From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org
Cc: "Juergen Gross" <jgross@suse.com>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Julien Grall" <julien@xen.org>, "Wei Liu" <wl@xen.org>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Jan Beulich" <jbeulich@suse.com>,
"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: [Xen-devel] [PATCH v7 1/5] xen: introduce smp_mb__[after|before]_atomic() barriers
Date: Wed, 25 Mar 2020 11:55:07 +0100 [thread overview]
Message-ID: <20200325105511.20882-2-jgross@suse.com> (raw)
In-Reply-To: <20200325105511.20882-1-jgross@suse.com>
When using atomic variables for synchronization barriers are needed
to ensure proper data serialization. Introduce smp_mb__before_atomic()
and smp_mb__after_atomic() as in the Linux kernel for that purpose.
Use the same definitions as in the Linux kernel.
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V7:
- new patch
---
xen/include/asm-arm/system.h | 3 +++
xen/include/asm-x86/system.h | 3 +++
2 files changed, 6 insertions(+)
diff --git a/xen/include/asm-arm/system.h b/xen/include/asm-arm/system.h
index e5d062667d..65d5c8e423 100644
--- a/xen/include/asm-arm/system.h
+++ b/xen/include/asm-arm/system.h
@@ -30,6 +30,9 @@
#define smp_wmb() dmb(ishst)
+#define smp_mb__before_atomic() smp_mb()
+#define smp_mb__after_atomic() smp_mb()
+
/*
* This is used to ensure the compiler did actually allocate the register we
* asked it for some inline assembly sequences. Apparently we can't trust
diff --git a/xen/include/asm-x86/system.h b/xen/include/asm-x86/system.h
index 069f422f0d..7e5891f3df 100644
--- a/xen/include/asm-x86/system.h
+++ b/xen/include/asm-x86/system.h
@@ -233,6 +233,9 @@ static always_inline unsigned long __xadd(
#define set_mb(var, value) do { xchg(&var, value); } while (0)
#define set_wmb(var, value) do { var = value; smp_wmb(); } while (0)
+#define smp_mb__before_atomic() do { } while (0)
+#define smp_mb__after_atomic() do { } while (0)
+
/**
* array_index_mask_nospec() - generate a mask that is ~0UL when the
* bounds check succeeds and 0 otherwise
--
2.16.4
next prev parent reply other threads:[~2020-03-25 10:55 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-25 10:55 [Xen-devel] [PATCH v7 0/5] xen/rcu: let rcu work better with core scheduling Juergen Gross
2020-03-25 10:55 ` Juergen Gross [this message]
2020-03-25 13:17 ` [Xen-devel] [PATCH v7 1/5] xen: introduce smp_mb__[after|before]_atomic() barriers Jan Beulich
2020-03-25 16:20 ` Julien Grall
2020-03-25 10:55 ` [Xen-devel] [PATCH v7 2/5] xen/rcu: don't use stop_machine_run() for rcu_barrier() Juergen Gross
2020-03-25 13:19 ` Jan Beulich
2020-03-25 16:13 ` Julien Grall
2020-03-26 6:58 ` Jan Beulich
2020-03-26 7:24 ` Jürgen Groß
2020-03-26 8:49 ` Jan Beulich
2020-03-26 8:50 ` Jürgen Groß
2020-03-26 9:14 ` Julien Grall
2020-03-25 10:55 ` [Xen-devel] [PATCH v7 3/5] xen: don't process rcu callbacks when holding a rcu_read_lock() Juergen Gross
2020-03-25 10:55 ` [Xen-devel] [PATCH v7 4/5] xen/rcu: add assertions to debug build Juergen Gross
2020-03-25 10:55 ` [Xen-devel] [PATCH v7 5/5] xen/rcu: add per-lock counter in debug builds Juergen Gross
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