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
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	aoe: remove do-nothing NAME="%k" term from example udev rules	2013-09-11 15:59:28 -07:00
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	backlight: lp855x_bl: support new LP8555 device	2013-11-13 12:09:14 +09:00
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	w1: optional bundling of netlink kernel replies	2014-05-27 13:56:21 -07:00
console
cpu-freq	intel_pstate: Add support for HWP	2014-11-12 00:04:38 +01:00
cpuidle	cpuidle: remove cpuidle_unregister_governor()	2013-10-30 01:21:24 +01:00
cris
crypto	drivers/dma: remove unused support for MEMSET operations	2013-07-03 16:07:42 -07:00
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
DocBook	sound updates for 3.19-rc1	2014-12-11 13:20:50 -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	Documentation: remove reference to 2.7 kernel in early-userspace	2013-08-20 12:47:28 +02:00
EDID	drm: Add 800x600 (SVGA) screen resolution to the built-in EDIDs	2014-05-26 12:53:40 +10:00
extcon	extcon: fix switch class porting guide (Documentation)	2014-01-07 11:54:28 +09:00
fault-injection
fb	doc: spelling error changes	2014-05-05 15:32:05 +02:00
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	FMC: make eeprom attribute writable	2014-02-28 15:12:08 -08:00
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	Documentation/: update 00-INDEX files	2014-02-10 16:01:40 -08:00
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	Documentation: Update stable address in Chinese and Japanese translations	2014-04-16 14:13:27 -07:00
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	Documentation: HOWTO: Updates on subsystem trees, patchwork, -next (vs. -mm) in ko_KR	2014-01-08 15:32:51 -08:00
laptops	Documentation: update .gitignore files	2014-09-26 11:02:59 +02:00
leds	Documentation/: update 00-INDEX files	2014-02-10 16:01:40 -08:00
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	Documentation/: update 00-INDEX files	2014-02-10 16:01:40 -08:00
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	parisc: document the shadow registers	2013-07-09 22:09:19 +02:00
PCI	doc: replace "practise" with "practice" in Documentation	2014-06-19 15:28:56 +02:00
pcmcia	Documentation: use subdir-y to avoid unnecessary built-in.o files	2014-09-26 11:02:55 +02:00
phy	phy: Add new Exynos USB 2.0 PHY driver	2014-03-08 12:39:44 +05:30
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	USB: serial: invoke dcd_change ldisc's handler.	2013-09-26 09:45:40 -07:00
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
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
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	drivers/tpm: add xen tpmfront interface	2013-08-09 10:57:06 -04:00
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	xtensa: remap io area defined in device tree	2014-01-15 00:25:14 +04:00
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
applying-patches.txt	Documentation: change "&" to "and" in Documentation/applying-patches.txt	2014-09-26 11:10:11 +02:00
assoc_array.txt	KEYS: Fix multiple key add into associative array	2013-12-02 11:24:18 +00:00
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	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-07-04 11:40:58 -07:00
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
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt	Documentation: fix typo and update version in cachetlb.txt	2013-08-20 12:46:52 +02:00
Changes	Update old iproute2 and Xen Remus links	2014-12-09 13:38:13 -05:00
circular-buffers.txt	documentation: Update circular buffer for load-acquire/store-release	2013-12-03 10:08:57 -08:00
clk.txt	clk: Improve clk_ops documentation	2014-05-12 17:08:33 -07:00
coccinelle.txt	Coccinelle: Update information about the minimal version required	2013-07-03 22:58:20 +02:00
CodingStyle	CodingStyle: fix a minor typo	2014-08-26 09:35:54 +02:00
cpu-hotplug.txt	Doc/cpu-hotplug: Specify race-free way to register CPU hotplug callbacks	2014-03-20 13:43:40 +01:00
cpu-load.txt
cputopology.txt	doc: Documentation/cputopology.txt fix typo	2013-09-04 12:59:47 +02:00
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt	firewire: revert to 4 GB RDMA, fix protocols using Memory Space	2014-05-29 15:50:30 +02:00
dell_rbu.txt
devices.txt	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media	2014-04-04 09:50:07 -07:00
digsig.txt
DMA-API-HOWTO.txt	Documentation: correct parameter error for dma_mapping_error	2014-09-26 11:22:29 +02:00
DMA-API.txt	DMA-API: Capitalize "CPU" consistently	2014-05-26 17:28:27 -06:00
DMA-attributes.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
dma-buf-sharing.txt	Documentation/dma-buf-sharing.txt: update API descriptions	2014-08-28 11:57:24 +05:30
DMA-ISA-LPC.txt	DMA-API: Clarify physical/bus address distinction	2014-05-20 16:54:21 -06:00
dmaengine.txt	dmaengine: Update documentation for inline wrapper	2014-08-28 12:37:55 +05:30
dmatest.txt	dmatest: add a 'wait' parameter	2013-11-14 11:04:40 -08:00
dontdiff	Documentation: LLVMLinux: Update Documentation/dontdiff	2014-04-09 13:44:34 -07:00
dynamic-debug-howto.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
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	doc: arm64: add description of EFI stub support	2014-04-30 19:57:05 +01:00
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	doc: fix double words	2014-03-21 13:16:58 +01:00
gcov.txt	gcov: compile specific gcov implementation based on gcc version	2013-11-13 12:09:34 +09:00
highuid.txt
HOWTO	Documentation: remove outdated references to the linux-next wiki	2014-10-28 09:06:11 -04:00
hsi.txt	Documentation: HSI: Add some general description for the HSI subsystem	2014-05-04 09:49:46 +02:00
hw_random.txt
hwspinlock.txt	doc: documentation/hwspinlock.txt fix typo	2013-08-27 10:46:02 +02:00
init.txt
initrd.txt
Intel-IOMMU.txt
intel_txt.txt
io-mapping.txt	doc: fix some typos	2013-12-02 14:48:28 +01:00
io_ordering.txt
iostats.txt
IPMI.txt
IRQ-affinity.txt	doc: fix a typo about irq affinity	2013-08-20 12:59:18 +02:00
IRQ-domain.txt	irqdomain: Introduce new interfaces to support hierarchy irqdomains	2014-11-23 13:01:45 +01:00
IRQ.txt
irqflags-tracing.txt	asm/system.h: clean asm/system.h from docs	2014-04-07 16:36:11 -07:00
isapnp.txt
java.txt	Documentation: update java sample wrapper for java 7	2014-05-25 12:39:00 -07:00
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	Documentation/kernel-per-CPU-kthreads.txt: Workqueue affinity	2014-02-17 14:56:08 -08:00
kmemcheck.txt	doc: fix double words	2014-03-21 13:16:58 +01:00
kmemleak.txt	Documentation: Add CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF case	2014-10-24 13:59:03 -04:00
kobject.txt	kobject: remove kset from sysfs immediately in kset_unregister()	2013-12-07 21:20:11 -08:00
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	Documentation/serial: Delete obsolete driver documentation	2014-04-16 14:20:34 -07:00
mailbox.txt	doc: add documentation for mailbox framework	2014-10-08 10:39:41 +05:30
Makefile	Documentation: add makefiles for more targets	2014-09-26 11:02:56 +02:00
ManagementStyle
md.txt	doc: fix some typos in documentations	2013-12-02 14:45:19 +01:00
media-framework.txt	Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media	2013-07-13 12:09:57 -07:00
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	Nothing major: the stricter permissions checking for sysfs broke	2014-04-06 09:38:07 -07:00
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	pwm: modify PWM_LOOKUP to initialize all struct pwm_lookup members	2014-05-21 11:19:36 +02:00
ramoops.txt
rbtree.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
remoteproc.txt
rfkill.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
robust-futex-ABI.txt	Documentation/robust-futex-API: Count properly to 4	2013-11-30 14:08:28 +01:00
robust-futexes.txt	doc: spelling error changes	2014-05-05 15:32:05 +02:00
rpmsg.txt
rtc.txt	rtc: add ability to push out an existing wakealarm using sysfs	2013-07-03 16:07:54 -07:00
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
SM501.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	doc: fix some typos in documentations	2013-12-02 14:45:19 +01:00
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
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	sysrq: Allow magic SysRq key functions to be disabled through Kconfig	2013-10-16 13:01:44 -07:00
this_cpu_ops.txt	Docs: this_cpu_ops: remove redundant add forms	2014-09-26 11:03:00 +02:00
unaligned-memory-access.txt	ether_addr_equal: Optimize implementation, remove unused compare_ether_addr	2013-12-06 16:37:43 -05:00
unicode.txt
unshare.txt
vfio.txt	drivers/vfio: EEH support for VFIO PCI device	2014-08-05 15:28:48 +10:00
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt	VME: Rename vme_slot_get to avoid confusion with reference counting	2013-12-03 11:15:58 -08:00
volatile-considered-harmful.txt
workqueue.txt	workqueue: Correct/Drop references to gcwq in Documentation	2013-08-21 10:32:09 -04:00
xillybus.txt	xillybus: Move out of staging	2014-09-23 23:44:16 -07:00
xz.txt
zorro.txt	zorro/UAPI: Disintegrate include/linux/zorro*.h	2013-11-26 11:09:08 +01:00