Граф коммитов

142 Коммитов

Автор SHA1 Сообщение Дата
Thomas Gleixner 2f7a3f8e87 x86/tsc: Remove unused tsc_pre_init() hook
No more users. Remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@suse.de>
2015-11-19 11:03:13 +01:00
Adrian Hunter b9511cd761 perf/x86: Fix time_shift in perf_event_mmap_page
Commit:

  b20112edea ("perf/x86: Improve accuracy of perf/sched clock")

allowed the time_shift value in perf_event_mmap_page to be as much
as 32.  Unfortunately the documented algorithms for using time_shift
have it shifting an integer, whereas to work correctly with the value
32, the type must be u64.

In the case of perf tools, Intel PT decodes correctly but the timestamps
that are output (for example by perf script) have lost 32-bits of
granularity so they look like they are not changing at all.

Fix by limiting the shift to 31 and adjusting the multiplier accordingly.

Also update the documentation of perf_event_mmap_page so that new code
based on it will be more future-proof.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: b20112edea ("perf/x86: Improve accuracy of perf/sched clock")
Link: http://lkml.kernel.org/r/1445001845-13688-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-20 10:30:52 +02:00
Ingo Molnar 02386c356a Merge branch 'perf/urgent' into perf/core, to pick up fixes before applying new changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18 09:24:01 +02:00
Linus Torvalds 42dc2a3048 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
 - misc fixes all around the map
 - block non-root vm86(old) if mmap_min_addr != 0
 - two small debuggability improvements
 - removal of obsolete paravirt op

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/platform: Fix Geode LX timekeeping in the generic x86 build
  x86/apic: Serialize LVTT and TSC_DEADLINE writes
  x86/ioapic: Force affinity setting in setup_ioapic_dest()
  x86/paravirt: Remove the unused pv_time_ops::get_tsc_khz method
  x86/ldt: Fix small LDT allocation for Xen
  x86/vm86: Fix the misleading CONFIG_VM86 Kconfig help text
  x86/cpu: Print family/model/stepping in hex
  x86/vm86: Block non-root vm86(old) if mmap_min_addr != 0
  x86/alternatives: Make optimize_nops() interrupt safe and synced
  x86/mm/srat: Print non-volatile flag in SRAT
  x86/cpufeatures: Enable cpuid for Intel SHA extensions
2015-09-17 11:01:34 -07:00
David Woodhouse 03da3ff1cf x86/platform: Fix Geode LX timekeeping in the generic x86 build
In 2007, commit 07190a08ee ("Mark TSC on GeodeLX reliable")
bypassed verification of the TSC on Geode LX. However, this code
(now in the check_system_tsc_reliable() function in
arch/x86/kernel/tsc.c) was only present if CONFIG_MGEODE_LX was
set.

OpenWRT has recently started building its generic Geode target
for Geode GX, not LX, to include support for additional
platforms. This broke the timekeeping on LX-based devices,
because the TSC wasn't marked as reliable:
https://dev.openwrt.org/ticket/20531

By adding a runtime check on is_geode_lx(), we can also include
the fix if CONFIG_MGEODEGX1 or CONFIG_X86_GENERIC are set, thus
fixing the problem.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: Andres Salomon <dilinger@queued.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marcelo Tosatti <marcelo@kvack.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1442409003.131189.87.camel@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-16 16:00:12 +02:00
Adrian Hunter b20112edea perf/x86: Improve accuracy of perf/sched clock
When TSC is stable perf/sched clock is based on it.
However the conversion from cycles to nanoseconds
is not as accurate as it could be.  Because
CYC2NS_SCALE_FACTOR is 10, the accuracy is +/- 1/2048

The change is to calculate the maximum shift that
results in a multiplier that is still a 32-bit number.
For example all frequencies over 1 GHz will have
a shift of 32, making the accuracy of the conversion
+/- 1/(2^33).  That is achieved by using the
'clocks_calc_mult_shift()' function.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1440147918-22250-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13 11:27:20 +02:00
Linus Torvalds ca520cab25 Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking and atomic updates from Ingo Molnar:
 "Main changes in this cycle are:

   - Extend atomic primitives with coherent logic op primitives
     (atomic_{or,and,xor}()) and deprecate the old partial APIs
     (atomic_{set,clear}_mask())

     The old ops were incoherent with incompatible signatures across
     architectures and with incomplete support.  Now every architecture
     supports the primitives consistently (by Peter Zijlstra)

   - Generic support for 'relaxed atomics':

       - _acquire/release/relaxed() flavours of xchg(), cmpxchg() and {add,sub}_return()
       - atomic_read_acquire()
       - atomic_set_release()

     This came out of porting qwrlock code to arm64 (by Will Deacon)

   - Clean up the fragile static_key APIs that were causing repeat bugs,
     by introducing a new one:

       DEFINE_STATIC_KEY_TRUE(name);
       DEFINE_STATIC_KEY_FALSE(name);

     which define a key of different types with an initial true/false
     value.

     Then allow:

       static_branch_likely()
       static_branch_unlikely()

     to take a key of either type and emit the right instruction for the
     case.  To be able to know the 'type' of the static key we encode it
     in the jump entry (by Peter Zijlstra)

   - Static key self-tests (by Jason Baron)

   - qrwlock optimizations (by Waiman Long)

   - small futex enhancements (by Davidlohr Bueso)

   - ... and misc other changes"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (63 commits)
  jump_label/x86: Work around asm build bug on older/backported GCCs
  locking, ARM, atomics: Define our SMP atomics in terms of _relaxed() operations
  locking, include/llist: Use linux/atomic.h instead of asm/cmpxchg.h
  locking/qrwlock: Make use of _{acquire|release|relaxed}() atomics
  locking/qrwlock: Implement queue_write_unlock() using smp_store_release()
  locking/lockref: Remove homebrew cmpxchg64_relaxed() macro definition
  locking, asm-generic: Add _{relaxed|acquire|release}() variants for 'atomic_long_t'
  locking, asm-generic: Rework atomic-long.h to avoid bulk code duplication
  locking/atomics: Add _{acquire|release|relaxed}() variants of some atomic operations
  locking, compiler.h: Cast away attributes in the WRITE_ONCE() magic
  locking/static_keys: Make verify_keys() static
  jump label, locking/static_keys: Update docs
  locking/static_keys: Provide a selftest
  jump_label: Provide a self-test
  s390/uaccess, locking/static_keys: employ static_branch_likely()
  x86, tsc, locking/static_keys: Employ static_branch_likely()
  locking/static_keys: Add selftest
  locking/static_keys: Add a new static_key interface
  locking/static_keys: Rework update logic
  locking/static_keys: Add static_key_{en,dis}able() helpers
  ...
2015-09-03 15:46:07 -07:00
Linus Torvalds 5778077d03 Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm changes from Ingo Molnar:
 "The biggest changes in this cycle were:

   - Revamp, simplify (and in some cases fix) Time Stamp Counter (TSC)
     primitives.  (Andy Lutomirski)

   - Add new, comprehensible entry and exit handlers written in C.
     (Andy Lutomirski)

   - vm86 mode cleanups and fixes.  (Brian Gerst)

   - 32-bit compat code cleanups.  (Brian Gerst)

  The amount of simplification in low level assembly code is already
  palpable:

     arch/x86/entry/entry_32.S                          | 130 +----
     arch/x86/entry/entry_64.S                          | 197 ++-----

  but more simplifications are planned.

  There's also the usual laudry mix of low level changes - see the
  changelog for details"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (83 commits)
  x86/asm: Drop repeated macro of X86_EFLAGS_AC definition
  x86/asm/msr: Make wrmsrl() a function
  x86/asm/delay: Introduce an MWAITX-based delay with a configurable timer
  x86/asm: Add MONITORX/MWAITX instruction support
  x86/traps: Weaken context tracking entry assertions
  x86/asm/tsc: Add rdtscll() merge helper
  selftests/x86: Add syscall_nt selftest
  selftests/x86: Disable sigreturn_64
  x86/vdso: Emit a GNU hash
  x86/entry: Remove do_notify_resume(), syscall_trace_leave(), and their TIF masks
  x86/entry/32: Migrate to C exit path
  x86/entry/32: Remove 32-bit syscall audit optimizations
  x86/vm86: Rename vm86->v86flags and v86mask
  x86/vm86: Rename vm86->vm86_info to user_vm86
  x86/vm86: Clean up vm86.h includes
  x86/vm86: Move the vm86 IRQ definitions to vm86.h
  x86/vm86: Use the normal pt_regs area for vm86
  x86/vm86: Eliminate 'struct kernel_vm86_struct'
  x86/vm86: Move fields from 'struct kernel_vm86_struct' to 'struct vm86'
  x86/vm86: Move vm86 fields out of 'thread_struct'
  ...
2015-09-01 08:40:25 -07:00
Andi Kleen a94cab2376 perf/x86: Add a native_perf_sched_clock_from_tsc()
PEBSv3 has a raw TSC time stamp in its memory buffer that
later needs to to be converted to perf_clock.

Add a native_sched_clock_from_tsc() that works the same
as native_sched_clock(), but starts with an already given
TSC value.

Paravirt is ignored, it will just get the native clock.
But there isn't a para virtualized PEBS anyway.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1431285767-27027-2-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-04 10:16:55 +02:00
Peter Zijlstra 3bbfafb77a x86, tsc, locking/static_keys: Employ static_branch_likely()
Because of the static_key restrictions we had to take an unconditional
jump for the most likely case, causing $I bloat.

Rewrite to use the new primitives.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-03 11:34:16 +02:00
Ingo Molnar 5b929bd11d Merge branch 'x86/urgent' into x86/asm, before applying dependent patches
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-31 10:23:35 +02:00
Andy Lutomirski 27c634054a x86/asm/tsc: Use rdtsc_ordered() in read_tsc() instead of get_cycles()
There are two logical changes here.  First, this removes a check
for cpu_has_tsc.  That check is unnecessary, as we don't
register the TSC as a clocksource on systems that have no TSC.

Second, it adds a barrier, thus preventing observable
non-monotonicity.

I suspect that the missing barrier was never a problem in
practice because system calls themselves were heavy enough
barriers to prevent user code from observing time warps due to
speculation. (Without the corresponding barrier in the vDSO,
however, non-monotonicity is easy to detect.)

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm ML <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/c6ff621a053127a65b70f175443578db7a0711be.1434501121.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-06 15:23:29 +02:00
Andy Lutomirski 4ea1636b04 x86/asm/tsc: Rename native_read_tsc() to rdtsc()
Now that there is no paravirt TSC, the "native" is
inappropriate. The function does RDTSC, so give it the obvious
name: rdtsc().

Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm ML <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/fd43e16281991f096c1e4d21574d9e1402c62d39.1434501121.git.luto@kernel.org
[ Ported it to v4.2-rc1. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-06 15:23:28 +02:00
Andy Lutomirski 87be28aaf1 x86/asm/tsc: Replace rdtscll() with native_read_tsc()
Now that the ->read_tsc() paravirt hook is gone, rdtscll() is
just a wrapper around native_read_tsc(). Unwrap it.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm ML <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/d2449ae62c1b1fb90195bcfb19ef4a35883a04dc.1434501121.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-06 15:23:26 +02:00
Andy Lutomirski c6e5ca35c4 x86/asm/tsc: Inline native_read_tsc() and remove __native_read_tsc()
In the following commit:

  cdc7957d19 ("x86: move native_read_tsc() offline")

... native_read_tsc() was moved out of line, presumably for some
now-obsolete vDSO-related reason. Undo it.

The entire rdtsc, shl, or sequence is only 11 bytes, and calls
via rdtscl() and similar helpers were already inlined.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm ML <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/d05ffe2aaf8468ca475ebc00efad7b2fa174af19.1434501121.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-06 15:23:25 +02:00
Adrian Hunter 5aac644a99 x86/tsc: Let high latency PIT fail fast in quick_pit_calibrate()
If it takes longer than 12us to read the PIT counter lsb/msb,
then the error margin will never fall below 500ppm within 50ms,
and Fast TSC calibration will always fail.

This patch detects when that will happen and fails fast. Note
the failure message is not printed in that case because:
1. it will always happen on that class of hardware
2. the absence of the message is more informative than its
presence

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/556EB717.9070607@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-06 09:41:00 +02:00
Alexandre Demers 520452172e x86/tsc: Change Fast TSC calibration failed from error to info
Many users see this message when booting without knowning that it is
of no importance and that TSC calibration may have succeeded by
another way.

As explained by Paul Bolle in
http://lkml.kernel.org/r/1348488259.1436.22.camel@x61.thuisdomein

  "Fast TSC calibration failed" should not be considered as an error
  since other calibration methods are being tried afterward. At most,
  those send a warning if they fail (not an error). So let's change
  the message from error to warning.

[ tglx: Make if pr_info. It's really not important at all ]

Fixes: c767a54ba0 x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level>
Signed-off-by: Alexandre Demers <alexandre.f.demers@gmail.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1418106470-6906-1-git-send-email-alexandre.f.demers@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-01-23 10:53:52 +01:00
Andy Lutomirski b47dcbdc51 x86, apic: Handle a bad TSC more gracefully
If the TSC is unusable or disabled, then this patch fixes:

 - Confusion while trying to clear old APIC interrupts.
 - Division by zero and incorrect programming of the TSC deadline
   timer.

This fixes boot if the CPU has a TSC deadline timer but a missing or
broken TSC.  The failure to boot can be observed with qemu using
-cpu qemu64,-tsc,+tsc-deadline

This also happens to me in nested KVM for unknown reasons.
With this patch, I can boot cleanly (although without a TSC).

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Bandan Das <bsd@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/e2fa274e498c33988efac0ba8b7e3120f7f92d78.1413393027.git.luto@amacapital.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-10-22 21:31:46 +02:00
Linus Torvalds e7fda6c4c3 Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer and time updates from Thomas Gleixner:
 "A rather large update of timers, timekeeping & co

   - Core timekeeping code is year-2038 safe now for 32bit machines.
     Now we just need to fix all in kernel users and the gazillion of
     user space interfaces which rely on timespec/timeval :)

   - Better cache layout for the timekeeping internal data structures.

   - Proper nanosecond based interfaces for in kernel users.

   - Tree wide cleanup of code which wants nanoseconds but does hoops
     and loops to convert back and forth from timespecs.  Some of it
     definitely belongs into the ugly code museum.

   - Consolidation of the timekeeping interface zoo.

   - A fast NMI safe accessor to clock monotonic for tracing.  This is a
     long standing request to support correlated user/kernel space
     traces.  With proper NTP frequency correction it's also suitable
     for correlation of traces accross separate machines.

   - Checkpoint/restart support for timerfd.

   - A few NOHZ[_FULL] improvements in the [hr]timer code.

   - Code move from kernel to kernel/time of all time* related code.

   - New clocksource/event drivers from the ARM universe.  I'm really
     impressed that despite an architected timer in the newer chips SoC
     manufacturers insist on inventing new and differently broken SoC
     specific timers.

[ Ed. "Impressed"? I don't think that word means what you think it means ]

   - Another round of code move from arch to drivers.  Looks like most
     of the legacy mess in ARM regarding timers is sorted out except for
     a few obnoxious strongholds.

   - The usual updates and fixlets all over the place"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
  timekeeping: Fixup typo in update_vsyscall_old definition
  clocksource: document some basic timekeeping concepts
  timekeeping: Use cached ntp_tick_length when accumulating error
  timekeeping: Rework frequency adjustments to work better w/ nohz
  timekeeping: Minor fixup for timespec64->timespec assignment
  ftrace: Provide trace clocks monotonic
  timekeeping: Provide fast and NMI safe access to CLOCK_MONOTONIC
  seqcount: Add raw_write_seqcount_latch()
  seqcount: Provide raw_read_seqcount()
  timekeeping: Use tk_read_base as argument for timekeeping_get_ns()
  timekeeping: Create struct tk_read_base and use it in struct timekeeper
  timekeeping: Restructure the timekeeper some more
  clocksource: Get rid of cycle_last
  clocksource: Move cycle_last validation to core code
  clocksource: Make delta calculation a function
  wireless: ath9k: Get rid of timespec conversions
  drm: vmwgfx: Use nsec based interfaces
  drm: i915: Use nsec based interfaces
  timekeeping: Provide ktime_get_raw()
  hangcheck-timer: Use ktime_get_ns()
  ...
2014-08-05 17:46:42 -07:00
Linus Torvalds 19d402c1e7 Merge branches 'x86-build-for-linus', 'x86-cleanups-for-linus' and 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 build/cleanup/debug updates from Ingo Molnar:
 "Robustify the build process with a quirk to avoid GCC reordering
  related bugs.

  Two code cleanups.

  Simplify entry_64.S CFI annotations, by Jan Beulich"

* 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, build: Change code16gcc.h from a C header to an assembly header

* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Simplify __HAVE_ARCH_CMPXCHG tests
  x86/tsc: Get rid of custom DIV_ROUND() macro

* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/debug: Drop several unnecessary CFI annotations
2014-08-04 16:56:16 -07:00
Thomas Gleixner 09ec54429c clocksource: Move cycle_last validation to core code
The only user of the cycle_last validation is the x86 TSC. In order to
provide NMI safe accessor functions for clock monotonic and
monotonic_raw we need to do that in the core.

We can't do the TSC specific

    if (now < cycle_last)
       	    now = cycle_last;

for the other wrapping around clocksources, but TSC has
CLOCKSOURCE_MASK(64) which actually does not mask out anything so if
now is less than cycle_last the subtraction will give a negative
result. So we can check for that in clocksource_delta() and return 0
for that case.

Implement and enable it for x86

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2014-07-23 15:01:51 -07:00
Peter Zijlstra 3896c329df x86, tsc: Fix cpufreq lockup
Mauro reported that his AMD X2 using the powernow-k8 cpufreq driver
locked up when doing cpu hotplug.

Because we called set_cyc2ns_scale() from the time_cpufreq_notifier()
unconditionally, it gets called multiple times for each freq change,
instead of only the once, when the tsc_khz value actually changes.

Because it gets called more than once, we run out of cyc2ns data slots
and stall, waiting for a free one, but because we're half way offline,
there's no consumers to free slots.

By placing the call inside the condition that actually changes tsc_khz
we avoid superfluous calls and avoid the problem.

Reported-by: Mauro <registosites@hotmail.com>
Tested-by: Mauro <registosites@hotmail.com>
Fixes: 20d1c86a57 ("sched/clock, x86: Rewrite cyc2ns() to avoid the need to disable IRQs")
Cc: <stable@vger.kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Bin Gao <bin.gao@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-02 08:33:47 +02:00
Michal Nazarewicz 891715793f x86/tsc: Get rid of custom DIV_ROUND() macro
When invoced for positive values, DIV_ROUND macro defined in
arch/x86/kernel/tsc.c behaves exactly like DIV_ROUND_CLOSEST from
include/linux/kernel.h file, so remove the custom macro in favour
of the shared one.

[ hpa: changed line breaks ]

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Link: http://lkml.kernel.org/r/1403143116-21755-1-git-send-email-mina86@mina86.com
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2014-06-19 22:04:50 -07:00
Linus Torvalds c6f21243ce Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 vdso changes from Peter Anvin:
 "This is the revamp of the 32-bit vdso and the associated cleanups.

  This adds timekeeping support to the 32-bit vdso that we already have
  in the 64-bit vdso.  Although 32-bit x86 is legacy, it is likely to
  remain in the embedded space for a very long time to come.

  This removes the traditional COMPAT_VDSO support; the configuration
  variable is reused for simply removing the 32-bit vdso, which will
  produce correct results but obviously suffer a performance penalty.
  Only one beta version of glibc was affected, but that version was
  unfortunately included in one OpenSUSE release.

  This is not the end of the vdso cleanups.  Stefani and Andy have
  agreed to continue work for the next kernel cycle; in fact Andy has
  already produced another set of cleanups that came too late for this
  cycle.

  An incidental, but arguably important, change is that this ensures
  that unused space in the VVAR page is properly zeroed.  It wasn't
  before, and would contain whatever garbage was left in memory by BIOS
  or the bootloader.  Since the VVAR page is accessible to user space
  this had the potential of information leaks"

* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  x86, vdso: Fix the symbol versions on the 32-bit vDSO
  x86, vdso, build: Don't rebuild 32-bit vdsos on every make
  x86, vdso: Actually discard the .discard sections
  x86, vdso: Fix size of get_unmapped_area()
  x86, vdso: Finish removing VDSO32_PRELINK
  x86, vdso: Move more vdso definitions into vdso.h
  x86: Load the 32-bit vdso in place, just like the 64-bit vdsos
  x86, vdso32: handle 32 bit vDSO larger one page
  x86, vdso32: Disable stack protector, adjust optimizations
  x86, vdso: Zero-pad the VVAR page
  x86, vdso: Add 32 bit VDSO time support for 64 bit kernel
  x86, vdso: Add 32 bit VDSO time support for 32 bit kernel
  x86, vdso: Patch alternatives in the 32-bit VDSO
  x86, vdso: Introduce VVAR marco for vdso32
  x86, vdso: Cleanup __vdso_gettimeofday()
  x86, vdso: Replace VVAR(vsyscall_gtod_data) by gtod macro
  x86, vdso: __vdso_clock_gettime() cleanup
  x86, vdso: Revamp vclock_gettime.c
  mm: Add new func _install_special_mapping() to mmap.c
  x86, vdso: Make vsyscall_gtod_data handling x86 generic
  ...
2014-04-02 12:26:43 -07:00
Viresh Kumar 0b443ead71 cpufreq: remove unused notifier: CPUFREQ_{SUSPENDCHANGE|RESUMECHANGE}
Two cpufreq notifiers CPUFREQ_RESUMECHANGE and CPUFREQ_SUSPENDCHANGE have
not been used for some time, so remove them to clean up code a bit.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
[rjw: Changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-19 14:10:24 +01:00
Stefani Seibold d2312e3379 x86, vdso: Make vsyscall_gtod_data handling x86 generic
This patch move the vsyscall_gtod_data handling out of vsyscall_64.c
into an additonal file vsyscall_gtod.c to make the functionality
available for x86 32 bit kernel.

It also adds a new vsyscall_32.c which setup the VVAR page.

Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/1395094933-14252-2-git-send-email-stefani@seibold.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-03-18 12:51:52 -07:00
Thomas Gleixner 5f0e030930 x86, tsc: Fallback to normal calibration if fast MSR calibration fails
If we cannot calibrate TSC via MSR based calibration
try_msr_calibrate_tsc() stores zero to fast_calibrate and returns that
to the caller. This value gets then propagated further to clockevents
code resulting division by zero oops like the one below:

 divide error: 0000 [#1] PREEMPT SMP
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W    3.13.0+ #47
 task: ffff880075508000 ti: ffff880075506000 task.ti: ffff880075506000
 RIP: 0010:[<ffffffff810aec14>]  [<ffffffff810aec14>] clockevents_config.part.3+0x24/0xa0
 RSP: 0000:ffff880075507e58  EFLAGS: 00010246
 RAX: ffffffffffffffff RBX: ffff880079c0cd80 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffffffffff
 RBP: ffff880075507e70 R08: 0000000000000001 R09: 00000000000000be
 R10: 00000000000000bd R11: 0000000000000003 R12: 000000000000b008
 R13: 0000000000000008 R14: 000000000000b010 R15: 0000000000000000
 FS:  0000000000000000(0000) GS:ffff880079c00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: ffff880079fff000 CR3: 0000000001c0b000 CR4: 00000000001006f0
 Stack:
  ffff880079c0cd80 000000000000b008 0000000000000008 ffff880075507e88
  ffffffff810aecb0 ffff880079c0cd80 ffff880075507e98 ffffffff81030168
  ffff880075507ed8 ffffffff81d1104f 00000000000000c3 0000000000000000
 Call Trace:
  [<ffffffff810aecb0>] clockevents_config_and_register+0x20/0x30
  [<ffffffff81030168>] setup_APIC_timer+0xc8/0xd0
  [<ffffffff81d1104f>] setup_boot_APIC_clock+0x4cc/0x4d8
  [<ffffffff81d0f5de>] native_smp_prepare_cpus+0x3dd/0x3f0
  [<ffffffff81d02ee9>] kernel_init_freeable+0xc3/0x205
  [<ffffffff8177c910>] ? rest_init+0x90/0x90
  [<ffffffff8177c91e>] kernel_init+0xe/0x120
  [<ffffffff8178deec>] ret_from_fork+0x7c/0xb0
  [<ffffffff8177c910>] ? rest_init+0x90/0x90

Prevent this from happening by:
 1) Modifying try_msr_calibrate_tsc() to return calibration value or zero
    if it fails.
 2) Check this return value in native_calibrate_tsc() and in case of zero
    fallback to use normal non-MSR based calibration.

[mw: Added subject and changelog]

Reported-and-tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Bin Gao <bin.gao@linux.intel.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1392810750-18660-1-git-send-email-mika.westerberg@linux.intel.com
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-02-19 17:12:24 +01:00
Steven Rostedt 569d6557ab x86: Use preempt_disable_notrace() in cycles_2_ns()
When debug preempt is enabled, preempt_disable() can be traced by
function and function graph tracing.

There's a place in the function graph tracer that calls trace_clock()
which eventually calls cycles_2_ns() outside of the recursion
protection. When cycles_2_ns() calls preempt_disable() it gets traced
and the graph tracer will go into a recursive loop causing a crash or
worse, a triple fault.

Simple fix is to use preempt_disable_notrace() in cycles_2_ns, which
makes sense because the preempt_disable() tracing may use that code
too, and it tracing it, even with recursion protection is rather
pointless.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140204141315.2a968a72@gandalf.local.home
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-02-09 13:09:08 +01:00
Peter Zijlstra 5e3c1afd45 sched/x86/tsc: Initialize multiplier to 0
Since we keep the clock value linearly continuous on frequency change,
make sure the initial multiplier is 0, such that our initial value is 0.
Without this we compute the initial value at whatever the TSC has
managed to reach since power-on.

Reported-and-Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Fixes: 20d1c86a57 ("sched/clock, x86: Rewrite cyc2ns() to avoid the need to disable IRQs")
Cc: lenb@kernel.org
Cc: rjw@rjwysocki.net
Cc: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Cc: rui.zhang@intel.com
Cc: jacob.jun.pan@linux.intel.com
Cc: Mike Galbraith <bitbucket@online.de>
Cc: hpa@zytor.com
Cc: paulmck@linux.vnet.ibm.com
Cc: John Stultz <john.stultz@linaro.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: dyoung@redhat.com
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140123094804.GP30183@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-23 14:48:36 +01:00
Linus Torvalds 74e8ee8262 Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull Intel SoC changes from Ingo Molnar:
 "Improved Intel SoC platform support"

* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, tsc, apic: Unbreak static (MSR) calibration when CONFIG_X86_LOCAL_APIC=n
  x86, tsc: Add static (MSR) TSC calibration on Intel Atom SoCs
  arch: x86: New MailBox support driver for Intel SOC's
2014-01-20 12:09:31 -08:00
Bin Gao 7da7c15613 x86, tsc: Add static (MSR) TSC calibration on Intel Atom SoCs
On SoCs that have the calibration MSRs available, either there is no
PIT, HPET or PMTIMER to calibrate against, or the PIT/HPET/PMTIMER is
driven from the same clock as the TSC, so calibration is redundant and
just slows down the boot.

TSC rate is caculated by this formula:
<maximum core-clock to bus-clock ratio> * <maximum resolved frequency>
The ratio and the resolved frequency ID can be obtained from MSR.
See Intel 64 and IA-32 System Programming Guid section 16.12 and 30.11.5
for details.

Signed-off-by: Bin Gao <bin.gao@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/n/tip-rgm7xmg7k6qnjlw3ynkcjsmh@git.kernel.org
2014-01-15 22:28:48 -08:00
Peter Zijlstra 10b033d434 sched/clock, x86: Avoid a runtime condition in native_sched_clock()
Use a static_key to avoid touching tsc_disabled and a runtime
condition in native_sched_clock() -- less cachelines touched is always
better.

                        MAINLINE   PRE       POST

    sched_clock_stable: 1          1         1
    (cold) sched_clock: 329841     215295    213039
    (cold) local_clock: 301773     220773    216084
    (warm) sched_clock: 38375      25659     25231
    (warm) local_clock: 100371     27242     27601
    (warm) rdtsc:       27340      24208     24203
    sched_clock_stable: 0          0         0
    (cold) sched_clock: 382634     237019    240055
    (cold) local_clock: 396890     294819    299942
    (warm) sched_clock: 38194      25609     25276
    (warm) local_clock: 143452     71232     73232
    (warm) rdtsc:       27345      24243     24244

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-hrz87bo37qke25bty6pnfy4b@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-13 15:13:17 +01:00
Peter Zijlstra 35af99e646 sched/clock, x86: Use a static_key for sched_clock_stable
In order to avoid the runtime condition and variable load turn
sched_clock_stable into a static_key.

Also provide a shorter implementation of local_clock() and
cpu_clock(int) when sched_clock_stable==1.

                        MAINLINE   PRE       POST

    sched_clock_stable: 1          1         1
    (cold) sched_clock: 329841     221876    215295
    (cold) local_clock: 301773     234692    220773
    (warm) sched_clock: 38375      25602     25659
    (warm) local_clock: 100371     33265     27242
    (warm) rdtsc:       27340      24214     24208
    sched_clock_stable: 0          0         0
    (cold) sched_clock: 382634     235941    237019
    (cold) local_clock: 396890     297017    294819
    (warm) sched_clock: 38194      25233     25609
    (warm) local_clock: 143452     71234     71232
    (warm) rdtsc:       27345      24245     24243

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-eummbdechzz37mwmpags1gjr@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-13 15:13:13 +01:00
Peter Zijlstra 20d1c86a57 sched/clock, x86: Rewrite cyc2ns() to avoid the need to disable IRQs
Use a ring-buffer like multi-version object structure which allows
always having a coherent object; we use this to avoid having to
disable IRQs while reading sched_clock() and avoids a problem when
getting an NMI while changing the cyc2ns data.

                        MAINLINE   PRE        POST

    sched_clock_stable: 1          1          1
    (cold) sched_clock: 329841     331312     257223
    (cold) local_clock: 301773     310296     309889
    (warm) sched_clock: 38375      38247      25280
    (warm) local_clock: 100371     102713     85268
    (warm) rdtsc:       27340      27289      24247
    sched_clock_stable: 0          0          0
    (cold) sched_clock: 382634     372706     301224
    (cold) local_clock: 396890     399275     399870
    (warm) sched_clock: 38194      38124      25630
    (warm) local_clock: 143452     148698     129629
    (warm) rdtsc:       27345      27365      24307

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-s567in1e5ekq2nlyhn8f987r@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-13 15:13:06 +01:00
Peter Zijlstra 57c67da274 sched/clock, x86: Move some cyc2ns() code around
There are no __cycles_2_ns() users outside of arch/x86/kernel/tsc.c,
so move it there.

There are no cycles_2_ns() users.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-01lslnavfgo3kmbo4532zlcj@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-01-13 13:47:39 +01:00
Adrian Hunter c73deb6aec perf/x86: Add ability to calculate TSC from perf sample timestamps
For modern CPUs, perf clock is directly related to TSC.  TSC
can be calculated from perf clock and vice versa using a simple
calculation.  Two of the three componenets of that calculation
are already exported in struct perf_event_mmap_page.  This patch
exports the third.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1372425741-1676-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-07-23 12:17:45 +02:00
Paul Gortmaker 148f9bb877 x86: delete __cpuinit usage from all x86 files
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit  -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings.  In any case, they are temporary and harmless.

This removes all the arch/x86 uses of the __cpuinit macros from
all C files.  x86 only had the one __CPUINIT used in assembly files,
and it wasn't paired off with a .previous or a __FINIT, so we can
delete it directly w/o any corresponding additional change there.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2013-07-14 19:36:56 -04:00
Feng Tang 82f9c080b2 x86: tsc: Add support for new S3_NONSTOP feature
Add support for new S3_NONSTOP feature

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-15 16:51:18 -07:00
Thomas Gleixner 90889a635a Merge branch 'fortglx/3.9/time' of git://git.linaro.org/people/jstultz/linux into timers/core
Trivial conflict in arch/x86/Kconfig

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-02-04 11:03:03 +01:00
Bernd Faust 2353b47bff Round the calculated scale factor in set_cyc2ns_scale()
During some experiments with an external clock (in a FPGA), we saw that
the TSC clock drifted approx. 2.5ms per second.

This drift was caused by the current way of calculating the scale.
In our case cpu_khz had a value of 3292725. This resulted in a scale
value of 310. But when doing the calculation by hand it shows that the
actual value is 310.9886188491, so a value of 311 would be more precise.

With this change the value is rounded.

Signed-off-by: Bernd Faust <berndfaust@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-01-15 18:16:07 -08:00
David Vrabel ce37f40033 x86: Allow tracing of functions in arch/x86/kernel/rtc.c
Move native_read_tsc() to tsc.c to allow profiling to be
re-enabled for rtc.c.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1349698050-6560-1-git-send-email-david.vrabel@citrix.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-10-24 13:14:22 +02:00
Joe Perches c767a54ba0 x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level>
Use a more current logging style:

 - Bare printks should have a KERN_<LEVEL> for consistency's sake
 - Add pr_fmt where appropriate
 - Neaten some macro definitions
 - Convert some Ok output to OK
 - Use "%s: ", __func__ in pr_fmt for summit
 - Convert some printks to pr_<level>

Message output is not identical in all cases.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: levinsasha928@gmail.com
Link: http://lkml.kernel.org/r/1337655007.24226.10.camel@joe2Laptop
[ merged two similar patches, tidied up the changelog ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-06-06 09:17:22 +02:00
Linus Torvalds bcd550745f Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer core updates from Thomas Gleixner.

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ia64: vsyscall: Add missing paranthesis
  alarmtimer: Don't call rtc_timer_init() when CONFIG_RTC_CLASS=n
  x86: vdso: Put declaration before code
  x86-64: Inline vdso clock_gettime helpers
  x86-64: Simplify and optimize vdso clock_gettime monotonic variants
  kernel-time: fix s/then/than/ spelling errors
  time: remove no_sync_cmos_clock
  time: Avoid scary backtraces when warning of > 11% adj
  alarmtimer: Make sure we initialize the rtctimer
  ntp: Fix leap-second hrtimer livelock
  x86, tsc: Skip refined tsc calibration on systems with reliable TSC
  rtc: Provide flag for rtc devices that don't support UIE
  ia64: vsyscall: Use seqcount instead of seqlock
  x86: vdso: Use seqcount instead of seqlock
  x86: vdso: Remove bogus locking in update_vsyscall_tz()
  time: Remove bogus comments
  time: Fix change_clocksource locking
  time: x86: Fix race switching from vsyscall to non-vsyscall clock
2012-03-29 14:16:48 -07:00
Linus Torvalds 2e7580b0e7 Merge branch 'kvm-updates/3.4' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Avi Kivity:
 "Changes include timekeeping improvements, support for assigning host
  PCI devices that share interrupt lines, s390 user-controlled guests, a
  large ppc update, and random fixes."

This is with the sign-off's fixed, hopefully next merge window we won't
have rebased commits.

* 'kvm-updates/3.4' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (130 commits)
  KVM: Convert intx_mask_lock to spin lock
  KVM: x86: fix kvm_write_tsc() TSC matching thinko
  x86: kvmclock: abstract save/restore sched_clock_state
  KVM: nVMX: Fix erroneous exception bitmap check
  KVM: Ignore the writes to MSR_K7_HWCR(3)
  KVM: MMU: make use of ->root_level in reset_rsvds_bits_mask
  KVM: PMU: add proper support for fixed counter 2
  KVM: PMU: Fix raw event check
  KVM: PMU: warn when pin control is set in eventsel msr
  KVM: VMX: Fix delayed load of shared MSRs
  KVM: use correct tlbs dirty type in cmpxchg
  KVM: Allow host IRQ sharing for assigned PCI 2.3 devices
  KVM: Ensure all vcpus are consistent with in-kernel irqchip settings
  KVM: x86 emulator: Allow PM/VM86 switch during task switch
  KVM: SVM: Fix CPL updates
  KVM: x86 emulator: VM86 segments must have DPL 3
  KVM: x86 emulator: Fix task switch privilege checks
  arch/powerpc/kvm/book3s_hv.c: included linux/sched.h twice
  KVM: x86 emulator: correctly mask pmc index bits in RDPMC instruction emulation
  KVM: mmu_notifier: Flush TLBs before releasing mmu_lock
  ...
2012-03-28 14:35:31 -07:00
Marcelo Tosatti b74f05d61b x86: kvmclock: abstract save/restore sched_clock_state
Upon resume from hibernation, CPU 0's hvclock area contains the old
values for system_time and tsc_timestamp. It is necessary for the
hypervisor to update these values with uptodate ones before the CPU uses
them.

Abstract TSC's save/restore sched_clock_state functions and use
restore_state to write to KVM_SYSTEM_TIME MSR, forcing an update.

Also move restore_sched_clock_state before __restore_processor_state,
since the later calls CONFIG_LOCK_STAT's lockstat_clock (also for TSC).
Thanks to Igor Mammedov for tracking it down.

Fixes suspend-to-disk with kvmclock.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-20 12:37:45 +02:00
Alok Kataria 57779dc2b3 x86, tsc: Skip refined tsc calibration on systems with reliable TSC
While running the latest Linux as guest under VMware in highly
over-committed situations, we have seen cases when the refined TSC
algorithm fails to get a valid tsc_start value in
tsc_refine_calibration_work from multiple attempts. As a result the
kernel keeps on scheduling the tsc_irqwork task for later. Subsequently
after several attempts when it gets a valid start value it goes through
the refined calibration and either bails out or uses the new results.
Given that the kernel originally read the TSC frequency from the
platform, which is the best it can get, I don't think there is much
value in refining it.

So  for systems which get the TSC frequency from the platform we
should skip the refined tsc algorithm.

We can use the TSC_RELIABLE cpu cap flag to detect this, right now it is
set only on VMware and for Moorestown Penwell both of which have there
own TSC calibration methods.

Signed-off-by: Alok N Kataria <akataria@vmware.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Dirk Brandewie <dirk.brandewie@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: stable@kernel.org
[jstultz: Reworked to simply not schedule the refining work,
rather then scheduling the work and bombing out later]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-03-15 18:23:11 -07:00
Salman Qazi 9993bc635d sched/x86: Fix overflow in cyc2ns_offset
When a machine boots up, the TSC generally gets reset.  However,
when kexec is used to boot into a kernel, the TSC value would be
carried over from the previous kernel.  The computation of
cycns_offset in set_cyc2ns_scale is prone to an overflow, if the
machine has been up more than 208 days prior to the kexec.  The
overflow happens when we multiply *scale, even though there is
enough room to store the final answer.

We fix this issue by decomposing tsc_now into the quotient and
remainder of division by CYC2NS_SCALE_FACTOR and then performing
the multiplication separately on the two components.

Refactor code to share the calculation with the previous
fix in __cycles_2_ns().

Signed-off-by: Salman Qazi <sqazi@google.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Turner <pjt@google.com>
Cc: john stultz <johnstul@us.ibm.com>
Link: http://lkml.kernel.org/r/20120310004027.19291.88460.stgit@dungbeetle.mtv.corp.google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-13 16:27:51 +01:00
H. Peter Anvin 282f445a77 Merge remote-tracking branch 'linus/master' into x86/urgent 2012-01-19 12:56:50 -08:00
Linus Torvalds 68f30fbee1 x86, tsc: Fix SMI induced variation in quick_pit_calibrate()
pit_expect_msb() returns success wrongly in the below SMI scenario:

a. pit_verify_msb() has not yet seen the MSB transition.

b. we are close to the MSB transition though and got a SMI immediately after
   returning from pit_verify_msb() which didn't see the MSB transition. PIT MSB
   transition has happened somewhere during SMI execution.

c. returned from SMI and we noted down the 'tsc', saw the pit MSB change now and
   exited the loop to calculate 'deltatsc'. Instead of noting the TSC at the MSB
   transition, we are way off because of the SMI.  And as the SMI happened
   between the pit_verify_msb() and before the 'tsc' is recorded in the
   for loop, 'delattsc' (d1/d2 in quick_pit_calibrate()) will be small and
   quick_pit_calibrate() will not notice this error.

Depending on whether SMI disturbance happens while computing d1 or d2, we will
see the TSC calibrated value smaller or bigger than the expected value. As a
result, in a cluster we were seeing a variation of approximately +/- 20MHz in
the calibrated values, resulting in NTP failures.

  [ As far as the SMI source is concerned, this is a periodic SMI that gets
    disabled after ACPI is enabled by the OS. But the TSC calibration happens
    before the ACPI is enabled. ]

To address this, change pit_expect_msb() so that

 - the 'tsc' is the TSC in between the two reads that read the MSB
change from the PIT (same as before)

 - the 'delta' is the difference in TSC from *before* the MSB changed
to *after* the MSB changed.

Now the delta is twice as big as before (it covers four PIT accesses,
roughly 4us) and quick_pit_calibrate() will loop a bit longer to get
the calibrated value with in the 500ppm precision. As the delta (d1/d2)
covers four PIT accesses, actual calibrated result might be closer to
250ppm precision.

As the loop now takes longer to stabilize, double MAX_QUICK_PIT_MS to 50.

SMI disturbance will showup as much larger delta's and the loop will take
longer than usual for the result to be with in the accepted precision. Or will
fallback to slow PIT calibration if it takes more than 50msec.

Also while we are at this, remove the calibration correction that aims to
get the result to the middle of the error bars. We really don't know which
direction to correct into, so remove it.

Reported-and-tested-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1326843337.5291.4.camel@sbsiddha-mobl2
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-01-17 15:46:51 -08:00
Linus Torvalds 9fc5c3e323 Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/intel config: Fix the APB_TIMER selection
  x86/mrst: Add additional debug prints for pb_keys
  x86/intel config: Revamp configuration to allow for Moorestown and Medfield
  x86/intel/scu/ipc: Match the changes in the x86 configuration
  x86/apb: Fix configuration constraints
  x86: Fix INTEL_MID silly
  x86/Kconfig: Cyclone-timer depends on x86-summit
  x86: Reduce clock calibration time during slave cpu startup
  x86/config: Revamp configuration for MID devices
  x86/sfi: Kill the IRQ as id hack
2012-01-11 19:13:40 -08:00