linux.git/arch/tile/kernel/time.c, branch v4.11

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:27+00:00

We are going to split  out of , which
will have to be picked up from other headers and .c files.

Create a trivial placeholder  file that just
maps to  to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

2016-12-18T01:05:49+00:00

Pull arch/tile updates from Chris Metcalf:
 "Another grab-bag of miscellaneous changes"

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  tile: use __ro_after_init instead of tile-specific __write_once
  tile: migrate exception table users off module.h and onto extable.h
  tile: remove #pragma unroll from finv_buffer_remote()
  tile-module: Rename jump labels in module_alloc()
  tile-module: Use kmalloc_array() in module_alloc()
  tile/pci_gx: fix spelling mistake: "delievered" -> "delivered"

tile: use __ro_after_init instead of tile-specific __write_once

2016-12-16T20:32:29+00:00

The semantics of the old tile __write_once are the same as the
newer generic __ro_after_init, so rename them all and get rid
of the tile-specific version.

This does not enable actual support for __ro_after_init,
which had been dropped from the tile architecture before the
initial upstreaming was done, since we had at that time switched
to using 16MB huge pages to map the kernel.

Signed-off-by: Chris Metcalf

tile: avoid using clocksource_cyc2ns with absolute cycle count

2016-11-23T20:28:54+00:00

For large values of "mult" and long uptimes, the intermediate
result of "cycles * mult" can overflow 64 bits.  For example,
the tile platform calls clocksource_cyc2ns with a 1.2 GHz clock;
we have mult = 853, and after 208.5 days, we overflow 64 bits.

Since clocksource_cyc2ns() is intended to be used for relative
cycle counts, not absolute cycle counts, performance is more
importance than accepting a wider range of cycle values.  So,
just use mult_frac() directly in tile's sched_clock().

Commit 4cecf6d401a0 ("sched, x86: Avoid unnecessary overflow
in sched_clock") by Salman Qazi results in essentially the same
generated code for x86 as this change does for tile.  In fact,
a follow-on change by Salman introduced mult_frac() and switched
to using it, so the C code was largely identical at that point too.

Peter Zijlstra then added mul_u64_u32_shr() and switched x86
to use it.  This is, in principle, better; by optimizing the
64x64->64 multiplies to be 32x32->64 multiplies we can potentially
save some time.  However, the compiler piplines the 64x64->64
multiplies pretty well, and the conditional branch in the generic
mul_u64_u32_shr() causes some bubbles in execution, with the
result that it's pretty much a wash.  If tilegx provided its own
implementation of mul_u64_u32_shr() without the conditional branch,
we could potentially save 3 cycles, but that seems like small gain
for a fair amount of additional build scaffolding; no other platform
currently provides a mul_u64_u32_shr() override, and tile doesn't
currently have an  header to put the override in.

Additionally, gcc currently has an optimization bug that prevents
it from recognizing the opportunity to use a 32x32->64 multiply,
and so the result would be no better than the existing mult_frac()
until such time as the compiler is fixed.

For now, just using mult_frac() seems like the right answer.

Cc: stable@kernel.org [v3.4+]
Signed-off-by: Chris Metcalf

tile/time: Migrate to new 'set-state' interface

2015-07-30T16:32:15+00:00

Migrate tile driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Cc: Chris Metcalf 
Signed-off-by: Viresh Kumar 
Signed-off-by: Chris Metcalf

time: Rename timekeeper::tkr to timekeeper::tkr_mono

2015-03-27T08:45:06+00:00

In preparation of adding another tkr field, rename this one to
tkr_mono. Also rename tk_read_base::base_mono to tk_read_base::base,
since the structure is not specific to CLOCK_MONOTONIC and the mono
name got added to the tk_read_base instance.

Lots of trivial churn.

Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: John Stultz 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20150319093400.344679419@infradead.org
Signed-off-by: Ingo Molnar

tile: Use the more common pr_warn instead of pr_warning

2014-11-11T20:51:42+00:00

And other message logging neatening.

Other miscellanea:

o coalesce formats
o realign arguments
o standardize a couple of macros
o use __func__ instead of embedding the function name

Signed-off-by: Joe Perches 
Signed-off-by: Chris Metcalf

Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2014-10-15T05:48:18+00:00

Pull percpu consistent-ops changes from Tejun Heo:
"Way back, before the current percpu allocator was implemented, static
and dynamic percpu memory areas were allocated and handled separately
and had their own accessors. The distinction has been gone for many
years now; however, the now duplicate two sets of accessors remained
with the pointer based ones - this_cpu_*() - evolving various other
operations over time. During the process, we also accumulated other
inconsistent operations.

This pull request contains Christoph's patches to clean up the
duplicate accessor situation. __get_cpu_var() uses are replaced with
with this_cpu_ptr() and __this_cpu_ptr() with raw_cpu_ptr().

Unfortunately, the former sometimes is tricky thanks to C being a bit
messy with the distinction between lvalues and pointers, which led to
a rather ugly solution for cpumask_var_t involving the introduction of
this_cpu_cpumask_var_ptr().

This converts most of the uses but not all. Christoph will follow up
with the remaining conversions in this merge window and hopefully
remove the obsolete accessors"

* 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (38 commits)
irqchip: Properly fetch the per cpu offset
percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t -fix
ia64: sn_nodepda cannot be assigned to after this_cpu conversion. Use __this_cpu_write.
percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t
Revert "powerpc: Replace __get_cpu_var uses"
percpu: Remove __this_cpu_ptr
clocksource: Replace __this_cpu_ptr with raw_cpu_ptr
sparc: Replace __get_cpu_var uses
avr32: Replace __get_cpu_var with __this_cpu_write
blackfin: Replace __get_cpu_var uses
tile: Use this_cpu_ptr() for hardware counters
tile: Replace __get_cpu_var uses
powerpc: Replace __get_cpu_var uses
alpha: Replace __get_cpu_var
ia64: Replace __get_cpu_var uses
s390: cio driver &__get_cpu_var replacements
s390: Replace __get_cpu_var uses
mips: Replace __get_cpu_var uses
MIPS: Replace __get_cpu_var uses in FPU emulator.
arm: Replace __this_cpu_ptr with raw_cpu_ptr
...

tile: add clock_gettime support to vDSO

2014-10-02T17:56:07+00:00

This change adds support for clock_gettime with CLOCK_REALTIME
and CLOCK_MONOTONIC using vDSO.  It also updates the vdso
struct nomenclature used for the clocks to match the x86 code
to keep it easier to update going forward.

We also support the *_COARSE clockid_t, for apps that want speed
but aren't concerned about fine-grained timestamps; this saves
about 20 cycles per call (see http://lwn.net/Articles/342018/).

Signed-off-by: Chris Metcalf 
Acked-by: John Stultz

tile: switch to using seqlocks for the vDSO time code

2014-10-02T14:48:12+00:00

Signed-off-by: Chris Metcalf