source: mainline/kernel/arch/ia64/src/start.S

#
# 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 <abi/asmtool.h>
#include <arch/register.h>
#include <arch/mm/page.h>
#include <arch/mm/asid.h>
#include <mm/asid.h>

#define RR_MASK    (0xFFFFFFFF00000002)
#define RID_SHIFT  8
#define PS_SHIFT   2

#define KERNEL_TRANSLATION_I    0x0010000000000661
#define KERNEL_TRANSLATION_D    0x0010000000000661

.section K_TEXT_START, "ax"

stack0:

#
# Kernel entry point.
#
# This is where we are passed control from the boot code.
# Register contents:
#
#       r2      Address of the boot code's bootinfo structure.
#
SYMBOL(kernel_image_start)
        .auto

        mov psr.l = r0
        srlz.i
        srlz.d

        # Fill TR.i and TR.d using Region Register #VRN_KERNEL

        movl r8 = (VRN_KERNEL << VRN_SHIFT)
        mov r9 = rr[r8]

        movl r10 = (RR_MASK)
        and r9 = r10, r9
        movl r10 = (((RID_KERNEL7) << RID_SHIFT) | (KERNEL_PAGE_WIDTH << PS_SHIFT))
        or r9 = r10, r9

        mov rr[r8] = r9

        movl r8 = (VRN_KERNEL << VRN_SHIFT)
        mov cr.ifa = r8

        mov r11 = cr.itir
        movl r10 = (KERNEL_PAGE_WIDTH << PS_SHIFT)
        or r10 = r10, r11
        mov cr.itir = r10

        movl r10 = (KERNEL_TRANSLATION_I)
        itr.i itr[r0] = r10
        movl r10 = (KERNEL_TRANSLATION_D)
        itr.d dtr[r0] = r10

        # Initialize DCR

        movl r10 = (DCR_DM_MASK | DCR_DP_MASK | DCR_DK_MASK | DCR_DX_MASK | DCR_DR_MASK | DCR_DA_MASK | DCR_DD_MASK | DCR_LC_MASK)
        mov r9 = cr.dcr
        or r10 = r10, r9
        mov cr.dcr = r10

        # Initialize PSR

        movl r10 = (PSR_DT_MASK | PSR_RT_MASK | PSR_IT_MASK | PSR_IC_MASK)  /* Enable paging */
        mov r9 = psr

        or r10 = r10, r9
        mov cr.ipsr = r10
        mov cr.ifs = r0
        movl r8 = paging_start
        mov cr.iip = r8
        srlz.d
        srlz.i

        .explicit

        /*
         * Return From Interrupt is the only way to
         * fill the upper half word of PSR.
         */
        rfi ;;

paging_start:

        /*
         * Now we are paging.
         */

        #
        # Set Interruption Vector Address
        # (i.e. location of interruption vector table)
        #
        movl r8 = ivt ;;
        mov cr.iva = r8
        srlz.d ;;


        # Switch to register bank 1
        bsw.1

        # Initialize register stack
        mov ar.rsc = r0
        movl r8 = (VRN_KERNEL << VRN_SHIFT) ;;
        mov ar.bspstore = r8
        loadrs

        #
        # Initialize memory stack to some sane value and allocate a scratch area
        # on it.
        #
        movl sp = stack0 ;;
        add sp = -16, sp

        # Initialize gp (Global Pointer) register
        movl gp = __gp

        #
        # Initialize bootinfo on BSP.
        #
        movl r20 = (VRN_KERNEL << VRN_SHIFT) ;;
        or r20 = r20, r2 ;;
        addl r21 = @gprel(bootinfo), gp ;;
        st8 [r21] = r20

        ssm (1 << 19) ;; /* Disable f32 - f127 */
        srlz.i
        srlz.d ;;

        br.call.sptk.many b0 = ia64_pre_main
0:
        br.call.sptk.many b0 = main_bsp
0:
        br 0b