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From: Andrew Jones <drjones@redhat.com>
To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: christoffer.dall@linaro.org, pbonzini@redhat.com
Subject: [PATCH v7 10/14] arm: Add spinlock implementation
Date: Wed, 16 Jul 2014 10:47:39 +0200	[thread overview]
Message-ID: <1405500463-20713-11-git-send-email-drjones@redhat.com> (raw)
In-Reply-To: <1405500463-20713-1-git-send-email-drjones@redhat.com>

From: Christoffer Dall <christoffer.dall@linaro.org>

Add simple busy-wait spinlock implementation for ARM.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 config/config-arm.mak  |  3 ++-
 lib/arm/asm/spinlock.h |  9 ++-------
 lib/arm/spinlock.c     | 28 ++++++++++++++++++++++++++++
 3 files changed, 32 insertions(+), 8 deletions(-)
 create mode 100644 lib/arm/spinlock.c

diff --git a/config/config-arm.mak b/config/config-arm.mak
index ff965428e0e5b..b7239810183d1 100644
--- a/config/config-arm.mak
+++ b/config/config-arm.mak
@@ -37,7 +37,8 @@ cflatobjs += \
 	lib/virtio-mmio.o \
 	lib/chr-testdev.o \
 	lib/arm/io.o \
-	lib/arm/setup.o
+	lib/arm/setup.o \
+	lib/arm/spinlock.o
 
 libeabi = lib/arm/libeabi.a
 eabiobjs = lib/arm/eabi_compat.o
diff --git a/lib/arm/asm/spinlock.h b/lib/arm/asm/spinlock.h
index 04f5a1a5538e2..2118a4b3751e0 100644
--- a/lib/arm/asm/spinlock.h
+++ b/lib/arm/asm/spinlock.h
@@ -5,12 +5,7 @@ struct spinlock {
 	int v;
 };
 
-//TODO
-static inline void spin_lock(struct spinlock *lock __unused)
-{
-}
-static inline void spin_unlock(struct spinlock *lock __unused)
-{
-}
+extern void spin_lock(struct spinlock *lock);
+extern void spin_unlock(struct spinlock *lock);
 
 #endif /* _ASMARM_SPINLOCK_H_ */
diff --git a/lib/arm/spinlock.c b/lib/arm/spinlock.c
new file mode 100644
index 0000000000000..d8a6d4c3383d6
--- /dev/null
+++ b/lib/arm/spinlock.c
@@ -0,0 +1,28 @@
+#include "libcflat.h"
+#include "asm/spinlock.h"
+#include "asm/barrier.h"
+
+void spin_lock(struct spinlock *lock)
+{
+	u32 val, fail;
+
+	dmb();
+	do {
+		asm volatile(
+		"1:	ldrex	%0, [%2]\n"
+		"	teq	%0, #0\n"
+		"	bne	1b\n"
+		"	mov	%0, #1\n"
+		"	strex	%1, %0, [%2]\n"
+		: "=&r" (val), "=&r" (fail)
+		: "r" (&lock->v)
+		: "cc" );
+	} while (fail);
+	dmb();
+}
+
+void spin_unlock(struct spinlock *lock)
+{
+	lock->v = 0;
+	dmb();
+}
-- 
1.9.3


  parent reply	other threads:[~2014-07-16  8:48 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-16  8:47 [PATCH v7 00/14] kvm-unit-tests/arm: initial drop Andrew Jones
2014-07-16  8:47 ` [PATCH v7 02/14] add support for Linux device trees Andrew Jones
2014-07-16  8:47 ` [PATCH v7 03/14] Introduce asm-generic/*.h files Andrew Jones
2014-07-16  8:47 ` [PATCH v7 04/14] Introduce lib/alloc Andrew Jones
2014-07-16  8:47 ` [PATCH v7 05/14] add minimal virtio support for devtree virtio-mmio Andrew Jones
2014-07-16  8:47 ` [PATCH v7 06/14] lib/asm-generic: add page.h and virt_to_phys/phys_to_virt Andrew Jones
2014-07-16  8:47 ` [PATCH v7 07/14] virtio: add minimal support for virtqueues Andrew Jones
2014-07-16  8:47 ` [PATCH v7 08/14] Introduce chr-testdev Andrew Jones
2014-07-16  9:31   ` Levente Kurusa
2014-07-16  9:33     ` Andrew Jones
2014-07-22 18:06       ` Radim Krčmář
2014-07-16  8:47 ` [PATCH v7 09/14] arm: initial drop Andrew Jones
2014-07-16  9:22   ` Paolo Bonzini
2014-07-16  9:39     ` Andrew Jones
2014-07-16 10:59       ` Paolo Bonzini
2014-07-16  8:47 ` Andrew Jones [this message]
2014-07-16  8:47 ` [PATCH v7 11/14] arm: Add IO accessors to avoid register-writeback Andrew Jones
2014-07-16  8:47 ` [PATCH v7 12/14] arm: Add arch-specific asm/page.h and __va/__pa Andrew Jones
2014-07-16  8:47 ` [PATCH v7 13/14] arm: add useful headers from the Linux kernel Andrew Jones
2014-07-16  8:47 ` [PATCH v7 14/14] arm: vectors support Andrew Jones
2014-08-22 18:51 ` [PATCH v7 00/14] kvm-unit-tests/arm: initial drop Paolo Bonzini

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