Merge branch 'devel'

[palacios-OLD.git] / kitten / include / arch-x86_64 / rwlock.h

diff --git a/kitten/include/arch-x86_64/rwlock.h b/kitten/include/arch-x86_64/rwlock.h
new file mode 100644 (file)
index 0000000..60036f3
--- /dev/null
+++ b/kitten/include/arch-x86_64/rwlock.h
@@ -0,0 +1,86 @@
+/* include/arch-x86_64/rwlock.h
+ *
+ *     Helpers used by both rw spinlocks and rw semaphores.
+ *
+ *     Based in part on code from semaphore.h and
+ *     spinlock.h Copyright 1996 Linus Torvalds.
+ *
+ *     Copyright 1999 Red Hat, Inc.
+ *     Copyright 2001,2002 SuSE labs 
+ *
+ *     Written by Benjamin LaHaise.
+ *
+ *     This program is free software; you can redistribute it and/or
+ *     modify it under the terms of the GNU General Public License
+ *     as published by the Free Software Foundation; either version
+ *     2 of the License, or (at your option) any later version.
+ */
+#ifndef _ARCH_X86_64_RWLOCK_H
+#define _ARCH_X86_64_RWLOCK_H
+
+#include <lwk/stringify.h>
+
+#define RW_LOCK_BIAS            0x01000000
+#define RW_LOCK_BIAS_STR       "0x01000000"
+
+#define __build_read_lock_ptr(rw, helper)   \
+       asm volatile("lock ; subl $1,(%0)\n\t" \
+                    "js 2f\n" \
+                    "1:\n" \
+                   LOCK_SECTION_START("") \
+                    "2:\tcall " helper "\n\t" \
+                    "jmp 1b\n" \
+                   LOCK_SECTION_END \
+                    ::"a" (rw) : "memory")
+
+#define __build_read_lock_const(rw, helper)   \
+       asm volatile("lock ; subl $1,%0\n\t" \
+                    "js 2f\n" \
+                    "1:\n" \
+                   LOCK_SECTION_START("") \
+                    "2:\tpushq %%rax\n\t" \
+                    "leaq %0,%%rax\n\t" \
+                    "call " helper "\n\t" \
+                    "popq %%rax\n\t" \
+                    "jmp 1b\n" \
+                   LOCK_SECTION_END \
+                    :"=m" (*((volatile int *)rw))::"memory")
+
+#define __build_read_lock(rw, helper)  do { \
+                                               if (__builtin_constant_p(rw)) \
+                                                       __build_read_lock_const(rw, helper); \
+                                               else \
+                                                       __build_read_lock_ptr(rw, helper); \
+                                       } while (0)
+
+#define __build_write_lock_ptr(rw, helper) \
+       asm volatile("lock ; subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \
+                    "jnz 2f\n" \
+                    "1:\n" \
+                    LOCK_SECTION_START("") \
+                    "2:\tcall " helper "\n\t" \
+                    "jmp 1b\n" \
+                    LOCK_SECTION_END \
+                    ::"a" (rw) : "memory")
+
+#define __build_write_lock_const(rw, helper) \
+       asm volatile("lock ; subl $" RW_LOCK_BIAS_STR ",%0\n\t" \
+                    "jnz 2f\n" \
+                    "1:\n" \
+                   LOCK_SECTION_START("") \
+                    "2:\tpushq %%rax\n\t" \
+                    "leaq %0,%%rax\n\t" \
+                    "call " helper "\n\t" \
+                    "popq %%rax\n\t" \
+                    "jmp 1b\n" \
+                   LOCK_SECTION_END \
+                    :"=m" (*((volatile long *)rw))::"memory")
+
+#define __build_write_lock(rw, helper) do { \
+                                               if (__builtin_constant_p(rw)) \
+                                                       __build_write_lock_const(rw, helper); \
+                                               else \
+                                                       __build_write_lock_ptr(rw, helper); \
+                                       } while (0)
+
+#endif