linux/arch/arm/include/asm
Russell King 112f38a4a3 ARM: sched_clock: provide common infrastructure for sched_clock()
Provide common sched_clock() infrastructure for platforms to use to
create a 64-bit ns based sched_clock() implementation from a counter
running at a non-variable clock rate.

This implementation is based upon maintaining an epoch for the counter
and an epoch for the nanosecond time.  When we desire a sched_clock()
time, we calculate the number of counter ticks since the last epoch
update, convert this to nanoseconds and add to the epoch nanoseconds.

We regularly refresh these epochs within the counter wrap interval.
We perform a similar calculation as above, and store the new epochs.

We read and write the epochs in such a way that sched_clock() can easily
(and locklessly) detect when an update is in progress, and repeat the
loading of these constants when they're known not to be stable.  The
one caveat is that sched_clock() is not called in the middle of an
update.  We achieve that by disabling IRQs.

Finally, if the clock rate is known at compile time, the counter to ns
conversion factors can be specified, allowing sched_clock() to be tightly
optimized.  We ensure that these factors are correct by providing an
initialization function which performs a run-time check.

Acked-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Tested-by: Mikael Pettersson <mikpe@it.uu.se>
Tested-by: Eric Miao <eric.y.miao@gmail.com>
Tested-by: Olof Johansson <olof@lixom.net>
Tested-by: Jamie Iles <jamie@jamieiles.com>
Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-12-22 22:44:43 +00:00
..
hardware ARM: pxa: fix the missing definition of IRQ_BOARD_END 2010-11-03 23:11:17 +08:00
mach arm: remove machine_desc.io_pg_offst and .phys_io 2010-10-20 00:27:46 -04:00
Kbuild archs: replace unifdef-y with header-y 2010-08-14 22:26:51 +02:00
a.out-core.h
a.out.h headers_check fix: arm, a.out.h 2009-02-01 11:01:22 +05:30
asm-offsets.h kbuild: move asm-offsets.h to include/generated 2009-12-12 13:08:14 +01:00
assembler.h ARM: 6489/1: thumb2: fix incorrect optimisation in usracc 2010-11-21 22:05:58 +00:00
atomic.h ARM: 6212/1: atomic ops: add memory constraints to inline asm 2010-07-09 11:29:35 +01:00
auxvec.h
bitops.h ARM: boolean bit testing 2009-10-11 16:25:06 +01:00
bitsperlong.h asm-generic: introduce asm/bitsperlong.h 2009-06-11 21:02:14 +02:00
bug.h [ARM] 5211/2: fix a couple warnings from BUG() usage 2008-09-01 12:06:27 +01:00
bugs.h
byteorder.h byteorder: make swab.h include asm/swab.h like a regular header 2009-01-14 19:56:50 -08:00
cache.h dma-mapping: rename ARCH_KMALLOC_MINALIGN to ARCH_DMA_MINALIGN 2010-08-11 08:59:21 -07:00
cacheflush.h Merge branches 'at91', 'dcache', 'ftrace', 'hwbpt', 'misc', 'mmci', 's3c', 'st-ux' and 'unwind' into devel 2010-10-18 22:34:25 +01:00
cachetype.h ARM: 6385/1: setup: detect aliasing I-cache when D-cache is non-aliasing 2010-10-04 20:57:09 +01:00
checksum.h
clkdev.h ARM: 6001/1: removing compilation warning comming from clkdev.h 2010-03-29 17:33:32 +01:00
cpu-multi32.h
cpu-single.h
cpu.h ARM: 5872/1: ARM: include needed linux/cpu.h in asm/cpu.h 2010-01-10 13:03:52 +00:00
cputime.h
cputype.h Merge branch 'devel' of git://git.kernel.org/pub/scm/linux/kernel/git/ycmiao/pxa-linux-2.6 into devel 2009-09-21 16:02:30 +01:00
current.h
delay.h
device.h Driver Core: Add platform device arch data V3 2009-07-22 00:28:38 +02:00
div64.h [ARM] 5320/1: fix assembly constraints in implementation of do_div() 2008-10-23 12:53:32 +01:00
dma-mapping.h Revert "[ARM] pxa: remove now unnecessary dma_needs_bounce()" 2010-09-08 12:28:39 +01:00
dma.h ARM: 5870/1: arch/arm: Fix build failure for defconfigs without CONFIG_ISA_DMA_API set 2010-01-10 00:08:03 +00:00
domain.h
ecard.h
elf.h ARM: add a vma entry for the user accessible vector page 2010-10-01 22:35:19 -04:00
emergency-restart.h
entry-macro-vic2.S ARM: Add common entry code for system with two VICs 2010-01-15 17:10:14 +09:00
errno.h
fb.h
fcntl.h
fiq.h
fixmap.h [ARM] fixmap support 2009-03-15 21:01:20 -04:00
flat.h flat: fix data sections alignment 2009-05-29 08:40:02 -07:00
floppy.h [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
fpstate.h
ftrace.h ARM: 6319/1: ftrace: add Thumb-2 support to dynamic ftrace 2010-09-02 15:28:43 +01:00
futex.h ARM: fix build error in arch/arm/kernel/process.c 2010-04-21 08:45:21 +01:00
glue.h ARM: 5727/1: Pass IFSR register to do_PrefetchAbort() 2009-10-02 22:34:32 +01:00
gpio.h [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
hardirq.h ARM: 6138/1: Add support for 10 hardirq bits 2010-05-20 23:51:07 +01:00
highmem.h mm: stack based kmap_atomic() 2010-10-26 16:52:08 -07:00
hw_breakpoint.h ARM: 6357/1: hw-breakpoint: add new ptrace requests for hw-breakpoint interaction 2010-09-08 10:05:00 +01:00
hw_irq.h arm: Use ARCH_IRQ_INIT_FLAGS 2010-10-16 22:57:38 +02:00
hwcap.h ARM: 6207/1: Replace CONFIG_HAS_TLS_REG with HWCAP_TLS and check for it on V6 2010-07-09 14:41:35 +01:00
ide.h
io.h ARM: implement CONFIG_STRICT_DEVMEM by disabling access to RAM via /dev/mem 2010-10-01 22:31:34 -04:00
ioctl.h
ioctls.h ioctl: Use asm-generic/ioctls.h on arm (enables termiox) 2010-10-22 10:19:59 -07:00
ipcbuf.h
irq.h ARM: 6197/2: preliminary support for sparse IRQ 2010-07-09 14:41:33 +01:00
irq_regs.h
irqflags.h Fix IRQ flag handling naming 2010-10-07 14:08:55 +01:00
kdebug.h
kexec.h ARM: 6117/1: kdump: implement crash_setup_regs() 2010-07-09 15:00:51 +01:00
kgdb.h kgdb,arm: fix register dump 2010-10-29 13:14:40 -05:00
kmap_types.h kdb: core for kgdb back end (2 of 2) 2010-05-20 21:04:21 -05:00
kprobes.h [ARM] 5206/1: remove kprobe_trap_handler() hack 2008-09-01 12:06:26 +01:00
leds.h
limits.h
linkage.h
local.h
local64.h arch: Implement local64_t 2010-06-09 11:12:36 +02:00
localtimer.h [ARM] smp: allow re-use of realview localtimer TWD support 2009-05-17 19:16:41 +01:00
locks.h
mach-types.h arm: move mach-types to include/generated 2009-12-12 13:08:14 +01:00
mc146818rtc.h [ARM] Convert asm/io.h to linux/io.h 2008-09-06 12:10:45 +01:00
memblock.h ARM: fix memblock breakage 2010-10-27 21:41:39 +01:00
memory.h Merge branch 'misc' into devel 2010-07-31 14:20:02 +01:00
mman.h arm: add arch_mmap_check(), get rid of sys_arm_mremap() 2009-12-11 06:34:09 -05:00
mmu.h ARM: 6490/1: MM: bugfix: initialize spinlock for init_mm.context 2010-11-23 22:46:12 +00:00
mmu_context.h ARM: add a vma entry for the user accessible vector page 2010-10-01 22:35:19 -04:00
module.h ARM: 6340/1: module - additional unwind tables for exit/devexit sections 2010-09-02 15:31:35 +01:00
msgbuf.h
mtd-xip.h [ARM] move asm/xip.h's mach/hardware.h include to mach/xip.h 2008-12-14 13:22:51 +00:00
mutex.h
nwflash.h
outercache.h arm: Disable outer (L2) cache in kexec 2010-10-26 11:39:56 +05:30
page-nommu.h nommu: Remove the memory_start/end variables from ARM page-nommu.h 2009-07-24 12:35:01 +01:00
page.h ARM: Pass VMA to copy_user_highpage() implementations 2009-10-05 15:17:45 +01:00
param.h
parport.h
pci.h ARM: 6058/1: Add support for PCI domains 2010-04-22 21:38:11 +01:00
percpu.h
perf_event.h irq_work: Add generic hardirq context callbacks 2010-10-18 19:58:50 +02:00
pgalloc.h ARM: implement highpte 2009-08-17 20:02:06 +01:00
pgtable-hwdef.h
pgtable-nommu.h ARM: 5988/1: pgprot_dmacoherent() for non-mmu builds 2010-03-13 10:48:22 +00:00
pgtable.h ARM: improve compiler's ability to optimize page tables 2010-11-21 14:42:47 +00:00
pmu.h ARM: 6064/1: pmu: register IRQs at runtime 2010-05-17 11:53:57 +01:00
poll.h
posix_types.h
proc-fns.h ARM: Kill CONFIG_CPU_32 2009-12-18 16:07:53 +00:00
processor.h ARM: 6357/1: hw-breakpoint: add new ptrace requests for hw-breakpoint interaction 2010-09-08 10:05:00 +01:00
procinfo.h
ptrace.h ARM: 6357/1: hw-breakpoint: add new ptrace requests for hw-breakpoint interaction 2010-09-08 10:05:00 +01:00
resource.h
scatterlist.h asm-generic: remove ARCH_HAS_SG_CHAIN in scatterlist.h 2010-05-27 09:12:54 -07:00
sched_clock.h ARM: sched_clock: provide common infrastructure for sched_clock() 2010-12-22 22:44:43 +00:00
seccomp.h ARM: SECCOMP support 2010-10-01 22:32:18 -04:00
sections.h
segment.h
sembuf.h
serial.h
setup.h ARM: Remove DISCONTIGMEM support 2010-07-16 10:57:35 +01:00
shmbuf.h
shmparam.h
sigcontext.h
siginfo.h
signal.h asm-generic: rename termios.h, signal.h and mman.h 2009-06-11 21:01:52 +02:00
sizes.h [ARM] Kirkwood: create a mapping for the Security Accelerator SRAM 2009-06-08 13:05:02 -04:00
smp.h ARM: rename mach_cpu_disable() to platform_cpu_disable() 2010-05-15 15:03:51 +01:00
smp_mpidr.h ARM: Allow SMP kernels to boot on UP systems 2010-10-04 20:23:36 +01:00
smp_plat.h Merge branches 'at91', 'dcache', 'ftrace', 'hwbpt', 'misc', 'mmci', 's3c', 'st-ux' and 'unwind' into devel 2010-10-18 22:34:25 +01:00
smp_scu.h [ARM] smp: separate SCU support code from realview 2009-05-17 19:00:37 +01:00
smp_twd.h ARM: 6125/1: ARM TWD: move TWD registers to common header 2010-05-12 11:18:13 +01:00
socket.h net: Generalize socket rx gap / receive queue overflow cmsg 2009-10-12 13:26:31 -07:00
sockios.h
sparsemem.h [ARM] mm: enable sparsemem on clps7500 and RiscPC 2008-10-01 17:24:04 +01:00
spinlock.h ARM: 5897/1: spinlock: don't use deprecated barriers on ARMv7 2010-02-15 21:39:50 +00:00
spinlock_types.h locking: Convert raw_rwlock to arch_rwlock 2009-12-14 23:55:32 +01:00
stackprotector.h ARM: initial stack protector (-fstack-protector) support 2010-06-14 21:31:00 -04:00
stacktrace.h [ARM] 5382/1: unwind: Reorganise the stacktrace support 2009-02-12 13:21:17 +00:00
stat.h
statfs.h ARM: Use <asm-generic/statfs.h> 2008-09-04 09:46:11 +01:00
string.h [ARM] remove memzero() 2008-11-27 12:37:59 +00:00
swab.h ARM: 5772/1: Use REV and REV16 for byte swapping on ARMv6+ 2009-10-25 15:59:53 +00:00
system.h ARM: place C irq handlers in IRQ_ENTRY for ftrace 2010-11-19 21:43:26 +05:30
tcm.h ARM: 5580/2: ARM TCM (Tightly-Coupled Memory) support v3 2009-09-15 22:11:05 +01:00
termbits.h tty: Add EXTPROC support for LINEMODE 2010-08-10 13:47:39 -07:00
termios.h
therm.h
thread_info.h ARM: SECCOMP support 2010-10-01 22:32:18 -04:00
thread_notify.h ARM: Convert VFP/Crunch/XscaleCP thread_release() to exit_thread() 2009-12-18 14:53:41 +00:00
timex.h [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/mach 2008-08-07 09:55:48 +01:00
tlb.h mm: Pass virtual address to [__]p{te,ud,md}_free_tlb() 2009-07-27 12:10:38 -07:00
tlbflush.h Merge branches 'at91', 'dcache', 'ftrace', 'hwbpt', 'misc', 'mmci', 's3c', 'st-ux' and 'unwind' into devel 2010-10-18 22:34:25 +01:00
tls.h ARM: 6207/1: Replace CONFIG_HAS_TLS_REG with HWCAP_TLS and check for it on V6 2010-07-09 14:41:35 +01:00
topology.h
traps.h ARM: place C irq handlers in IRQ_ENTRY for ftrace 2010-11-19 21:43:26 +05:30
types.h
uaccess.h ARM: fix build error in arch/arm/kernel/process.c 2010-04-21 08:45:21 +01:00
ucontext.h ARM: 6051/1: VFP: preserve the HW context when calling signal handlers 2010-04-14 11:11:30 +01:00
unaligned.h
unified.h Fix "W" macro in arch/arm/include/asm/unified.h 2009-09-18 23:30:11 +01:00
unistd.h ARM: 6343/1: wire up fanotify and prlimit64 syscalls on ARM 2010-09-01 10:06:08 +01:00
unwind.h [ARM] 5383/2: unwind: Add core support for ARM stack unwinding 2009-02-19 11:26:24 +00:00
user.h ARM: 6051/1: VFP: preserve the HW context when calling signal handlers 2010-04-14 11:11:30 +01:00
vfp.h
vfpmacros.h ARM: 6203/1: Make VFPv3 usable on ARMv6 2010-07-09 14:41:34 +01:00
vga.h [ARM] Convert asm/io.h to linux/io.h 2008-09-06 12:10:45 +01:00
xor.h