Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / arch / x86 / kernel / head32.c
blobec6fefbfd3c0454b009a2a7a04a76edc44b8c5e8
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/arch/i386/kernel/head32.c -- prepare to run common code
5 * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
6 * Copyright (C) 2007 Eric Biederman <ebiederm@xmission.com>
7 */
9 #include <linux/init.h>
10 #include <linux/start_kernel.h>
11 #include <linux/mm.h>
12 #include <linux/memblock.h>
14 #include <asm/desc.h>
15 #include <asm/setup.h>
16 #include <asm/sections.h>
17 #include <asm/e820/api.h>
18 #include <asm/page.h>
19 #include <asm/apic.h>
20 #include <asm/io_apic.h>
21 #include <asm/bios_ebda.h>
22 #include <asm/tlbflush.h>
23 #include <asm/bootparam_utils.h>
25 static void __init i386_default_early_setup(void)
27 /* Initialize 32bit specific setup functions */
28 x86_init.resources.reserve_resources = i386_reserve_resources;
29 x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc;
32 asmlinkage __visible void __init i386_start_kernel(void)
34 /* Make sure IDT is set up before any exception happens */
35 idt_setup_early_handler();
37 cr4_init_shadow();
39 sanitize_boot_params(&boot_params);
41 x86_early_init_platform_quirks();
43 /* Call the subarch specific early setup function */
44 switch (boot_params.hdr.hardware_subarch) {
45 case X86_SUBARCH_INTEL_MID:
46 x86_intel_mid_early_setup();
47 break;
48 case X86_SUBARCH_CE4100:
49 x86_ce4100_early_setup();
50 break;
51 default:
52 i386_default_early_setup();
53 break;
56 start_kernel();
60 * Initialize page tables. This creates a PDE and a set of page
61 * tables, which are located immediately beyond __brk_base. The variable
62 * _brk_end is set up to point to the first "safe" location.
63 * Mappings are created both at virtual address 0 (identity mapping)
64 * and PAGE_OFFSET for up to _end.
66 * In PAE mode initial_page_table is statically defined to contain
67 * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3
68 * entries). The identity mapping is handled by pointing two PGD entries
69 * to the first kernel PMD. Note the upper half of each PMD or PTE are
70 * always zero at this stage.
72 void __init mk_early_pgtbl_32(void)
74 #ifdef __pa
75 #undef __pa
76 #endif
77 #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET)
78 pte_t pte, *ptep;
79 int i;
80 unsigned long *ptr;
81 /* Enough space to fit pagetables for the low memory linear map */
82 const unsigned long limit = __pa(_end) +
83 (PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT);
84 #ifdef CONFIG_X86_PAE
85 pmd_t pl2, *pl2p = (pmd_t *)__pa(initial_pg_pmd);
86 #define SET_PL2(pl2, val) { (pl2).pmd = (val); }
87 #else
88 pgd_t pl2, *pl2p = (pgd_t *)__pa(initial_page_table);
89 #define SET_PL2(pl2, val) { (pl2).pgd = (val); }
90 #endif
92 ptep = (pte_t *)__pa(__brk_base);
93 pte.pte = PTE_IDENT_ATTR;
95 while ((pte.pte & PTE_PFN_MASK) < limit) {
97 SET_PL2(pl2, (unsigned long)ptep | PDE_IDENT_ATTR);
98 *pl2p = pl2;
99 #ifndef CONFIG_X86_PAE
100 /* Kernel PDE entry */
101 *(pl2p + ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2;
102 #endif
103 for (i = 0; i < PTRS_PER_PTE; i++) {
104 *ptep = pte;
105 pte.pte += PAGE_SIZE;
106 ptep++;
109 pl2p++;
112 ptr = (unsigned long *)__pa(&max_pfn_mapped);
113 /* Can't use pte_pfn() since it's a call with CONFIG_PARAVIRT */
114 *ptr = (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT;
116 ptr = (unsigned long *)__pa(&_brk_end);
117 *ptr = (unsigned long)ptep + PAGE_OFFSET;