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1 : : // SPDX-License-Identifier: GPL-2.0
2 : : /*
3 : : * prepare to run common code
4 : : *
5 : : * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
6 : : */
7 : :
8 : : #define DISABLE_BRANCH_PROFILING
9 : :
10 : : /* cpu_feature_enabled() cannot be used this early */
11 : : #define USE_EARLY_PGTABLE_L5
12 : :
13 : : #include <linux/init.h>
14 : : #include <linux/linkage.h>
15 : : #include <linux/types.h>
16 : : #include <linux/kernel.h>
17 : : #include <linux/string.h>
18 : : #include <linux/percpu.h>
19 : : #include <linux/start_kernel.h>
20 : : #include <linux/io.h>
21 : : #include <linux/memblock.h>
22 : : #include <linux/mem_encrypt.h>
23 : :
24 : : #include <asm/processor.h>
25 : : #include <asm/proto.h>
26 : : #include <asm/smp.h>
27 : : #include <asm/setup.h>
28 : : #include <asm/desc.h>
29 : : #include <asm/pgtable.h>
30 : : #include <asm/tlbflush.h>
31 : : #include <asm/sections.h>
32 : : #include <asm/kdebug.h>
33 : : #include <asm/e820/api.h>
34 : : #include <asm/bios_ebda.h>
35 : : #include <asm/bootparam_utils.h>
36 : : #include <asm/microcode.h>
37 : : #include <asm/kasan.h>
38 : : #include <asm/fixmap.h>
39 : :
40 : : /*
41 : : * Manage page tables very early on.
42 : : */
43 : : extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
44 : : static unsigned int __initdata next_early_pgt;
45 : : pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
46 : :
47 : : #ifdef CONFIG_X86_5LEVEL
48 : : unsigned int __pgtable_l5_enabled __ro_after_init;
49 : : unsigned int pgdir_shift __ro_after_init = 39;
50 : : EXPORT_SYMBOL(pgdir_shift);
51 : : unsigned int ptrs_per_p4d __ro_after_init = 1;
52 : : EXPORT_SYMBOL(ptrs_per_p4d);
53 : : #endif
54 : :
55 : : #ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT
56 : : unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE_L4;
57 : : EXPORT_SYMBOL(page_offset_base);
58 : : unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE_L4;
59 : : EXPORT_SYMBOL(vmalloc_base);
60 : : unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE_L4;
61 : : EXPORT_SYMBOL(vmemmap_base);
62 : : #endif
63 : :
64 : : #define __head __section(.head.text)
65 : :
66 : 0 : static void __head *fixup_pointer(void *ptr, unsigned long physaddr)
67 : : {
68 : 0 : return ptr - (void *)_text + (void *)physaddr;
69 : : }
70 : :
71 : 0 : static unsigned long __head *fixup_long(void *ptr, unsigned long physaddr)
72 : : {
73 : 0 : return fixup_pointer(ptr, physaddr);
74 : : }
75 : :
76 : : #ifdef CONFIG_X86_5LEVEL
77 : 0 : static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr)
78 : : {
79 : 0 : return fixup_pointer(ptr, physaddr);
80 : : }
81 : :
82 : 0 : static bool __head check_la57_support(unsigned long physaddr)
83 : : {
84 : : /*
85 : : * 5-level paging is detected and enabled at kernel decomression
86 : : * stage. Only check if it has been enabled there.
87 : : */
88 [ # # ]: 0 : if (!(native_read_cr4() & X86_CR4_LA57))
89 : : return false;
90 : :
91 : 0 : *fixup_int(&__pgtable_l5_enabled, physaddr) = 1;
92 : 0 : *fixup_int(&pgdir_shift, physaddr) = 48;
93 : 0 : *fixup_int(&ptrs_per_p4d, physaddr) = 512;
94 : 0 : *fixup_long(&page_offset_base, physaddr) = __PAGE_OFFSET_BASE_L5;
95 : 0 : *fixup_long(&vmalloc_base, physaddr) = __VMALLOC_BASE_L5;
96 : 0 : *fixup_long(&vmemmap_base, physaddr) = __VMEMMAP_BASE_L5;
97 : :
98 : 0 : return true;
99 : : }
100 : : #else
101 : : static bool __head check_la57_support(unsigned long physaddr)
102 : : {
103 : : return false;
104 : : }
105 : : #endif
106 : :
107 : : /* Code in __startup_64() can be relocated during execution, but the compiler
108 : : * doesn't have to generate PC-relative relocations when accessing globals from
109 : : * that function. Clang actually does not generate them, which leads to
110 : : * boot-time crashes. To work around this problem, every global pointer must
111 : : * be adjusted using fixup_pointer().
112 : : */
113 : 0 : unsigned long __head __startup_64(unsigned long physaddr,
114 : : struct boot_params *bp)
115 : : {
116 : 0 : unsigned long vaddr, vaddr_end;
117 : 0 : unsigned long load_delta, *p;
118 : 0 : unsigned long pgtable_flags;
119 : 0 : pgdval_t *pgd;
120 : 0 : p4dval_t *p4d;
121 : 0 : pudval_t *pud;
122 : 0 : pmdval_t *pmd, pmd_entry;
123 : 0 : pteval_t *mask_ptr;
124 : 0 : bool la57;
125 : 0 : int i;
126 : 0 : unsigned int *next_pgt_ptr;
127 : :
128 : 0 : la57 = check_la57_support(physaddr);
129 : :
130 : : /* Is the address too large? */
131 [ # # # # ]: 0 : if (physaddr >> MAX_PHYSMEM_BITS)
132 : 0 : for (;;);
133 : :
134 : : /*
135 : : * Compute the delta between the address I am compiled to run at
136 : : * and the address I am actually running at.
137 : : */
138 : 0 : load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map);
139 : :
140 : : /* Is the address not 2M aligned? */
141 [ # # ]: 0 : if (load_delta & ~PMD_PAGE_MASK)
142 : 0 : for (;;);
143 : :
144 : : /* Activate Secure Memory Encryption (SME) if supported and enabled */
145 [ # # ]: 0 : sme_enable(bp);
146 : :
147 : : /* Include the SME encryption mask in the fixup value */
148 [ # # ]: 0 : load_delta += sme_get_me_mask();
149 : :
150 : : /* Fixup the physical addresses in the page table */
151 : :
152 : 0 : pgd = fixup_pointer(&early_top_pgt, physaddr);
153 : 0 : p = pgd + pgd_index(__START_KERNEL_map);
154 [ # # ]: 0 : if (la57)
155 : 0 : *p = (unsigned long)level4_kernel_pgt;
156 : : else
157 : 0 : *p = (unsigned long)level3_kernel_pgt;
158 : 0 : *p += _PAGE_TABLE_NOENC - __START_KERNEL_map + load_delta;
159 : :
160 [ # # ]: 0 : if (la57) {
161 : 0 : p4d = fixup_pointer(&level4_kernel_pgt, physaddr);
162 : 0 : p4d[511] += load_delta;
163 : : }
164 : :
165 : 0 : pud = fixup_pointer(&level3_kernel_pgt, physaddr);
166 : 0 : pud[510] += load_delta;
167 : 0 : pud[511] += load_delta;
168 : :
169 : 0 : pmd = fixup_pointer(level2_fixmap_pgt, physaddr);
170 [ # # ]: 0 : for (i = FIXMAP_PMD_TOP; i > FIXMAP_PMD_TOP - FIXMAP_PMD_NUM; i--)
171 : 0 : pmd[i] += load_delta;
172 : :
173 : : /*
174 : : * Set up the identity mapping for the switchover. These
175 : : * entries should *NOT* have the global bit set! This also
176 : : * creates a bunch of nonsense entries but that is fine --
177 : : * it avoids problems around wraparound.
178 : : */
179 : :
180 : 0 : next_pgt_ptr = fixup_pointer(&next_early_pgt, physaddr);
181 : 0 : pud = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
182 : 0 : pmd = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
183 : :
184 [ # # ]: 0 : pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();
185 : :
186 [ # # ]: 0 : if (la57) {
187 : 0 : p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++],
188 : : physaddr);
189 : :
190 : 0 : i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
191 : 0 : pgd[i + 0] = (pgdval_t)p4d + pgtable_flags;
192 : 0 : pgd[i + 1] = (pgdval_t)p4d + pgtable_flags;
193 : :
194 : 0 : i = physaddr >> P4D_SHIFT;
195 : 0 : p4d[(i + 0) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
196 : 0 : p4d[(i + 1) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
197 : : } else {
198 : 0 : i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
199 : 0 : pgd[i + 0] = (pgdval_t)pud + pgtable_flags;
200 : 0 : pgd[i + 1] = (pgdval_t)pud + pgtable_flags;
201 : : }
202 : :
203 : 0 : i = physaddr >> PUD_SHIFT;
204 : 0 : pud[(i + 0) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
205 : 0 : pud[(i + 1) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
206 : :
207 : 0 : pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
208 : : /* Filter out unsupported __PAGE_KERNEL_* bits: */
209 : 0 : mask_ptr = fixup_pointer(&__supported_pte_mask, physaddr);
210 : 0 : pmd_entry &= *mask_ptr;
211 : 0 : pmd_entry += sme_get_me_mask();
212 : 0 : pmd_entry += physaddr;
213 : :
214 [ # # ]: 0 : for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) {
215 : 0 : int idx = i + (physaddr >> PMD_SHIFT);
216 : :
217 : 0 : pmd[idx % PTRS_PER_PMD] = pmd_entry + i * PMD_SIZE;
218 : : }
219 : :
220 : : /*
221 : : * Fixup the kernel text+data virtual addresses. Note that
222 : : * we might write invalid pmds, when the kernel is relocated
223 : : * cleanup_highmap() fixes this up along with the mappings
224 : : * beyond _end.
225 : : *
226 : : * Only the region occupied by the kernel image has so far
227 : : * been checked against the table of usable memory regions
228 : : * provided by the firmware, so invalidate pages outside that
229 : : * region. A page table entry that maps to a reserved area of
230 : : * memory would allow processor speculation into that area,
231 : : * and on some hardware (particularly the UV platform) even
232 : : * speculative access to some reserved areas is caught as an
233 : : * error, causing the BIOS to halt the system.
234 : : */
235 : :
236 : 0 : pmd = fixup_pointer(level2_kernel_pgt, physaddr);
237 : :
238 : : /* invalidate pages before the kernel image */
239 [ # # ]: 0 : for (i = 0; i < pmd_index((unsigned long)_text); i++)
240 : 0 : pmd[i] &= ~_PAGE_PRESENT;
241 : :
242 : : /* fixup pages that are part of the kernel image */
243 [ # # ]: 0 : for (; i <= pmd_index((unsigned long)_end); i++)
244 [ # # ]: 0 : if (pmd[i] & _PAGE_PRESENT)
245 : 0 : pmd[i] += load_delta;
246 : :
247 : : /* invalidate pages after the kernel image */
248 [ # # ]: 0 : for (; i < PTRS_PER_PMD; i++)
249 : 0 : pmd[i] &= ~_PAGE_PRESENT;
250 : :
251 : : /*
252 : : * Fixup phys_base - remove the memory encryption mask to obtain
253 : : * the true physical address.
254 : : */
255 : 0 : *fixup_long(&phys_base, physaddr) += load_delta - sme_get_me_mask();
256 : :
257 : : /* Encrypt the kernel and related (if SME is active) */
258 : 0 : sme_encrypt_kernel(bp);
259 : :
260 : : /*
261 : : * Clear the memory encryption mask from the .bss..decrypted section.
262 : : * The bss section will be memset to zero later in the initialization so
263 : : * there is no need to zero it after changing the memory encryption
264 : : * attribute.
265 : : */
266 : 0 : if (mem_encrypt_active()) {
267 : : vaddr = (unsigned long)__start_bss_decrypted;
268 : : vaddr_end = (unsigned long)__end_bss_decrypted;
269 : : for (; vaddr < vaddr_end; vaddr += PMD_SIZE) {
270 : : i = pmd_index(vaddr);
271 : : pmd[i] -= sme_get_me_mask();
272 : : }
273 : : }
274 : :
275 : : /*
276 : : * Return the SME encryption mask (if SME is active) to be used as a
277 : : * modifier for the initial pgdir entry programmed into CR3.
278 : : */
279 : 0 : return sme_get_me_mask();
280 : : }
281 : :
282 : 0 : unsigned long __startup_secondary_64(void)
283 : : {
284 : : /*
285 : : * Return the SME encryption mask (if SME is active) to be used as a
286 : : * modifier for the initial pgdir entry programmed into CR3.
287 : : */
288 : 0 : return sme_get_me_mask();
289 : : }
290 : :
291 : : /* Wipe all early page tables except for the kernel symbol map */
292 : 0 : static void __init reset_early_page_tables(void)
293 : : {
294 : 0 : memset(early_top_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1));
295 : 0 : next_early_pgt = 0;
296 [ # # ]: 0 : write_cr3(__sme_pa_nodebug(early_top_pgt));
297 : 0 : }
298 : :
299 : : /* Create a new PMD entry */
300 : 52 : int __init __early_make_pgtable(unsigned long address, pmdval_t pmd)
301 : : {
302 : 52 : unsigned long physaddr = address - __PAGE_OFFSET;
303 : 52 : pgdval_t pgd, *pgd_p;
304 : 52 : p4dval_t p4d, *p4d_p;
305 : 52 : pudval_t pud, *pud_p;
306 : 52 : pmdval_t *pmd_p;
307 : :
308 : : /* Invalid address or early pgt is done ? */
309 [ + - + - : 208 : if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt))
- + + - ]
310 : 0 : return -1;
311 : :
312 : 52 : again:
313 : 52 : pgd_p = &early_top_pgt[pgd_index(address)].pgd;
314 : 52 : pgd = *pgd_p;
315 : :
316 : : /*
317 : : * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is
318 : : * critical -- __PAGE_OFFSET would point us back into the dynamic
319 : : * range and we might end up looping forever...
320 : : */
321 [ - + ]: 52 : if (!pgtable_l5_enabled())
322 : : p4d_p = pgd_p;
323 [ # # ]: 0 : else if (pgd)
324 : 0 : p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
325 : : else {
326 [ # # ]: 0 : if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
327 : 0 : reset_early_page_tables();
328 : 0 : goto again;
329 : : }
330 : :
331 : 0 : p4d_p = (p4dval_t *)early_dynamic_pgts[next_early_pgt++];
332 : 0 : memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D);
333 : 0 : *pgd_p = (pgdval_t)p4d_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
334 : : }
335 [ + + ]: 52 : p4d_p += p4d_index(address);
336 : 52 : p4d = *p4d_p;
337 : :
338 [ + + ]: 52 : if (p4d)
339 : 39 : pud_p = (pudval_t *)((p4d & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
340 : : else {
341 [ - + ]: 13 : if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
342 : 0 : reset_early_page_tables();
343 : 0 : goto again;
344 : : }
345 : :
346 : 13 : pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
347 : 13 : memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
348 : 13 : *p4d_p = (p4dval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
349 : : }
350 [ + + ]: 52 : pud_p += pud_index(address);
351 : 52 : pud = *pud_p;
352 : :
353 [ + + ]: 52 : if (pud)
354 : 39 : pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
355 : : else {
356 [ - + ]: 13 : if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
357 : 0 : reset_early_page_tables();
358 : 0 : goto again;
359 : : }
360 : :
361 : 13 : pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
362 : 13 : memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
363 : 13 : *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
364 : : }
365 : 52 : pmd_p[pmd_index(address)] = pmd;
366 : :
367 : 52 : return 0;
368 : : }
369 : :
370 : 52 : int __init early_make_pgtable(unsigned long address)
371 : : {
372 : 52 : unsigned long physaddr = address - __PAGE_OFFSET;
373 : 52 : pmdval_t pmd;
374 : :
375 : 52 : pmd = (physaddr & PMD_MASK) + early_pmd_flags;
376 : :
377 : 52 : return __early_make_pgtable(address, pmd);
378 : : }
379 : :
380 : : /* Don't add a printk in there. printk relies on the PDA which is not initialized
381 : : yet. */
382 : 0 : static void __init clear_bss(void)
383 : : {
384 : 0 : memset(__bss_start, 0,
385 : : (unsigned long) __bss_stop - (unsigned long) __bss_start);
386 : 13 : }
387 : :
388 : 13 : static unsigned long get_cmd_line_ptr(void)
389 : : {
390 : 13 : unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
391 : :
392 : 13 : cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
393 : :
394 : 13 : return cmd_line_ptr;
395 : : }
396 : :
397 : 13 : static void __init copy_bootdata(char *real_mode_data)
398 : : {
399 : 13 : char * command_line;
400 : 13 : unsigned long cmd_line_ptr;
401 : :
402 : : /*
403 : : * If SME is active, this will create decrypted mappings of the
404 : : * boot data in advance of the copy operations.
405 : : */
406 : 13 : sme_map_bootdata(real_mode_data);
407 : :
408 : 13 : memcpy(&boot_params, real_mode_data, sizeof(boot_params));
409 : 13 : sanitize_boot_params(&boot_params);
410 : 13 : cmd_line_ptr = get_cmd_line_ptr();
411 [ + - ]: 13 : if (cmd_line_ptr) {
412 : 13 : command_line = __va(cmd_line_ptr);
413 : 13 : memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
414 : : }
415 : :
416 : : /*
417 : : * The old boot data is no longer needed and won't be reserved,
418 : : * freeing up that memory for use by the system. If SME is active,
419 : : * we need to remove the mappings that were created so that the
420 : : * memory doesn't remain mapped as decrypted.
421 : : */
422 : 13 : sme_unmap_bootdata(real_mode_data);
423 : 13 : }
424 : :
425 : 0 : asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
426 : : {
427 : : /*
428 : : * Build-time sanity checks on the kernel image and module
429 : : * area mappings. (these are purely build-time and produce no code)
430 : : */
431 : 0 : BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map);
432 : 0 : BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE);
433 : 0 : BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
434 : 0 : BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0);
435 : 0 : BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
436 : 0 : BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
437 [ # # # # : 0 : MAYBE_BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
# # ]
438 : : (__START_KERNEL & PGDIR_MASK)));
439 : 0 : BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
440 : :
441 : 0 : cr4_init_shadow();
442 : :
443 : : /* Kill off the identity-map trampoline */
444 : 0 : reset_early_page_tables();
445 : :
446 : 0 : clear_bss();
447 : :
448 : 13 : clear_page(init_top_pgt);
449 : :
450 : : /*
451 : : * SME support may update early_pmd_flags to include the memory
452 : : * encryption mask, so it needs to be called before anything
453 : : * that may generate a page fault.
454 : : */
455 : 13 : sme_early_init();
456 : :
457 : 13 : kasan_early_init();
458 : :
459 : 13 : idt_setup_early_handler();
460 : :
461 : 13 : copy_bootdata(__va(real_mode_data));
462 : :
463 : : /*
464 : : * Load microcode early on BSP.
465 : : */
466 : 13 : load_ucode_bsp();
467 : :
468 : : /* set init_top_pgt kernel high mapping*/
469 : 13 : init_top_pgt[511] = early_top_pgt[511];
470 : :
471 : 13 : x86_64_start_reservations(real_mode_data);
472 : 0 : }
473 : :
474 : 13 : void __init x86_64_start_reservations(char *real_mode_data)
475 : : {
476 : : /* version is always not zero if it is copied */
477 [ - + ]: 13 : if (!boot_params.hdr.version)
478 : 0 : copy_bootdata(__va(real_mode_data));
479 : :
480 : 13 : x86_early_init_platform_quirks();
481 : :
482 : 13 : switch (boot_params.hdr.hardware_subarch) {
483 : : case X86_SUBARCH_INTEL_MID:
484 : : x86_intel_mid_early_setup();
485 : : break;
486 : : default:
487 : : break;
488 : : }
489 : :
490 : 13 : start_kernel();
491 : 0 : }
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