1 /* 2 * (C) Copyright 2008-2011 3 * Graeme Russ, <graeme.russ@gmail.com> 4 * 5 * (C) Copyright 2002 6 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se> 7 * 8 * (C) Copyright 2002 9 * Sysgo Real-Time Solutions, GmbH <www.elinos.com> 10 * Marius Groeger <mgroeger@sysgo.de> 11 * 12 * (C) Copyright 2002 13 * Sysgo Real-Time Solutions, GmbH <www.elinos.com> 14 * Alex Zuepke <azu@sysgo.de> 15 * 16 * See file CREDITS for list of people who contributed to this 17 * project. 18 * 19 * This program is free software; you can redistribute it and/or 20 * modify it under the terms of the GNU General Public License as 21 * published by the Free Software Foundation; either version 2 of 22 * the License, or (at your option) any later version. 23 * 24 * This program is distributed in the hope that it will be useful, 25 * but WITHOUT ANY WARRANTY; without even the implied warranty of 26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 27 * GNU General Public License for more details. 28 * 29 * You should have received a copy of the GNU General Public License 30 * along with this program; if not, write to the Free Software 31 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 32 * MA 02111-1307 USA 33 */ 34 35 #include <common.h> 36 #include <command.h> 37 #include <asm/processor.h> 38 #include <asm/processor-flags.h> 39 #include <asm/interrupt.h> 40 #include <linux/compiler.h> 41 42 /* 43 * Constructor for a conventional segment GDT (or LDT) entry 44 * This is a macro so it can be used in initialisers 45 */ 46 #define GDT_ENTRY(flags, base, limit) \ 47 ((((base) & 0xff000000ULL) << (56-24)) | \ 48 (((flags) & 0x0000f0ffULL) << 40) | \ 49 (((limit) & 0x000f0000ULL) << (48-16)) | \ 50 (((base) & 0x00ffffffULL) << 16) | \ 51 (((limit) & 0x0000ffffULL))) 52 53 struct gdt_ptr { 54 u16 len; 55 u32 ptr; 56 } __packed; 57 58 static void reload_gdt(void) 59 { 60 /* 61 * There are machines which are known to not boot with the GDT 62 * being 8-byte unaligned. Intel recommends 16 byte alignment 63 */ 64 static const u64 boot_gdt[] __attribute__((aligned(16))) = { 65 /* CS: code, read/execute, 4 GB, base 0 */ 66 [GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff), 67 /* DS: data, read/write, 4 GB, base 0 */ 68 [GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff), 69 /* 16-bit CS: code, read/execute, 64 kB, base 0 */ 70 [GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x109b, 0, 0x0ffff), 71 /* 16-bit DS: data, read/write, 64 kB, base 0 */ 72 [GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x1093, 0, 0x0ffff), 73 }; 74 static struct gdt_ptr gdt; 75 76 gdt.len = sizeof(boot_gdt)-1; 77 gdt.ptr = (u32)&boot_gdt; 78 79 asm volatile("lgdtl %0\n" \ 80 "movl $((2+1)*8), %%ecx\n" \ 81 "movl %%ecx, %%ds\n" \ 82 "movl %%ecx, %%es\n" \ 83 "movl %%ecx, %%fs\n" \ 84 "movl %%ecx, %%gs\n" \ 85 "movl %%ecx, %%ss" \ 86 : : "m" (gdt) : "ecx"); 87 } 88 89 int x86_cpu_init_f(void) 90 { 91 const u32 em_rst = ~X86_CR0_EM; 92 const u32 mp_ne_set = X86_CR0_MP | X86_CR0_NE; 93 94 /* initialize FPU, reset EM, set MP and NE */ 95 asm ("fninit\n" \ 96 "movl %%cr0, %%eax\n" \ 97 "andl %0, %%eax\n" \ 98 "orl %1, %%eax\n" \ 99 "movl %%eax, %%cr0\n" \ 100 : : "i" (em_rst), "i" (mp_ne_set) : "eax"); 101 102 return 0; 103 } 104 int cpu_init_f(void) __attribute__((weak, alias("x86_cpu_init_f"))); 105 106 int x86_cpu_init_r(void) 107 { 108 const u32 nw_cd_rst = ~(X86_CR0_NW | X86_CR0_CD); 109 110 /* turn on the cache and disable write through */ 111 asm("movl %%cr0, %%eax\n" 112 "andl %0, %%eax\n" 113 "movl %%eax, %%cr0\n" 114 "wbinvd\n" : : "i" (nw_cd_rst) : "eax"); 115 116 reload_gdt(); 117 118 /* Initialize core interrupt and exception functionality of CPU */ 119 cpu_init_interrupts(); 120 return 0; 121 } 122 int cpu_init_r(void) __attribute__((weak, alias("x86_cpu_init_r"))); 123 124 int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) 125 { 126 printf("resetting ...\n"); 127 128 /* wait 50 ms */ 129 udelay(50000); 130 disable_interrupts(); 131 reset_cpu(0); 132 133 /*NOTREACHED*/ 134 return 0; 135 } 136 137 void flush_cache(unsigned long dummy1, unsigned long dummy2) 138 { 139 asm("wbinvd\n"); 140 } 141 142 void __attribute__ ((regparm(0))) generate_gpf(void); 143 144 /* segment 0x70 is an arbitrary segment which does not exist */ 145 asm(".globl generate_gpf\n" 146 ".hidden generate_gpf\n" 147 ".type generate_gpf, @function\n" 148 "generate_gpf:\n" 149 "ljmp $0x70, $0x47114711\n"); 150 151 void __reset_cpu(ulong addr) 152 { 153 printf("Resetting using x86 Triple Fault\n"); 154 set_vector(13, generate_gpf); /* general protection fault handler */ 155 set_vector(8, generate_gpf); /* double fault handler */ 156 generate_gpf(); /* start the show */ 157 } 158 void reset_cpu(ulong addr) __attribute__((weak, alias("__reset_cpu"))); 159