/* * linux/kernel/time/timecounter.c * * based on code that migrated away from * linux/kernel/time/clocksource.c * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include #include void timecounter_init(struct timecounter *tc, const struct cyclecounter *cc, u64 start_tstamp) { tc->cc = cc; tc->cycle_last = cc->read(cc); tc->nsec = start_tstamp; tc->mask = (1ULL << cc->shift) - 1; tc->frac = 0; } EXPORT_SYMBOL_GPL(timecounter_init); /** * timecounter_read_delta - get nanoseconds since last call of this function * @tc: Pointer to time counter * * When the underlying cycle counter runs over, this will be handled * correctly as long as it does not run over more than once between * calls. * * The first call to this function for a new time counter initializes * the time tracking and returns an undefined result. */ static u64 timecounter_read_delta(struct timecounter *tc) { u64 cycle_now, cycle_delta; u64 ns_offset; /* read cycle counter: */ cycle_now = tc->cc->read(tc->cc); /* calculate the delta since the last timecounter_read_delta(): */ cycle_delta = (cycle_now - tc->cycle_last) & tc->cc->mask; /* convert to nanoseconds: */ ns_offset = cyclecounter_cyc2ns(tc->cc, cycle_delta, tc->mask, &tc->frac); /* update time stamp of timecounter_read_delta() call: */ tc->cycle_last = cycle_now; return ns_offset; } u64 timecounter_read(struct timecounter *tc) { u64 nsec; /* increment time by nanoseconds since last call */ nsec = timecounter_read_delta(tc); nsec += tc->nsec; tc->nsec = nsec; return nsec; } EXPORT_SYMBOL_GPL(timecounter_read); /* * This is like cyclecounter_cyc2ns(), but it is used for computing a * time previous to the time stored in the cycle counter. */ static u64 cc_cyc2ns_backwards(const struct cyclecounter *cc, u64 cycles, u64 mask, u64 frac) { u64 ns = (u64) cycles; ns = ((ns * cc->mult) - frac) >> cc->shift; return ns; } u64 timecounter_cyc2time(struct timecounter *tc, u64 cycle_tstamp) { u64 delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask; u64 nsec = tc->nsec, frac = tc->frac; /* * Instead of always treating cycle_tstamp as more recent * than tc->cycle_last, detect when it is too far in the * future and treat it as old time stamp instead. */ if (delta > tc->cc->mask / 2) { delta = (tc->cycle_last - cycle_tstamp) & tc->cc->mask; nsec -= cc_cyc2ns_backwards(tc->cc, delta, tc->mask, frac); } else { nsec += cyclecounter_cyc2ns(tc->cc, delta, tc->mask, &frac); } return nsec; } EXPORT_SYMBOL_GPL(timecounter_cyc2time); d=d7df2443cd5f67fc6ee7c05a88e4996e8177f91b'>usx2y/usbusx2y.h
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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2017-02-03 17:10:28 +1100
committerMichael Ellerman <mpe@ellerman.id.au>2017-02-08 23:36:29 +1100
commitd7df2443cd5f67fc6ee7c05a88e4996e8177f91b (patch)
tree098a7c0ca4fceb8a65cb1f693c9d71990388933d /sound/usb/usx2y/usbusx2y.h
parenta0615a16f7d0ceb5804d295203c302d496d8ee91 (diff)
powerpc/mm: Fix spurrious segfaults on radix with autonuma
When autonuma (Automatic NUMA balancing) marks a PTE inaccessible it clears all the protection bits but leave the PTE valid. With the Radix MMU, an attempt at executing from such a PTE will take a fault with bit 35 of SRR1 set "SRR1_ISI_N_OR_G". It is thus incorrect to treat all such faults as errors. We should pass them to handle_mm_fault() for autonuma to deal with. The case of pages that are really not executable is handled by the existing test for VM_EXEC further down. That leaves us with catching the kernel attempts at executing user pages. We can catch that earlier, even before we do find_vma. It is never valid on powerpc for the kernel to take an exec fault to begin with. So fold that test with the existing test for the kernel faulting on kernel addresses to bail out early. Fixes: 1d18ad026844 ("powerpc/mm: Detect instruction fetch denied and report") Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'sound/usb/usx2y/usbusx2y.h')