Mikulas Patocka 54505a1e20 alpha: fix memory barriers so that they conform to the specification ... The commits cd0e00c106 and 92d7223a74 broke boot on the Alpha Avanti platform. The patches move memory barriers after a write before the write. The result is that if there's iowrite followed by ioread, there is no barrier between them. The Alpha architecture allows reordering of the accesses to the I/O space, and the missing barrier between write and read causes hang with serial port and real time clock. This patch makes barriers confiorm to the specification. 1. We add mb() before readX_relaxed and writeX_relaxed - memory-barriers.txt claims that these functions must be ordered w.r.t. each other. Alpha doesn't order them, so we need an explicit barrier. 2. We add mb() before reads from the I/O space - so that if there's a write followed by a read, there should be a barrier between them. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Fixes: cd0e00c106 ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering") Fixes: 92d7223a74 ("alpha: io: reorder barriers to guarantee writeX() and iowriteX() ordering #2") Cc: stable@vger.kernel.org # v4.17+ Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Reviewed-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Matt Turner <mattst88@gmail.com>		2020-06-12 17:43:18 -07:00
..
boot	alpha: Replace strncmp with str_has_prefix	2020-06-12 17:43:17 -07:00
configs	Char/Misc driver patches for 5.7-rc1	2020-04-03 13:22:40 -07:00
include	alpha: fix memory barriers so that they conform to the specification	2020-06-12 17:43:18 -07:00
kernel	alpha: fix memory barriers so that they conform to the specification	2020-06-12 17:43:18 -07:00
lib	alpha: turn csum_partial_copy_from_user() into csum_and_copy_from_user()	2020-05-29 16:11:49 -04:00
math-emu	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
mm	mmap locking API: convert mmap_sem API comments	2020-06-09 09:39:14 -07:00
oprofile	smp: Remove smp_call_function() and on_each_cpu() return values	2019-06-23 14:26:26 +02:00
Kconfig	alpha: Kconfig: pedantic formatting	2020-06-12 17:43:17 -07:00
Kconfig.debug	Kconfig: consolidate the "Kernel hacking" menu	2018-08-02 08:06:48 +09:00
Makefile	kconfig: make arch/*/configs/defconfig the default of KBUILD_DEFCONFIG	2019-06-09 15:08:18 +09:00