kernel/linux.git/arch/arm64/include/asm/atomic.h, branch linux-5.9.y

locking/atomic: Move ATOMIC_INIT into linux/types.h

2020-07-29T14:14:18+00:00

This patch moves ATOMIC_INIT from asm/atomic.h into linux/types.h. This allows users of atomic_t to use ATOMIC_INIT without having to include atomic.h as that way may lead to header loops. Signed-off-by: Herbert Xu Signed-off-by: Peter Zijlstra (Intel) Acked-by: Waiman Long Link: https://lkml.kernel.org/r/20200729123105.GB7047@gondor.apana.org.au

locking/atomics: Flip fallbacks and instrumentation

2020-06-11T06:03:24+00:00

Currently instrumentation of atomic primitives is done at the architecture level, while composites or fallbacks are provided at the generic level. The result is that there are no uninstrumented variants of the fallbacks. Since there is now need of such variants to isolate text poke from any form of instrumentation invert this ordering. Doing this means moving the instrumentation into the generic code as well as having (for now) two variants of the fallbacks. Notes: - the various *cond_read* primitives are not proper fallbacks and got moved into linux/atomic.c. No arch_ variants are generated because the base primitives smp_cond_load*() are instrumented. - once all architectures are moved over to arch_atomic_ one of the fallback variants can be removed and some 2300 lines reclaimed. - atomic_{read,set}*() are no longer double-instrumented Reported-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Acked-by: Mark Rutland Link: https://lkml.kernel.org/r/20200505134058.769149955@linutronix.de

Merge branch 'for-next/atomics' into for-next/core

2019-08-30T11:55:39+00:00

* for-next/atomics: (10 commits) Rework LSE instruction selection to use static keys instead of alternatives

arm64: atomics: Undefine internal macros after use

2019-08-30T10:18:37+00:00

We use a bunch of internal macros when constructing our atomic and cmpxchg routines in order to save on boilerplate. Avoid exposing these directly to users of the header files. Reviewed-by: Andrew Murray Signed-off-by: Will Deacon

arm64: asm: Kill 'asm/atomic_arch.h'

2019-08-30T10:18:29+00:00

The contents of 'asm/atomic_arch.h' can be split across some of our other 'asm/' headers. Remove it. Reviewed-by: Andrew Murray Signed-off-by: Will Deacon

arm64: atomics: avoid out-of-line ll/sc atomics

2019-08-29T14:53:42+00:00

When building for LSE atomics (CONFIG_ARM64_LSE_ATOMICS), if the hardware or toolchain doesn't support it the existing code will fallback to ll/sc atomics. It achieves this by branching from inline assembly to a function that is built with special compile flags. Further this results in the clobbering of registers even when the fallback isn't used increasing register pressure. Improve this by providing inline implementations of both LSE and ll/sc and use a static key to select between them, which allows for the compiler to generate better atomics code. Put the LL/SC fallback atomics in their own subsection to improve icache performance. Signed-off-by: Andrew Murray Signed-off-by: Will Deacon

arm64: remove pointless KERNEL guards

2019-08-05T10:06:33+00:00

For a number of years, UAPI headers have been split from kernel-internal headers. The latter are never exposed to userspace, and always built with __KERNEL__ defined. Most headers under arch/arm64 don't have __KERNEL__ guards, but there are a few stragglers lying around. To make things more consistent, and to set a good example going forward, let's remove these redundant __KERNEL__ guards. In a couple of cases, a trailing #endif lacked a comment describing its corresponding #if or #ifdef, so these are fixes up at the same time. Guards in auto-generated crypto code are left as-is, as these guards are generated by scripting imported from the upstream openssl project scripts. Guards in UAPI headers are left as-is, as these can be included by userspace or the kernel. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Will Deacon

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234

2019-06-19T15:09:07+00:00

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 you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 503 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Alexios Zavras Reviewed-by: Allison Randal Reviewed-by: Enrico Weigelt Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de Signed-off-by: Greg Kroah-Hartman

arm64, locking/atomics: Use instrumented atomics

2018-11-01T10:01:40+00:00

Now that the generic atomic headers provide instrumented wrappers of all the atomics implemented by arm64, let's migrate arm64 over to these. The additional instrumentation will help to find bugs (e.g. when fuzzing with Syzkaller). Mostly this change involves adding an arch_ prefix to a number of function names and macro definitions. When LSE atomics are used, the out-of-line LL/SC atomics will be named __ll_sc_arch_atomic_${OP}. Adding the arch_ prefix requires some whitespace fixups to keep things aligned. Some other unusual whitespace is fixed up at the same time (e.g. in the cmpxchg wrappers). Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Cc: Catalin Marinas Cc: linuxdrivers@attotech.com Cc: dvyukov@google.com Cc: boqun.feng@gmail.com Cc: arnd@arndb.de Cc: aryabinin@virtuozzo.com Cc: glider@google.com Link: http://lkml.kernel.org/r/20180904104830.2975-7-mark.rutland@arm.com Signed-off-by: Ingo Molnar

atomics/treewide: Make conditional inc/dec ops optional

2018-06-21T12:25:24+00:00

The conditional inc/dec ops differ for atomic_t and atomic64_t: - atomic_inc_unless_positive() is optional for atomic_t, and doesn't exist for atomic64_t. - atomic_dec_unless_negative() is optional for atomic_t, and doesn't exist for atomic64_t. - atomic_dec_if_positive is optional for atomic_t, and is mandatory for atomic64_t. Let's make these consistently optional for both. At the same time, let's clean up the existing fallbacks to use atomic_try_cmpxchg(). The instrumented atomics are updated accordingly. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Reviewed-by: Will Deacon Acked-by: Peter Zijlstra (Intel) Cc: Boqun Feng Cc: Linus Torvalds Cc: Thomas Gleixner Link: https://lore.kernel.org/lkml/20180621121321.4761-18-mark.rutland@arm.com Signed-off-by: Ingo Molnar