This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / arch / i386 / lib / semaphore.S

diff --git a/arch/i386/lib/semaphore.S b/arch/i386/lib/semaphore.S
new file mode 100644 (file)
index 0000000..c01eb39
--- /dev/null
+++ b/arch/i386/lib/semaphore.S
@@ -0,0 +1,219 @@
+/*
+ * i386 semaphore implementation.
+ *
+ * (C) Copyright 1999 Linus Torvalds
+ *
+ * Portions Copyright 1999 Red Hat, Inc.
+ *
+ *     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.
+ *
+ * rw semaphores implemented November 1999 by Benjamin LaHaise <bcrl@kvack.org>
+ */
+
+#include <linux/linkage.h>
+#include <asm/rwlock.h>
+#include <asm/alternative-asm.i>
+#include <asm/frame.i>
+#include <asm/dwarf2.h>
+
+/*
+ * The semaphore operations have a special calling sequence that
+ * allow us to do a simpler in-line version of them. These routines
+ * need to convert that sequence back into the C sequence when
+ * there is contention on the semaphore.
+ *
+ * %eax contains the semaphore pointer on entry. Save the C-clobbered
+ * registers (%eax, %edx and %ecx) except %eax whish is either a return
+ * value or just clobbered..
+ */
+       .section .sched.text
+ENTRY(__down_failed)
+       CFI_STARTPROC
+       FRAME
+       pushl %edx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET edx,0
+       pushl %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       call __down
+       popl %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE ecx
+       popl %edx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE edx
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__down_failed)
+
+ENTRY(__down_failed_interruptible)
+       CFI_STARTPROC
+       FRAME
+       pushl %edx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET edx,0
+       pushl %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       call __down_interruptible
+       popl %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE ecx
+       popl %edx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE edx
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__down_failed_interruptible)
+
+ENTRY(__down_failed_trylock)
+       CFI_STARTPROC
+       FRAME
+       pushl %edx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET edx,0
+       pushl %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       call __down_trylock
+       popl %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE ecx
+       popl %edx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE edx
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__down_failed_trylock)
+
+ENTRY(__up_wakeup)
+       CFI_STARTPROC
+       FRAME
+       pushl %edx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET edx,0
+       pushl %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       call __up
+       popl %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE ecx
+       popl %edx
+       CFI_ADJUST_CFA_OFFSET -4
+       CFI_RESTORE edx
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__up_wakeup)
+
+/*
+ * rw spinlock fallbacks
+ */
+#ifdef CONFIG_SMP
+ENTRY(__write_lock_failed)
+       CFI_STARTPROC simple
+       FRAME
+2:     LOCK_PREFIX
+       addl    $ RW_LOCK_BIAS,(%eax)
+1:     rep; nop
+       cmpl    $ RW_LOCK_BIAS,(%eax)
+       jne     1b
+       LOCK_PREFIX
+       subl    $ RW_LOCK_BIAS,(%eax)
+       jnz     2b
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__write_lock_failed)
+
+ENTRY(__read_lock_failed)
+       CFI_STARTPROC
+       FRAME
+2:     LOCK_PREFIX
+       incl    (%eax)
+1:     rep; nop
+       cmpl    $1,(%eax)
+       js      1b
+       LOCK_PREFIX
+       decl    (%eax)
+       js      2b
+       ENDFRAME
+       ret
+       CFI_ENDPROC
+       END(__read_lock_failed)
+
+#endif
+
+#ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM
+
+/* Fix up special calling conventions */
+ENTRY(call_rwsem_down_read_failed)
+       CFI_STARTPROC
+       push %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       push %edx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET edx,0
+       call rwsem_down_read_failed
+       pop %edx
+       CFI_ADJUST_CFA_OFFSET -4
+       pop %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+       ret
+       CFI_ENDPROC
+       END(call_rwsem_down_read_failed)
+
+ENTRY(call_rwsem_down_write_failed)
+       CFI_STARTPROC
+       push %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       calll rwsem_down_write_failed
+       pop %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+       ret
+       CFI_ENDPROC
+       END(call_rwsem_down_write_failed)
+
+ENTRY(call_rwsem_wake)
+       CFI_STARTPROC
+       decw %dx    /* do nothing if still outstanding active readers */
+       jnz 1f
+       push %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       call rwsem_wake
+       pop %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+1:     ret
+       CFI_ENDPROC
+       END(call_rwsem_wake)
+
+/* Fix up special calling conventions */
+ENTRY(call_rwsem_downgrade_wake)
+       CFI_STARTPROC
+       push %ecx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET ecx,0
+       push %edx
+       CFI_ADJUST_CFA_OFFSET 4
+       CFI_REL_OFFSET edx,0
+       call rwsem_downgrade_wake
+       pop %edx
+       CFI_ADJUST_CFA_OFFSET -4
+       pop %ecx
+       CFI_ADJUST_CFA_OFFSET -4
+       ret
+       CFI_ENDPROC
+       END(call_rwsem_downgrade_wake)
+
+#endif