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Diffstat (limited to 'arch/mips/kernel/head.S')
| -rw-r--r-- | arch/mips/kernel/head.S | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/arch/mips/kernel/head.S b/arch/mips/kernel/head.S new file mode 100644 index 000000000..61b73580b --- /dev/null +++ b/arch/mips/kernel/head.S @@ -0,0 +1,185 @@ +/* + * 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_KERNEL_CUMASK|\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 /* CONFIG_BOOT_RAW */ + + __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 +#if defined(CONFIG_MIPS_RAW_APPENDED_DTB) || \ + defined(CONFIG_MIPS_ELF_APPENDED_DTB) + + PTR_LA t2, __appended_dtb + +#ifdef CONFIG_CPU_BIG_ENDIAN + li t1, 0xd00dfeed +#else /* !CONFIG_CPU_BIG_ENDIAN */ + li t1, 0xedfe0dd0 +#endif /* !CONFIG_CPU_BIG_ENDIAN */ + lw t0, (t2) + beq t0, t1, dtb_found +#endif /* CONFIG_MIPS_RAW_APPENDED_DTB || CONFIG_MIPS_ELF_APPENDED_DTB */ + li t1, -2 + move t2, a1 + beq a0, t1, dtb_found + +#ifdef CONFIG_BUILTIN_DTB + PTR_LA t2, __dtb_start + PTR_LA t1, __dtb_end + bne t1, t2, dtb_found +#endif /* CONFIG_BUILTIN_DTB */ + + li t2, 0 +dtb_found: +#endif /* CONFIG_USE_OF */ + 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 +#ifdef CONFIG_64BIT + MTC0 zero, CP0_XCONTEXT +#endif + 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 /* !CONFIG_RELOCATABLE */ + j start_kernel +#endif /* !CONFIG_RELOCATABLE */ + 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 */ |