f0d43100f1
introduce init_pg_table_start, so xen PV could specify the value. Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
92 lines
2.7 KiB
C
92 lines
2.7 KiB
C
/*
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* linux/arch/i386/kernel/head32.c -- prepare to run common code
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*
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* Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
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* Copyright (C) 2007 Eric Biederman <ebiederm@xmission.com>
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*/
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#include <linux/init.h>
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#include <linux/start_kernel.h>
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#include <asm/setup.h>
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#include <asm/sections.h>
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#include <asm/e820.h>
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#include <asm/bios_ebda.h>
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#define BIOS_LOWMEM_KILOBYTES 0x413
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/*
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* The BIOS places the EBDA/XBDA at the top of conventional
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* memory, and usually decreases the reported amount of
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* conventional memory (int 0x12) too. This also contains a
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* workaround for Dell systems that neglect to reserve EBDA.
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* The same workaround also avoids a problem with the AMD768MPX
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* chipset: reserve a page before VGA to prevent PCI prefetch
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* into it (errata #56). Usually the page is reserved anyways,
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* unless you have no PS/2 mouse plugged in.
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*/
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static void __init reserve_ebda_region(void)
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{
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unsigned int lowmem, ebda_addr;
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/* To determine the position of the EBDA and the */
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/* end of conventional memory, we need to look at */
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/* the BIOS data area. In a paravirtual environment */
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/* that area is absent. We'll just have to assume */
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/* that the paravirt case can handle memory setup */
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/* correctly, without our help. */
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if (paravirt_enabled())
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return;
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/* end of low (conventional) memory */
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lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES);
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lowmem <<= 10;
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/* start of EBDA area */
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ebda_addr = get_bios_ebda();
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/* Fixup: bios puts an EBDA in the top 64K segment */
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/* of conventional memory, but does not adjust lowmem. */
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if ((lowmem - ebda_addr) <= 0x10000)
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lowmem = ebda_addr;
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/* Fixup: bios does not report an EBDA at all. */
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/* Some old Dells seem to need 4k anyhow (bugzilla 2990) */
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if ((ebda_addr == 0) && (lowmem >= 0x9f000))
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lowmem = 0x9f000;
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/* Paranoia: should never happen, but... */
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if ((lowmem == 0) || (lowmem >= 0x100000))
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lowmem = 0x9f000;
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/* reserve all memory between lowmem and the 1MB mark */
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reserve_early(lowmem, 0x100000, "BIOS reserved");
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}
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void __init i386_start_kernel(void)
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{
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reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
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#ifdef CONFIG_BLK_DEV_INITRD
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/* Reserve INITRD */
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if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
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u64 ramdisk_image = boot_params.hdr.ramdisk_image;
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u64 ramdisk_size = boot_params.hdr.ramdisk_size;
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u64 ramdisk_end = ramdisk_image + ramdisk_size;
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reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");
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}
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#endif
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reserve_early(init_pg_tables_start, init_pg_tables_end,
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"INIT_PG_TABLE");
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reserve_ebda_region();
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/*
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* At this point everything still needed from the boot loader
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* or BIOS or kernel text should be early reserved or marked not
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* RAM in e820. All other memory is free game.
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*/
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start_kernel();
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}
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