2 * prepare to run common code
4 * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
7 #include <linux/init.h>
8 #include <linux/linkage.h>
9 #include <linux/types.h>
10 #include <linux/kernel.h>
11 #include <linux/string.h>
12 #include <linux/percpu.h>
13 #include <linux/start_kernel.h>
16 #include <asm/processor.h>
17 #include <asm/proto.h>
19 #include <asm/setup.h>
21 #include <asm/pgtable.h>
22 #include <asm/tlbflush.h>
23 #include <asm/sections.h>
24 #include <asm/kdebug.h>
26 #include <asm/bios_ebda.h>
28 static void __init
zap_identity_mappings(void)
30 pgd_t
*pgd
= pgd_offset_k(0UL);
35 /* Don't add a printk in there. printk relies on the PDA which is not initialized
37 static void __init
clear_bss(void)
39 memset(__bss_start
, 0,
40 (unsigned long) __bss_stop
- (unsigned long) __bss_start
);
43 static void __init
copy_bootdata(char *real_mode_data
)
47 memcpy(&boot_params
, real_mode_data
, sizeof boot_params
);
48 if (boot_params
.hdr
.cmd_line_ptr
) {
49 command_line
= __va(boot_params
.hdr
.cmd_line_ptr
);
50 memcpy(boot_command_line
, command_line
, COMMAND_LINE_SIZE
);
54 #define BIOS_LOWMEM_KILOBYTES 0x413
57 * The BIOS places the EBDA/XBDA at the top of conventional
58 * memory, and usually decreases the reported amount of
59 * conventional memory (int 0x12) too. This also contains a
60 * workaround for Dell systems that neglect to reserve EBDA.
61 * The same workaround also avoids a problem with the AMD768MPX
62 * chipset: reserve a page before VGA to prevent PCI prefetch
63 * into it (errata #56). Usually the page is reserved anyways,
64 * unless you have no PS/2 mouse plugged in.
66 static void __init
reserve_ebda_region(void)
68 unsigned int lowmem
, ebda_addr
;
70 /* To determine the position of the EBDA and the */
71 /* end of conventional memory, we need to look at */
72 /* the BIOS data area. In a paravirtual environment */
73 /* that area is absent. We'll just have to assume */
74 /* that the paravirt case can handle memory setup */
75 /* correctly, without our help. */
76 if (paravirt_enabled())
79 /* end of low (conventional) memory */
80 lowmem
= *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES
);
83 /* start of EBDA area */
84 ebda_addr
= get_bios_ebda();
86 /* Fixup: bios puts an EBDA in the top 64K segment */
87 /* of conventional memory, but does not adjust lowmem. */
88 if ((lowmem
- ebda_addr
) <= 0x10000)
91 /* Fixup: bios does not report an EBDA at all. */
92 /* Some old Dells seem to need 4k anyhow (bugzilla 2990) */
93 if ((ebda_addr
== 0) && (lowmem
>= 0x9f000))
96 /* Paranoia: should never happen, but... */
97 if ((lowmem
== 0) || (lowmem
>= 0x100000))
100 /* reserve all memory between lowmem and the 1MB mark */
101 reserve_early(lowmem
, 0x100000, "BIOS reserved");
104 static void __init
reserve_setup_data(void)
106 struct setup_data
*data
;
107 unsigned long pa_data
;
110 if (boot_params
.hdr
.version
< 0x0209)
112 pa_data
= boot_params
.hdr
.setup_data
;
114 data
= early_ioremap(pa_data
, sizeof(*data
));
115 sprintf(buf
, "setup data %x", data
->type
);
116 reserve_early(pa_data
, pa_data
+sizeof(*data
)+data
->len
, buf
);
117 pa_data
= data
->next
;
118 early_iounmap(data
, sizeof(*data
));
122 void __init
x86_64_start_kernel(char * real_mode_data
)
127 * Build-time sanity checks on the kernel image and module
128 * area mappings. (these are purely build-time and produce no code)
130 BUILD_BUG_ON(MODULES_VADDR
< KERNEL_IMAGE_START
);
131 BUILD_BUG_ON(MODULES_VADDR
-KERNEL_IMAGE_START
< KERNEL_IMAGE_SIZE
);
132 BUILD_BUG_ON(MODULES_LEN
+ KERNEL_IMAGE_SIZE
> 2*PUD_SIZE
);
133 BUILD_BUG_ON((KERNEL_IMAGE_START
& ~PMD_MASK
) != 0);
134 BUILD_BUG_ON((MODULES_VADDR
& ~PMD_MASK
) != 0);
135 BUILD_BUG_ON(!(MODULES_VADDR
> __START_KERNEL
));
136 BUILD_BUG_ON(!(((MODULES_END
- 1) & PGDIR_MASK
) ==
137 (__START_KERNEL
& PGDIR_MASK
)));
139 /* clear bss before set_intr_gate with early_idt_handler */
142 /* Make NULL pointers segfault */
143 zap_identity_mappings();
145 /* Cleanup the over mapped high alias */
148 for (i
= 0; i
< NUM_EXCEPTION_VECTORS
; i
++) {
149 #ifdef CONFIG_EARLY_PRINTK
150 set_intr_gate(i
, &early_idt_handlers
[i
]);
152 set_intr_gate(i
, early_idt_handler
);
155 load_idt((const struct desc_ptr
*)&idt_descr
);
157 early_printk("Kernel alive\n");
159 for (i
= 0; i
< NR_CPUS
; i
++)
160 cpu_pda(i
) = &boot_cpu_pda
[i
];
163 copy_bootdata(__va(real_mode_data
));
165 reserve_early(__pa_symbol(&_text
), __pa_symbol(&_end
), "TEXT DATA BSS");
167 #ifdef CONFIG_BLK_DEV_INITRD
169 if (boot_params
.hdr
.type_of_loader
&& boot_params
.hdr
.ramdisk_image
) {
170 unsigned long ramdisk_image
= boot_params
.hdr
.ramdisk_image
;
171 unsigned long ramdisk_size
= boot_params
.hdr
.ramdisk_size
;
172 unsigned long ramdisk_end
= ramdisk_image
+ ramdisk_size
;
173 reserve_early(ramdisk_image
, ramdisk_end
, "RAMDISK");
177 reserve_ebda_region();
178 reserve_setup_data();
181 * At this point everything still needed from the boot loader
182 * or BIOS or kernel text should be early reserved or marked not
183 * RAM in e820. All other memory is free game.