Commit Graph

4 Commits

Author SHA1 Message Date
Arnd Bergmann 4008cb3ad2 asm-generic: temporarily add back asm-generic/io-64-nonatomic*.h
New users of these files still start showing up in linux-next, so it's
better to have a migration strategy. All existing users as of 4.3-rc4
are converted to use linux/io-64-nonatomic-*.h, and after 4.4-rc1
we can change all the new ones that have come in since, and then
remove this file again.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: LKP project <lkp@linux.intel.com>
2015-10-16 12:08:53 +02:00
Christoph Hellwig 2f8e2c8777 move io-64-nonatomic*.h out of asm-generic
These are not implementations of default architecture code but helpers
for drivers. Move them to the place they belong to.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Acked-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2015-10-15 00:21:07 +02:00
Jason Baron 3a044178cc readq/writeq: Add explicit lo_hi_[read|write]_q and hi_lo_[read|write]_q
Even on x86-64, I've found the need to break up a readq() into 2 readl()
calls. According to the Intel datasheet for the E3-1200 processor:

"
Software must not access B0/D0/F0 32-bit memory-mapped registers with
requests that cross a DW boundary.
"

(http://www.intel.com/content/www/us/en/processors/xeon/xeon-e3-1200-family-vol-2-datasheet.html p. 16)

I can confirm this is true via several hard machine lockups.

Thus, add explicit hi_lo_[readq|write]_q and lo_hi_[read|write]_q so that these
uses are spelled out.

Signed-off-by: Jason Baron <jbaron@akamai.com>
Link: http://lkml.kernel.org/r/281f09da7ad01e5cea99737ec34d2399bdbbbf63.1403818526.git.jbaron@akamai.com
Signed-off-by: Borislav Petkov <bp@suse.de>
2014-07-04 13:27:30 +02:00
Hitoshi Mitake 797a796a13 asm-generic: architecture independent readq/writeq for 32bit environment
This provides unified readq()/writeq() helper functions for 32-bit
drivers.

For some cases, readq/writeq without atomicity is harmful, and order of
io access has to be specified explicitly.  So in this patch, new two
header files which contain non-atomic readq/writeq are added.

 - <asm-generic/io-64-nonatomic-lo-hi.h> provides non-atomic readq/
   writeq with the order of lower address -> higher address

 - <asm-generic/io-64-nonatomic-hi-lo.h> provides non-atomic readq/
   writeq with reversed order

This allows us to remove some readq()s that were added drivers when the
default non-atomic ones were removed in commit dbee8a0aff ("x86:
remove 32-bit versions of readq()/writeq()")

The drivers which need readq/writeq but can do with the non-atomic ones
must add the line:

  #include <asm-generic/io-64-nonatomic-lo-hi.h> /* or hi-lo.h */

But this will be nop in 64-bit environments, and no other #ifdefs are
required.  So I believe that this patch can solve the problem of
 1. driver-specific readq/writeq
 2. atomicity and order of io access

This patch is tested with building allyesconfig and allmodconfig as
ARCH=x86 and ARCH=i386 on top of tip/master.

Cc: Kashyap Desai <Kashyap.Desai@lsi.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Ravi Anand <ravi.anand@qlogic.com>
Cc: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Jason Uhlenkott <juhlenko@akamai.com>
Cc: James Bottomley <James.Bottomley@parallels.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: James Bottomley <jbottomley@parallels.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Hitoshi Mitake <h.mitake@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-21 16:47:28 -08:00