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https://github.com/edk2-porting/linux-next.git
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f6eb62b692
Explicitly reserve_early the whole address range from the end of conventional memory as reported by the bios data area up to the 1Mb mark. Regard the info retrieved from the BIOS data area with a bit of paranoia, though, because some biosses forget to register the EBDA correctly. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
153 lines
4.0 KiB
C
153 lines
4.0 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.
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*/
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static __init void reserve_ebda(void)
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{
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unsigned int lowmem, ebda_addr;
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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 >= 0x100000)
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lowmem = 0xa0000;
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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();
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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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