shared/start/start.S

0001 #
0002 # Copyright (c) 2006 Martin Decky
0003 # Copyright (c) 2006 Jakub Jermar
0004 # All rights reserved.
0005 #
0006 # Redistribution and use in source and binary forms, with or without
0007 # modification, are permitted provided that the following conditions
0008 # are met:
0009 #
0010 # - Redistributions of source code must retain the above copyright
0011 #   notice, this list of conditions and the following disclaimer.
0012 # - Redistributions in binary form must reproduce the above copyright
0013 #   notice, this list of conditions and the following disclaimer in the
0014 #   documentation and/or other materials provided with the distribution.
0015 # - The name of the author may not be used to endorse or promote products
0016 #   derived from this software without specific prior written permission.
0017 #
0018 # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
0019 # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
0020 # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
0021 # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
0022 # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
0023 # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
0024 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
0025 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
0026 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
0027 # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
0028 #
0029
0030 /*
0031  * start.S
0032  *
0033  * Start code for Sparc64 RTEMS
0034  *
0035  * This is based on the boot.S file of the HelenOS sparc64 architecture.
0036  * http://www.helenos.org/
0037  * ${helenos}/boot/arch/sparc64/loader/boot.S
0038  *
0039  * Modifications for the RTEMS executive are
0040  *   COPYRIGHT (c) 2010 Gedare Bloom.
0041  *   COPYRIGHT (c) 2010 Eugen Leontie.
0042  */
0043
0044 #include <rtems/asm.h>
0045 #include <rtems/score/cpu.h>
0046
0047 #define PSTATE_PRIV_BIT 4
0048
0049 .register %g2, #scratch
0050 .register %g3, #scratch
0051 .register %g6, #scratch
0052 .register %g7, #scratch
0053
0054 .section BOOTSTRAP, "ax"
0055
0056 PUBLIC(_start)
0057   .global _start
0058   SYM(_start):
0059     start:
0060     b 1f
0061     nop
0062
0063     /*
0064      * This header forces SILO to load the image at 0x4000.
0065      * More precisely, SILO will think this is an old version of Linux.
0066      */
0067     .ascii "HdrS"
0068     .word 0
0069     .half 0
0070     .half 0
0071     .half 0
0072     .half 0
0073     .global silo_ramdisk_image
0074     silo_ramdisk_image:
0075     .word 0
0076     .global silo_ramdisk_size
0077     silo_ramdisk_size:
0078     .word 0
0079
0080     .align 8
0081     1:
0082     /*
0083      * Disable interrupts and disable address masking.
0084      */
0085     wrpr %g0, PSTATE_PRIV_BIT, %pstate
0086
0087     wrpr %g0, SPARC_NUMBER_OF_REGISTER_WINDOWS - 2, %cansave    ! set maximum saveable windows
0088     wrpr %g0, 0, %canrestore        ! get rid of windows we will never need again
0089     wrpr %g0, 0, %otherwin          ! make sure the window state is consistent
0090     wrpr %g0, SPARC_NUMBER_OF_REGISTER_WINDOWS - 1, %cleanwin   ! prevent needless clean_window traps for kernel
0091
0092   /* g4 needs to be cleared for gcc */
0093   mov %g0, %g4
0094
0095   /* Clear the bss */
0096     setx    SYM(bss_start), %l0, %g2    ! g2 = start of bss
0097     setx    SYM(_end), %l0, %g3         ! g3 = end of bss
0098 zerobss:
0099     stx %g0, [%g2]
0100     add %g2, 8, %g2
0101     cmp %g2, %g3
0102     bleu,a  zerobss
0103     nop
0104
0105   /* Install stack */
0106     set SYM(_ISR_Stack_area_end), %sp
0107     add %sp, -SPARC64_MINIMUM_STACK_FRAME_SIZE, %sp
0108     add %sp, -STACK_BIAS, %sp
0109
0110   /* BSP-specific pre-bootcard initializations */
0111   call SYM(_BSP_init)
0112   nop
0113
0114     setx ofw_cif, %l0, %l1
0115
0116     call ofw_init       ! initialize OpenFirmware
0117     stx %o4, [%l1]
0118
0119   call bootstrap
0120   nop
0121
0122
0123   /* Set up ISR handler for interrupt enable/disable */
0124     setx SYM(syscall), %l0, %o1
0125     setx param_space, %l0, %o2
0126     call SYM(_CPU_ISR_install_raw_handler)
0127     mov 0x100, %o0
0128
0129   /* Don't need to copy initialized data to RAM--link puts all in RAM already */
0130
0131     mov %g0, %o0        ! clear command line passed to main
0132     call SYM(boot_card)
0133     sub %sp, 0x60, %sp      ! make room on stack (necessary?)
0134
0135   call SYM(halt)
0136   nop
0137
0138 halted: nop
0139         b SYM(halted)
0140
0141 .section BOOTSTRAP
0142   .align CPU_ALIGNMENT
0143   param_space:
0144     .space 8