Alexander Duyck 1077fa36f2 arch: Add lightweight memory barriers dma_rmb() and dma_wmb() ... There are a number of situations where the mandatory barriers rmb() and wmb() are used to order memory/memory operations in the device drivers and those barriers are much heavier than they actually need to be. For example in the case of PowerPC wmb() calls the heavy-weight sync instruction when for coherent memory operations all that is really needed is an lsync or eieio instruction. This commit adds a coherent only version of the mandatory memory barriers rmb() and wmb(). In most cases this should result in the barrier being the same as the SMP barriers for the SMP case, however in some cases we use a barrier that is somewhere in between rmb() and smp_rmb(). For example on ARM the rmb barriers break down as follows: Barrier Call Explanation --------- -------- ---------------------------------- rmb() dsb() Data synchronization barrier - system dma_rmb() dmb(osh) data memory barrier - outer sharable smp_rmb() dmb(ish) data memory barrier - inner sharable These new barriers are not as safe as the standard rmb() and wmb(). Specifically they do not guarantee ordering between coherent and incoherent memories. The primary use case for these would be to enforce ordering of reads and writes when accessing coherent memory that is shared between the CPU and a device. It may also be noted that there is no dma_mb(). Most architectures don't provide a good mechanism for performing a coherent only full barrier without resorting to the same mechanism used in mb(). As such there isn't much to be gained in trying to define such a function. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Michael Neuling <mikey@neuling.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: David Miller <davem@davemloft.net> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2014-12-11 21:15:06 -05:00
..
ABI	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2014-12-11 14:27:06 -08:00
DocBook	sound updates for 3.19-rc1	2014-12-11 13:20:50 -08:00
EDID	…
PCI	doc: replace "practise" with "practice" in Documentation	2014-06-19 15:28:56 +02:00
RCU	Merge branches 'torture.2014.11.03a', 'cpu.2014.11.03a', 'doc.2014.11.13a', 'fixes.2014.11.13a', 'signal.2014.10.29a' and 'rt.2014.10.29a' into HEAD	2014-11-13 10:39:04 -08:00
accounting	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
acpi	ACPI / GPIO: Document ACPI GPIO mappings API	2014-11-04 21:58:24 +01:00
aoe	…
arm	Allwinner Core Additions for 3.19	2014-11-20 17:23:57 +01:00
arm64	arm64: Emulate CP15 Barrier instructions	2014-11-20 16:34:48 +00:00
auxdisplay	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
backlight	…
blackfin	Documentation: add makefiles for more targets	2014-09-26 11:02:56 +02:00
block	scsi: add new scsi-command flag for tagged commands	2014-11-12 11:19:40 +01:00
blockdev	zram: report maximum used memory	2014-10-09 22:26:02 -04:00
bus-devices	…
cdrom	…
cgroups	mm: embed the memcg pointer directly into struct page	2014-12-10 17:41:09 -08:00
connector	…
console	…
cpu-freq	intel_pstate: Add support for HWP	2014-11-12 00:04:38 +01:00
cpuidle	…
cris	…
crypto	…
development-process	Documentation: remove outdated references to the linux-next wiki	2014-10-28 09:06:11 -04:00
device-mapper	dm cache policy mq: simplify ability to promote sequential IO to the cache	2014-11-10 15:25:30 -05:00
devicetree	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2014-12-11 14:27:06 -08:00
driver-model	PCI changes for the v3.18 merge window:	2014-10-09 15:03:49 -04:00
dvb	[media] get_dvb_firmware: Update firmware of ITEtech IT9135	2014-09-21 17:03:04 -03:00
early-userspace	…
extcon	…
fault-injection	…
fb	…
filesystems	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2014-12-10 16:10:49 -08:00
firmware_class	doc: fix minor typos in firmware_class README	2014-07-17 18:43:40 -07:00
fmc	…
frv	…
gpio	ACPI / GPIO: Document ACPI GPIO mappings API	2014-11-04 21:58:24 +01:00
hid	HID: uhid: update documentation	2014-08-25 03:28:09 -05:00
hwmon	hwmon: (tmp401) Detect TMP435 on all addresses it supports	2014-12-08 06:48:37 -08:00
i2c	i2c: i801: Add Device IDs for Intel Sunrise Point PCH	2014-10-16 09:16:22 +02:00
i2o	…
ia64	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
ide	…
infiniband	IB/mad: add new ioctl to ABI to support new registration options	2014-08-10 20:36:00 -07:00
input	Input: elantech - update the documentation	2014-11-13 17:50:23 -08:00
ioctl	cxl: Add documentation for userspace APIs	2014-10-08 20:16:19 +11:00
isdn	…
ja_JP	…
kbuild	Documentation: kbuild: Improve grammar	2014-08-19 10:02:56 +02:00
kdump	kernel: add panic_on_warn	2014-12-10 17:41:10 -08:00
ko_KR	…
laptops	Documentation: update .gitignore files	2014-09-26 11:02:59 +02:00
leds	…
locking	Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-12-09 19:59:22 -08:00
m68k	…
memory-devices	…
metag	…
mic	Documentation: update include path for mpssd	2014-10-03 15:48:20 +02:00
mips	Documentation: au1xxx-ide.c has moved	2014-08-26 09:35:53 +02:00
misc-devices	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
mmc	…
mn10300	…
mtd	MTD updates for 3.16:	2014-06-11 08:35:34 -07:00
namespaces	…
netlabel	…
networking	Documentation (ixgbe.txt): use a decimal address.	2014-12-09 16:02:32 -05:00
nfc	…
nios2	Documentation: Add documentation for Nios2 architecture	2014-12-08 12:56:06 +08:00
parisc	…
pcmcia	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
phy	…
platform	Documentation: Add list of laptop models supported by the Compal driver	2014-06-10 19:11:06 -04:00
power	Merge branch 'pm-qos'	2014-10-23 23:02:36 +02:00
powerpc	cxl: Add documentation for userspace APIs	2014-10-08 20:16:19 +11:00
pps	…
prctl	Documentation: Restrict TSC test code to x86	2014-10-28 08:46:27 -04:00
pti	…
ptp	ptp: restore the makefile for building the test program.	2014-10-24 16:07:10 -04:00
rapidio	rapidio/tsi721_dma: rework scatter-gather list handling	2014-08-08 15:57:24 -07:00
s390	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial into next	2014-06-04 08:50:34 -07:00
scheduler	Documentation/scheduler/sched-deadline.txt: Add minimal main() appendix	2014-09-16 10:23:45 +02:00
scsi	libsas: remove task_collector mode	2014-11-27 16:40:24 +01:00
security	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security	2014-10-12 10:13:55 -04:00
serial	TTY/Serial driver patches for 3.18-rc1	2014-10-08 06:52:11 -04:00
sh	…
sound	ALSA: hda - Add "eapd" model string for AD1986A codec	2014-12-10 14:00:13 +01:00
spi	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/doc	2014-10-07 21:14:57 -04:00
sysctl	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2014-12-11 14:27:06 -08:00
target	target: Add documentation on the target userspace pass-through driver	2014-10-02 21:35:54 -07:00
thermal	drm/nouveau/doc: update the thermal documentation	2014-06-17 14:50:17 +10:00
timers	Documentation: update .gitignore files	2014-09-26 11:02:59 +02:00
tpm	…
trace	tracing: Add additional marks to signal very large time deltas	2014-12-03 17:10:13 -05:00
usb	USB / PM: Drop CONFIG_PM_RUNTIME from the USB core	2014-12-04 00:51:54 +01:00
vDSO	vdso: don't require 64-bit math in standalone test	2014-10-25 10:53:44 -04:00
video4linux	[media] platform: Make use of media_bus_format enum	2014-11-14 17:54:08 -02:00
virtual	Changes for KVM for arm/arm64 for 3.18	2014-09-27 11:03:33 +02:00
vm	Docs: Document that the sticky bit is understood by hugetlbfs	2014-10-22 14:26:04 -04:00
w1	w1: new w1_ds2406 driver	2014-06-19 17:45:14 -07:00
watchdog	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
wimax	…
x86	x86, mpx: Add documentation on Intel MPX	2014-11-18 00:58:54 +01:00
xtensa	…
zh_CN	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2014-08-06 21:03:53 -07:00
00-INDEX	locking/Documentation: Move locking related docs into Documentation/locking/	2014-08-13 10:32:03 +02:00
BUG-HUNTING	…
Changes	Update old iproute2 and Xen Remus links	2014-12-09 13:38:13 -05:00
CodingStyle	CodingStyle: fix a minor typo	2014-08-26 09:35:54 +02:00
DMA-API-HOWTO.txt	Documentation: correct parameter error for dma_mapping_error	2014-09-26 11:22:29 +02:00
DMA-API.txt	…
DMA-ISA-LPC.txt	…
DMA-attributes.txt	…
HOWTO	Documentation: remove outdated references to the linux-next wiki	2014-10-28 09:06:11 -04:00
IPMI.txt	…
IRQ-affinity.txt	…
IRQ-domain.txt	irqdomain: Introduce new interfaces to support hierarchy irqdomains	2014-11-23 13:01:45 +01:00
IRQ.txt	…
Intel-IOMMU.txt	…
Makefile	Documentation: add makefiles for more targets	2014-09-26 11:02:56 +02:00
ManagementStyle	…
SAK.txt	…
SM501.txt	…
SecurityBugs	…
SubmitChecklist	…
SubmittingDrivers	doc: SubmittingPatches: remove dead link, kerneltrap.org no longer works	2014-06-19 15:15:27 +02:00
SubmittingPatches	Documentation/SubmittingPatches: Reported-by tags and permission	2014-10-29 08:56:46 -04:00
VGA-softcursor.txt	…
applying-patches.txt	Documentation: change "&" to "and" in Documentation/applying-patches.txt	2014-09-26 11:10:11 +02:00
assoc_array.txt	…
atomic_ops.txt	documentation: Add atomic_long_t to atomic_ops.txt	2014-11-13 10:34:54 -08:00
bad_memory.txt	…
basic_profiling.txt	…
bcache.txt	…
binfmt_misc.txt	binfmt_misc: touch up documentation a bit	2014-10-14 02:18:16 +02:00
braille-console.txt	…
bt8xxgpio.txt	…
btmrvl.txt	…
bus-virt-phys-mapping.txt	…
cachetlb.txt	…
circular-buffers.txt	…
clk.txt	…
coccinelle.txt	…
cpu-hotplug.txt	…
cpu-load.txt	…
cputopology.txt	…
crc32.txt	…
dcdbas.txt	…
debugging-modules.txt	…
debugging-via-ohci1394.txt	…
dell_rbu.txt	…
devices.txt	…
digsig.txt	…
dma-buf-sharing.txt	Documentation/dma-buf-sharing.txt: update API descriptions	2014-08-28 11:57:24 +05:30
dmaengine.txt	dmaengine: Update documentation for inline wrapper	2014-08-28 12:37:55 +05:30
dmatest.txt	…
dontdiff	…
dynamic-debug-howto.txt	…
edac.txt	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial into next	2014-06-04 08:50:34 -07:00
efi-stub.txt	…
eisa.txt	…
email-clients.txt	Documentation: add section about git to email-clients.txt	2014-06-29 13:38:33 -07:00
flexible-arrays.txt	…
futex-requeue-pi.txt	…
gcov.txt	…
highuid.txt	…
hsi.txt	…
hw_random.txt	…
hwspinlock.txt	…
init.txt	…
initrd.txt	…
intel_txt.txt	…
io-mapping.txt	…
io_ordering.txt	…
iostats.txt	…
irqflags-tracing.txt	…
isapnp.txt	…
java.txt	…
kernel-doc-nano-HOWTO.txt	…
kernel-docs.txt	…
kernel-parameters.txt	ACPI and power management updates for 3.19-rc1	2014-12-10 21:17:00 -08:00
kernel-per-CPU-kthreads.txt	…
kmemcheck.txt	…
kmemleak.txt	Documentation: Add CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF case	2014-10-24 13:59:03 -04:00
kobject.txt	…
kprobes.txt	Documentation/kprobes: add s390 to list of supported architectures	2014-09-09 08:53:27 +02:00
kref.txt	…
ldm.txt	…
local_ops.txt	…
lockup-watchdogs.txt	lockup-watchdogs: Fix a typo	2014-08-26 09:35:52 +02:00
logo.gif	…
logo.txt	…
lzo.txt	Documentation: lzo: document part of the encoding	2014-09-28 11:08:00 +02:00
magic-number.txt	…
mailbox.txt	doc: add documentation for mailbox framework	2014-10-08 10:39:41 +05:30
md.txt	…
media-framework.txt	…
memory-barriers.txt	arch: Add lightweight memory barriers dma_rmb() and dma_wmb()	2014-12-11 21:15:06 -05:00
memory-hotplug.txt	memory-hotplug: add sysfs valid_zones attribute	2014-10-09 22:25:52 -04:00
module-signing.txt	…
mono.txt	…
nommu-mmap.txt	…
numastat.txt	…
oops-tracing.txt	panic: add TAINT_SOFTLOCKUP	2014-08-08 15:57:24 -07:00
padata.txt	…
parport-lowlevel.txt	…
parport.txt	…
percpu-rw-semaphore.txt	…
phy.txt	phy: core: Let node ptr of PHY point to PHY and not of PHY provider	2014-07-22 12:46:11 +05:30
pi-futex.txt	…
pinctrl.txt	pinctrl: clean up after enable refactoring	2014-09-04 10:05:07 +02:00
pnp.txt	…
preempt-locking.txt	…
printk-formats.txt	lib/vsprintf: add %*pE[achnops] format specifier	2014-10-14 02:18:26 +02:00
pwm.txt	…
ramoops.txt	…
rbtree.txt	…
remoteproc.txt	…
rfkill.txt	…
robust-futex-ABI.txt	…
robust-futexes.txt	…
rpmsg.txt	…
rtc.txt	…
serial-console.txt	…
sgi-ioc4.txt	…
smsc_ece1099.txt	…
sparse.txt	…
stable_api_nonsense.txt	…
stable_kernel_rules.txt	stable_kernel_rules: Add pointer to netdev-FAQ for network patches	2014-07-09 15:54:27 -07:00
static-keys.txt	…
svga.txt	…
sysfs-rules.txt	Documentation/sysfs-rules.txt: Add device attribute error code documentation	2014-09-19 14:44:51 -07:00
sysrq.txt	…
this_cpu_ops.txt	Docs: this_cpu_ops: remove redundant add forms	2014-09-26 11:03:00 +02:00
unaligned-memory-access.txt	…
unicode.txt	…
unshare.txt	…
vfio.txt	drivers/vfio: EEH support for VFIO PCI device	2014-08-05 15:28:48 +10:00
vgaarbiter.txt	…
video-output.txt	…
vme_api.txt	…
volatile-considered-harmful.txt	…
workqueue.txt	…
xillybus.txt	xillybus: Move out of staging	2014-09-23 23:44:16 -07:00
xz.txt	…
zorro.txt	…