From mboxrd@z Thu Jan 1 00:00:00 1970 From: greg@kroah.com (Greg KH) Date: Sun, 8 Jul 2018 20:40:49 +0200 Subject: [PATCH v2] devres: Really align data field to unsigned long long In-Reply-To: <20180708175621.6951-1-abrodkin@synopsys.com> References: <20180708175621.6951-1-abrodkin@synopsys.com> List-ID: Message-ID: <20180708184049.GA1645@kroah.com> To: linux-snps-arc@lists.infradead.org On Sun, Jul 08, 2018@08:56:21PM +0300, Alexey Brodkin wrote: > Depending on ABI "long long" type of a particular 32-bit CPU > might be aligned by either word (32-bits) or double word (64-bits). > Make sure "data" is really 64-bit aligned for any 32-bit CPU. > > At least for 32-bit ARC cores ABI requires "long long" types > to be aligned by normal 32-bit word. This makes "data" field aligned to > 12 bytes. Which is still OK as long as we use 32-bit data only. > > But once we want to use native atomic64_t type (i.e. when we use special > instructions LLOCKD/SCONDD for accessing 64-bit data) we easily hit > misaligned access exception. > > That's because even on CPUs capable of non-aligned data access LL/SC > instructions require strict alignment. > > Signed-off-by: Alexey Brodkin > Cc: Thomas Gleixner > Cc: stable at vger.kernel.org > --- > > Changes v1 -> v2: > > * Reworded commit message > * Inserted comment right in source [Thomas] > > drivers/base/devres.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) Always use scripts/get_maintainer.pl to properly cc: the needed developer/maintainer. As it is, this patch is going to get dropped on the floor, sorry... greg k-h