summaryrefslogtreecommitdiffstats
path: root/drivers/mmc
diff options
context:
space:
mode:
authorWill Deacon <will.deacon@arm.com>2014-02-07 19:12:32 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2014-02-10 11:44:50 +0000
commit7c8746a9eb287642deaad0e7c2cdf482dce5e4be (patch)
treed8740bb7222926df4bae9f93a6564839b08dc6c3 /drivers/mmc
parentbae0ca2bc550d1ec6a118fb8f2696f18c4da3d8e (diff)
downloadop-kernel-dev-7c8746a9eb287642deaad0e7c2cdf482dce5e4be.zip
op-kernel-dev-7c8746a9eb287642deaad0e7c2cdf482dce5e4be.tar.gz
ARM: 7955/1: spinlock: ensure we have a compiler barrier before sev
When unlocking a spinlock, we require the following, strictly ordered sequence of events: <barrier> /* dmb */ <unlock> <barrier> /* dsb */ <sev> Whilst the code does indeed reflect this in terms of the architecture, the final <barrier> + <sev> have been contracted into a single inline asm without a "memory" clobber, therefore the compiler is at liberty to reorder the unlock to the end of the above sequence. In such a case, a waiting CPU may be woken up before the lock has been unlocked, leading to extremely poor performance. This patch reworks the dsb_sev() function to make use of the dsb() macro and ensure ordering against the unlock. Cc: <stable@vger.kernel.org> Reported-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'drivers/mmc')
0 files changed, 0 insertions, 0 deletions
OpenPOWER on IntegriCloud