From: Feng Wu <feng.wu@intel.com>
To: xen-devel@lists.xen.org
Cc: Keir Fraser <keir@xen.org>, Feng Wu <feng.wu@intel.com>,
Jan Beulich <jbeulich@suse.com>,
Andrew Cooper <andrew.cooper3@citrix.com>
Subject: [v4 03/17] Add cmpxchg16b support for x86-64
Date: Thu, 23 Jul 2015 19:35:39 +0800 [thread overview]
Message-ID: <1437651353-5275-4-git-send-email-feng.wu@intel.com> (raw)
In-Reply-To: <1437651353-5275-1-git-send-email-feng.wu@intel.com>
This patch adds cmpxchg16b support for x86-64, so software
can perform 128-bit atomic write/read.
CC: Keir Fraser <keir@xen.org>
CC: Jan Beulich <jbeulich@suse.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Feng Wu <feng.wu@intel.com>
---
v4:
- Use pointer as the parameter of __cmpxchg16b().
- Use gcc's __uint128_t built-in type
- Make the parameters of __cmpxchg16b() void *
v3:
- Newly added.
xen/include/asm-x86/x86_64/system.h | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/xen/include/asm-x86/x86_64/system.h b/xen/include/asm-x86/x86_64/system.h
index 662813a..0267797 100644
--- a/xen/include/asm-x86/x86_64/system.h
+++ b/xen/include/asm-x86/x86_64/system.h
@@ -6,6 +6,38 @@
(unsigned long)(n),sizeof(*(ptr))))
/*
+ * Atomic 16 bytes compare and exchange. Compare OLD with MEM, if
+ * identical, store NEW in MEM. Return the initial value in MEM.
+ * Success is indicated by comparing RETURN with OLD.
+ *
+ * This function can only be called when cpu_has_cx16 is ture.
+ */
+
+static always_inline __uint128_t __cmpxchg16b(
+ volatile void *ptr, void *old, void *new)
+{
+ uint64_t prev_high, prev_low;
+ uint64_t new_high = (*(__uint128_t *)new) >> 64;
+ uint64_t new_low = (uint64_t)(*(__uint128_t *)new);
+ uint64_t old_high = (*(__uint128_t *)old) >> 64;
+ uint64_t old_low = (uint64_t)(*(__uint128_t *)old);
+
+ ASSERT(cpu_has_cx16);
+
+ asm volatile ( "lock; cmpxchg16b %4"
+ : "=d" (prev_high), "=a" (prev_low)
+ : "c" (new_high), "b" (new_low),
+ "m" (*__xg((volatile void *)ptr)),
+ "0" (old_high), "1" (old_low)
+ : "memory" );
+
+ return ( ((__uint128_t)prev_high) << 64 | prev_low );
+}
+
+#define cmpxchg16b(ptr,o,n) \
+ __cmpxchg16b((ptr), (__uint128_t *)(o), (__uint128_t *)(n))
+
+/*
* This function causes value _o to be changed to _n at location _p.
* If this access causes a fault then we return 1, otherwise we return 0.
* If no fault occurs then _o is updated to the value we saw at _p. If this
--
2.1.0
next prev parent reply other threads:[~2015-07-23 11:35 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-23 11:35 [v4 00/17] Add VT-d Posted-Interrupts support Feng Wu
2015-07-23 11:35 ` [v4 01/17] VT-d Posted-intterrupt (PI) design Feng Wu
2015-07-23 11:35 ` [v4 02/17] Add helper macro for X86_FEATURE_CX16 feature detection Feng Wu
2015-07-23 11:35 ` Feng Wu [this message]
2015-07-24 15:03 ` [v4 03/17] Add cmpxchg16b support for x86-64 Jan Beulich
2015-07-23 11:35 ` [v4 04/17] iommu: Add iommu_intpost to control VT-d Posted-Interrupts feature Feng Wu
2015-07-23 14:01 ` Andrew Cooper
2015-07-23 14:05 ` Andrew Cooper
2015-07-24 0:47 ` Wu, Feng
2015-07-23 11:35 ` [v4 05/17] vt-d: VT-d Posted-Interrupts feature detection Feng Wu
2015-07-24 15:05 ` Jan Beulich
2015-07-23 11:35 ` [v4 06/17] vmx: Extend struct pi_desc to support VT-d Posted-Interrupts Feng Wu
2015-07-23 11:35 ` [v4 07/17] vmx: Add some helper functions for Posted-Interrupts Feng Wu
2015-07-23 11:35 ` [v4 08/17] vmx: Initialize VT-d Posted-Interrupts Descriptor Feng Wu
2015-07-23 11:35 ` [v4 09/17] vmx: Suppress posting interrupts when 'SN' is set Feng Wu
2015-07-24 15:11 ` Jan Beulich
2015-07-23 11:35 ` [v4 10/17] vt-d: Extend struct iremap_entry to support VT-d Posted-Interrupts Feng Wu
2015-07-24 15:13 ` Jan Beulich
2015-07-23 11:35 ` [v4 11/17] vt-d: Add API to update IRTE when VT-d PI is used Feng Wu
2015-07-23 13:51 ` Andrew Cooper
2015-07-23 15:52 ` Jan Beulich
2015-07-23 15:55 ` Andrew Cooper
2015-07-23 16:00 ` Jan Beulich
2015-07-23 16:11 ` Andrew Cooper
2015-07-24 0:39 ` Wu, Feng
2015-07-24 15:27 ` Jan Beulich
2015-07-28 7:34 ` Wu, Feng
2015-08-11 10:18 ` Jan Beulich
2015-07-23 11:35 ` [v4 12/17] Update IRTE according to guest interrupt config changes Feng Wu
2015-07-23 11:35 ` [v4 13/17] vmx: posted-interrupt handling when vCPU is blocked Feng Wu
2015-07-23 11:35 ` [v4 14/17] vmx: Properly handle notification event when vCPU is running Feng Wu
2015-07-23 11:35 ` [v4 15/17] arm: add a dummy arch hooks for scheduler Feng Wu
2015-07-23 11:54 ` Julien Grall
2015-07-24 0:39 ` Wu, Feng
2015-07-23 11:58 ` Jan Beulich
2015-07-23 11:35 ` [v4 16/17] vmx: Add some scheduler hooks for VT-d posted interrupts Feng Wu
2015-07-23 12:50 ` Dario Faggioli
2015-07-24 0:49 ` Wu, Feng
2015-07-28 14:15 ` Dario Faggioli
2015-07-30 2:04 ` Wu, Feng
2015-07-30 18:26 ` Dario Faggioli
2015-08-11 10:23 ` Jan Beulich
2015-07-23 11:35 ` [v4 17/17] VT-d: Dump the posted format IRTE Feng Wu
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