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authorCatalin Marinas <catalin.marinas@arm.com>2013-06-12 16:11:35 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2013-06-12 16:11:35 +0100
commitd822d2a1e33144967b01f9535ce217639aa75279 (patch)
treee6d93143b55a66f607493cf9d3c06b5cc79ac62b /arch/arm64/include/asm/sync_bitops.h
parentarm64: debug: consolidate software breakpoint handlers (diff)
parentMAINTAINERS: add myself as arm64/xen maintainer (diff)
downloadlinux-dev-d822d2a1e33144967b01f9535ce217639aa75279.tar.xz
linux-dev-d822d2a1e33144967b01f9535ce217639aa75279.zip
Merge tag 'xen-arm64-3.1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/sstabellini/xen into upstream
Introduce Xen support to ARM64 * tag 'xen-arm64-3.1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/sstabellini/xen: MAINTAINERS: add myself as arm64/xen maintainer arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64 arm64/xen: use XEN_IO_PROTO_ABI_ARM on ARM64 arm64/xen: implement ioremap_cached on arm64 arm64/xen: introduce asm/xen header files on arm64 arm/xen: define xen_remap as ioremap_cached
Diffstat (limited to 'arch/arm64/include/asm/sync_bitops.h')
-rw-r--r--arch/arm64/include/asm/sync_bitops.h26
1 files changed, 26 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/sync_bitops.h b/arch/arm64/include/asm/sync_bitops.h
new file mode 100644
index 000000000000..8da0bf4f7659
--- /dev/null
+++ b/arch/arm64/include/asm/sync_bitops.h
@@ -0,0 +1,26 @@
+#ifndef __ASM_SYNC_BITOPS_H__
+#define __ASM_SYNC_BITOPS_H__
+
+#include <asm/bitops.h>
+#include <asm/cmpxchg.h>
+
+/* sync_bitops functions are equivalent to the SMP implementation of the
+ * original functions, independently from CONFIG_SMP being defined.
+ *
+ * We need them because _set_bit etc are not SMP safe if !CONFIG_SMP. But
+ * under Xen you might be communicating with a completely external entity
+ * who might be on another CPU (e.g. two uniprocessor guests communicating
+ * via event channels and grant tables). So we need a variant of the bit
+ * ops which are SMP safe even on a UP kernel.
+ */
+
+#define sync_set_bit(nr, p) set_bit(nr, p)
+#define sync_clear_bit(nr, p) clear_bit(nr, p)
+#define sync_change_bit(nr, p) change_bit(nr, p)
+#define sync_test_and_set_bit(nr, p) test_and_set_bit(nr, p)
+#define sync_test_and_clear_bit(nr, p) test_and_clear_bit(nr, p)
+#define sync_test_and_change_bit(nr, p) test_and_change_bit(nr, p)
+#define sync_test_bit(nr, addr) test_bit(nr, addr)
+#define sync_cmpxchg cmpxchg
+
+#endif