freebsd-dev/sys/powerpc/aim/locore64.S
Nathan Whitehorn d929c32b7f Enter 64-bit mode as early as possible in the 64-bit PowerPC boot sequence.
Most of the effect of setting MSR[SF] is that the CPU will stop ignoring
the high 32 bits of registers containing addresses in load/store
instructions. As such, the kernel was setting it only when it began to
need access to high memory. MSR[SF] also affects the operation of some
conditional instructions, however, and so setting it at late times could
subtly break code at very early times. This fixes use of the FDT mode in
loader, and FDT boot more generally, on 64-bit PowerPC systems.

Hardware provided by: IBM LTC
Approved by: re (kib)
2016-06-26 18:43:42 +00:00

140 lines
3.2 KiB
ArmAsm

/* $FreeBSD$ */
/*-
* Copyright (C) 2010-2016 Nathan Whitehorn
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* 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 TOOLS GMBH 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.
*
* $FreeBSD$
*/
#include "assym.s"
#include <sys/syscall.h>
#include <machine/trap.h>
#include <machine/param.h>
#include <machine/spr.h>
#include <machine/asm.h>
#ifdef _CALL_ELF
.abiversion _CALL_ELF
#endif
/* Glue for linker script */
.globl kernbase
.set kernbase, KERNBASE
/*
* Globals
*/
.data
.align 3
GLOBAL(__startkernel)
.llong begin
GLOBAL(__endkernel)
.llong end
.align 4
#define TMPSTKSZ 16384 /* 16K temporary stack */
GLOBAL(tmpstk)
.space TMPSTKSZ
TOC_ENTRY(tmpstk)
.text
.globl btext
btext:
/*
* Main kernel entry point.
*
* Calling convention:
* r3: Flattened Device Tree pointer (or zero)
* r4: ignored
* r5: OF client interface pointer (or zero)
* r6: Loader metadata pointer (or zero)
*/
.text
ASENTRY_NOPROF(__start)
/* Set 64-bit mode if not yet set before branching to C */
mfmsr %r20
li %r21,1
insrdi %r20,%r21,1,0
mtmsrd %r20
isync
nop /* Make this block a multiple of 8 bytes */
/* Set up the TOC pointer */
b 0f
.align 3
0: nop
bl 1f
.llong __tocbase + 0x8000 - .
1: mflr %r2
ld %r1,0(%r2)
add %r2,%r1,%r2
/* Get load offset */
ld %r31,-0x8000(%r2) /* First TOC entry is TOC base */
subf %r31,%r31,%r2 /* Subtract from real TOC base to get base */
/* Set up the stack pointer */
ld %r1,TOC_REF(tmpstk)(%r2)
addi %r1,%r1,TMPSTKSZ-96
add %r1,%r1,%r31
/* Relocate kernel */
std %r3,48(%r1)
std %r4,56(%r1)
std %r5,64(%r1)
std %r6,72(%r1)
bl 1f
.llong _DYNAMIC-.
1: mflr %r3
ld %r4,0(%r3)
add %r3,%r4,%r3
mr %r4,%r31
bl elf_reloc_self
nop
ld %r3,48(%r1)
ld %r4,56(%r1)
ld %r5,64(%r1)
ld %r6,72(%r1)
/* Begin CPU init */
mr %r4,%r2 /* Replace ignored r4 with tocbase for trap handlers */
bl powerpc_init
nop
/* Set stack pointer to new value and branch to mi_startup */
mr %r1, %r3
li %r3, 0
std %r3, 0(%r1)
bl mi_startup
nop
/* Unreachable */
b .
#include <powerpc/aim/trap_subr64.S>