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42344113ba
linux/arch/mips
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Peter Zijlstra 42344113ba
mips/atomic: Fix smp_mb__{before,after}_atomic() 
Recent probing at the Linux Kernel Memory Model uncovered a
'surprise'. Strongly ordered architectures where the atomic RmW
primitive implies full memory ordering and
smp_mb__{before,after}_atomic() are a simple barrier() (such as MIPS
without WEAK_REORDERING_BEYOND_LLSC) fail for:

	*x = 1;
	atomic_inc(u);
	smp_mb__after_atomic();
	r0 = *y;

Because, while the atomic_inc() implies memory order, it
(surprisingly) does not provide a compiler barrier. This then allows
the compiler to re-order like so:

	atomic_inc(u);
	*x = 1;
	smp_mb__after_atomic();
	r0 = *y;

Which the CPU is then allowed to re-order (under TSO rules) like:

	atomic_inc(u);
	r0 = *y;
	*x = 1;

And this very much was not intended. Therefore strengthen the atomic
RmW ops to include a compiler barrier.

Reported-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paul Burton <paul.burton@mips.com>
2019-08-31 11:06:02 +01:00
..
alchemy treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 182 2019-05-30 11:29:20 -07:00
ar7 The main MIPS changes for a pretty light v5.3 cycle, including: 2019-07-17 09:42:03 -07:00
ath25 PCI: consolidate PCI config entry in drivers/pci 2018-11-23 11:45:34 +09:00
ath79 The main MIPS changes for a pretty light v5.3 cycle, including: 2019-07-17 09:42:03 -07:00
bcm47xx MIPS: BCM47XX: Add support for Netgear R6200 V1 2019-07-25 22:10:05 -07:00
bcm63xx MIPS: fix some more fall through errors in arch/mips 2019-07-16 12:40:16 +01:00
bmips docs: arm: convert docs to ReST and rename to *.rst 2019-07-15 09:20:24 -03:00
boot MIPS: dts: mscc: describe the PTP ready interrupt 2019-08-24 15:17:37 +01:00
cavium-octeon MIPS: Octeon: remove duplicated include from dma-octeon.c 2019-08-27 10:59:56 +01:00
cobalt treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 1 2019-05-21 11:28:39 +02:00
configs MIPS: configs: LB60: update defconfig 2019-07-30 10:41:53 -07:00
crypto MIPS: crypto: Add crc32 and crc32c hw accelerated module 2018-02-19 20:50:36 +00:00
dec treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
emma treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
fw MIPS: fw: Record prom memory 2019-08-23 14:47:10 +01:00
generic treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
include mips/atomic: Fix smp_mb__{before,after}_atomic() 2019-08-31 11:06:02 +01:00
jazz MIPS: use the generic uncached segment support in dma-direct 2019-06-03 16:00:08 +02:00
jz4740 Merge branch 'ingenic-tcu-v5.4' into mips-next 2019-08-08 15:33:16 -07:00
kernel mips/atomic: Fix loongson_llsc_mb() wreckage 2019-08-31 11:05:17 +01:00
kvm KVM: Directly return result from kvm_arch_check_processor_compat() 2019-06-04 19:27:32 +02:00
lantiq MIPS: lantiq: update the clock alias' for the mainline PCIe PHY driver 2019-08-24 15:13:22 +01:00
lasat treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 182 2019-05-30 11:29:20 -07:00
lib treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504 2019-06-19 17:09:56 +02:00
loongson32 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
loongson64 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
math-emu treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 454 2019-06-19 17:09:09 +02:00
mm MIPS: mm: Fix highmem compile 2019-08-23 17:50:30 +01:00
mti-malta MIPS: malta: Drop prom_free_prom_memory 2019-08-23 14:47:13 +01:00
net treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
netlogic MIPS: xlp: Drop boot_mem_map 2019-08-23 14:47:21 +01:00
oprofile Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
paravirt mips: unify prom_putchar() declarations 2018-07-17 09:40:17 -07:00
pci treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pic32 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 445 2019-06-05 17:37:18 +02:00
pistachio A batch of MIPS fixes: 2019-06-08 13:09:31 -07:00
pmcs-msp71xx MIPS: msp: Record prom memory 2019-08-23 14:47:16 +01:00
pnx833x A batch of MIPS fixes: 2019-06-08 13:09:31 -07:00
power treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 305 2019-06-05 17:37:04 +02:00
ralink MIPS: Remove dev_err() usage after platform_get_irq() 2019-08-26 11:26:04 +01:00
rb532 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 182 2019-05-30 11:29:20 -07:00
sgi-ip22 MIPS: ip22: Drop addr_is_ram 2019-08-23 14:47:18 +01:00
sgi-ip27 Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2019-07-08 21:48:15 -07:00
sgi-ip32 Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2019-07-08 21:48:15 -07:00
sibyte treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
sni treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 210 2019-05-30 11:29:53 -07:00
tools treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
txx9 A batch of MIPS fixes: 2019-06-08 13:09:31 -07:00
vdso mips: fix vdso32 build, again 2019-08-06 14:32:15 -07:00
vr41xx treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
Kbuild treewide: Add SPDX license identifier - Kbuild 2019-05-30 11:32:33 -07:00
Kbuild.platforms treewide: Add SPDX license identifier - Kbuild 2019-05-30 11:32:33 -07:00
Kconfig MIPS: Kconfig: remove HAVE_LATENCYTOP_SUPPORT 2019-07-30 09:43:52 -07:00
Kconfig.debug Kconfig: consolidate the "Kernel hacking" menu 2018-08-02 08:06:48 +09:00
Makefile MIPS: Remove unused R8000 CPU support 2019-07-23 14:33:51 -07:00
Makefile.postlink License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00