--- /dev/null
+ /*
+ * Save registers before calling assembly functions. This avoids
+ * disturbance of register allocation in some inline assembly constructs.
+ * Copyright 2001,2002 by Andi Kleen, SuSE Labs.
+ * Subject to the GNU public license, v.2. No warranty of any kind.
+ * $Id: thunk.S,v 1.2 2002/03/13 20:06:58 ak Exp $
+ */
+
+ #include <lwk/linkage.h>
+ #include <arch/dwarf2.h>
+ #include <arch/calling.h>
+ #include <arch/rwlock.h>
+
+ /* rdi: arg1 ... normal C conventions. rax is saved/restored. */
+ .macro thunk name,func
+ .globl \name
+\name:
+ CFI_STARTPROC
+ SAVE_ARGS
+ call \func
+ jmp restore
+ CFI_ENDPROC
+ .endm
+
+ /* rdi: arg1 ... normal C conventions. rax is passed from C. */
+ .macro thunk_retrax name,func
+ .globl \name
+\name:
+ CFI_STARTPROC
+ SAVE_ARGS
+ call \func
+ jmp restore_norax
+ CFI_ENDPROC
+ .endm
+
+
+#if 0
+ .section .sched.text
+#ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM
+ thunk rwsem_down_read_failed_thunk,rwsem_down_read_failed
+ thunk rwsem_down_write_failed_thunk,rwsem_down_write_failed
+ thunk rwsem_wake_thunk,rwsem_wake
+ thunk rwsem_downgrade_thunk,rwsem_downgrade_wake
+#endif
+
+ thunk __down_failed,__down
+ thunk_retrax __down_failed_interruptible,__down_interruptible
+ thunk_retrax __down_failed_trylock,__down_trylock
+ thunk __up_wakeup,__up
+#endif
+
+ /* SAVE_ARGS below is used only for the .cfi directives it contains. */
+ CFI_STARTPROC
+ SAVE_ARGS
+restore:
+ RESTORE_ARGS
+ ret
+ CFI_ENDPROC
+
+ CFI_STARTPROC
+ SAVE_ARGS
+restore_norax:
+ RESTORE_ARGS 1
+ ret
+ CFI_ENDPROC
+
+/* Support for read/write spinlocks. */
+ .text
+/* rax: pointer to rwlock_t */
+ENTRY(__write_lock_failed)
+ lock
+ addl $RW_LOCK_BIAS,(%rax)
+1: rep
+ nop
+ cmpl $RW_LOCK_BIAS,(%rax)
+ jne 1b
+ lock
+ subl $RW_LOCK_BIAS,(%rax)
+ jnz __write_lock_failed
+ ret
+
+/* rax: pointer to rwlock_t */
+ENTRY(__read_lock_failed)
+ lock
+ incl (%rax)
+1: rep
+ nop
+ cmpl $1,(%rax)
+ js 1b
+ lock
+ decl (%rax)
+ js __read_lock_failed
+ ret
