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1077fa36f2
linux/arch/s390/include/asm
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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
..
airq.h s390/airq: add support for irq ranges 2014-03-04 10:41:04 +01:00
appldata.h s390/appldata: change return value of appldata_asm 2012-09-26 15:45:15 +02:00
asm-offsets.h
atomic.h arch,s390: Convert smp_mb__*() 2014-04-18 14:20:42 +02:00
barrier.h arch: Add lightweight memory barriers dma_rmb() and dma_wmb() 2014-12-11 21:15:06 -05:00
bitops.h s390/bitops,atomic: add missing memory barriers 2014-04-01 09:23:35 +02:00
bug.h
bugs.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
cache.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
cacheflush.h module: undo module RONX protection correctly. 2011-05-19 16:55:26 +09:30
ccwdev.h s390/cio: fix multiple structure definitions 2014-05-20 08:58:53 +02:00
ccwgroup.h s390: fix new ccwgroup.h kernel-doc warning 2014-05-20 08:58:45 +02:00
checksum.h s390/checksum: remove memset() within csum_partial_copy_from_user() 2014-02-24 17:14:08 +01:00
chpid.h s390/cio: fix multiple structure definitions 2014-05-20 08:58:53 +02:00
cio.h treewide: Fix typo in Documentation/DocBook 2014-02-19 14:58:17 +01:00
clp.h s390/pci: cleanup clp page allocation 2013-02-14 15:55:16 +01:00
cmb.h UAPI: (Scripted) Disintegrate arch/s390/include/asm 2012-10-09 09:47:31 +01:00
cmpxchg.h s390/32bit: fix cmpxchg64 2014-01-22 14:02:15 +01:00
compat.h s390/compat: build error for large compat syscall args 2014-03-06 16:30:47 +01:00
cpcmd.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
cpu_mf.h s390/cpum_sf: Add raw data sampling to support the diagnostic-sampling function 2013-12-16 14:38:00 +01:00
cpu.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
cputime.h Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2014-10-14 03:47:00 +02:00
crw.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
css_chars.h s390/qdio: bridgeport support - CHSC part 2014-01-15 14:48:01 -08:00
ctl_reg.h s390/ctl_reg: add union type for control register 0 2014-04-22 13:24:36 +02:00
current.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
debug.h s390/s390dbf: add debug_level_enabled() function 2013-10-24 17:16:53 +02:00
delay.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
device.h
diag.h [S390] replace diag10() with diag10_range() function 2011-05-10 17:13:43 +02:00
dis.h s390/disassembler: add vector instructions 2014-10-09 09:14:15 +02:00
div64.h
dma-mapping.h s390: Implement dma_{alloc,free}_attrs() 2014-08-26 07:39:12 +02:00
dma.h s390/pci: define isa_dma_bridge_buggy 2013-01-08 10:57:09 +01:00
eadm.h s390/scm_block: do not hide eadm subchannel dependency 2013-11-15 14:08:42 +01:00
ebcdic.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
elf.h s390/kdump: add support for vector extension 2014-10-09 09:14:16 +02:00
emergency-restart.h
etr.h s390/etr,stp: use -EOPNOTSUPP instead of -ENOSYS 2012-09-26 15:45:14 +02:00
exec.h Disintegrate asm/system.h for S390 2012-03-28 18:30:02 +01:00
extmem.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
facility.h s390/facility: decompose test_facility() 2013-06-26 21:10:25 +02:00
fb.h
fcx.h s390/cio: fix error-prone defines 2013-10-24 17:17:04 +02:00
ftrace.h s390/ftrace: remove 31 bit ftrace support 2014-10-09 09:14:18 +02:00
futex.h s390/uaccess: simplify control register updates 2014-05-20 08:58:46 +02:00
hardirq.h hardirq: Make hardirq bits generic 2013-11-13 20:21:46 +01:00
hugetlb.h s390/mm: cleanup page table definitions 2013-08-22 12:20:06 +02:00
hw_irq.h s390: convert interrupt handling to use generic hardirq 2013-08-22 12:20:04 +02:00
idals.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
idle.h s390/idle: consolidate idle functions and definitions 2014-10-09 09:14:03 +02:00
io.h Merge branch 'io' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into asm-generic 2014-11-11 19:55:45 +01:00
ipl.h s390/kdump: add support for vector extension 2014-10-09 09:14:16 +02:00
irq_regs.h
irq.h Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu 2014-10-15 07:48:18 +02:00
irqflags.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
isc.h s390/pci: PCI adapter interrupts for MSI/MSI-X 2012-11-30 17:47:21 +01:00
itcw.h UAPI: Alter the S390 asm include guards to be recognisable by the UAPI splitter 2011-12-13 09:26:45 +00:00
jump_label.h compiler/gcc4: Add quirk for 'asm goto' miscompilation bug 2013-10-11 07:39:14 +02:00
Kbuild net, lib: kill arch_fast_hash library bits 2014-12-10 15:17:46 -05:00
kdebug.h [S390] cleanup trap handling 2011-12-27 11:27:12 +01:00
kexec.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
kmap_types.h s390/headers: remove #ifdef __KERNEL__ from not exported headers 2012-05-24 10:10:05 +02:00
kprobes.h s390/uprobes: common library for kprobes and uprobes 2014-09-25 10:52:14 +02:00
kvm_host.h KVM: s390: count vcpu wakeups in stat.halt_wakeup 2014-10-01 14:42:14 +02:00
kvm_para.h UAPI: (Scripted) Disintegrate arch/s390/include/asm 2012-10-09 09:47:31 +01:00
linkage.h [S390] fix s390 assembler code alignments 2011-07-24 10:48:21 +02:00
local64.h
local.h
lowcore.h s390/kdump: add support for vector extension 2014-10-09 09:14:16 +02:00
mathemu.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
mman.h s390/mm: Fix crst upgrade of mmap with MAP_FIXED 2013-02-14 15:55:22 +01:00
mmu_context.h mm: Make arch_unmap()/bprm_mm_init() available to all architectures 2014-11-19 11:54:13 +01:00
mmu.h KVM: s390: Adding skey bit to mmu context 2014-04-22 09:36:23 +02:00
module.h Make most arch asm/module.h files use asm-generic/module.h 2012-09-28 14:31:03 +09:30
mutex.h mutex: replace CONFIG_HAVE_ARCH_MUTEX_CPU_RELAX with simple ifdef 2013-09-28 12:46:21 +02:00
nmi.h s390: add support for vector extension 2014-10-09 09:14:13 +02:00
os_info.h s390/kernel: Remove OS info init function call and diag 308 for kdump 2012-05-23 17:06:50 +02:00
page.h arm64,ia64,ppc,s390,sh,tile,um,x86,mm: remove default gate area 2014-08-08 15:57:27 -07:00
pci_clp.h s390/pci: add some new arch specific pci attributes 2014-05-20 08:58:50 +02:00
pci_debug.h s390/pci: remove CONFIG_PCI_DEBUG dependancy 2013-10-24 17:17:16 +02:00
pci_dma.h s390/pci: DMA support 2012-11-30 17:47:23 +01:00
pci_insn.h s390/pci: cleanup function information block 2013-10-24 17:17:17 +02:00
pci_io.h s390/pci: cleanup function names 2013-08-22 12:20:03 +02:00
pci.h s390/pci: add some new arch specific pci attributes 2014-05-20 08:58:50 +02:00
percpu.h s390: Replace __get_cpu_var uses 2014-08-26 13:45:52 -04:00
perf_event.h s390/cpum_sf: Add flag to process full SDBs only 2013-12-16 14:38:01 +01:00
pgalloc.h KVM: s390/mm: use radix trees for guest to host mappings 2014-08-26 10:09:02 +02:00
pgtable.h Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2014-10-14 03:47:00 +02:00
processor.h s390: add support for vector extension 2014-10-09 09:14:13 +02:00
ptrace.h s390/uprobes: architecture backend for uprobes 2014-09-25 10:52:17 +02:00
qdio.h s390/qdio: add helpers to manage qdio buffers 2014-07-22 09:26:13 +02:00
reset.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
runtime_instr.h s390: add support for runtime instrumentation 2012-09-26 15:45:02 +02:00
rwsem.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
schid.h UAPI: (Scripted) Disintegrate arch/s390/include/asm 2012-10-09 09:47:31 +01:00
sclp.h s390/sclp: add sclp_get_ibc function 2014-05-16 14:57:30 +02:00
scsw.h s390: add eadm related structures 2012-09-26 15:44:57 +02:00
seccomp.h
sections.h
segment.h
serial.h s390: convert interrupt handling to use generic hardirq 2013-08-22 12:20:04 +02:00
setup.h s390: add support for vector extension 2014-10-09 09:14:13 +02:00
sfp-machine.h
sfp-util.h s390/headers: replace __s390x__ with CONFIG_64BIT where possible 2012-05-24 10:10:10 +02:00
shmparam.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
signal.h s390: switch to generic old sigaction() 2013-02-03 18:16:14 -05:00
sigp.h s390/kdump: add support for vector extension 2014-10-09 09:14:16 +02:00
smp.h s390/rwlock: use directed yield for write-locked rwlocks 2014-09-25 10:52:05 +02:00
sparsemem.h s390/mm: remove MAX_PHYSADDR_BITS define 2012-08-08 07:32:55 -07:00
spinlock_types.h s390/rwlock: use directed yield for write-locked rwlocks 2014-09-25 10:52:05 +02:00
spinlock.h s390/rwlock: use the interlocked-access facility 1 instructions 2014-09-25 10:52:13 +02:00
string.h s390/string: provide asm lib functions for memcpy and memcmp 2012-09-26 15:44:50 +02:00
switch_to.h s390/kdump: add support for vector extension 2014-10-09 09:14:16 +02:00
syscall.h s390/seccomp: fix error return for filtered system calls 2014-07-28 10:02:31 +02:00
sysinfo.h s390/sysinfo,stsi: change return code handling 2012-09-26 15:45:12 +02:00
termios.h UAPI: (Scripted) Disintegrate arch/s390/include/asm 2012-10-09 09:47:31 +01:00
thread_info.h s390/uprobes: architecture backend for uprobes 2014-09-25 10:52:17 +02:00
timex.h s390/time: fix get_tod_clock_ext inline assembly 2013-10-31 09:52:48 +01:00
tlb.h KVM: s390/mm: use radix trees for guest to host mappings 2014-08-26 10:09:02 +02:00
tlbflush.h s390/mm,tlb: optimize TLB flushing for zEC12 2014-04-03 14:31:00 +02:00
topology.h sched, s390: Create a dedicated topology table 2014-05-07 13:33:50 +02:00
types.h UAPI: (Scripted) Disintegrate arch/s390/include/asm 2012-10-09 09:47:31 +01:00
uaccess.h s390/uaccess: provide inline variants of get_user/put_user 2014-05-20 08:58:50 +02:00
unaligned.h
unistd.h consolidate cond_syscall and SYSCALL_ALIAS declarations 2013-03-03 22:55:19 -05:00
uprobes.h s390/uprobes: architecture backend for uprobes 2014-09-25 10:52:17 +02:00
user.h s390/comments: unify copyright messages and remove file names 2012-07-20 11:15:04 +02:00
vdso.h s390/vdso: add vdso support for coarse clocks 2014-09-09 08:53:27 +02:00
vga.h vga: compile fix, disable vga for s390 2012-11-30 17:47:28 +01:00
vtime.h vtime: Describe overriden functions in dedicated arch headers 2013-08-14 17:14:53 +02:00
vtimer.h s390/idle: consolidate idle functions and definitions 2014-10-09 09:14:03 +02:00
xor.h