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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/arch/i386/kernel/head32.c -- prepare to run common code
4 *
5 * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
6 * Copyright (C) 2007 Eric Biederman <ebiederm@xmission.com>
7 */
8
9#include <linux/init.h>
10#include <linux/start_kernel.h>
11#include <linux/mm.h>
12#include <linux/memblock.h>
13
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>
24
25static void __init i386_default_early_setup(void)
26{
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;
30}
31
32asmlinkage __visible void __init i386_start_kernel(void)
33{
34 /* Make sure IDT is set up before any exception happens */
35 idt_setup_early_handler();
36
37 cr4_init_shadow();
38
39 sanitize_boot_params(&boot_params);
40
41 x86_early_init_platform_quirks();
42
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;
54 }
55
56 start_kernel();
57}
58
59/*
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.
65 *
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.
71 */
72void __init mk_early_pgtbl_32(void)
73{
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
91
92 ptep = (pte_t *)__pa(__brk_base);
93 pte.pte = PTE_IDENT_ATTR;
94
95 while ((pte.pte & PTE_PFN_MASK) < limit) {
96
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++;
107 }
108
109 pl2p++;
110 }
111
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;
115
116 ptr = (unsigned long *)__pa(&_brk_end);
117 *ptr = (unsigned long)ptep + PAGE_OFFSET;
118}
119
1/*
2 * linux/arch/i386/kernel/head32.c -- prepare to run common code
3 *
4 * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
5 * Copyright (C) 2007 Eric Biederman <ebiederm@xmission.com>
6 */
7
8#include <linux/init.h>
9#include <linux/start_kernel.h>
10#include <linux/mm.h>
11#include <linux/memblock.h>
12
13#include <asm/setup.h>
14#include <asm/sections.h>
15#include <asm/e820.h>
16#include <asm/page.h>
17#include <asm/apic.h>
18#include <asm/io_apic.h>
19#include <asm/bios_ebda.h>
20#include <asm/tlbflush.h>
21
22static void __init i386_default_early_setup(void)
23{
24 /* Initialize 32bit specific setup functions */
25 x86_init.resources.reserve_resources = i386_reserve_resources;
26 x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc;
27
28 reserve_ebda_region();
29}
30
31void __init i386_start_kernel(void)
32{
33 memblock_reserve(__pa_symbol(&_text),
34 __pa_symbol(&__bss_stop) - __pa_symbol(&_text));
35
36#ifdef CONFIG_BLK_DEV_INITRD
37 /* Reserve INITRD */
38 if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
39 /* Assume only end is not page aligned */
40 u64 ramdisk_image = boot_params.hdr.ramdisk_image;
41 u64 ramdisk_size = boot_params.hdr.ramdisk_size;
42 u64 ramdisk_end = PAGE_ALIGN(ramdisk_image + ramdisk_size);
43 memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
44 }
45#endif
46
47 /* Call the subarch specific early setup function */
48 switch (boot_params.hdr.hardware_subarch) {
49 case X86_SUBARCH_MRST:
50 x86_mrst_early_setup();
51 break;
52 case X86_SUBARCH_CE4100:
53 x86_ce4100_early_setup();
54 break;
55 default:
56 i386_default_early_setup();
57 break;
58 }
59
60 /*
61 * At this point everything still needed from the boot loader
62 * or BIOS or kernel text should be early reserved or marked not
63 * RAM in e820. All other memory is free game.
64 */
65
66 start_kernel();
67}