arch/s390/kernel/debug.c +++ b/arch/s390/kernel/debug.c @@ -866,7 +866,7 @@ static inline void debug_finish_entry(debug_info_t * id, debug_entry_t* active, int level, int exception) { - active->id.stck = get_tod_clock_fast(); + active->id.stck = get_tod_clock_fast() - sched_clock_base_cc; active->id.fields.cpuid = smp_processor_id(); active->caller = __builtin_return_address(0); active->id.fields.exception = exception; @@ -1455,23 +1455,24 @@ int debug_dflt_header_fn(debug_info_t * id, struct debug_view *view, int area, debug_entry_t * entry, char *out_buf) { - struct timespec64 time_spec; + unsigned long sec, usec; char *except_str; unsigned long caller; int rc = 0; unsigned int level; level = entry->id.fields.level; - stck_to_timespec64(entry->id.stck, &time_spec); + sec = (entry->id.stck >> 12) + (sched_clock_base_cc >> 12); + sec = sec - (TOD_UNIX_EPOCH >> 12); + usec = do_div(sec, USEC_PER_SEC); if (entry->id.fields.exception) except_str = "*"; else except_str = "-"; caller = (unsigned long) entry->caller; - rc += sprintf(out_buf, "%02i %011lld:%06lu %1u %1s %02i %p ", - area, (long long)time_spec.tv_sec, - time_spec.tv_nsec / 1000, level, except_str, + rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %02i %p ", + area, sec, usec, level, except_str, entry->id.fields.cpuid, (void *)caller); return rc; } diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c index eebbd6a..546e513 100644 --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -110,7 +110,7 @@ unsigned long long monotonic_clock(void) } EXPORT_SYMBOL(monotonic_clock); -void tod_to_timeval(__u64 todval, struct timespec64 *xt) +static void tod_to_timeval(__u64 todval, struct timespec64 *xt) { unsigned long long sec; @@ -120,7 +120,6 @@ void tod_to_timeval(__u64 todval, struct timespec64 *xt) todval -= (sec * 1000000) << 12; xt->tv_nsec = ((todval * 1000) >> 12); } -EXPORT_SYMBOL(tod_to_timeval); void clock_comparator_work(void) { -- 2.7.4