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authorIngo Molnar <mingo@elte.hu>2008-07-29 00:07:55 +0200
committerIngo Molnar <mingo@elte.hu>2008-07-29 00:07:55 +0200
commitcb28a1bbdb4790378e7366d6c9ee1d2340b84f92 (patch)
tree316436f77dac75335fd2c3ef5f109e71606c50d3 /arch/sparc/include/asm/smpprim.h
parentb6d4f7e3ef25beb8c658c97867d98883e69dc544 (diff)
parentf934fb19ef34730263e6afc01e8ec27a8a71470f (diff)
Merge branch 'linus' into core/generic-dma-coherent
Conflicts: arch/x86/Kconfig Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/sparc/include/asm/smpprim.h')
-rw-r--r--arch/sparc/include/asm/smpprim.h54
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/sparc/include/asm/smpprim.h b/arch/sparc/include/asm/smpprim.h
new file mode 100644
index 00000000000..eb849d862c6
--- /dev/null
+++ b/arch/sparc/include/asm/smpprim.h
@@ -0,0 +1,54 @@
+/*
+ * smpprim.h: SMP locking primitives on the Sparc
+ *
+ * God knows we won't be actually using this code for some time
+ * but I thought I'd write it since I knew how.
+ *
+ * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+#ifndef __SPARC_SMPPRIM_H
+#define __SPARC_SMPPRIM_H
+
+/* Test and set the unsigned byte at ADDR to 1. Returns the previous
+ * value. On the Sparc we use the ldstub instruction since it is
+ * atomic.
+ */
+
+static inline __volatile__ char test_and_set(void *addr)
+{
+ char state = 0;
+
+ __asm__ __volatile__("ldstub [%0], %1 ! test_and_set\n\t"
+ "=r" (addr), "=r" (state) :
+ "0" (addr), "1" (state) : "memory");
+
+ return state;
+}
+
+/* Initialize a spin-lock. */
+static inline __volatile__ smp_initlock(void *spinlock)
+{
+ /* Unset the lock. */
+ *((unsigned char *) spinlock) = 0;
+
+ return;
+}
+
+/* This routine spins until it acquires the lock at ADDR. */
+static inline __volatile__ smp_lock(void *addr)
+{
+ while(test_and_set(addr) == 0xff)
+ ;
+
+ /* We now have the lock */
+ return;
+}
+
+/* This routine releases the lock at ADDR. */
+static inline __volatile__ smp_unlock(void *addr)
+{
+ *((unsigned char *) addr) = 0;
+}
+
+#endif /* !(__SPARC_SMPPRIM_H) */