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Viewing changes to arch/x86/vdso/vclock_gettime.c

  • Committer: Bazaar Package Importer
  • Author(s): John Rigby, Upstream Fixes, Andy Green, John Rigby
  • Date: 2011-04-14 12:16:06 UTC
  • Revision ID: james.westby@ubuntu.com-20110414121606-b77podkyqgr2oix7
Tags: 2.6.38-1002.3
https://launchpad.net/bugs/745737
https://launchpad.net/bugs/747639
https://launchpad.net/bugs/752900
https://launchpad.net/bugs/745737
https://launchpad.net/bugs/732842
https://launchpad.net/bugs/732912
[ Upstream Fixes ]

* MUSB: shutdown: Make sure block is awake before doing shutdown
  - LP: #745737
* Fixed gpio polarity of gpio USB-phy reset.
  - LP: #747639

[ Andy Green ]

* LINARO: SAUCE: disable CONFIG_OMAP_RESET_CLOCKS
  - LP: #752900

[ John Rigby ]

* Rebase to new upstreams:
  Linux v2.6.38.1
  linaro-linux-2.6.38-upstream-29Mar2011
  Ubuntu-2.6.38-7.35
* SAUCE: OMAP4: clock: wait for module to become accessible on
  a clk enable
  - LP: #745737
* Rebase to new upstreams:
  Linux v2.6.38.2
  linaro-linux-2.6.38-upstream-5Apr2011
  Ubuntu-2.6.38-8.41
  - LP: #732842
* Update configs for device tree, dvfs and lttng
* LINARO: add building of dtb's
* LINARO: SAUCE: Disable lowest operating freqs on omap34xx
  - LP: #732912

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Lines of Context:
arch/x86/vdso/vclock_gettime.c
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#include <asm/hpet.h>
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#include <asm/unistd.h>
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#include <asm/io.h>
 
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#include <asm/trace-clock.h>
 
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#include <asm/timer.h>
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#include "vextern.h"
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#define gtod vdso_vsyscall_gtod_data
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        return 0;
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}
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/*
 
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 * If the TSC is synchronized across all CPUs, read the current TSC
 
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 * and export its value in the nsec field of the timespec
 
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 */
 
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notrace static noinline int do_trace_clock(struct timespec *ts)
 
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{
 
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        unsigned long seq;
 
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        union lttng_timespec *lts = (union lttng_timespec *) ts;
 
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        do {
 
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                seq = read_seqbegin(&gtod->lock);
 
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                if (unlikely(!gtod->trace_clock_is_sync))
 
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                        return vdso_fallback_gettime(CLOCK_TRACE, ts);
 
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                /*
 
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                 * We don't protect the rdtsc with the rdtsc_barrier because
 
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                 * we can't obtain with tracing that level of precision.
 
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                 * The operation of recording an event is not atomic therefore
 
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                 * the small chance of imprecision doesn't justify the overhead
 
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                 * of a barrier.
 
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                 */
 
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                /*
 
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                 * TODO: check that vget_cycles(), using paravirt ops, will
 
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                 * match the TSC read by get_cycles() at the kernel level.
 
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                 */
 
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                lts->lttng_ts = vget_cycles();
 
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        } while (unlikely(read_seqretry(&gtod->lock, seq)));
 
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        return 0;
 
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}
 
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/*
 
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 * Returns the cpu_khz, it needs to be a syscall because we can't access
 
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 * this value from userspace and it will only be called at the beginning
 
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 * of the tracing session
 
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 */
 
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notrace static noinline int do_trace_clock_freq(struct timespec *ts)
 
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{
 
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        return vdso_fallback_gettime(CLOCK_TRACE_FREQ, ts);
 
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}
 
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notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
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{
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        if (likely(gtod->sysctl_enabled))
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                        return do_realtime_coarse(ts);
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                case CLOCK_MONOTONIC_COARSE:
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                        return do_monotonic_coarse(ts);
 
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                case CLOCK_TRACE:
 
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                        return do_trace_clock(ts);
 
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                case CLOCK_TRACE_FREQ:
 
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                        return do_trace_clock_freq(ts);
 
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                default:
 
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                        return -EINVAL;
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                }
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        return vdso_fallback_gettime(clock, ts);
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}