arch/x86/cpu/cpu.c

   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
  41 /*
  42  * Constructor for a conventional segment GDT (or LDT) entry
  43  * This is a macro so it can be used in initialisers
  44  */
  45 #define GDT_ENTRY(flags, base, limit)                   \
  46         ((((base)  & 0xff000000ULL) << (56-24)) |       \
  47          (((flags) & 0x0000f0ffULL) << 40) |            \
  48          (((limit) & 0x000f0000ULL) << (48-16)) |       \
  49          (((base)  & 0x00ffffffULL) << 16) |            \
  50          (((limit) & 0x0000ffffULL)))
  51
  52 struct gdt_ptr {
  53         u16 len;
  54         u32 ptr;
  55 } __attribute__((packed));
  56
  57 static void reload_gdt(void)
  58 {
  59         /*
  60          * There are machines which are known to not boot with the GDT
  61          * being 8-byte unaligned.  Intel recommends 16 byte alignment
  62          */
  63         static const u64 boot_gdt[] __attribute__((aligned(16))) = {
  64                 /* CS: code, read/execute, 4 GB, base 0 */
  65                 [GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff),
  66                 /* DS: data, read/write, 4 GB, base 0 */
  67                 [GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff),
  68                 /* 16-bit CS: code, read/execute, 64 kB, base 0 */
  69                 [GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x109b, 0, 0x0ffff),
  70                 /* 16-bit DS: data, read/write, 64 kB, base 0 */
  71                 [GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x1093, 0, 0x0ffff),
  72         };
  73         static struct gdt_ptr gdt;
  74
  75         gdt.len = sizeof(boot_gdt)-1;
  76         gdt.ptr = (u32)&boot_gdt;
  77
  78         asm volatile("lgdtl %0\n" \
  79                      "movl $((2+1)*8), %%ecx\n" \
  80                      "movl %%ecx, %%ds\n" \
  81                      "movl %%ecx, %%es\n" \
  82                      "movl %%ecx, %%fs\n" \
  83                      "movl %%ecx, %%gs\n" \
  84                      "movl %%ecx, %%ss" \
  85                      : : "m" (gdt) : "ecx");
  86 }
  87
  88 int x86_cpu_init_f(void)
  89 {
  90         const u32 em_rst = ~X86_CR0_EM;
  91         const u32 mp_ne_set = X86_CR0_MP | X86_CR0_NE;
  92
  93         /* initialize FPU, reset EM, set MP and NE */
  94         asm ("fninit\n" \
  95              "movl %%cr0, %%eax\n" \
  96              "andl %0, %%eax\n" \
  97              "orl  %1, %%eax\n" \
  98              "movl %%eax, %%cr0\n" \
  99              : : "i" (em_rst), "i" (mp_ne_set) : "eax");
 100
 101         return 0;
 102 }
 103 int cpu_init_f(void) __attribute__((weak, alias("x86_cpu_init_f")));
 104
 105 int x86_cpu_init_r(void)
 106 {
 107         const u32 nw_cd_rst = ~(X86_CR0_NW | X86_CR0_CD);
 108
 109         /* turn on the cache and disable write through */
 110         asm("movl       %%cr0, %%eax\n"
 111             "andl       %0, %%eax\n"
 112             "movl       %%eax, %%cr0\n"
 113             "wbinvd\n" : : "i" (nw_cd_rst) : "eax");
 114
 115         reload_gdt();
 116
 117         /* Initialize core interrupt and exception functionality of CPU */
 118         cpu_init_interrupts ();
 119         return 0;
 120 }
 121 int cpu_init_r(void) __attribute__((weak, alias("x86_cpu_init_r")));
 122
 123 int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 124 {
 125         printf ("resetting ...\n");
 126
 127         /* wait 50 ms */
 128         udelay(50000);
 129         disable_interrupts();
 130         reset_cpu(0);
 131
 132         /*NOTREACHED*/
 133         return 0;
 134 }
 135
 136 void  flush_cache (unsigned long dummy1, unsigned long dummy2)
 137 {
 138         asm("wbinvd\n");
 139 }
 140
 141 void __attribute__ ((regparm(0))) generate_gpf(void);
 142
 143 /* segment 0x70 is an arbitrary segment which does not exist */
 144 asm(".globl generate_gpf\n"
 145     ".hidden generate_gpf\n"
 146     ".type generate_gpf, @function\n"
 147     "generate_gpf:\n"
 148     "ljmp   $0x70, $0x47114711\n");
 149
 150 void __reset_cpu(ulong addr)
 151 {
 152         printf("Resetting using x86 Triple Fault\n");
 153         set_vector(13, generate_gpf);  /* general protection fault handler */
 154         set_vector(8, generate_gpf);   /* double fault handler */
 155         generate_gpf();                /* start the show */
 156 }
 157 void reset_cpu(ulong addr) __attribute__((weak, alias("__reset_cpu")));