~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/arch/x86/kernel/head64.c

Version: ~ [ linux-5.15-rc1 ] ~ [ linux-5.14.5 ] ~ [ linux-5.13.18 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.66 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.147 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.206 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.246 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.282 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.283 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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 static void __head *fixup_pointer(void *ptr, unsigned long physaddr)
 67 {
 68         return ptr - (void *)_text + (void *)physaddr;
 69 }
 70 
 71 static unsigned long __head *fixup_long(void *ptr, unsigned long physaddr)
 72 {
 73         return fixup_pointer(ptr, physaddr);
 74 }
 75 
 76 #ifdef CONFIG_X86_5LEVEL
 77 static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr)
 78 {
 79         return fixup_pointer(ptr, physaddr);
 80 }
 81 
 82 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         if (!(native_read_cr4() & X86_CR4_LA57))
 89                 return false;
 90 
 91         *fixup_int(&__pgtable_l5_enabled, physaddr) = 1;
 92         *fixup_int(&pgdir_shift, physaddr) = 48;
 93         *fixup_int(&ptrs_per_p4d, physaddr) = 512;
 94         *fixup_long(&page_offset_base, physaddr) = __PAGE_OFFSET_BASE_L5;
 95         *fixup_long(&vmalloc_base, physaddr) = __VMALLOC_BASE_L5;
 96         *fixup_long(&vmemmap_base, physaddr) = __VMEMMAP_BASE_L5;
 97 
 98         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 unsigned long __head __startup_64(unsigned long physaddr,
114                                   struct boot_params *bp)
115 {
116         unsigned long vaddr, vaddr_end;
117         unsigned long load_delta, *p;
118         unsigned long pgtable_flags;
119         pgdval_t *pgd;
120         p4dval_t *p4d;
121         pudval_t *pud;
122         pmdval_t *pmd, pmd_entry;
123         pteval_t *mask_ptr;
124         bool la57;
125         int i;
126         unsigned int *next_pgt_ptr;
127 
128         la57 = check_la57_support(physaddr);
129 
130         /* Is the address too large? */
131         if (physaddr >> MAX_PHYSMEM_BITS)
132                 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         load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map);
139 
140         /* Is the address not 2M aligned? */
141         if (load_delta & ~PMD_PAGE_MASK)
142                 for (;;);
143 
144         /* Activate Secure Memory Encryption (SME) if supported and enabled */
145         sme_enable(bp);
146 
147         /* Include the SME encryption mask in the fixup value */
148         load_delta += sme_get_me_mask();
149 
150         /* Fixup the physical addresses in the page table */
151 
152         pgd = fixup_pointer(&early_top_pgt, physaddr);
153         p = pgd + pgd_index(__START_KERNEL_map);
154         if (la57)
155                 *p = (unsigned long)level4_kernel_pgt;
156         else
157                 *p = (unsigned long)level3_kernel_pgt;
158         *p += _PAGE_TABLE_NOENC - __START_KERNEL_map + load_delta;
159 
160         if (la57) {
161                 p4d = fixup_pointer(&level4_kernel_pgt, physaddr);
162                 p4d[511] += load_delta;
163         }
164 
165         pud = fixup_pointer(&level3_kernel_pgt, physaddr);
166         pud[510] += load_delta;
167         pud[511] += load_delta;
168 
169         pmd = fixup_pointer(level2_fixmap_pgt, physaddr);
170         for (i = FIXMAP_PMD_TOP; i > FIXMAP_PMD_TOP - FIXMAP_PMD_NUM; i--)
171                 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         next_pgt_ptr = fixup_pointer(&next_early_pgt, physaddr);
181         pud = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
182         pmd = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr);
183 
184         pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();
185 
186         if (la57) {
187                 p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++],
188                                     physaddr);
189 
190                 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
191                 pgd[i + 0] = (pgdval_t)p4d + pgtable_flags;
192                 pgd[i + 1] = (pgdval_t)p4d + pgtable_flags;
193 
194                 i = physaddr >> P4D_SHIFT;
195                 p4d[(i + 0) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
196                 p4d[(i + 1) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
197         } else {
198                 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
199                 pgd[i + 0] = (pgdval_t)pud + pgtable_flags;
200                 pgd[i + 1] = (pgdval_t)pud + pgtable_flags;
201         }
202 
203         i = physaddr >> PUD_SHIFT;
204         pud[(i + 0) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
205         pud[(i + 1) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
206 
207         pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
208         /* Filter out unsupported __PAGE_KERNEL_* bits: */
209         mask_ptr = fixup_pointer(&__supported_pte_mask, physaddr);
210         pmd_entry &= *mask_ptr;
211         pmd_entry += sme_get_me_mask();
212         pmd_entry +=  physaddr;
213 
214         for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) {
215                 int idx = i + (physaddr >> PMD_SHIFT);
216 
217                 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         pmd = fixup_pointer(level2_kernel_pgt, physaddr);
237 
238         /* invalidate pages before the kernel image */
239         for (i = 0; i < pmd_index((unsigned long)_text); i++)
240                 pmd[i] &= ~_PAGE_PRESENT;
241 
242         /* fixup pages that are part of the kernel image */
243         for (; i <= pmd_index((unsigned long)_end); i++)
244                 if (pmd[i] & _PAGE_PRESENT)
245                         pmd[i] += load_delta;
246 
247         /* invalidate pages after the kernel image */
248         for (; i < PTRS_PER_PMD; i++)
249                 pmd[i] &= ~_PAGE_PRESENT;
250 
251         /*
252          * Fixup phys_base - remove the memory encryption mask to obtain
253          * the true physical address.
254          */
255         *fixup_long(&phys_base, physaddr) += load_delta - sme_get_me_mask();
256 
257         /* Encrypt the kernel and related (if SME is active) */
258         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         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         return sme_get_me_mask();
280 }
281 
282 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         return sme_get_me_mask();
289 }
290 
291 /* Wipe all early page tables except for the kernel symbol map */
292 static void __init reset_early_page_tables(void)
293 {
294         memset(early_top_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1));
295         next_early_pgt = 0;
296         write_cr3(__sme_pa_nodebug(early_top_pgt));
297 }
298 
299 /* Create a new PMD entry */
300 int __init __early_make_pgtable(unsigned long address, pmdval_t pmd)
301 {
302         unsigned long physaddr = address - __PAGE_OFFSET;
303         pgdval_t pgd, *pgd_p;
304         p4dval_t p4d, *p4d_p;
305         pudval_t pud, *pud_p;
306         pmdval_t *pmd_p;
307 
308         /* Invalid address or early pgt is done ?  */
309         if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt))
310                 return -1;
311 
312 again:
313         pgd_p = &early_top_pgt[pgd_index(address)].pgd;
314         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         if (!pgtable_l5_enabled())
322                 p4d_p = pgd_p;
323         else if (pgd)
324                 p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
325         else {
326                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
327                         reset_early_page_tables();
328                         goto again;
329                 }
330 
331                 p4d_p = (p4dval_t *)early_dynamic_pgts[next_early_pgt++];
332                 memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D);
333                 *pgd_p = (pgdval_t)p4d_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
334         }
335         p4d_p += p4d_index(address);
336         p4d = *p4d_p;
337 
338         if (p4d)
339                 pud_p = (pudval_t *)((p4d & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
340         else {
341                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
342                         reset_early_page_tables();
343                         goto again;
344                 }
345 
346                 pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
347                 memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
348                 *p4d_p = (p4dval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
349         }
350         pud_p += pud_index(address);
351         pud = *pud_p;
352 
353         if (pud)
354                 pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
355         else {
356                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
357                         reset_early_page_tables();
358                         goto again;
359                 }
360 
361                 pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
362                 memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
363                 *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
364         }
365         pmd_p[pmd_index(address)] = pmd;
366 
367         return 0;
368 }
369 
370 int __init early_make_pgtable(unsigned long address)
371 {
372         unsigned long physaddr = address - __PAGE_OFFSET;
373         pmdval_t pmd;
374 
375         pmd = (physaddr & PMD_MASK) + early_pmd_flags;
376 
377         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 static void __init clear_bss(void)
383 {
384         memset(__bss_start, 0,
385                (unsigned long) __bss_stop - (unsigned long) __bss_start);
386 }
387 
388 static unsigned long get_cmd_line_ptr(void)
389 {
390         unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
391 
392         cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
393 
394         return cmd_line_ptr;
395 }
396 
397 static void __init copy_bootdata(char *real_mode_data)
398 {
399         char * command_line;
400         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         sme_map_bootdata(real_mode_data);
407 
408         memcpy(&boot_params, real_mode_data, sizeof(boot_params));
409         sanitize_boot_params(&boot_params);
410         cmd_line_ptr = get_cmd_line_ptr();
411         if (cmd_line_ptr) {
412                 command_line = __va(cmd_line_ptr);
413                 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         sme_unmap_bootdata(real_mode_data);
423 }
424 
425 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         BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map);
432         BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE);
433         BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
434         BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0);
435         BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
436         BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
437         MAYBE_BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
438                                 (__START_KERNEL & PGDIR_MASK)));
439         BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
440 
441         cr4_init_shadow();
442 
443         /* Kill off the identity-map trampoline */
444         reset_early_page_tables();
445 
446         clear_bss();
447 
448         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         sme_early_init();
456 
457         kasan_early_init();
458 
459         idt_setup_early_handler();
460 
461         copy_bootdata(__va(real_mode_data));
462 
463         /*
464          * Load microcode early on BSP.
465          */
466         load_ucode_bsp();
467 
468         /* set init_top_pgt kernel high mapping*/
469         init_top_pgt[511] = early_top_pgt[511];
470 
471         x86_64_start_reservations(real_mode_data);
472 }
473 
474 void __init x86_64_start_reservations(char *real_mode_data)
475 {
476         /* version is always not zero if it is copied */
477         if (!boot_params.hdr.version)
478                 copy_bootdata(__va(real_mode_data));
479 
480         x86_early_init_platform_quirks();
481 
482         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         start_kernel();
491 }
492 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp