ecd94c0809
Jeremy Fitzhardinge pointed out that looking at the boot_params struct to determine if the system is running in a paravirtual environment is not reliable for the Xen case, currently. He also points out that there already exists a function to determine if the system is running in a paravirtual environment. So let's use that instead. This gets rid of the preprocessor test too. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
167 lines
4.7 KiB
C
167 lines
4.7 KiB
C
/*
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* 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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*/
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#include <linux/init.h>
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#include <linux/linkage.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/percpu.h>
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#include <linux/start_kernel.h>
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#include <asm/processor.h>
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#include <asm/proto.h>
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#include <asm/smp.h>
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#include <asm/setup.h>
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#include <asm/desc.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include <asm/sections.h>
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#include <asm/kdebug.h>
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#include <asm/e820.h>
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static void __init zap_identity_mappings(void)
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{
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pgd_t *pgd = pgd_offset_k(0UL);
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pgd_clear(pgd);
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__flush_tlb_all();
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}
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/* Don't add a printk in there. printk relies on the PDA which is not initialized
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yet. */
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static void __init clear_bss(void)
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{
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memset(__bss_start, 0,
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(unsigned long) __bss_stop - (unsigned long) __bss_start);
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}
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static void __init copy_bootdata(char *real_mode_data)
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{
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char * command_line;
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memcpy(&boot_params, real_mode_data, sizeof boot_params);
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if (boot_params.hdr.cmd_line_ptr) {
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command_line = __va(boot_params.hdr.cmd_line_ptr);
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memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
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}
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}
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#define BIOS_EBDA_SEGMENT 0x40E
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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 = *(unsigned short *)__va(BIOS_EBDA_SEGMENT);
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ebda_addr <<= 4;
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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 x86_64_start_kernel(char * real_mode_data)
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{
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int i;
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/*
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* Build-time sanity checks on the kernel image and module
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* area mappings. (these are purely build-time and produce no code)
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*/
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BUILD_BUG_ON(MODULES_VADDR < KERNEL_IMAGE_START);
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BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE);
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BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
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BUILD_BUG_ON((KERNEL_IMAGE_START & ~PMD_MASK) != 0);
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BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
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BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
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BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
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(__START_KERNEL & PGDIR_MASK)));
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/* clear bss before set_intr_gate with early_idt_handler */
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clear_bss();
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/* Make NULL pointers segfault */
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zap_identity_mappings();
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/* Cleanup the over mapped high alias */
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cleanup_highmap();
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for (i = 0; i < IDT_ENTRIES; i++) {
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#ifdef CONFIG_EARLY_PRINTK
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set_intr_gate(i, &early_idt_handlers[i]);
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#else
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set_intr_gate(i, early_idt_handler);
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#endif
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}
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load_idt((const struct desc_ptr *)&idt_descr);
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early_printk("Kernel alive\n");
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for (i = 0; i < NR_CPUS; i++)
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cpu_pda(i) = &boot_cpu_pda[i];
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pda_init(0);
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copy_bootdata(__va(real_mode_data));
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reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
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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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unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
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unsigned long ramdisk_size = boot_params.hdr.ramdisk_size;
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unsigned long 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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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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