1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 1994, 1995 Waldorf Electronics 7 * Written by Ralf Baechle and Andreas Busse 8 * Copyright (C) 1994 - 99, 2003, 06 Ralf Baechle 9 * Copyright (C) 1996 Paul M. Antoine 10 * Modified for DECStation and hence R3000 support by Paul M. Antoine 11 * Further modifications by David S. Miller and Harald Koerfgen 12 * Copyright (C) 1999 Silicon Graphics, Inc. 13 * Kevin Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com 14 * Copyright (C) 2000 MIPS Technologies, Inc. All rights reserved. 15 */ 16 #include <linux/init.h> 17 #include <linux/threads.h> 18 19 #include <asm/addrspace.h> 20 #include <asm/asm.h> 21 #include <asm/asmmacro.h> 22 #include <asm/irqflags.h> 23 #include <asm/regdef.h> 24 #include <asm/mipsregs.h> 25 #include <asm/stackframe.h> 26 27 #include <kernel-entry-init.h> 28 29 /* 30 * For the moment disable interrupts, mark the kernel mode and 31 * set ST0_KX so that the CPU does not spit fire when using 32 * 64-bit addresses. A full initialization of the CPU's status 33 * register is done later in per_cpu_trap_init(). 34 */ 35 .macro setup_c0_status set clr 36 .set push 37 mfc0 t0, CP0_STATUS 38 or t0, ST0_KERNEL_CUMASK|\set|0x1f|\clr 39 xor t0, 0x1f|\clr 40 mtc0 t0, CP0_STATUS 41 .set noreorder 42 sll zero,3 # ehb 43 .set pop 44 .endm 45 46 .macro setup_c0_status_pri 47 #ifdef CONFIG_64BIT 48 setup_c0_status ST0_KX 0 49 #else 50 setup_c0_status 0 0 51 #endif 52 .endm 53 54 .macro setup_c0_status_sec 55 #ifdef CONFIG_64BIT 56 setup_c0_status ST0_KX ST0_BEV 57 #else 58 setup_c0_status 0 ST0_BEV 59 #endif 60 .endm 61 62 #ifndef CONFIG_NO_EXCEPT_FILL 63 /* 64 * Reserved space for exception handlers. 65 * Necessary for machines which link their kernels at KSEG0. 66 */ 67 .fill 0x400 68 #endif 69 70 EXPORT(_stext) 71 72 #ifdef CONFIG_BOOT_RAW 73 /* 74 * Give us a fighting chance of running if execution beings at the 75 * kernel load address. This is needed because this platform does 76 * not have a ELF loader yet. 77 */ 78 FEXPORT(__kernel_entry) 79 j kernel_entry 80 #endif /* CONFIG_BOOT_RAW */ 81 82 __REF 83 84 NESTED(kernel_entry, 16, sp) # kernel entry point 85 86 kernel_entry_setup # cpu specific setup 87 88 setup_c0_status_pri 89 90 /* We might not get launched at the address the kernel is linked to, 91 so we jump there. */ 92 PTR_LA t0, 0f 93 jr t0 94 0: 95 96 PTR_LA t0, __bss_start # clear .bss 97 LONG_S zero, (t0) 98 PTR_LA t1, __bss_stop - LONGSIZE 99 1: 100 PTR_ADDIU t0, LONGSIZE 101 LONG_S zero, (t0) 102 bne t0, t1, 1b 103 104 LONG_S a0, fw_arg0 # firmware arguments 105 LONG_S a1, fw_arg1 106 LONG_S a2, fw_arg2 107 LONG_S a3, fw_arg3 108 109 MTC0 zero, CP0_CONTEXT # clear context register 110 #ifdef CONFIG_64BIT 111 MTC0 zero, CP0_XCONTEXT 112 #endif 113 PTR_LA $28, init_thread_union 114 /* Set the SP after an empty pt_regs. */ 115 PTR_LI sp, _THREAD_SIZE - 32 - PT_SIZE 116 PTR_ADDU sp, $28 117 back_to_back_c0_hazard 118 set_saved_sp sp, t0, t1 119 PTR_SUBU sp, 4 * SZREG # init stack pointer 120 121 #ifdef CONFIG_RELOCATABLE 122 /* Copy kernel and apply the relocations */ 123 jal relocate_kernel 124 125 /* Repoint the sp into the new kernel image */ 126 PTR_LI sp, _THREAD_SIZE - 32 - PT_SIZE 127 PTR_ADDU sp, $28 128 set_saved_sp sp, t0, t1 129 PTR_SUBU sp, 4 * SZREG # init stack pointer 130 131 /* 132 * relocate_kernel returns the entry point either 133 * in the relocated kernel or the original if for 134 * some reason relocation failed - jump there now 135 * with instruction hazard barrier because of the 136 * newly sync'd icache. 137 */ 138 jr.hb v0 139 #else /* !CONFIG_RELOCATABLE */ 140 j start_kernel 141 #endif /* !CONFIG_RELOCATABLE */ 142 END(kernel_entry) 143 144 #ifdef CONFIG_SMP 145 /* 146 * SMP slave cpus entry point. Board specific code for bootstrap calls this 147 * function after setting up the stack and gp registers. 148 */ 149 NESTED(smp_bootstrap, 16, sp) 150 smp_slave_setup 151 setup_c0_status_sec 152 j start_secondary 153 END(smp_bootstrap) 154 #endif /* CONFIG_SMP */ 155