f6c2e3330d
We should zap the low mappings, as soon as possible, so that we can catch kernel bugs more effectively. Previously early boot had NULL mapped and didn't trap on NULL references. This patch introduces boot_level4_pgt, which will always have low identity addresses mapped. Druing boot, all the processors will use this as their level4 pgt. On BP, we will switch to init_level4_pgt as soon as we enter C code and zap the low mappings as soon as we are done with the usage of identity low mapped addresses. On AP's we will zap the low mappings as soon as we jump to C code. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
121 lines
3.2 KiB
C
121 lines
3.2 KiB
C
/*
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* linux/arch/x86_64/kernel/head64.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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*
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* $Id: head64.c,v 1.22 2001/07/06 14:28:20 ak Exp $
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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 <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/bootsetup.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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/* 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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extern char __bss_start[], __bss_end[];
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memset(__bss_start, 0,
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(unsigned long) __bss_end - (unsigned long) __bss_start);
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}
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#define NEW_CL_POINTER 0x228 /* Relative to real mode data */
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#define OLD_CL_MAGIC_ADDR 0x90020
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#define OLD_CL_MAGIC 0xA33F
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#define OLD_CL_BASE_ADDR 0x90000
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#define OLD_CL_OFFSET 0x90022
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extern char saved_command_line[];
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static void __init copy_bootdata(char *real_mode_data)
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{
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int new_data;
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char * command_line;
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memcpy(x86_boot_params, real_mode_data, BOOT_PARAM_SIZE);
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new_data = *(int *) (x86_boot_params + NEW_CL_POINTER);
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if (!new_data) {
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if (OLD_CL_MAGIC != * (u16 *) OLD_CL_MAGIC_ADDR) {
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printk("so old bootloader that it does not support commandline?!\n");
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return;
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}
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new_data = OLD_CL_BASE_ADDR + * (u16 *) OLD_CL_OFFSET;
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printk("old bootloader convention, maybe loadlin?\n");
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}
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command_line = (char *) ((u64)(new_data));
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memcpy(saved_command_line, command_line, COMMAND_LINE_SIZE);
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printk("Bootdata ok (command line is %s)\n", saved_command_line);
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}
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static void __init setup_boot_cpu_data(void)
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{
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unsigned int dummy, eax;
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/* get vendor info */
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cpuid(0, (unsigned int *)&boot_cpu_data.cpuid_level,
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(unsigned int *)&boot_cpu_data.x86_vendor_id[0],
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(unsigned int *)&boot_cpu_data.x86_vendor_id[8],
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(unsigned int *)&boot_cpu_data.x86_vendor_id[4]);
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/* get cpu type */
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cpuid(1, &eax, &dummy, &dummy,
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(unsigned int *) &boot_cpu_data.x86_capability);
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boot_cpu_data.x86 = (eax >> 8) & 0xf;
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boot_cpu_data.x86_model = (eax >> 4) & 0xf;
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boot_cpu_data.x86_mask = eax & 0xf;
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}
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extern char _end[];
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void __init x86_64_start_kernel(char * real_mode_data)
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{
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char *s;
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int i;
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for (i = 0; i < 256; i++)
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set_intr_gate(i, early_idt_handler);
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asm volatile("lidt %0" :: "m" (idt_descr));
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clear_bss();
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/*
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* switch to init_level4_pgt from boot_level4_pgt
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*/
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memcpy(init_level4_pgt, boot_level4_pgt, PTRS_PER_PGD*sizeof(pgd_t));
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asm volatile("movq %0,%%cr3" :: "r" (__pa_symbol(&init_level4_pgt)));
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pda_init(0);
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copy_bootdata(real_mode_data);
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#ifdef CONFIG_SMP
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cpu_set(0, cpu_online_map);
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#endif
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s = strstr(saved_command_line, "earlyprintk=");
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if (s != NULL)
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setup_early_printk(s);
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#ifdef CONFIG_NUMA
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s = strstr(saved_command_line, "numa=");
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if (s != NULL)
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numa_setup(s+5);
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#endif
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#ifdef CONFIG_X86_IO_APIC
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if (strstr(saved_command_line, "disableapic"))
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disable_apic = 1;
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#endif
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/* You need early console to see that */
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if (__pa_symbol(&_end) >= KERNEL_TEXT_SIZE)
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panic("Kernel too big for kernel mapping\n");
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setup_boot_cpu_data();
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start_kernel();
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}
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