Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*
 * 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.h>
#include <asm/frame.h>
#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