2 * (C) Copyright 2008-2011
3 * Graeme Russ, <graeme.russ@gmail.com>
6 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
9 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
10 * Marius Groeger <mgroeger@sysgo.de>
13 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
14 * Alex Zuepke <azu@sysgo.de>
16 * See file CREDITS for list of people who contributed to this
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.
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.
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,
37 #include <asm/processor.h>
38 #include <asm/processor-flags.h>
39 #include <asm/interrupt.h>
40 #include <linux/compiler.h>
43 * Constructor for a conventional segment GDT (or LDT) entry
44 * This is a macro so it can be used in initialisers
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)))
58 static void load_ds(u32 segment)
60 asm volatile("movl %0, %%ds" : : "r" (segment * X86_GDT_ENTRY_SIZE));
63 static void load_es(u32 segment)
65 asm volatile("movl %0, %%es" : : "r" (segment * X86_GDT_ENTRY_SIZE));
68 static void load_fs(u32 segment)
70 asm volatile("movl %0, %%fs" : : "r" (segment * X86_GDT_ENTRY_SIZE));
73 static void load_gs(u32 segment)
75 asm volatile("movl %0, %%gs" : : "r" (segment * X86_GDT_ENTRY_SIZE));
78 static void load_ss(u32 segment)
80 asm volatile("movl %0, %%ss" : : "r" (segment * X86_GDT_ENTRY_SIZE));
83 static void load_gdt(const u64 *boot_gdt, u16 num_entries)
87 gdt.len = (num_entries * 8) - 1;
88 gdt.ptr = (u32)boot_gdt;
90 asm volatile("lgdtl %0\n" : : "m" (gdt));
93 int x86_cpu_init_f(void)
95 const u32 em_rst = ~X86_CR0_EM;
96 const u32 mp_ne_set = X86_CR0_MP | X86_CR0_NE;
98 /* initialize FPU, reset EM, set MP and NE */
100 "movl %%cr0, %%eax\n" \
103 "movl %%eax, %%cr0\n" \
104 : : "i" (em_rst), "i" (mp_ne_set) : "eax");
108 int cpu_init_f(void) __attribute__((weak, alias("x86_cpu_init_f")));
110 int x86_cpu_init_r(void)
112 const u32 nw_cd_rst = ~(X86_CR0_NW | X86_CR0_CD);
114 /* turn on the cache and disable write through */
115 asm("movl %%cr0, %%eax\n"
117 "movl %%eax, %%cr0\n"
118 "wbinvd\n" : : "i" (nw_cd_rst) : "eax");
121 * There are machines which are known to not boot with the GDT
122 * being 8-byte unaligned. Intel recommends 16 byte alignment
124 static const u64 boot_gdt[] __aligned(16) = {
125 /* CS: code, read/execute, 4 GB, base 0 */
126 [X86_GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff),
127 /* DS: data, read/write, 4 GB, base 0 */
128 [X86_GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff),
129 /* 16-bit CS: code, read/execute, 64 kB, base 0 */
130 [X86_GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x109b, 0, 0x0ffff),
131 /* 16-bit DS: data, read/write, 64 kB, base 0 */
132 [X86_GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x1093, 0, 0x0ffff),
135 load_gdt(boot_gdt, X86_GDT_NUM_ENTRIES);
136 load_ds(X86_GDT_ENTRY_32BIT_DS);
137 load_es(X86_GDT_ENTRY_32BIT_DS);
138 load_fs(X86_GDT_ENTRY_32BIT_DS);
139 load_gs(X86_GDT_ENTRY_32BIT_DS);
140 load_ss(X86_GDT_ENTRY_32BIT_DS);
142 /* Initialize core interrupt and exception functionality of CPU */
143 cpu_init_interrupts();
146 int cpu_init_r(void) __attribute__((weak, alias("x86_cpu_init_r")));
148 int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
150 printf("resetting ...\n");
154 disable_interrupts();
161 void flush_cache(unsigned long dummy1, unsigned long dummy2)
166 void __attribute__ ((regparm(0))) generate_gpf(void);
168 /* segment 0x70 is an arbitrary segment which does not exist */
169 asm(".globl generate_gpf\n"
170 ".hidden generate_gpf\n"
171 ".type generate_gpf, @function\n"
173 "ljmp $0x70, $0x47114711\n");
175 void __reset_cpu(ulong addr)
177 printf("Resetting using x86 Triple Fault\n");
178 set_vector(13, generate_gpf); /* general protection fault handler */
179 set_vector(8, generate_gpf); /* double fault handler */
180 generate_gpf(); /* start the show */
182 void reset_cpu(ulong addr) __attribute__((weak, alias("__reset_cpu")));