Subversion Repositories HelenOS-historic

#

# Copyright (C) 2005 Jakub Jermar

# All rights reserved.

#

# Redistribution and use in source and binary forms, with or without

# modification, are permitted provided that the following conditions

# are met:

#

# - Redistributions of source code must retain the above copyright

#   notice, this list of conditions and the following disclaimer.

# - Redistributions in binary form must reproduce the above copyright

#   notice, this list of conditions and the following disclaimer in the

#   documentation and/or other materials provided with the distribution.

# - The name of the author may not be used to endorse or promote products

#   derived from this software without specific prior written permission.

#

# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#

#include <arch/context_offset.h>

#include <arch/stack.h>

/**

 * Both context_save_arch() and context_restore_arch() are

 * leaf-optimized procedures. Both of them touch %sp and

 * %fp and thus break SCD 2.4 compliance. However, these

 * functions are special enough to be allowed this

 * kind of behavior. Moreover, this kind of optimization

 * is very important and prevents any window spill/

 * fill/clean traps in these very core kernel functions.

 */

.text   

.global context_save_arch

.global context_restore_arch

.macro CONTEXT_STORE r

	stx %o1, [\r + OFFSET_O1]

	stx %o2, [\r + OFFSET_O2]

	stx %o3, [\r + OFFSET_O3]

	stx %o4, [\r + OFFSET_O4]

	stx %o5, [\r + OFFSET_O5]

	stx %o7, [\r + OFFSET_PC]

	stx %sp, [\r + OFFSET_SP]

	stx %fp, [\r + OFFSET_FP]

.endm

.macro CONTEXT_LOAD r

	ldx [\r + OFFSET_O1], %o1

	ldx [\r + OFFSET_O2], %o2

	ldx [\r + OFFSET_O3], %o3

	ldx [\r + OFFSET_O4], %o4

	ldx [\r + OFFSET_O5], %o5

	ldx [\r + OFFSET_PC], %o7

	ldx [\r + OFFSET_SP], %sp

	ldx [\r + OFFSET_FP], %fp

.endm

context_save_arch:

	CONTEXT_STORE %o0

	retl

	mov 1, %o0		! context_save_arch returns 1

context_restore_arch:

	#

	# Flush all active windows.

	# This is essential, because CONTEXT_LOAD overwrites

	# %sp of CWP - 1 with the value written to %fp of CWP.

	# Flushing all active windows mitigates this problem

	# as CWP - 1 becomes the overlap window.

	#

	flushw

	CONTEXT_LOAD %o0

	retl

	xor %o0, %o0, %o0	! context_restore_arch returns 0