Date: Mon, 1 Feb 2021 12:40:44 GMT From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: fc301c224b27 - stable/13 - atomic: add stub atomic_load_consume_ptr Message-ID: <202102011240.111CeiX9094867@gitrepo.freebsd.org>
next in thread | raw e-mail | index | archive | help
The branch stable/13 has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=fc301c224b272a522bff817e12fcbf99a7a17330 commit fc301c224b272a522bff817e12fcbf99a7a17330 Author: Mateusz Guzik <mjg@FreeBSD.org> AuthorDate: 2021-01-25 20:09:41 +0000 Commit: Mateusz Guzik <mjg@FreeBSD.org> CommitDate: 2021-02-01 12:39:16 +0000 atomic: add stub atomic_load_consume_ptr (cherry picked from commit 054ce2b0371042c0dbc4b3ab1d7e7795ad75d51e) --- sys/sys/_cscan_atomic.h | 5 +++++ sys/sys/atomic_common.h | 8 ++++++++ 2 files changed, 13 insertions(+) diff --git a/sys/sys/_cscan_atomic.h b/sys/sys/_cscan_atomic.h index 3bd9455102b1..aed96580e1e4 100644 --- a/sys/sys/_cscan_atomic.h +++ b/sys/sys/_cscan_atomic.h @@ -236,6 +236,11 @@ void kcsan_atomic_thread_fence_seq_cst(void); __retptr; \ }) #define atomic_load_acq_ptr kcsan_atomic_load_acq_ptr +#define atomic_load_consume_ptr(x) ({ \ + __typeof(*x) __retptr; \ + __retptr = (void *)kcsan_atomic_load_acq_ptr((volatile uintptr_t *)(x));\ + __retptr; \ +}) #define atomic_readandclear_ptr kcsan_atomic_readandclear_ptr #define atomic_set_ptr kcsan_atomic_set_ptr #define atomic_set_acq_ptr kcsan_atomic_set_acq_ptr diff --git a/sys/sys/atomic_common.h b/sys/sys/atomic_common.h index 4c29d132c369..48f0a8b8939c 100644 --- a/sys/sys/atomic_common.h +++ b/sys/sys/atomic_common.h @@ -70,4 +70,12 @@ (*(volatile uint64_t *)(p) = (uint64_t)(v)) #endif +/* + * Currently all architectures provide acquire and release fences on their own, + * but they don't provide consume. Kludge below allows relevant code to stop + * openly resorting to the stronger acquire fence, to be sorted out. + */ +#define atomic_load_consume_ptr(p) \ + ((__typeof(*p)) atomic_load_acq_ptr((uintptr_t *)p)) + #endif
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?202102011240.111CeiX9094867>