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- // SPDX-License-Identifier: GPL-2.0
- /*
- * linux/arch/i386/kernel/head32.c -- prepare to run common code
- *
- * Copyright (C) 2000 Andrea Arcangeli <[email protected]> SuSE
- * Copyright (C) 2007 Eric Biederman <[email protected]>
- */
- #include <linux/init.h>
- #include <linux/start_kernel.h>
- #include <linux/mm.h>
- #include <linux/memblock.h>
- #include <asm/desc.h>
- #include <asm/setup.h>
- #include <asm/sections.h>
- #include <asm/e820/api.h>
- #include <asm/page.h>
- #include <asm/apic.h>
- #include <asm/io_apic.h>
- #include <asm/bios_ebda.h>
- #include <asm/tlbflush.h>
- #include <asm/bootparam_utils.h>
- static void __init i386_default_early_setup(void)
- {
- /* Initialize 32bit specific setup functions */
- x86_init.resources.reserve_resources = i386_reserve_resources;
- x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc;
- }
- asmlinkage __visible void __init i386_start_kernel(void)
- {
- /* Make sure IDT is set up before any exception happens */
- idt_setup_early_handler();
- cr4_init_shadow();
- sanitize_boot_params(&boot_params);
- x86_early_init_platform_quirks();
- /* Call the subarch specific early setup function */
- switch (boot_params.hdr.hardware_subarch) {
- case X86_SUBARCH_INTEL_MID:
- x86_intel_mid_early_setup();
- break;
- case X86_SUBARCH_CE4100:
- x86_ce4100_early_setup();
- break;
- default:
- i386_default_early_setup();
- break;
- }
- start_kernel();
- }
- /*
- * Initialize page tables. This creates a PDE and a set of page
- * tables, which are located immediately beyond __brk_base. The variable
- * _brk_end is set up to point to the first "safe" location.
- * Mappings are created both at virtual address 0 (identity mapping)
- * and PAGE_OFFSET for up to _end.
- *
- * In PAE mode initial_page_table is statically defined to contain
- * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3
- * entries). The identity mapping is handled by pointing two PGD entries
- * to the first kernel PMD. Note the upper half of each PMD or PTE are
- * always zero at this stage.
- */
- void __init mk_early_pgtbl_32(void)
- {
- #ifdef __pa
- #undef __pa
- #endif
- #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET)
- pte_t pte, *ptep;
- int i;
- unsigned long *ptr;
- /* Enough space to fit pagetables for the low memory linear map */
- const unsigned long limit = __pa(_end) +
- (PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT);
- #ifdef CONFIG_X86_PAE
- pmd_t pl2, *pl2p = (pmd_t *)__pa(initial_pg_pmd);
- #define SET_PL2(pl2, val) { (pl2).pmd = (val); }
- #else
- pgd_t pl2, *pl2p = (pgd_t *)__pa(initial_page_table);
- #define SET_PL2(pl2, val) { (pl2).pgd = (val); }
- #endif
- ptep = (pte_t *)__pa(__brk_base);
- pte.pte = PTE_IDENT_ATTR;
- while ((pte.pte & PTE_PFN_MASK) < limit) {
- SET_PL2(pl2, (unsigned long)ptep | PDE_IDENT_ATTR);
- *pl2p = pl2;
- #ifndef CONFIG_X86_PAE
- /* Kernel PDE entry */
- *(pl2p + ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2;
- #endif
- for (i = 0; i < PTRS_PER_PTE; i++) {
- *ptep = pte;
- pte.pte += PAGE_SIZE;
- ptep++;
- }
- pl2p++;
- }
- ptr = (unsigned long *)__pa(&max_pfn_mapped);
- /* Can't use pte_pfn() since it's a call with CONFIG_PARAVIRT */
- *ptr = (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
- ptr = (unsigned long *)__pa(&_brk_end);
- *ptr = (unsigned long)ptep + PAGE_OFFSET;
- }
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