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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-sparc/smpprim.h
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'include/asm-sparc/smpprim.h')
-rw-r--r--include/asm-sparc/smpprim.h54
1 files changed, 54 insertions, 0 deletions
diff --git a/include/asm-sparc/smpprim.h b/include/asm-sparc/smpprim.h
new file mode 100644
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+++ b/include/asm-sparc/smpprim.h
@@ -0,0 +1,54 @@
+/* $Id: smpprim.h,v 1.5 1996/08/29 09:48:49 davem Exp $
+ * 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.
+ */
+
+extern __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. */
+extern __inline__ __volatile__ smp_initlock(void *spinlock)
+{
+ /* Unset the lock. */
+ *((unsigned char *) spinlock) = 0;
+
+ return;
+}
+
+/* This routine spins until it acquires the lock at ADDR. */
+extern __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. */
+extern __inline__ __volatile__ smp_unlock(void *addr)
+{
+ *((unsigned char *) addr) = 0;
+}
+
+#endif /* !(__SPARC_SMPPRIM_H) */