/* * prepare to run common code * * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE */ #include <linux/init.h> #include <linux/linkage.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/percpu.h> #include <linux/start_kernel.h> #include <asm/processor.h> #include <asm/proto.h> #include <asm/smp.h> #include <asm/setup.h> #include <asm/desc.h> #include <asm/pgtable.h> #include <asm/tlbflush.h> #include <asm/sections.h> #include <asm/kdebug.h> #include <asm/e820.h> static void __init zap_identity_mappings(void) { pgd_t *pgd = pgd_offset_k(0UL); pgd_clear(pgd); __flush_tlb_all(); } /* Don't add a printk in there. printk relies on the PDA which is not initialized yet. */ static void __init clear_bss(void) { memset(__bss_start, 0, (unsigned long) __bss_stop - (unsigned long) __bss_start); } static void __init copy_bootdata(char *real_mode_data) { char * command_line; memcpy(&boot_params, real_mode_data, sizeof boot_params); if (boot_params.hdr.cmd_line_ptr) { command_line = __va(boot_params.hdr.cmd_line_ptr); memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE); } } #define BIOS_EBDA_SEGMENT 0x40E #define BIOS_LOWMEM_KILOBYTES 0x413 /* * The BIOS places the EBDA/XBDA at the top of conventional * memory, and usually decreases the reported amount of * conventional memory (int 0x12) too. This also contains a * workaround for Dell systems that neglect to reserve EBDA. * The same workaround also avoids a problem with the AMD768MPX * chipset: reserve a page before VGA to prevent PCI prefetch * into it (errata #56). Usually the page is reserved anyways, * unless you have no PS/2 mouse plugged in. */ static void __init reserve_ebda_region(void) { unsigned int lowmem, ebda_addr; /* To determine the position of the EBDA and the */ /* end of conventional memory, we need to look at */ /* the BIOS data area. In a paravirtual environment */ /* that area is absent. We'll just have to assume */ /* that the paravirt case can handle memory setup */ /* correctly, without our help. */ if (paravirt_enabled()) return; /* end of low (conventional) memory */ lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES); lowmem <<= 10; /* start of EBDA area */ ebda_addr = *(unsigned short *)__va(BIOS_EBDA_SEGMENT); ebda_addr <<= 4; /* Fixup: bios puts an EBDA in the top 64K segment */ /* of conventional memory, but does not adjust lowmem. */ if ((lowmem - ebda_addr) <= 0x10000) lowmem = ebda_addr; /* Fixup: bios does not report an EBDA at all. */ /* Some old Dells seem to need 4k anyhow (bugzilla 2990) */ if ((ebda_addr == 0) && (lowmem >= 0x9f000)) lowmem = 0x9f000; /* Paranoia: should never happen, but... */ if ((lowmem == 0) || (lowmem >= 0x100000)) lowmem = 0x9f000; /* reserve all memory between lowmem and the 1MB mark */ reserve_early(lowmem, 0x100000, "BIOS reserved"); } void __init x86_64_start_kernel(char * real_mode_data) { int i; /* * Build-time sanity checks on the kernel image and module * area mappings. (these are purely build-time and produce no code) */ BUILD_BUG_ON(MODULES_VADDR < KERNEL_IMAGE_START); BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE); BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE); BUILD_BUG_ON((KERNEL_IMAGE_START & ~PMD_MASK) != 0); BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0); BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL)); BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == (__START_KERNEL & PGDIR_MASK))); /* clear bss before set_intr_gate with early_idt_handler */ clear_bss(); /* Make NULL pointers segfault */ zap_identity_mappings(); /* Cleanup the over mapped high alias */ cleanup_highmap(); for (i = 0; i < IDT_ENTRIES; i++) { #ifdef CONFIG_EARLY_PRINTK set_intr_gate(i, &early_idt_handlers[i]); #else set_intr_gate(i, early_idt_handler); #endif } load_idt((const struct desc_ptr *)&idt_descr); early_printk("Kernel alive\n"); for (i = 0; i < NR_CPUS; i++) cpu_pda(i) = &boot_cpu_pda[i]; pda_init(0); copy_bootdata(__va(real_mode_data)); reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS"); /* Reserve INITRD */ if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) { unsigned long ramdisk_image = boot_params.hdr.ramdisk_image; unsigned long ramdisk_size = boot_params.hdr.ramdisk_size; unsigned long ramdisk_end = ramdisk_image + ramdisk_size; reserve_early(ramdisk_image, ramdisk_end, "RAMDISK"); } reserve_ebda_region(); /* * At this point everything still needed from the boot loader * or BIOS or kernel text should be early reserved or marked not * RAM in e820. All other memory is free game. */ start_kernel(); }