The Arm documentation has moved to Documentation/arch/arm; update
references within arch/arm to match.
Cc: Russell King <linux@armlinux.org.uk>
Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: linux-doc@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Similar to commit a6c30873ee ("ARM: 8989/1: use .fpu assembler
directives instead of assembler arguments").
GCC and GNU binutils support setting the "sub arch" via -march=,
-Wa,-march, target function attribute, and .arch assembler directive.
Clang was missing support for -Wa,-march=, but this was implemented in
clang-13.
The behavior of both GCC and Clang is to
prefer -Wa,-march= over -march= for assembler and assembler-with-cpp
sources, but Clang will warn about the -march= being unused.
clang: warning: argument unused during compilation: '-march=armv6k'
[-Wunused-command-line-argument]
Since most assembler is non-conditionally assembled with one sub arch
(modulo arch/arm/delay-loop.S which conditionally is assembled as armv4
based on CONFIG_ARCH_RPC, and arch/arm/mach-at91/pm-suspend.S which is
conditionally assembled as armv7-a based on CONFIG_CPU_V7), prefer the
.arch assembler directive.
Add a few more instances found in compile testing as found by Arnd and
Nathan.
Link: 1d51c699b9
Link: https://bugs.llvm.org/show_bug.cgi?id=48894
Link: https://github.com/ClangBuiltLinux/linux/issues/1195
Link: https://github.com/ClangBuiltLinux/linux/issues/1315
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Converts ARM the text files to ReST, preparing them to be an
architecture book.
The conversion is actually:
- add blank lines and identation in order to identify paragraphs;
- fix tables markups;
- add some lists markups;
- mark literal blocks;
- adjust title markups.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by Corentin Labbe <clabbe.montjoie@gmail.com> # For sun4i-ss
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 655 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070034.575739538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In a similar manner to our spinlock implementation, mcpm uses sev to
wake up cores waiting on a lock when the lock is unlocked. In order to
ensure that the final write unlocking the lock is visible, a dsb
instruction is executed immediately prior to the sev.
This patch changes these dsbs to use the -st option, since we only
require that the store unlocking the lock is made visible.
Acked-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This patch adds a simple low-level voting mutex implementation
to be used to arbitrate during first man selection when no load/store
exclusive instructions are usable.
For want of a better name, these are called "vlocks". (I was
tempted to call them ballot locks, but "block" is way too confusing
an abbreviation...)
There is no function to wait for the lock to be released, and no
vlock_lock() function since we don't need these at the moment.
These could straightforwardly be added if vlocks get used for other
purposes.
For architectural correctness even Strongly-Ordered memory accesses
require barriers in order to guarantee that multiple CPUs have a
coherent view of the ordering of memory accesses. Whether or not
this matters depends on hardware implementation details of the
memory system. Since the purpose of this code is to provide a clean,
generic locking mechanism with no platform-specific dependencies the
barriers should be present to avoid unpleasant surprises on future
platforms.
Note:
* When taking the lock, we don't care about implicit background
memory operations and other signalling which may be pending,
because those are not part of the critical section anyway.
A DMB is sufficient to ensure correctly observed ordering if
the explicit memory accesses in vlock_trylock.
* No barrier is required after checking the election result,
because the result is determined by the store to
VLOCK_OWNER_OFFSET and is already globally observed due to the
barriers in voting_end. This means that global agreement on
the winner is guaranteed, even before the winner is known
locally.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
