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Linux/arch/arm/mm/mmu.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  *  linux/arch/arm/mm/mmu.c
  4  *
  5  *  Copyright (C) 1995-2005 Russell King
  6  */
  7 #include <linux/module.h>
  8 #include <linux/kernel.h>
  9 #include <linux/errno.h>
 10 #include <linux/init.h>
 11 #include <linux/mman.h>
 12 #include <linux/nodemask.h>
 13 #include <linux/memblock.h>
 14 #include <linux/fs.h>
 15 #include <linux/vmalloc.h>
 16 #include <linux/sizes.h>
 17 
 18 #include <asm/cp15.h>
 19 #include <asm/cputype.h>
 20 #include <asm/cachetype.h>
 21 #include <asm/sections.h>
 22 #include <asm/setup.h>
 23 #include <asm/smp_plat.h>
 24 #include <asm/tcm.h>
 25 #include <asm/tlb.h>
 26 #include <asm/highmem.h>
 27 #include <asm/system_info.h>
 28 #include <asm/traps.h>
 29 #include <asm/procinfo.h>
 30 #include <asm/page.h>
 31 #include <asm/pgalloc.h>
 32 #include <asm/kasan_def.h>
 33 
 34 #include <asm/mach/arch.h>
 35 #include <asm/mach/map.h>
 36 #include <asm/mach/pci.h>
 37 #include <asm/fixmap.h>
 38 
 39 #include "fault.h"
 40 #include "mm.h"
 41 
 42 extern unsigned long __atags_pointer;
 43 
 44 /*
 45  * empty_zero_page is a special page that is used for
 46  * zero-initialized data and COW.
 47  */
 48 struct page *empty_zero_page;
 49 EXPORT_SYMBOL(empty_zero_page);
 50 
 51 /*
 52  * The pmd table for the upper-most set of pages.
 53  */
 54 pmd_t *top_pmd;
 55 
 56 pmdval_t user_pmd_table = _PAGE_USER_TABLE;
 57 
 58 #define CPOLICY_UNCACHED        0
 59 #define CPOLICY_BUFFERED        1
 60 #define CPOLICY_WRITETHROUGH    2
 61 #define CPOLICY_WRITEBACK       3
 62 #define CPOLICY_WRITEALLOC      4
 63 
 64 static unsigned int cachepolicy __initdata = CPOLICY_WRITEBACK;
 65 static unsigned int ecc_mask __initdata = 0;
 66 pgprot_t pgprot_user;
 67 pgprot_t pgprot_kernel;
 68 
 69 EXPORT_SYMBOL(pgprot_user);
 70 EXPORT_SYMBOL(pgprot_kernel);
 71 
 72 struct cachepolicy {
 73         const char      policy[16];
 74         unsigned int    cr_mask;
 75         pmdval_t        pmd;
 76         pteval_t        pte;
 77 };
 78 
 79 static struct cachepolicy cache_policies[] __initdata = {
 80         {
 81                 .policy         = "uncached",
 82                 .cr_mask        = CR_W|CR_C,
 83                 .pmd            = PMD_SECT_UNCACHED,
 84                 .pte            = L_PTE_MT_UNCACHED,
 85         }, {
 86                 .policy         = "buffered",
 87                 .cr_mask        = CR_C,
 88                 .pmd            = PMD_SECT_BUFFERED,
 89                 .pte            = L_PTE_MT_BUFFERABLE,
 90         }, {
 91                 .policy         = "writethrough",
 92                 .cr_mask        = 0,
 93                 .pmd            = PMD_SECT_WT,
 94                 .pte            = L_PTE_MT_WRITETHROUGH,
 95         }, {
 96                 .policy         = "writeback",
 97                 .cr_mask        = 0,
 98                 .pmd            = PMD_SECT_WB,
 99                 .pte            = L_PTE_MT_WRITEBACK,
100         }, {
101                 .policy         = "writealloc",
102                 .cr_mask        = 0,
103                 .pmd            = PMD_SECT_WBWA,
104                 .pte            = L_PTE_MT_WRITEALLOC,
105         }
106 };
107 
108 #ifdef CONFIG_CPU_CP15
109 static unsigned long initial_pmd_value __initdata = 0;
110 
111 /*
112  * Initialise the cache_policy variable with the initial state specified
113  * via the "pmd" value.  This is used to ensure that on ARMv6 and later,
114  * the C code sets the page tables up with the same policy as the head
115  * assembly code, which avoids an illegal state where the TLBs can get
116  * confused.  See comments in early_cachepolicy() for more information.
117  */
118 void __init init_default_cache_policy(unsigned long pmd)
119 {
120         int i;
121 
122         initial_pmd_value = pmd;
123 
124         pmd &= PMD_SECT_CACHE_MASK;
125 
126         for (i = 0; i < ARRAY_SIZE(cache_policies); i++)
127                 if (cache_policies[i].pmd == pmd) {
128                         cachepolicy = i;
129                         break;
130                 }
131 
132         if (i == ARRAY_SIZE(cache_policies))
133                 pr_err("ERROR: could not find cache policy\n");
134 }
135 
136 /*
137  * These are useful for identifying cache coherency problems by allowing
138  * the cache or the cache and writebuffer to be turned off.  (Note: the
139  * write buffer should not be on and the cache off).
140  */
141 static int __init early_cachepolicy(char *p)
142 {
143         int i, selected = -1;
144 
145         for (i = 0; i < ARRAY_SIZE(cache_policies); i++) {
146                 int len = strlen(cache_policies[i].policy);
147 
148                 if (memcmp(p, cache_policies[i].policy, len) == 0) {
149                         selected = i;
150                         break;
151                 }
152         }
153 
154         if (selected == -1)
155                 pr_err("ERROR: unknown or unsupported cache policy\n");
156 
157         /*
158          * This restriction is partly to do with the way we boot; it is
159          * unpredictable to have memory mapped using two different sets of
160          * memory attributes (shared, type, and cache attribs).  We can not
161          * change these attributes once the initial assembly has setup the
162          * page tables.
163          */
164         if (cpu_architecture() >= CPU_ARCH_ARMv6 && selected != cachepolicy) {
165                 pr_warn("Only cachepolicy=%s supported on ARMv6 and later\n",
166                         cache_policies[cachepolicy].policy);
167                 return 0;
168         }
169 
170         if (selected != cachepolicy) {
171                 unsigned long cr = __clear_cr(cache_policies[selected].cr_mask);
172                 cachepolicy = selected;
173                 flush_cache_all();
174                 set_cr(cr);
175         }
176         return 0;
177 }
178 early_param("cachepolicy", early_cachepolicy);
179 
180 static int __init early_nocache(char *__unused)
181 {
182         char *p = "buffered";
183         pr_warn("nocache is deprecated; use cachepolicy=%s\n", p);
184         early_cachepolicy(p);
185         return 0;
186 }
187 early_param("nocache", early_nocache);
188 
189 static int __init early_nowrite(char *__unused)
190 {
191         char *p = "uncached";
192         pr_warn("nowb is deprecated; use cachepolicy=%s\n", p);
193         early_cachepolicy(p);
194         return 0;
195 }
196 early_param("nowb", early_nowrite);
197 
198 #ifndef CONFIG_ARM_LPAE
199 static int __init early_ecc(char *p)
200 {
201         if (memcmp(p, "on", 2) == 0)
202                 ecc_mask = PMD_PROTECTION;
203         else if (memcmp(p, "off", 3) == 0)
204                 ecc_mask = 0;
205         return 0;
206 }
207 early_param("ecc", early_ecc);
208 #endif
209 
210 #else /* ifdef CONFIG_CPU_CP15 */
211 
212 static int __init early_cachepolicy(char *p)
213 {
214         pr_warn("cachepolicy kernel parameter not supported without cp15\n");
215         return 0;
216 }
217 early_param("cachepolicy", early_cachepolicy);
218 
219 static int __init noalign_setup(char *__unused)
220 {
221         pr_warn("noalign kernel parameter not supported without cp15\n");
222         return 1;
223 }
224 __setup("noalign", noalign_setup);
225 
226 #endif /* ifdef CONFIG_CPU_CP15 / else */
227 
228 #define PROT_PTE_DEVICE         L_PTE_PRESENT|L_PTE_YOUNG|L_PTE_DIRTY|L_PTE_XN
229 #define PROT_PTE_S2_DEVICE      PROT_PTE_DEVICE
230 #define PROT_SECT_DEVICE        PMD_TYPE_SECT|PMD_SECT_AP_WRITE
231 
232 static struct mem_type mem_types[] __ro_after_init = {
233         [MT_DEVICE] = {           /* Strongly ordered / ARMv6 shared device */
234                 .prot_pte       = PROT_PTE_DEVICE | L_PTE_MT_DEV_SHARED |
235                                   L_PTE_SHARED,
236                 .prot_l1        = PMD_TYPE_TABLE,
237                 .prot_sect      = PROT_SECT_DEVICE | PMD_SECT_S,
238                 .domain         = DOMAIN_IO,
239         },
240         [MT_DEVICE_NONSHARED] = { /* ARMv6 non-shared device */
241                 .prot_pte       = PROT_PTE_DEVICE | L_PTE_MT_DEV_NONSHARED,
242                 .prot_l1        = PMD_TYPE_TABLE,
243                 .prot_sect      = PROT_SECT_DEVICE,
244                 .domain         = DOMAIN_IO,
245         },
246         [MT_DEVICE_CACHED] = {    /* ioremap_cache */
247                 .prot_pte       = PROT_PTE_DEVICE | L_PTE_MT_DEV_CACHED,
248                 .prot_l1        = PMD_TYPE_TABLE,
249                 .prot_sect      = PROT_SECT_DEVICE | PMD_SECT_WB,
250                 .domain         = DOMAIN_IO,
251         },
252         [MT_DEVICE_WC] = {      /* ioremap_wc */
253                 .prot_pte       = PROT_PTE_DEVICE | L_PTE_MT_DEV_WC,
254                 .prot_l1        = PMD_TYPE_TABLE,
255                 .prot_sect      = PROT_SECT_DEVICE,
256                 .domain         = DOMAIN_IO,
257         },
258         [MT_UNCACHED] = {
259                 .prot_pte       = PROT_PTE_DEVICE,
260                 .prot_l1        = PMD_TYPE_TABLE,
261                 .prot_sect      = PMD_TYPE_SECT | PMD_SECT_XN,
262                 .domain         = DOMAIN_IO,
263         },
264         [MT_CACHECLEAN] = {
265                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_XN,
266                 .domain    = DOMAIN_KERNEL,
267         },
268 #ifndef CONFIG_ARM_LPAE
269         [MT_MINICLEAN] = {
270                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_XN | PMD_SECT_MINICACHE,
271                 .domain    = DOMAIN_KERNEL,
272         },
273 #endif
274         [MT_LOW_VECTORS] = {
275                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
276                                 L_PTE_RDONLY,
277                 .prot_l1   = PMD_TYPE_TABLE,
278                 .domain    = DOMAIN_VECTORS,
279         },
280         [MT_HIGH_VECTORS] = {
281                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
282                                 L_PTE_USER | L_PTE_RDONLY,
283                 .prot_l1   = PMD_TYPE_TABLE,
284                 .domain    = DOMAIN_VECTORS,
285         },
286         [MT_MEMORY_RWX] = {
287                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY,
288                 .prot_l1   = PMD_TYPE_TABLE,
289                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
290                 .domain    = DOMAIN_KERNEL,
291         },
292         [MT_MEMORY_RW] = {
293                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
294                              L_PTE_XN,
295                 .prot_l1   = PMD_TYPE_TABLE,
296                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
297                 .domain    = DOMAIN_KERNEL,
298         },
299         [MT_MEMORY_RO] = {
300                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
301                              L_PTE_XN | L_PTE_RDONLY,
302                 .prot_l1   = PMD_TYPE_TABLE,
303 #ifdef CONFIG_ARM_LPAE
304                 .prot_sect = PMD_TYPE_SECT | L_PMD_SECT_RDONLY | PMD_SECT_AP2,
305 #else
306                 .prot_sect = PMD_TYPE_SECT,
307 #endif
308                 .domain    = DOMAIN_KERNEL,
309         },
310         [MT_ROM] = {
311                 .prot_sect = PMD_TYPE_SECT,
312                 .domain    = DOMAIN_KERNEL,
313         },
314         [MT_MEMORY_RWX_NONCACHED] = {
315                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
316                                 L_PTE_MT_BUFFERABLE,
317                 .prot_l1   = PMD_TYPE_TABLE,
318                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
319                 .domain    = DOMAIN_KERNEL,
320         },
321         [MT_MEMORY_RW_DTCM] = {
322                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
323                                 L_PTE_XN,
324                 .prot_l1   = PMD_TYPE_TABLE,
325                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_XN,
326                 .domain    = DOMAIN_KERNEL,
327         },
328         [MT_MEMORY_RWX_ITCM] = {
329                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY,
330                 .prot_l1   = PMD_TYPE_TABLE,
331                 .domain    = DOMAIN_KERNEL,
332         },
333         [MT_MEMORY_RW_SO] = {
334                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
335                                 L_PTE_MT_UNCACHED | L_PTE_XN,
336                 .prot_l1   = PMD_TYPE_TABLE,
337                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_S |
338                                 PMD_SECT_UNCACHED | PMD_SECT_XN,
339                 .domain    = DOMAIN_KERNEL,
340         },
341         [MT_MEMORY_DMA_READY] = {
342                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
343                                 L_PTE_XN,
344                 .prot_l1   = PMD_TYPE_TABLE,
345                 .domain    = DOMAIN_KERNEL,
346         },
347 };
348 
349 const struct mem_type *get_mem_type(unsigned int type)
350 {
351         return type < ARRAY_SIZE(mem_types) ? &mem_types[type] : NULL;
352 }
353 EXPORT_SYMBOL(get_mem_type);
354 
355 static pte_t *(*pte_offset_fixmap)(pmd_t *dir, unsigned long addr);
356 
357 static pte_t bm_pte[PTRS_PER_PTE + PTE_HWTABLE_PTRS]
358         __aligned(PTE_HWTABLE_OFF + PTE_HWTABLE_SIZE) __initdata;
359 
360 static pte_t * __init pte_offset_early_fixmap(pmd_t *dir, unsigned long addr)
361 {
362         return &bm_pte[pte_index(addr)];
363 }
364 
365 static pte_t *pte_offset_late_fixmap(pmd_t *dir, unsigned long addr)
366 {
367         return pte_offset_kernel(dir, addr);
368 }
369 
370 static inline pmd_t * __init fixmap_pmd(unsigned long addr)
371 {
372         return pmd_off_k(addr);
373 }
374 
375 void __init early_fixmap_init(void)
376 {
377         pmd_t *pmd;
378 
379         /*
380          * The early fixmap range spans multiple pmds, for which
381          * we are not prepared:
382          */
383         BUILD_BUG_ON((__fix_to_virt(__end_of_early_ioremap_region) >> PMD_SHIFT)
384                      != FIXADDR_TOP >> PMD_SHIFT);
385 
386         pmd = fixmap_pmd(FIXADDR_TOP);
387         pmd_populate_kernel(&init_mm, pmd, bm_pte);
388 
389         pte_offset_fixmap = pte_offset_early_fixmap;
390 }
391 
392 /*
393  * To avoid TLB flush broadcasts, this uses local_flush_tlb_kernel_range().
394  * As a result, this can only be called with preemption disabled, as under
395  * stop_machine().
396  */
397 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
398 {
399         unsigned long vaddr = __fix_to_virt(idx);
400         pte_t *pte = pte_offset_fixmap(pmd_off_k(vaddr), vaddr);
401 
402         /* Make sure fixmap region does not exceed available allocation. */
403         BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) < FIXADDR_START);
404         BUG_ON(idx >= __end_of_fixed_addresses);
405 
406         /* We support only device mappings before pgprot_kernel is set. */
407         if (WARN_ON(pgprot_val(prot) != pgprot_val(FIXMAP_PAGE_IO) &&
408                     pgprot_val(prot) && pgprot_val(pgprot_kernel) == 0))
409                 return;
410 
411         if (pgprot_val(prot))
412                 set_pte_at(NULL, vaddr, pte,
413                         pfn_pte(phys >> PAGE_SHIFT, prot));
414         else
415                 pte_clear(NULL, vaddr, pte);
416         local_flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE);
417 }
418 
419 static pgprot_t protection_map[16] __ro_after_init = {
420         [VM_NONE]                                       = __PAGE_NONE,
421         [VM_READ]                                       = __PAGE_READONLY,
422         [VM_WRITE]                                      = __PAGE_COPY,
423         [VM_WRITE | VM_READ]                            = __PAGE_COPY,
424         [VM_EXEC]                                       = __PAGE_READONLY_EXEC,
425         [VM_EXEC | VM_READ]                             = __PAGE_READONLY_EXEC,
426         [VM_EXEC | VM_WRITE]                            = __PAGE_COPY_EXEC,
427         [VM_EXEC | VM_WRITE | VM_READ]                  = __PAGE_COPY_EXEC,
428         [VM_SHARED]                                     = __PAGE_NONE,
429         [VM_SHARED | VM_READ]                           = __PAGE_READONLY,
430         [VM_SHARED | VM_WRITE]                          = __PAGE_SHARED,
431         [VM_SHARED | VM_WRITE | VM_READ]                = __PAGE_SHARED,
432         [VM_SHARED | VM_EXEC]                           = __PAGE_READONLY_EXEC,
433         [VM_SHARED | VM_EXEC | VM_READ]                 = __PAGE_READONLY_EXEC,
434         [VM_SHARED | VM_EXEC | VM_WRITE]                = __PAGE_SHARED_EXEC,
435         [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]      = __PAGE_SHARED_EXEC
436 };
437 DECLARE_VM_GET_PAGE_PROT
438 
439 /*
440  * Adjust the PMD section entries according to the CPU in use.
441  */
442 static void __init build_mem_type_table(void)
443 {
444         struct cachepolicy *cp;
445         unsigned int cr = get_cr();
446         pteval_t user_pgprot, kern_pgprot, vecs_pgprot;
447         int cpu_arch = cpu_architecture();
448         int i;
449 
450         if (cpu_arch < CPU_ARCH_ARMv6) {
451 #if defined(CONFIG_CPU_DCACHE_DISABLE)
452                 if (cachepolicy > CPOLICY_BUFFERED)
453                         cachepolicy = CPOLICY_BUFFERED;
454 #elif defined(CONFIG_CPU_DCACHE_WRITETHROUGH)
455                 if (cachepolicy > CPOLICY_WRITETHROUGH)
456                         cachepolicy = CPOLICY_WRITETHROUGH;
457 #endif
458         }
459         if (cpu_arch < CPU_ARCH_ARMv5) {
460                 if (cachepolicy >= CPOLICY_WRITEALLOC)
461                         cachepolicy = CPOLICY_WRITEBACK;
462                 ecc_mask = 0;
463         }
464 
465         if (is_smp()) {
466                 if (cachepolicy != CPOLICY_WRITEALLOC) {
467                         pr_warn("Forcing write-allocate cache policy for SMP\n");
468                         cachepolicy = CPOLICY_WRITEALLOC;
469                 }
470                 if (!(initial_pmd_value & PMD_SECT_S)) {
471                         pr_warn("Forcing shared mappings for SMP\n");
472                         initial_pmd_value |= PMD_SECT_S;
473                 }
474         }
475 
476         /*
477          * Strip out features not present on earlier architectures.
478          * Pre-ARMv5 CPUs don't have TEX bits.  Pre-ARMv6 CPUs or those
479          * without extended page tables don't have the 'Shared' bit.
480          */
481         if (cpu_arch < CPU_ARCH_ARMv5)
482                 for (i = 0; i < ARRAY_SIZE(mem_types); i++)
483                         mem_types[i].prot_sect &= ~PMD_SECT_TEX(7);
484         if ((cpu_arch < CPU_ARCH_ARMv6 || !(cr & CR_XP)) && !cpu_is_xsc3())
485                 for (i = 0; i < ARRAY_SIZE(mem_types); i++)
486                         mem_types[i].prot_sect &= ~PMD_SECT_S;
487 
488         /*
489          * ARMv5 and lower, bit 4 must be set for page tables (was: cache
490          * "update-able on write" bit on ARM610).  However, Xscale and
491          * Xscale3 require this bit to be cleared.
492          */
493         if (cpu_is_xscale_family()) {
494                 for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
495                         mem_types[i].prot_sect &= ~PMD_BIT4;
496                         mem_types[i].prot_l1 &= ~PMD_BIT4;
497                 }
498         } else if (cpu_arch < CPU_ARCH_ARMv6) {
499                 for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
500                         if (mem_types[i].prot_l1)
501                                 mem_types[i].prot_l1 |= PMD_BIT4;
502                         if (mem_types[i].prot_sect)
503                                 mem_types[i].prot_sect |= PMD_BIT4;
504                 }
505         }
506 
507         /*
508          * Mark the device areas according to the CPU/architecture.
509          */
510         if (cpu_is_xsc3() || (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP))) {
511                 if (!cpu_is_xsc3()) {
512                         /*
513                          * Mark device regions on ARMv6+ as execute-never
514                          * to prevent speculative instruction fetches.
515                          */
516                         mem_types[MT_DEVICE].prot_sect |= PMD_SECT_XN;
517                         mem_types[MT_DEVICE_NONSHARED].prot_sect |= PMD_SECT_XN;
518                         mem_types[MT_DEVICE_CACHED].prot_sect |= PMD_SECT_XN;
519                         mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_XN;
520 
521                         /* Also setup NX memory mapping */
522                         mem_types[MT_MEMORY_RW].prot_sect |= PMD_SECT_XN;
523                         mem_types[MT_MEMORY_RO].prot_sect |= PMD_SECT_XN;
524                 }
525                 if (cpu_arch >= CPU_ARCH_ARMv7 && (cr & CR_TRE)) {
526                         /*
527                          * For ARMv7 with TEX remapping,
528                          * - shared device is SXCB=1100
529                          * - nonshared device is SXCB=0100
530                          * - write combine device mem is SXCB=0001
531                          * (Uncached Normal memory)
532                          */
533                         mem_types[MT_DEVICE].prot_sect |= PMD_SECT_TEX(1);
534                         mem_types[MT_DEVICE_NONSHARED].prot_sect |= PMD_SECT_TEX(1);
535                         mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_BUFFERABLE;
536                 } else if (cpu_is_xsc3()) {
537                         /*
538                          * For Xscale3,
539                          * - shared device is TEXCB=00101
540                          * - nonshared device is TEXCB=01000
541                          * - write combine device mem is TEXCB=00100
542                          * (Inner/Outer Uncacheable in xsc3 parlance)
543                          */
544                         mem_types[MT_DEVICE].prot_sect |= PMD_SECT_TEX(1) | PMD_SECT_BUFFERED;
545                         mem_types[MT_DEVICE_NONSHARED].prot_sect |= PMD_SECT_TEX(2);
546                         mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_TEX(1);
547                 } else {
548                         /*
549                          * For ARMv6 and ARMv7 without TEX remapping,
550                          * - shared device is TEXCB=00001
551                          * - nonshared device is TEXCB=01000
552                          * - write combine device mem is TEXCB=00100
553                          * (Uncached Normal in ARMv6 parlance).
554                          */
555                         mem_types[MT_DEVICE].prot_sect |= PMD_SECT_BUFFERED;
556                         mem_types[MT_DEVICE_NONSHARED].prot_sect |= PMD_SECT_TEX(2);
557                         mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_TEX(1);
558                 }
559         } else {
560                 /*
561                  * On others, write combining is "Uncached/Buffered"
562                  */
563                 mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_BUFFERABLE;
564         }
565 
566         /*
567          * Now deal with the memory-type mappings
568          */
569         cp = &cache_policies[cachepolicy];
570         vecs_pgprot = kern_pgprot = user_pgprot = cp->pte;
571 
572 #ifndef CONFIG_ARM_LPAE
573         /*
574          * We don't use domains on ARMv6 (since this causes problems with
575          * v6/v7 kernels), so we must use a separate memory type for user
576          * r/o, kernel r/w to map the vectors page.
577          */
578         if (cpu_arch == CPU_ARCH_ARMv6)
579                 vecs_pgprot |= L_PTE_MT_VECTORS;
580 
581         /*
582          * Check is it with support for the PXN bit
583          * in the Short-descriptor translation table format descriptors.
584          */
585         if (cpu_arch == CPU_ARCH_ARMv7 &&
586                 (read_cpuid_ext(CPUID_EXT_MMFR0) & 0xF) >= 4) {
587                 user_pmd_table |= PMD_PXNTABLE;
588         }
589 #endif
590 
591         /*
592          * ARMv6 and above have extended page tables.
593          */
594         if (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP)) {
595 #ifndef CONFIG_ARM_LPAE
596                 /*
597                  * Mark cache clean areas and XIP ROM read only
598                  * from SVC mode and no access from userspace.
599                  */
600                 mem_types[MT_ROM].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
601                 mem_types[MT_MINICLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
602                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
603                 mem_types[MT_MEMORY_RO].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
604 #endif
605 
606                 /*
607                  * If the initial page tables were created with the S bit
608                  * set, then we need to do the same here for the same
609                  * reasons given in early_cachepolicy().
610                  */
611                 if (initial_pmd_value & PMD_SECT_S) {
612                         user_pgprot |= L_PTE_SHARED;
613                         kern_pgprot |= L_PTE_SHARED;
614                         vecs_pgprot |= L_PTE_SHARED;
615                         mem_types[MT_DEVICE_WC].prot_sect |= PMD_SECT_S;
616                         mem_types[MT_DEVICE_WC].prot_pte |= L_PTE_SHARED;
617                         mem_types[MT_DEVICE_CACHED].prot_sect |= PMD_SECT_S;
618                         mem_types[MT_DEVICE_CACHED].prot_pte |= L_PTE_SHARED;
619                         mem_types[MT_MEMORY_RWX].prot_sect |= PMD_SECT_S;
620                         mem_types[MT_MEMORY_RWX].prot_pte |= L_PTE_SHARED;
621                         mem_types[MT_MEMORY_RW].prot_sect |= PMD_SECT_S;
622                         mem_types[MT_MEMORY_RW].prot_pte |= L_PTE_SHARED;
623                         mem_types[MT_MEMORY_RO].prot_sect |= PMD_SECT_S;
624                         mem_types[MT_MEMORY_RO].prot_pte |= L_PTE_SHARED;
625                         mem_types[MT_MEMORY_DMA_READY].prot_pte |= L_PTE_SHARED;
626                         mem_types[MT_MEMORY_RWX_NONCACHED].prot_sect |= PMD_SECT_S;
627                         mem_types[MT_MEMORY_RWX_NONCACHED].prot_pte |= L_PTE_SHARED;
628                 }
629         }
630 
631         /*
632          * Non-cacheable Normal - intended for memory areas that must
633          * not cause dirty cache line writebacks when used
634          */
635         if (cpu_arch >= CPU_ARCH_ARMv6) {
636                 if (cpu_arch >= CPU_ARCH_ARMv7 && (cr & CR_TRE)) {
637                         /* Non-cacheable Normal is XCB = 001 */
638                         mem_types[MT_MEMORY_RWX_NONCACHED].prot_sect |=
639                                 PMD_SECT_BUFFERED;
640                 } else {
641                         /* For both ARMv6 and non-TEX-remapping ARMv7 */
642                         mem_types[MT_MEMORY_RWX_NONCACHED].prot_sect |=
643                                 PMD_SECT_TEX(1);
644                 }
645         } else {
646                 mem_types[MT_MEMORY_RWX_NONCACHED].prot_sect |= PMD_SECT_BUFFERABLE;
647         }
648 
649 #ifdef CONFIG_ARM_LPAE
650         /*
651          * Do not generate access flag faults for the kernel mappings.
652          */
653         for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
654                 mem_types[i].prot_pte |= PTE_EXT_AF;
655                 if (mem_types[i].prot_sect)
656                         mem_types[i].prot_sect |= PMD_SECT_AF;
657         }
658         kern_pgprot |= PTE_EXT_AF;
659         vecs_pgprot |= PTE_EXT_AF;
660 
661         /*
662          * Set PXN for user mappings
663          */
664         user_pgprot |= PTE_EXT_PXN;
665 #endif
666 
667         for (i = 0; i < 16; i++) {
668                 pteval_t v = pgprot_val(protection_map[i]);
669                 protection_map[i] = __pgprot(v | user_pgprot);
670         }
671 
672         mem_types[MT_LOW_VECTORS].prot_pte |= vecs_pgprot;
673         mem_types[MT_HIGH_VECTORS].prot_pte |= vecs_pgprot;
674 
675         pgprot_user   = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | user_pgprot);
676         pgprot_kernel = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG |
677                                  L_PTE_DIRTY | kern_pgprot);
678 
679         mem_types[MT_LOW_VECTORS].prot_l1 |= ecc_mask;
680         mem_types[MT_HIGH_VECTORS].prot_l1 |= ecc_mask;
681         mem_types[MT_MEMORY_RWX].prot_sect |= ecc_mask | cp->pmd;
682         mem_types[MT_MEMORY_RWX].prot_pte |= kern_pgprot;
683         mem_types[MT_MEMORY_RW].prot_sect |= ecc_mask | cp->pmd;
684         mem_types[MT_MEMORY_RW].prot_pte |= kern_pgprot;
685         mem_types[MT_MEMORY_RO].prot_sect |= ecc_mask | cp->pmd;
686         mem_types[MT_MEMORY_RO].prot_pte |= kern_pgprot;
687         mem_types[MT_MEMORY_DMA_READY].prot_pte |= kern_pgprot;
688         mem_types[MT_MEMORY_RWX_NONCACHED].prot_sect |= ecc_mask;
689         mem_types[MT_ROM].prot_sect |= cp->pmd;
690 
691         switch (cp->pmd) {
692         case PMD_SECT_WT:
693                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WT;
694                 break;
695         case PMD_SECT_WB:
696         case PMD_SECT_WBWA:
697                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WB;
698                 break;
699         }
700         pr_info("Memory policy: %sData cache %s\n",
701                 ecc_mask ? "ECC enabled, " : "", cp->policy);
702 
703         for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
704                 struct mem_type *t = &mem_types[i];
705                 if (t->prot_l1)
706                         t->prot_l1 |= PMD_DOMAIN(t->domain);
707                 if (t->prot_sect)
708                         t->prot_sect |= PMD_DOMAIN(t->domain);
709         }
710 }
711 
712 #ifdef CONFIG_ARM_DMA_MEM_BUFFERABLE
713 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
714                               unsigned long size, pgprot_t vma_prot)
715 {
716         if (!pfn_valid(pfn))
717                 return pgprot_noncached(vma_prot);
718         else if (file->f_flags & O_SYNC)
719                 return pgprot_writecombine(vma_prot);
720         return vma_prot;
721 }
722 EXPORT_SYMBOL(phys_mem_access_prot);
723 #endif
724 
725 #define vectors_base()  (vectors_high() ? 0xffff0000 : 0)
726 
727 static void __init *early_alloc(unsigned long sz)
728 {
729         void *ptr = memblock_alloc(sz, sz);
730 
731         if (!ptr)
732                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
733                       __func__, sz, sz);
734 
735         return ptr;
736 }
737 
738 static void *__init late_alloc(unsigned long sz)
739 {
740         void *ptdesc = pagetable_alloc(GFP_PGTABLE_KERNEL & ~__GFP_HIGHMEM,
741                         get_order(sz));
742 
743         if (!ptdesc || !pagetable_pte_ctor(ptdesc))
744                 BUG();
745         return ptdesc_to_virt(ptdesc);
746 }
747 
748 static pte_t * __init arm_pte_alloc(pmd_t *pmd, unsigned long addr,
749                                 unsigned long prot,
750                                 void *(*alloc)(unsigned long sz))
751 {
752         if (pmd_none(*pmd)) {
753                 pte_t *pte = alloc(PTE_HWTABLE_OFF + PTE_HWTABLE_SIZE);
754                 __pmd_populate(pmd, __pa(pte), prot);
755         }
756         BUG_ON(pmd_bad(*pmd));
757         return pte_offset_kernel(pmd, addr);
758 }
759 
760 static pte_t * __init early_pte_alloc(pmd_t *pmd, unsigned long addr,
761                                       unsigned long prot)
762 {
763         return arm_pte_alloc(pmd, addr, prot, early_alloc);
764 }
765 
766 static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr,
767                                   unsigned long end, unsigned long pfn,
768                                   const struct mem_type *type,
769                                   void *(*alloc)(unsigned long sz),
770                                   bool ng)
771 {
772         pte_t *pte = arm_pte_alloc(pmd, addr, type->prot_l1, alloc);
773         do {
774                 set_pte_ext(pte, pfn_pte(pfn, __pgprot(type->prot_pte)),
775                             ng ? PTE_EXT_NG : 0);
776                 pfn++;
777         } while (pte++, addr += PAGE_SIZE, addr != end);
778 }
779 
780 static void __init __map_init_section(pmd_t *pmd, unsigned long addr,
781                         unsigned long end, phys_addr_t phys,
782                         const struct mem_type *type, bool ng)
783 {
784         pmd_t *p = pmd;
785 
786 #ifndef CONFIG_ARM_LPAE
787         /*
788          * In classic MMU format, puds and pmds are folded in to
789          * the pgds. pmd_offset gives the PGD entry. PGDs refer to a
790          * group of L1 entries making up one logical pointer to
791          * an L2 table (2MB), where as PMDs refer to the individual
792          * L1 entries (1MB). Hence increment to get the correct
793          * offset for odd 1MB sections.
794          * (See arch/arm/include/asm/pgtable-2level.h)
795          */
796         if (addr & SECTION_SIZE)
797                 pmd++;
798 #endif
799         do {
800                 *pmd = __pmd(phys | type->prot_sect | (ng ? PMD_SECT_nG : 0));
801                 phys += SECTION_SIZE;
802         } while (pmd++, addr += SECTION_SIZE, addr != end);
803 
804         flush_pmd_entry(p);
805 }
806 
807 static void __init alloc_init_pmd(pud_t *pud, unsigned long addr,
808                                       unsigned long end, phys_addr_t phys,
809                                       const struct mem_type *type,
810                                       void *(*alloc)(unsigned long sz), bool ng)
811 {
812         pmd_t *pmd = pmd_offset(pud, addr);
813         unsigned long next;
814 
815         do {
816                 /*
817                  * With LPAE, we must loop over to map
818                  * all the pmds for the given range.
819                  */
820                 next = pmd_addr_end(addr, end);
821 
822                 /*
823                  * Try a section mapping - addr, next and phys must all be
824                  * aligned to a section boundary.
825                  */
826                 if (type->prot_sect &&
827                                 ((addr | next | phys) & ~SECTION_MASK) == 0) {
828                         __map_init_section(pmd, addr, next, phys, type, ng);
829                 } else {
830                         alloc_init_pte(pmd, addr, next,
831                                        __phys_to_pfn(phys), type, alloc, ng);
832                 }
833 
834                 phys += next - addr;
835 
836         } while (pmd++, addr = next, addr != end);
837 }
838 
839 static void __init alloc_init_pud(p4d_t *p4d, unsigned long addr,
840                                   unsigned long end, phys_addr_t phys,
841                                   const struct mem_type *type,
842                                   void *(*alloc)(unsigned long sz), bool ng)
843 {
844         pud_t *pud = pud_offset(p4d, addr);
845         unsigned long next;
846 
847         do {
848                 next = pud_addr_end(addr, end);
849                 alloc_init_pmd(pud, addr, next, phys, type, alloc, ng);
850                 phys += next - addr;
851         } while (pud++, addr = next, addr != end);
852 }
853 
854 static void __init alloc_init_p4d(pgd_t *pgd, unsigned long addr,
855                                   unsigned long end, phys_addr_t phys,
856                                   const struct mem_type *type,
857                                   void *(*alloc)(unsigned long sz), bool ng)
858 {
859         p4d_t *p4d = p4d_offset(pgd, addr);
860         unsigned long next;
861 
862         do {
863                 next = p4d_addr_end(addr, end);
864                 alloc_init_pud(p4d, addr, next, phys, type, alloc, ng);
865                 phys += next - addr;
866         } while (p4d++, addr = next, addr != end);
867 }
868 
869 #ifndef CONFIG_ARM_LPAE
870 static void __init create_36bit_mapping(struct mm_struct *mm,
871                                         struct map_desc *md,
872                                         const struct mem_type *type,
873                                         bool ng)
874 {
875         unsigned long addr, length, end;
876         phys_addr_t phys;
877         pgd_t *pgd;
878 
879         addr = md->virtual;
880         phys = __pfn_to_phys(md->pfn);
881         length = PAGE_ALIGN(md->length);
882 
883         if (!(cpu_architecture() >= CPU_ARCH_ARMv6 || cpu_is_xsc3())) {
884                 pr_err("MM: CPU does not support supersection mapping for 0x%08llx at 0x%08lx\n",
885                        (long long)__pfn_to_phys((u64)md->pfn), addr);
886                 return;
887         }
888 
889         /* N.B. ARMv6 supersections are only defined to work with domain 0.
890          *      Since domain assignments can in fact be arbitrary, the
891          *      'domain == 0' check below is required to insure that ARMv6
892          *      supersections are only allocated for domain 0 regardless
893          *      of the actual domain assignments in use.
894          */
895         if (type->domain) {
896                 pr_err("MM: invalid domain in supersection mapping for 0x%08llx at 0x%08lx\n",
897                        (long long)__pfn_to_phys((u64)md->pfn), addr);
898                 return;
899         }
900 
901         if ((addr | length | __pfn_to_phys(md->pfn)) & ~SUPERSECTION_MASK) {
902                 pr_err("MM: cannot create mapping for 0x%08llx at 0x%08lx invalid alignment\n",
903                        (long long)__pfn_to_phys((u64)md->pfn), addr);
904                 return;
905         }
906 
907         /*
908          * Shift bits [35:32] of address into bits [23:20] of PMD
909          * (See ARMv6 spec).
910          */
911         phys |= (((md->pfn >> (32 - PAGE_SHIFT)) & 0xF) << 20);
912 
913         pgd = pgd_offset(mm, addr);
914         end = addr + length;
915         do {
916                 p4d_t *p4d = p4d_offset(pgd, addr);
917                 pud_t *pud = pud_offset(p4d, addr);
918                 pmd_t *pmd = pmd_offset(pud, addr);
919                 int i;
920 
921                 for (i = 0; i < 16; i++)
922                         *pmd++ = __pmd(phys | type->prot_sect | PMD_SECT_SUPER |
923                                        (ng ? PMD_SECT_nG : 0));
924 
925                 addr += SUPERSECTION_SIZE;
926                 phys += SUPERSECTION_SIZE;
927                 pgd += SUPERSECTION_SIZE >> PGDIR_SHIFT;
928         } while (addr != end);
929 }
930 #endif  /* !CONFIG_ARM_LPAE */
931 
932 static void __init __create_mapping(struct mm_struct *mm, struct map_desc *md,
933                                     void *(*alloc)(unsigned long sz),
934                                     bool ng)
935 {
936         unsigned long addr, length, end;
937         phys_addr_t phys;
938         const struct mem_type *type;
939         pgd_t *pgd;
940 
941         type = &mem_types[md->type];
942 
943 #ifndef CONFIG_ARM_LPAE
944         /*
945          * Catch 36-bit addresses
946          */
947         if (md->pfn >= 0x100000) {
948                 create_36bit_mapping(mm, md, type, ng);
949                 return;
950         }
951 #endif
952 
953         addr = md->virtual & PAGE_MASK;
954         phys = __pfn_to_phys(md->pfn);
955         length = PAGE_ALIGN(md->length + (md->virtual & ~PAGE_MASK));
956 
957         if (type->prot_l1 == 0 && ((addr | phys | length) & ~SECTION_MASK)) {
958                 pr_warn("BUG: map for 0x%08llx at 0x%08lx can not be mapped using pages, ignoring.\n",
959                         (long long)__pfn_to_phys(md->pfn), addr);
960                 return;
961         }
962 
963         pgd = pgd_offset(mm, addr);
964         end = addr + length;
965         do {
966                 unsigned long next = pgd_addr_end(addr, end);
967 
968                 alloc_init_p4d(pgd, addr, next, phys, type, alloc, ng);
969 
970                 phys += next - addr;
971                 addr = next;
972         } while (pgd++, addr != end);
973 }
974 
975 /*
976  * Create the page directory entries and any necessary
977  * page tables for the mapping specified by `md'.  We
978  * are able to cope here with varying sizes and address
979  * offsets, and we take full advantage of sections and
980  * supersections.
981  */
982 static void __init create_mapping(struct map_desc *md)
983 {
984         if (md->virtual != vectors_base() && md->virtual < TASK_SIZE) {
985                 pr_warn("BUG: not creating mapping for 0x%08llx at 0x%08lx in user region\n",
986                         (long long)__pfn_to_phys((u64)md->pfn), md->virtual);
987                 return;
988         }
989 
990         if (md->type == MT_DEVICE &&
991             md->virtual >= PAGE_OFFSET && md->virtual < FIXADDR_START &&
992             (md->virtual < VMALLOC_START || md->virtual >= VMALLOC_END)) {
993                 pr_warn("BUG: mapping for 0x%08llx at 0x%08lx out of vmalloc space\n",
994                         (long long)__pfn_to_phys((u64)md->pfn), md->virtual);
995         }
996 
997         __create_mapping(&init_mm, md, early_alloc, false);
998 }
999 
1000 void __init create_mapping_late(struct mm_struct *mm, struct map_desc *md,
1001                                 bool ng)
1002 {
1003 #ifdef CONFIG_ARM_LPAE
1004         p4d_t *p4d;
1005         pud_t *pud;
1006 
1007         p4d = p4d_alloc(mm, pgd_offset(mm, md->virtual), md->virtual);
1008         if (WARN_ON(!p4d))
1009                 return;
1010         pud = pud_alloc(mm, p4d, md->virtual);
1011         if (WARN_ON(!pud))
1012                 return;
1013         pmd_alloc(mm, pud, 0);
1014 #endif
1015         __create_mapping(mm, md, late_alloc, ng);
1016 }
1017 
1018 /*
1019  * Create the architecture specific mappings
1020  */
1021 void __init iotable_init(struct map_desc *io_desc, int nr)
1022 {
1023         struct map_desc *md;
1024         struct vm_struct *vm;
1025         struct static_vm *svm;
1026 
1027         if (!nr)
1028                 return;
1029 
1030         svm = memblock_alloc(sizeof(*svm) * nr, __alignof__(*svm));
1031         if (!svm)
1032                 panic("%s: Failed to allocate %zu bytes align=0x%zx\n",
1033                       __func__, sizeof(*svm) * nr, __alignof__(*svm));
1034 
1035         for (md = io_desc; nr; md++, nr--) {
1036                 create_mapping(md);
1037 
1038                 vm = &svm->vm;
1039                 vm->addr = (void *)(md->virtual & PAGE_MASK);
1040                 vm->size = PAGE_ALIGN(md->length + (md->virtual & ~PAGE_MASK));
1041                 vm->phys_addr = __pfn_to_phys(md->pfn);
1042                 vm->flags = VM_IOREMAP | VM_ARM_STATIC_MAPPING;
1043                 vm->flags |= VM_ARM_MTYPE(md->type);
1044                 vm->caller = iotable_init;
1045                 add_static_vm_early(svm++);
1046         }
1047 }
1048 
1049 void __init vm_reserve_area_early(unsigned long addr, unsigned long size,
1050                                   void *caller)
1051 {
1052         struct vm_struct *vm;
1053         struct static_vm *svm;
1054 
1055         svm = memblock_alloc(sizeof(*svm), __alignof__(*svm));
1056         if (!svm)
1057                 panic("%s: Failed to allocate %zu bytes align=0x%zx\n",
1058                       __func__, sizeof(*svm), __alignof__(*svm));
1059 
1060         vm = &svm->vm;
1061         vm->addr = (void *)addr;
1062         vm->size = size;
1063         vm->flags = VM_IOREMAP | VM_ARM_EMPTY_MAPPING;
1064         vm->caller = caller;
1065         add_static_vm_early(svm);
1066 }
1067 
1068 #ifndef CONFIG_ARM_LPAE
1069 
1070 /*
1071  * The Linux PMD is made of two consecutive section entries covering 2MB
1072  * (see definition in include/asm/pgtable-2level.h).  However a call to
1073  * create_mapping() may optimize static mappings by using individual
1074  * 1MB section mappings.  This leaves the actual PMD potentially half
1075  * initialized if the top or bottom section entry isn't used, leaving it
1076  * open to problems if a subsequent ioremap() or vmalloc() tries to use
1077  * the virtual space left free by that unused section entry.
1078  *
1079  * Let's avoid the issue by inserting dummy vm entries covering the unused
1080  * PMD halves once the static mappings are in place.
1081  */
1082 
1083 static void __init pmd_empty_section_gap(unsigned long addr)
1084 {
1085         vm_reserve_area_early(addr, SECTION_SIZE, pmd_empty_section_gap);
1086 }
1087 
1088 static void __init fill_pmd_gaps(void)
1089 {
1090         struct static_vm *svm;
1091         struct vm_struct *vm;
1092         unsigned long addr, next = 0;
1093         pmd_t *pmd;
1094 
1095         list_for_each_entry(svm, &static_vmlist, list) {
1096                 vm = &svm->vm;
1097                 addr = (unsigned long)vm->addr;
1098                 if (addr < next)
1099                         continue;
1100 
1101                 /*
1102                  * Check if this vm starts on an odd section boundary.
1103                  * If so and the first section entry for this PMD is free
1104                  * then we block the corresponding virtual address.
1105                  */
1106                 if ((addr & ~PMD_MASK) == SECTION_SIZE) {
1107                         pmd = pmd_off_k(addr);
1108                         if (pmd_none(*pmd))
1109                                 pmd_empty_section_gap(addr & PMD_MASK);
1110                 }
1111 
1112                 /*
1113                  * Then check if this vm ends on an odd section boundary.
1114                  * If so and the second section entry for this PMD is empty
1115                  * then we block the corresponding virtual address.
1116                  */
1117                 addr += vm->size;
1118                 if ((addr & ~PMD_MASK) == SECTION_SIZE) {
1119                         pmd = pmd_off_k(addr) + 1;
1120                         if (pmd_none(*pmd))
1121                                 pmd_empty_section_gap(addr);
1122                 }
1123 
1124                 /* no need to look at any vm entry until we hit the next PMD */
1125                 next = (addr + PMD_SIZE - 1) & PMD_MASK;
1126         }
1127 }
1128 
1129 #else
1130 #define fill_pmd_gaps() do { } while (0)
1131 #endif
1132 
1133 #if defined(CONFIG_PCI) && !defined(CONFIG_NEED_MACH_IO_H)
1134 static void __init pci_reserve_io(void)
1135 {
1136         struct static_vm *svm;
1137 
1138         svm = find_static_vm_vaddr((void *)PCI_IO_VIRT_BASE);
1139         if (svm)
1140                 return;
1141 
1142         vm_reserve_area_early(PCI_IO_VIRT_BASE, SZ_2M, pci_reserve_io);
1143 }
1144 #else
1145 #define pci_reserve_io() do { } while (0)
1146 #endif
1147 
1148 #ifdef CONFIG_DEBUG_LL
1149 void __init debug_ll_io_init(void)
1150 {
1151         struct map_desc map;
1152 
1153         debug_ll_addr(&map.pfn, &map.virtual);
1154         if (!map.pfn || !map.virtual)
1155                 return;
1156         map.pfn = __phys_to_pfn(map.pfn);
1157         map.virtual &= PAGE_MASK;
1158         map.length = PAGE_SIZE;
1159         map.type = MT_DEVICE;
1160         iotable_init(&map, 1);
1161 }
1162 #endif
1163 
1164 static unsigned long __initdata vmalloc_size = 240 * SZ_1M;
1165 
1166 /*
1167  * vmalloc=size forces the vmalloc area to be exactly 'size'
1168  * bytes. This can be used to increase (or decrease) the vmalloc
1169  * area - the default is 240MiB.
1170  */
1171 static int __init early_vmalloc(char *arg)
1172 {
1173         unsigned long vmalloc_reserve = memparse(arg, NULL);
1174         unsigned long vmalloc_max;
1175 
1176         if (vmalloc_reserve < SZ_16M) {
1177                 vmalloc_reserve = SZ_16M;
1178                 pr_warn("vmalloc area is too small, limiting to %luMiB\n",
1179                         vmalloc_reserve >> 20);
1180         }
1181 
1182         vmalloc_max = VMALLOC_END - (PAGE_OFFSET + SZ_32M + VMALLOC_OFFSET);
1183         if (vmalloc_reserve > vmalloc_max) {
1184                 vmalloc_reserve = vmalloc_max;
1185                 pr_warn("vmalloc area is too big, limiting to %luMiB\n",
1186                         vmalloc_reserve >> 20);
1187         }
1188 
1189         vmalloc_size = vmalloc_reserve;
1190         return 0;
1191 }
1192 early_param("vmalloc", early_vmalloc);
1193 
1194 phys_addr_t arm_lowmem_limit __initdata = 0;
1195 
1196 void __init adjust_lowmem_bounds(void)
1197 {
1198         phys_addr_t block_start, block_end, memblock_limit = 0;
1199         u64 vmalloc_limit, i;
1200         phys_addr_t lowmem_limit = 0;
1201 
1202         /*
1203          * Let's use our own (unoptimized) equivalent of __pa() that is
1204          * not affected by wrap-arounds when sizeof(phys_addr_t) == 4.
1205          * The result is used as the upper bound on physical memory address
1206          * and may itself be outside the valid range for which phys_addr_t
1207          * and therefore __pa() is defined.
1208          */
1209         vmalloc_limit = (u64)VMALLOC_END - vmalloc_size - VMALLOC_OFFSET -
1210                         PAGE_OFFSET + PHYS_OFFSET;
1211 
1212         /*
1213          * The first usable region must be PMD aligned. Mark its start
1214          * as MEMBLOCK_NOMAP if it isn't
1215          */
1216         for_each_mem_range(i, &block_start, &block_end) {
1217                 if (!IS_ALIGNED(block_start, PMD_SIZE)) {
1218                         phys_addr_t len;
1219 
1220                         len = round_up(block_start, PMD_SIZE) - block_start;
1221                         memblock_mark_nomap(block_start, len);
1222                 }
1223                 break;
1224         }
1225 
1226         for_each_mem_range(i, &block_start, &block_end) {
1227                 if (block_start < vmalloc_limit) {
1228                         if (block_end > lowmem_limit)
1229                                 /*
1230                                  * Compare as u64 to ensure vmalloc_limit does
1231                                  * not get truncated. block_end should always
1232                                  * fit in phys_addr_t so there should be no
1233                                  * issue with assignment.
1234                                  */
1235                                 lowmem_limit = min_t(u64,
1236                                                          vmalloc_limit,
1237                                                          block_end);
1238 
1239                         /*
1240                          * Find the first non-pmd-aligned page, and point
1241                          * memblock_limit at it. This relies on rounding the
1242                          * limit down to be pmd-aligned, which happens at the
1243                          * end of this function.
1244                          *
1245                          * With this algorithm, the start or end of almost any
1246                          * bank can be non-pmd-aligned. The only exception is
1247                          * that the start of the bank 0 must be section-
1248                          * aligned, since otherwise memory would need to be
1249                          * allocated when mapping the start of bank 0, which
1250                          * occurs before any free memory is mapped.
1251                          */
1252                         if (!memblock_limit) {
1253                                 if (!IS_ALIGNED(block_start, PMD_SIZE))
1254                                         memblock_limit = block_start;
1255                                 else if (!IS_ALIGNED(block_end, PMD_SIZE))
1256                                         memblock_limit = lowmem_limit;
1257                         }
1258 
1259                 }
1260         }
1261 
1262         arm_lowmem_limit = lowmem_limit;
1263 
1264         high_memory = __va(arm_lowmem_limit - 1) + 1;
1265 
1266         if (!memblock_limit)
1267                 memblock_limit = arm_lowmem_limit;
1268 
1269         /*
1270          * Round the memblock limit down to a pmd size.  This
1271          * helps to ensure that we will allocate memory from the
1272          * last full pmd, which should be mapped.
1273          */
1274         memblock_limit = round_down(memblock_limit, PMD_SIZE);
1275 
1276         if (!IS_ENABLED(CONFIG_HIGHMEM) || cache_is_vipt_aliasing()) {
1277                 if (memblock_end_of_DRAM() > arm_lowmem_limit) {
1278                         phys_addr_t end = memblock_end_of_DRAM();
1279 
1280                         pr_notice("Ignoring RAM at %pa-%pa\n",
1281                                   &memblock_limit, &end);
1282                         pr_notice("Consider using a HIGHMEM enabled kernel.\n");
1283 
1284                         memblock_remove(memblock_limit, end - memblock_limit);
1285                 }
1286         }
1287 
1288         memblock_set_current_limit(memblock_limit);
1289 }
1290 
1291 static __init void prepare_page_table(void)
1292 {
1293         unsigned long addr;
1294         phys_addr_t end;
1295 
1296         /*
1297          * Clear out all the mappings below the kernel image.
1298          */
1299 #ifdef CONFIG_KASAN
1300         /*
1301          * KASan's shadow memory inserts itself between the TASK_SIZE
1302          * and MODULES_VADDR. Do not clear the KASan shadow memory mappings.
1303          */
1304         for (addr = 0; addr < KASAN_SHADOW_START; addr += PMD_SIZE)
1305                 pmd_clear(pmd_off_k(addr));
1306         /*
1307          * Skip over the KASan shadow area. KASAN_SHADOW_END is sometimes
1308          * equal to MODULES_VADDR and then we exit the pmd clearing. If we
1309          * are using a thumb-compiled kernel, there there will be 8MB more
1310          * to clear as KASan always offset to 16 MB below MODULES_VADDR.
1311          */
1312         for (addr = KASAN_SHADOW_END; addr < MODULES_VADDR; addr += PMD_SIZE)
1313                 pmd_clear(pmd_off_k(addr));
1314 #else
1315         for (addr = 0; addr < MODULES_VADDR; addr += PMD_SIZE)
1316                 pmd_clear(pmd_off_k(addr));
1317 #endif
1318 
1319 #ifdef CONFIG_XIP_KERNEL
1320         /* The XIP kernel is mapped in the module area -- skip over it */
1321         addr = ((unsigned long)_exiprom + PMD_SIZE - 1) & PMD_MASK;
1322 #endif
1323         for ( ; addr < PAGE_OFFSET; addr += PMD_SIZE)
1324                 pmd_clear(pmd_off_k(addr));
1325 
1326         /*
1327          * Find the end of the first block of lowmem.
1328          */
1329         end = memblock.memory.regions[0].base + memblock.memory.regions[0].size;
1330         if (end >= arm_lowmem_limit)
1331                 end = arm_lowmem_limit;
1332 
1333         /*
1334          * Clear out all the kernel space mappings, except for the first
1335          * memory bank, up to the vmalloc region.
1336          */
1337         for (addr = __phys_to_virt(end);
1338              addr < VMALLOC_START; addr += PMD_SIZE)
1339                 pmd_clear(pmd_off_k(addr));
1340 }
1341 
1342 #ifdef CONFIG_ARM_LPAE
1343 /* the first page is reserved for pgd */
1344 #define SWAPPER_PG_DIR_SIZE     (PAGE_SIZE + \
1345                                  PTRS_PER_PGD * PTRS_PER_PMD * sizeof(pmd_t))
1346 #else
1347 #define SWAPPER_PG_DIR_SIZE     (PTRS_PER_PGD * sizeof(pgd_t))
1348 #endif
1349 
1350 /*
1351  * Reserve the special regions of memory
1352  */
1353 void __init arm_mm_memblock_reserve(void)
1354 {
1355         /*
1356          * Reserve the page tables.  These are already in use,
1357          * and can only be in node 0.
1358          */
1359         memblock_reserve(__pa(swapper_pg_dir), SWAPPER_PG_DIR_SIZE);
1360 
1361 #ifdef CONFIG_SA1111
1362         /*
1363          * Because of the SA1111 DMA bug, we want to preserve our
1364          * precious DMA-able memory...
1365          */
1366         memblock_reserve(PHYS_OFFSET, __pa(swapper_pg_dir) - PHYS_OFFSET);
1367 #endif
1368 }
1369 
1370 /*
1371  * Set up the device mappings.  Since we clear out the page tables for all
1372  * mappings above VMALLOC_START, except early fixmap, we might remove debug
1373  * device mappings.  This means earlycon can be used to debug this function
1374  * Any other function or debugging method which may touch any device _will_
1375  * crash the kernel.
1376  */
1377 static void __init devicemaps_init(const struct machine_desc *mdesc)
1378 {
1379         struct map_desc map;
1380         unsigned long addr;
1381         void *vectors;
1382 
1383         /*
1384          * Allocate the vector page early.
1385          */
1386         vectors = early_alloc(PAGE_SIZE * 2);
1387 
1388         early_trap_init(vectors);
1389 
1390         /*
1391          * Clear page table except top pmd used by early fixmaps
1392          */
1393         for (addr = VMALLOC_START; addr < (FIXADDR_TOP & PMD_MASK); addr += PMD_SIZE)
1394                 pmd_clear(pmd_off_k(addr));
1395 
1396         if (__atags_pointer) {
1397                 /* create a read-only mapping of the device tree */
1398                 map.pfn = __phys_to_pfn(__atags_pointer & SECTION_MASK);
1399                 map.virtual = FDT_FIXED_BASE;
1400                 map.length = FDT_FIXED_SIZE;
1401                 map.type = MT_MEMORY_RO;
1402                 create_mapping(&map);
1403         }
1404 
1405         /*
1406          * Map the kernel if it is XIP.
1407          * It is always first in the modulearea.
1408          */
1409 #ifdef CONFIG_XIP_KERNEL
1410         map.pfn = __phys_to_pfn(CONFIG_XIP_PHYS_ADDR & SECTION_MASK);
1411         map.virtual = MODULES_VADDR;
1412         map.length = ((unsigned long)_exiprom - map.virtual + ~SECTION_MASK) & SECTION_MASK;
1413         map.type = MT_ROM;
1414         create_mapping(&map);
1415 #endif
1416 
1417         /*
1418          * Map the cache flushing regions.
1419          */
1420 #ifdef FLUSH_BASE
1421         map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS);
1422         map.virtual = FLUSH_BASE;
1423         map.length = SZ_1M;
1424         map.type = MT_CACHECLEAN;
1425         create_mapping(&map);
1426 #endif
1427 #ifdef FLUSH_BASE_MINICACHE
1428         map.pfn = __phys_to_pfn(FLUSH_BASE_PHYS + SZ_1M);
1429         map.virtual = FLUSH_BASE_MINICACHE;
1430         map.length = SZ_1M;
1431         map.type = MT_MINICLEAN;
1432         create_mapping(&map);
1433 #endif
1434 
1435         /*
1436          * Create a mapping for the machine vectors at the high-vectors
1437          * location (0xffff0000).  If we aren't using high-vectors, also
1438          * create a mapping at the low-vectors virtual address.
1439          */
1440         map.pfn = __phys_to_pfn(virt_to_phys(vectors));
1441         map.virtual = 0xffff0000;
1442         map.length = PAGE_SIZE;
1443 #ifdef CONFIG_KUSER_HELPERS
1444         map.type = MT_HIGH_VECTORS;
1445 #else
1446         map.type = MT_LOW_VECTORS;
1447 #endif
1448         create_mapping(&map);
1449 
1450         if (!vectors_high()) {
1451                 map.virtual = 0;
1452                 map.length = PAGE_SIZE * 2;
1453                 map.type = MT_LOW_VECTORS;
1454                 create_mapping(&map);
1455         }
1456 
1457         /* Now create a kernel read-only mapping */
1458         map.pfn += 1;
1459         map.virtual = 0xffff0000 + PAGE_SIZE;
1460         map.length = PAGE_SIZE;
1461         map.type = MT_LOW_VECTORS;
1462         create_mapping(&map);
1463 
1464         /*
1465          * Ask the machine support to map in the statically mapped devices.
1466          */
1467         if (mdesc->map_io)
1468                 mdesc->map_io();
1469         else
1470                 debug_ll_io_init();
1471         fill_pmd_gaps();
1472 
1473         /* Reserve fixed i/o space in VMALLOC region */
1474         pci_reserve_io();
1475 
1476         /*
1477          * Finally flush the caches and tlb to ensure that we're in a
1478          * consistent state wrt the writebuffer.  This also ensures that
1479          * any write-allocated cache lines in the vector page are written
1480          * back.  After this point, we can start to touch devices again.
1481          */
1482         local_flush_tlb_all();
1483         flush_cache_all();
1484 
1485         /* Enable asynchronous aborts */
1486         early_abt_enable();
1487 }
1488 
1489 static void __init kmap_init(void)
1490 {
1491 #ifdef CONFIG_HIGHMEM
1492         pkmap_page_table = early_pte_alloc(pmd_off_k(PKMAP_BASE),
1493                 PKMAP_BASE, _PAGE_KERNEL_TABLE);
1494 #endif
1495 
1496         early_pte_alloc(pmd_off_k(FIXADDR_START), FIXADDR_START,
1497                         _PAGE_KERNEL_TABLE);
1498 }
1499 
1500 static void __init map_lowmem(void)
1501 {
1502         phys_addr_t start, end;
1503         u64 i;
1504 
1505         /* Map all the lowmem memory banks. */
1506         for_each_mem_range(i, &start, &end) {
1507                 struct map_desc map;
1508 
1509                 pr_debug("map lowmem start: 0x%08llx, end: 0x%08llx\n",
1510                          (long long)start, (long long)end);
1511                 if (end > arm_lowmem_limit)
1512                         end = arm_lowmem_limit;
1513                 if (start >= end)
1514                         break;
1515 
1516                 /*
1517                  * If our kernel image is in the VMALLOC area we need to remove
1518                  * the kernel physical memory from lowmem since the kernel will
1519                  * be mapped separately.
1520                  *
1521                  * The kernel will typically be at the very start of lowmem,
1522                  * but any placement relative to memory ranges is possible.
1523                  *
1524                  * If the memblock contains the kernel, we have to chisel out
1525                  * the kernel memory from it and map each part separately. We
1526                  * get 6 different theoretical cases:
1527                  *
1528                  *                            +--------+ +--------+
1529                  *  +-- start --+  +--------+ | Kernel | | Kernel |
1530                  *  |           |  | Kernel | | case 2 | | case 5 |
1531                  *  |           |  | case 1 | +--------+ |        | +--------+
1532                  *  |  Memory   |  +--------+            |        | | Kernel |
1533                  *  |  range    |  +--------+            |        | | case 6 |
1534                  *  |           |  | Kernel | +--------+ |        | +--------+
1535                  *  |           |  | case 3 | | Kernel | |        |
1536                  *  +-- end ----+  +--------+ | case 4 | |        |
1537                  *                            +--------+ +--------+
1538                  */
1539 
1540                 /* Case 5: kernel covers range, don't map anything, should be rare */
1541                 if ((start > kernel_sec_start) && (end < kernel_sec_end))
1542                         break;
1543 
1544                 /* Cases where the kernel is starting inside the range */
1545                 if ((kernel_sec_start >= start) && (kernel_sec_start <= end)) {
1546                         /* Case 6: kernel is embedded in the range, we need two mappings */
1547                         if ((start < kernel_sec_start) && (end > kernel_sec_end)) {
1548                                 /* Map memory below the kernel */
1549                                 map.pfn = __phys_to_pfn(start);
1550                                 map.virtual = __phys_to_virt(start);
1551                                 map.length = kernel_sec_start - start;
1552                                 map.type = MT_MEMORY_RW;
1553                                 create_mapping(&map);
1554                                 /* Map memory above the kernel */
1555                                 map.pfn = __phys_to_pfn(kernel_sec_end);
1556                                 map.virtual = __phys_to_virt(kernel_sec_end);
1557                                 map.length = end - kernel_sec_end;
1558                                 map.type = MT_MEMORY_RW;
1559                                 create_mapping(&map);
1560                                 break;
1561                         }
1562                         /* Case 1: kernel and range start at the same address, should be common */
1563                         if (kernel_sec_start == start)
1564                                 start = kernel_sec_end;
1565                         /* Case 3: kernel and range end at the same address, should be rare */
1566                         if (kernel_sec_end == end)
1567                                 end = kernel_sec_start;
1568                 } else if ((kernel_sec_start < start) && (kernel_sec_end > start) && (kernel_sec_end < end)) {
1569                         /* Case 2: kernel ends inside range, starts below it */
1570                         start = kernel_sec_end;
1571                 } else if ((kernel_sec_start > start) && (kernel_sec_start < end) && (kernel_sec_end > end)) {
1572                         /* Case 4: kernel starts inside range, ends above it */
1573                         end = kernel_sec_start;
1574                 }
1575                 map.pfn = __phys_to_pfn(start);
1576                 map.virtual = __phys_to_virt(start);
1577                 map.length = end - start;
1578                 map.type = MT_MEMORY_RW;
1579                 create_mapping(&map);
1580         }
1581 }
1582 
1583 static void __init map_kernel(void)
1584 {
1585         /*
1586          * We use the well known kernel section start and end and split the area in the
1587          * middle like this:
1588          *  .                .
1589          *  | RW memory      |
1590          *  +----------------+ kernel_x_start
1591          *  | Executable     |
1592          *  | kernel memory  |
1593          *  +----------------+ kernel_x_end / kernel_nx_start
1594          *  | Non-executable |
1595          *  | kernel memory  |
1596          *  +----------------+ kernel_nx_end
1597          *  | RW memory      |
1598          *  .                .
1599          *
1600          * Notice that we are dealing with section sized mappings here so all of this
1601          * will be bumped to the closest section boundary. This means that some of the
1602          * non-executable part of the kernel memory is actually mapped as executable.
1603          * This will only persist until we turn on proper memory management later on
1604          * and we remap the whole kernel with page granularity.
1605          */
1606         phys_addr_t kernel_x_start = kernel_sec_start;
1607         phys_addr_t kernel_x_end = round_up(__pa(__init_end), SECTION_SIZE);
1608         phys_addr_t kernel_nx_start = kernel_x_end;
1609         phys_addr_t kernel_nx_end = kernel_sec_end;
1610         struct map_desc map;
1611 
1612         map.pfn = __phys_to_pfn(kernel_x_start);
1613         map.virtual = __phys_to_virt(kernel_x_start);
1614         map.length = kernel_x_end - kernel_x_start;
1615         map.type = MT_MEMORY_RWX;
1616         create_mapping(&map);
1617 
1618         /* If the nx part is small it may end up covered by the tail of the RWX section */
1619         if (kernel_x_end == kernel_nx_end)
1620                 return;
1621 
1622         map.pfn = __phys_to_pfn(kernel_nx_start);
1623         map.virtual = __phys_to_virt(kernel_nx_start);
1624         map.length = kernel_nx_end - kernel_nx_start;
1625         map.type = MT_MEMORY_RW;
1626         create_mapping(&map);
1627 }
1628 
1629 #ifdef CONFIG_ARM_PV_FIXUP
1630 typedef void pgtables_remap(long long offset, unsigned long pgd);
1631 pgtables_remap lpae_pgtables_remap_asm;
1632 
1633 /*
1634  * early_paging_init() recreates boot time page table setup, allowing machines
1635  * to switch over to a high (>4G) address space on LPAE systems
1636  */
1637 static void __init early_paging_init(const struct machine_desc *mdesc)
1638 {
1639         pgtables_remap *lpae_pgtables_remap;
1640         unsigned long pa_pgd;
1641         unsigned int cr, ttbcr;
1642         long long offset;
1643 
1644         if (!mdesc->pv_fixup)
1645                 return;
1646 
1647         offset = mdesc->pv_fixup();
1648         if (offset == 0)
1649                 return;
1650 
1651         /*
1652          * Offset the kernel section physical offsets so that the kernel
1653          * mapping will work out later on.
1654          */
1655         kernel_sec_start += offset;
1656         kernel_sec_end += offset;
1657 
1658         /*
1659          * Get the address of the remap function in the 1:1 identity
1660          * mapping setup by the early page table assembly code.  We
1661          * must get this prior to the pv update.  The following barrier
1662          * ensures that this is complete before we fixup any P:V offsets.
1663          */
1664         lpae_pgtables_remap = (pgtables_remap *)(unsigned long)__pa(lpae_pgtables_remap_asm);
1665         pa_pgd = __pa(swapper_pg_dir);
1666         barrier();
1667 
1668         pr_info("Switching physical address space to 0x%08llx\n",
1669                 (u64)PHYS_OFFSET + offset);
1670 
1671         /* Re-set the phys pfn offset, and the pv offset */
1672         __pv_offset += offset;
1673         __pv_phys_pfn_offset += PFN_DOWN(offset);
1674 
1675         /* Run the patch stub to update the constants */
1676         fixup_pv_table(&__pv_table_begin,
1677                 (&__pv_table_end - &__pv_table_begin) << 2);
1678 
1679         /*
1680          * We changing not only the virtual to physical mapping, but also
1681          * the physical addresses used to access memory.  We need to flush
1682          * all levels of cache in the system with caching disabled to
1683          * ensure that all data is written back, and nothing is prefetched
1684          * into the caches.  We also need to prevent the TLB walkers
1685          * allocating into the caches too.  Note that this is ARMv7 LPAE
1686          * specific.
1687          */
1688         cr = get_cr();
1689         set_cr(cr & ~(CR_I | CR_C));
1690         ttbcr = cpu_get_ttbcr();
1691         cpu_set_ttbcr(ttbcr & ~(3 << 8 | 3 << 10));
1692         flush_cache_all();
1693 
1694         /*
1695          * Fixup the page tables - this must be in the idmap region as
1696          * we need to disable the MMU to do this safely, and hence it
1697          * needs to be assembly.  It's fairly simple, as we're using the
1698          * temporary tables setup by the initial assembly code.
1699          */
1700         lpae_pgtables_remap(offset, pa_pgd);
1701 
1702         /* Re-enable the caches and cacheable TLB walks */
1703         cpu_set_ttbcr(ttbcr);
1704         set_cr(cr);
1705 }
1706 
1707 #else
1708 
1709 static void __init early_paging_init(const struct machine_desc *mdesc)
1710 {
1711         long long offset;
1712 
1713         if (!mdesc->pv_fixup)
1714                 return;
1715 
1716         offset = mdesc->pv_fixup();
1717         if (offset == 0)
1718                 return;
1719 
1720         pr_crit("Physical address space modification is only to support Keystone2.\n");
1721         pr_crit("Please enable ARM_LPAE and ARM_PATCH_PHYS_VIRT support to use this\n");
1722         pr_crit("feature. Your kernel may crash now, have a good day.\n");
1723         add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
1724 }
1725 
1726 #endif
1727 
1728 static void __init early_fixmap_shutdown(void)
1729 {
1730         int i;
1731         unsigned long va = fix_to_virt(__end_of_permanent_fixed_addresses - 1);
1732 
1733         pte_offset_fixmap = pte_offset_late_fixmap;
1734         pmd_clear(fixmap_pmd(va));
1735         local_flush_tlb_kernel_page(va);
1736 
1737         for (i = 0; i < __end_of_permanent_fixed_addresses; i++) {
1738                 pte_t *pte;
1739                 struct map_desc map;
1740 
1741                 map.virtual = fix_to_virt(i);
1742                 pte = pte_offset_early_fixmap(pmd_off_k(map.virtual), map.virtual);
1743 
1744                 /* Only i/o device mappings are supported ATM */
1745                 if (pte_none(*pte) ||
1746                     (pte_val(*pte) & L_PTE_MT_MASK) != L_PTE_MT_DEV_SHARED)
1747                         continue;
1748 
1749                 map.pfn = pte_pfn(*pte);
1750                 map.type = MT_DEVICE;
1751                 map.length = PAGE_SIZE;
1752 
1753                 create_mapping(&map);
1754         }
1755 }
1756 
1757 /*
1758  * paging_init() sets up the page tables, initialises the zone memory
1759  * maps, and sets up the zero page, bad page and bad page tables.
1760  */
1761 void __init paging_init(const struct machine_desc *mdesc)
1762 {
1763         void *zero_page;
1764 
1765         pr_debug("physical kernel sections: 0x%08llx-0x%08llx\n",
1766                  kernel_sec_start, kernel_sec_end);
1767 
1768         prepare_page_table();
1769         map_lowmem();
1770         memblock_set_current_limit(arm_lowmem_limit);
1771         pr_debug("lowmem limit is %08llx\n", (long long)arm_lowmem_limit);
1772         /*
1773          * After this point early_alloc(), i.e. the memblock allocator, can
1774          * be used
1775          */
1776         map_kernel();
1777         dma_contiguous_remap();
1778         early_fixmap_shutdown();
1779         devicemaps_init(mdesc);
1780         kmap_init();
1781         tcm_init();
1782 
1783         top_pmd = pmd_off_k(0xffff0000);
1784 
1785         /* allocate the zero page. */
1786         zero_page = early_alloc(PAGE_SIZE);
1787 
1788         bootmem_init();
1789 
1790         empty_zero_page = virt_to_page(zero_page);
1791         __flush_dcache_folio(NULL, page_folio(empty_zero_page));
1792 }
1793 
1794 void __init early_mm_init(const struct machine_desc *mdesc)
1795 {
1796         build_mem_type_table();
1797         early_paging_init(mdesc);
1798 }
1799 
1800 void set_ptes(struct mm_struct *mm, unsigned long addr,
1801                               pte_t *ptep, pte_t pteval, unsigned int nr)
1802 {
1803         unsigned long ext = 0;
1804 
1805         if (addr < TASK_SIZE && pte_valid_user(pteval)) {
1806                 if (!pte_special(pteval))
1807                         __sync_icache_dcache(pteval);
1808                 ext |= PTE_EXT_NG;
1809         }
1810 
1811         for (;;) {
1812                 set_pte_ext(ptep, pteval, ext);
1813                 if (--nr == 0)
1814                         break;
1815                 ptep++;
1816                 pteval = pte_next_pfn(pteval);
1817         }
1818 }
1819 

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