31eedd823c
The early boot code maps KERNEL_TEXT_SIZE (currently 40MB) starting from __START_KERNEL_map. The kernel itself only needs _text to _end mapped in the high alias. On relocatible kernels the ASM setup code adjusts the compile time created high mappings to the relocation. This creates invalid pmd entries for negative offsets: 0xffffffff80000000 -> pmd entry: ffffffffff2001e3 It points outside of the physical address space and is marked present. This starts at the virtual address __START_KERNEL_map and goes up to the point where the first valid physical address (0x0) is mapped. Zap the mappings before _text and after _end right away in early boot. This removes also the invalid entries. Furthermore it simplifies the range check for high aliases. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
131 lines
3.0 KiB
C
131 lines
3.0 KiB
C
/*
|
|
* 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 EBDA_ADDR_POINTER 0x40E
|
|
|
|
static __init void reserve_ebda(void)
|
|
{
|
|
unsigned ebda_addr, ebda_size;
|
|
|
|
/*
|
|
* there is a real-mode segmented pointer pointing to the
|
|
* 4K EBDA area at 0x40E
|
|
*/
|
|
ebda_addr = *(unsigned short *)__va(EBDA_ADDR_POINTER);
|
|
ebda_addr <<= 4;
|
|
|
|
if (!ebda_addr)
|
|
return;
|
|
|
|
ebda_size = *(unsigned short *)__va(ebda_addr);
|
|
|
|
/* Round EBDA up to pages */
|
|
if (ebda_size == 0)
|
|
ebda_size = 1;
|
|
ebda_size <<= 10;
|
|
ebda_size = round_up(ebda_size + (ebda_addr & ~PAGE_MASK), PAGE_SIZE);
|
|
if (ebda_size > 64*1024)
|
|
ebda_size = 64*1024;
|
|
|
|
reserve_early(ebda_addr, ebda_addr + ebda_size, "EBDA");
|
|
}
|
|
|
|
void __init x86_64_start_kernel(char * real_mode_data)
|
|
{
|
|
int i;
|
|
|
|
/* 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();
|
|
|
|
/*
|
|
* 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();
|
|
}
|