linux/arch/arm64
Will Deacon 3a5facd09d arm64: spinlock: fix spin_unlock_wait for LSE atomics
Commit d86b8da04d ("arm64: spinlock: serialise spin_unlock_wait against
concurrent lockers") fixed spin_unlock_wait for LL/SC-based atomics under
the premise that the LSE atomics (in particular, the LDADDA instruction)
are indivisible.

Unfortunately, these instructions are only indivisible when used with the
-AL (full ordering) suffix and, consequently, the same issue can
theoretically be observed with LSE atomics, where a later (in program
order) load can be speculated before the write portion of the atomic
operation.

This patch fixes the issue by performing a CAS of the lock once we've
established that it's unlocked, in much the same way as the LL/SC code.

Fixes: d86b8da04d ("arm64: spinlock: serialise spin_unlock_wait against concurrent lockers")
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-06-15 09:51:36 +01:00
..
boot ARM: SoC: late DT updates for v4.7 2016-05-24 15:46:06 -07:00
configs Merge git://www.linux-watchdog.org/linux-watchdog 2016-05-25 10:19:17 -07:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2016-03-17 11:22:54 -07:00
include arm64: spinlock: fix spin_unlock_wait for LSE atomics 2016-06-15 09:51:36 +01:00
kernel arm64: fix dump_instr when PAN and UAO are in use 2016-06-14 15:02:33 +01:00
kvm arm64: KVM: vgic-v3: Relax synchronization when SRE==1 2016-05-31 16:12:17 +02:00
lib arm64 updates for 4.6: 2016-03-17 20:03:47 -07:00
mm arm64: mm: mark fault_info table const 2016-06-14 15:02:34 +01:00
net bpf: arm64: remove callee-save registers use for tmp registers 2016-05-17 14:03:33 -04:00
xen xen/arm: introduce HYPERVISOR_platform_op on arm and arm64 2015-12-21 14:40:56 +00:00
Kconfig Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-06-03 16:12:35 -07:00
Kconfig.debug arm64: enable CONFIG_SET_MODULE_RONX by default 2016-05-31 14:23:29 +01:00
Kconfig.platforms ARM: SoC 64-bit changes for v4.7 2016-05-18 12:43:08 -07:00
Makefile arm64: fix alignment when RANDOMIZE_TEXT_OFFSET is enabled 2016-06-03 10:57:18 +01:00