2 * prepare to run common code
4 * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
7 #define DISABLE_BRANCH_PROFILING
8 #include <linux/init.h>
9 #include <linux/linkage.h>
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/string.h>
13 #include <linux/percpu.h>
14 #include <linux/start_kernel.h>
16 #include <linux/memblock.h>
18 #include <asm/processor.h>
19 #include <asm/proto.h>
21 #include <asm/setup.h>
23 #include <asm/pgtable.h>
24 #include <asm/tlbflush.h>
25 #include <asm/sections.h>
26 #include <asm/kdebug.h>
27 #include <asm/e820/api.h>
28 #include <asm/bios_ebda.h>
29 #include <asm/bootparam_utils.h>
30 #include <asm/microcode.h>
31 #include <asm/kasan.h>
34 * Manage page tables very early on.
36 extern pgd_t early_top_pgt[PTRS_PER_PGD];
37 extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
38 static unsigned int __initdata next_early_pgt;
39 pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
41 #define __head __section(.head.text)
43 static void __head *fixup_pointer(void *ptr, unsigned long physaddr)
45 return ptr - (void *)_text + (void *)physaddr;
48 void __head __startup_64(unsigned long physaddr)
50 unsigned long load_delta, *p;
54 pmdval_t *pmd, pmd_entry;
57 /* Is the address too large? */
58 if (physaddr >> MAX_PHYSMEM_BITS)
62 * Compute the delta between the address I am compiled to run at
63 * and the address I am actually running at.
65 load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map);
67 /* Is the address not 2M aligned? */
68 if (load_delta & ~PMD_PAGE_MASK)
71 /* Fixup the physical addresses in the page table */
73 pgd = fixup_pointer(&early_top_pgt, physaddr);
74 pgd[pgd_index(__START_KERNEL_map)] += load_delta;
76 if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
77 p4d = fixup_pointer(&level4_kernel_pgt, physaddr);
78 p4d[511] += load_delta;
81 pud = fixup_pointer(&level3_kernel_pgt, physaddr);
82 pud[510] += load_delta;
83 pud[511] += load_delta;
85 pmd = fixup_pointer(level2_fixmap_pgt, physaddr);
86 pmd[506] += load_delta;
89 * Set up the identity mapping for the switchover. These
90 * entries should *NOT* have the global bit set! This also
91 * creates a bunch of nonsense entries but that is fine --
92 * it avoids problems around wraparound.
95 pud = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
96 pmd = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
98 if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
99 p4d = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
101 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
102 pgd[i + 0] = (pgdval_t)p4d + _KERNPG_TABLE;
103 pgd[i + 1] = (pgdval_t)p4d + _KERNPG_TABLE;
105 i = (physaddr >> P4D_SHIFT) % PTRS_PER_P4D;
106 p4d[i + 0] = (pgdval_t)pud + _KERNPG_TABLE;
107 p4d[i + 1] = (pgdval_t)pud + _KERNPG_TABLE;
109 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
110 pgd[i + 0] = (pgdval_t)pud + _KERNPG_TABLE;
111 pgd[i + 1] = (pgdval_t)pud + _KERNPG_TABLE;
114 i = (physaddr >> PUD_SHIFT) % PTRS_PER_PUD;
115 pud[i + 0] = (pudval_t)pmd + _KERNPG_TABLE;
116 pud[i + 1] = (pudval_t)pmd + _KERNPG_TABLE;
118 pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
119 pmd_entry += physaddr;
121 for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) {
122 int idx = i + (physaddr >> PMD_SHIFT) % PTRS_PER_PMD;
123 pmd[idx] = pmd_entry + i * PMD_SIZE;
127 * Fixup the kernel text+data virtual addresses. Note that
128 * we might write invalid pmds, when the kernel is relocated
129 * cleanup_highmap() fixes this up along with the mappings
133 pmd = fixup_pointer(level2_kernel_pgt, physaddr);
134 for (i = 0; i < PTRS_PER_PMD; i++) {
135 if (pmd[i] & _PAGE_PRESENT)
136 pmd[i] += load_delta;
139 /* Fixup phys_base */
140 p = fixup_pointer(&phys_base, physaddr);
144 /* Wipe all early page tables except for the kernel symbol map */
145 static void __init reset_early_page_tables(void)
147 memset(early_top_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1));
149 write_cr3(__pa_nodebug(early_top_pgt));
152 /* Create a new PMD entry */
153 int __init early_make_pgtable(unsigned long address)
155 unsigned long physaddr = address - __PAGE_OFFSET;
156 pgdval_t pgd, *pgd_p;
157 p4dval_t p4d, *p4d_p;
158 pudval_t pud, *pud_p;
159 pmdval_t pmd, *pmd_p;
161 /* Invalid address or early pgt is done ? */
162 if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt))
166 pgd_p = &early_top_pgt[pgd_index(address)].pgd;
170 * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is
171 * critical -- __PAGE_OFFSET would point us back into the dynamic
172 * range and we might end up looping forever...
174 if (!IS_ENABLED(CONFIG_X86_5LEVEL))
177 p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
179 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
180 reset_early_page_tables();
184 p4d_p = (p4dval_t *)early_dynamic_pgts[next_early_pgt++];
185 memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D);
186 *pgd_p = (pgdval_t)p4d_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
188 p4d_p += p4d_index(address);
192 pud_p = (pudval_t *)((p4d & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
194 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
195 reset_early_page_tables();
199 pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
200 memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
201 *p4d_p = (p4dval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
203 pud_p += pud_index(address);
207 pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
209 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
210 reset_early_page_tables();
214 pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
215 memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
216 *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
218 pmd = (physaddr & PMD_MASK) + early_pmd_flags;
219 pmd_p[pmd_index(address)] = pmd;
224 /* Don't add a printk in there. printk relies on the PDA which is not initialized
226 static void __init clear_bss(void)
228 memset(__bss_start, 0,
229 (unsigned long) __bss_stop - (unsigned long) __bss_start);
232 static unsigned long get_cmd_line_ptr(void)
234 unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
236 cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
241 static void __init copy_bootdata(char *real_mode_data)
244 unsigned long cmd_line_ptr;
246 memcpy(&boot_params, real_mode_data, sizeof boot_params);
247 sanitize_boot_params(&boot_params);
248 cmd_line_ptr = get_cmd_line_ptr();
250 command_line = __va(cmd_line_ptr);
251 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
255 asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
260 * Build-time sanity checks on the kernel image and module
261 * area mappings. (these are purely build-time and produce no code)
263 BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map);
264 BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE);
265 BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
266 BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0);
267 BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
268 BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
269 BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
270 (__START_KERNEL & PGDIR_MASK)));
271 BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
275 /* Kill off the identity-map trampoline */
276 reset_early_page_tables();
280 clear_page(init_top_pgt);
284 for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
285 set_intr_gate(i, early_idt_handler_array[i]);
286 load_idt((const struct desc_ptr *)&idt_descr);
288 copy_bootdata(__va(real_mode_data));
291 * Load microcode early on BSP.
295 /* set init_top_pgt kernel high mapping*/
296 init_top_pgt[511] = early_top_pgt[511];
298 x86_64_start_reservations(real_mode_data);
301 void __init x86_64_start_reservations(char *real_mode_data)
303 /* version is always not zero if it is copied */
304 if (!boot_params.hdr.version)
305 copy_bootdata(__va(real_mode_data));
307 x86_early_init_platform_quirks();
309 switch (boot_params.hdr.hardware_subarch) {
310 case X86_SUBARCH_INTEL_MID:
311 x86_intel_mid_early_setup();