linux_dsm_epyc7002/arch/mips/kernel/head.S
Jonas Gorski 15f37e1588 MIPS: store the appended dtb address in a variable
Instead of rewriting the arguments to match the UHI spec, store the
address of a appended or UHI supplied dtb in fw_supplied_dtb.

That way the original bootloader arugments are kept intact while still
making the use of an appended dtb invisible for mach code.

Mach code can still find out if it is an appended dtb by comparing
fw_arg1 with fw_supplied_dtb.

Signed-off-by: Jonas Gorski <jogo@openwrt.org>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: John Crispin <john@phrozen.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Alban Bedel <albeu@free.fr>
Cc: Daniel Gimpelevich <daniel@gimpelevich.san-francisco.ca.us>
Cc: Antony Pavlov <antonynpavlov@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13699/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-08-02 14:00:16 +02:00

175 lines
4.0 KiB
ArmAsm

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994, 1995 Waldorf Electronics
* Written by Ralf Baechle and Andreas Busse
* Copyright (C) 1994 - 99, 2003, 06 Ralf Baechle
* Copyright (C) 1996 Paul M. Antoine
* Modified for DECStation and hence R3000 support by Paul M. Antoine
* Further modifications by David S. Miller and Harald Koerfgen
* Copyright (C) 1999 Silicon Graphics, Inc.
* Kevin Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
* Copyright (C) 2000 MIPS Technologies, Inc. All rights reserved.
*/
#include <linux/init.h>
#include <linux/threads.h>
#include <asm/addrspace.h>
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/irqflags.h>
#include <asm/regdef.h>
#include <asm/mipsregs.h>
#include <asm/stackframe.h>
#include <kernel-entry-init.h>
/*
* For the moment disable interrupts, mark the kernel mode and
* set ST0_KX so that the CPU does not spit fire when using
* 64-bit addresses. A full initialization of the CPU's status
* register is done later in per_cpu_trap_init().
*/
.macro setup_c0_status set clr
.set push
mfc0 t0, CP0_STATUS
or t0, ST0_CU0|\set|0x1f|\clr
xor t0, 0x1f|\clr
mtc0 t0, CP0_STATUS
.set noreorder
sll zero,3 # ehb
.set pop
.endm
.macro setup_c0_status_pri
#ifdef CONFIG_64BIT
setup_c0_status ST0_KX 0
#else
setup_c0_status 0 0
#endif
.endm
.macro setup_c0_status_sec
#ifdef CONFIG_64BIT
setup_c0_status ST0_KX ST0_BEV
#else
setup_c0_status 0 ST0_BEV
#endif
.endm
#ifndef CONFIG_NO_EXCEPT_FILL
/*
* Reserved space for exception handlers.
* Necessary for machines which link their kernels at KSEG0.
*/
.fill 0x400
#endif
EXPORT(_stext)
#ifdef CONFIG_BOOT_RAW
/*
* Give us a fighting chance of running if execution beings at the
* kernel load address. This is needed because this platform does
* not have a ELF loader yet.
*/
FEXPORT(__kernel_entry)
j kernel_entry
#endif
__REF
NESTED(kernel_entry, 16, sp) # kernel entry point
kernel_entry_setup # cpu specific setup
setup_c0_status_pri
/* We might not get launched at the address the kernel is linked to,
so we jump there. */
PTR_LA t0, 0f
jr t0
0:
#ifdef CONFIG_USE_OF
#ifdef CONFIG_MIPS_RAW_APPENDED_DTB
PTR_LA t2, __appended_dtb
#ifdef CONFIG_CPU_BIG_ENDIAN
li t1, 0xd00dfeed
#else
li t1, 0xedfe0dd0
#endif
lw t0, (t2)
beq t0, t1, dtb_found
#endif
li t1, -2
beq a0, t1, dtb_found
move t2, a1
li t2, 0
dtb_found:
#endif
PTR_LA t0, __bss_start # clear .bss
LONG_S zero, (t0)
PTR_LA t1, __bss_stop - LONGSIZE
1:
PTR_ADDIU t0, LONGSIZE
LONG_S zero, (t0)
bne t0, t1, 1b
LONG_S a0, fw_arg0 # firmware arguments
LONG_S a1, fw_arg1
LONG_S a2, fw_arg2
LONG_S a3, fw_arg3
#ifdef CONFIG_USE_OF
LONG_S t2, fw_passed_dtb
#endif
MTC0 zero, CP0_CONTEXT # clear context register
PTR_LA $28, init_thread_union
/* Set the SP after an empty pt_regs. */
PTR_LI sp, _THREAD_SIZE - 32 - PT_SIZE
PTR_ADDU sp, $28
back_to_back_c0_hazard
set_saved_sp sp, t0, t1
PTR_SUBU sp, 4 * SZREG # init stack pointer
#ifdef CONFIG_RELOCATABLE
/* Copy kernel and apply the relocations */
jal relocate_kernel
/* Repoint the sp into the new kernel image */
PTR_LI sp, _THREAD_SIZE - 32 - PT_SIZE
PTR_ADDU sp, $28
set_saved_sp sp, t0, t1
PTR_SUBU sp, 4 * SZREG # init stack pointer
/*
* relocate_kernel returns the entry point either
* in the relocated kernel or the original if for
* some reason relocation failed - jump there now
* with instruction hazard barrier because of the
* newly sync'd icache.
*/
jr.hb v0
#else
j start_kernel
#endif
END(kernel_entry)
#ifdef CONFIG_SMP
/*
* SMP slave cpus entry point. Board specific code for bootstrap calls this
* function after setting up the stack and gp registers.
*/
NESTED(smp_bootstrap, 16, sp)
smp_slave_setup
setup_c0_status_sec
j start_secondary
END(smp_bootstrap)
#endif /* CONFIG_SMP */