1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_POWERPC_BOOK3S_32_PGTABLE_H
3 #define _ASM_POWERPC_BOOK3S_32_PGTABLE_H
4 
5 #include <asm-generic/pgtable-nopmd.h>
6 
7 #include <asm/book3s/32/hash.h>
8 
9 /* And here we include common definitions */
10 
11 #define _PAGE_KERNEL_RO		0
12 #define _PAGE_KERNEL_ROX	(_PAGE_EXEC)
13 #define _PAGE_KERNEL_RW		(_PAGE_DIRTY | _PAGE_RW)
14 #define _PAGE_KERNEL_RWX	(_PAGE_DIRTY | _PAGE_RW | _PAGE_EXEC)
15 
16 #define _PAGE_HPTEFLAGS _PAGE_HASHPTE
17 
18 #ifndef __ASSEMBLY__
19 
20 static inline bool pte_user(pte_t pte)
21 {
22 	return pte_val(pte) & _PAGE_USER;
23 }
24 #endif /* __ASSEMBLY__ */
25 
26 /*
27  * Location of the PFN in the PTE. Most 32-bit platforms use the same
28  * as _PAGE_SHIFT here (ie, naturally aligned).
29  * Platform who don't just pre-define the value so we don't override it here.
30  */
31 #define PTE_RPN_SHIFT	(PAGE_SHIFT)
32 
33 /*
34  * The mask covered by the RPN must be a ULL on 32-bit platforms with
35  * 64-bit PTEs.
36  */
37 #ifdef CONFIG_PTE_64BIT
38 #define PTE_RPN_MASK	(~((1ULL << PTE_RPN_SHIFT) - 1))
39 #else
40 #define PTE_RPN_MASK	(~((1UL << PTE_RPN_SHIFT) - 1))
41 #endif
42 
43 /*
44  * _PAGE_CHG_MASK masks of bits that are to be preserved across
45  * pgprot changes.
46  */
47 #define _PAGE_CHG_MASK	(PTE_RPN_MASK | _PAGE_HASHPTE | _PAGE_DIRTY | \
48 			 _PAGE_ACCESSED | _PAGE_SPECIAL)
49 
50 /*
51  * We define 2 sets of base prot bits, one for basic pages (ie,
52  * cacheable kernel and user pages) and one for non cacheable
53  * pages. We always set _PAGE_COHERENT when SMP is enabled or
54  * the processor might need it for DMA coherency.
55  */
56 #define _PAGE_BASE_NC	(_PAGE_PRESENT | _PAGE_ACCESSED)
57 #define _PAGE_BASE	(_PAGE_BASE_NC | _PAGE_COHERENT)
58 
59 /*
60  * Permission masks used to generate the __P and __S table.
61  *
62  * Note:__pgprot is defined in arch/powerpc/include/asm/page.h
63  *
64  * Write permissions imply read permissions for now.
65  */
66 #define PAGE_NONE	__pgprot(_PAGE_BASE)
67 #define PAGE_SHARED	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW)
68 #define PAGE_SHARED_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC)
69 #define PAGE_COPY	__pgprot(_PAGE_BASE | _PAGE_USER)
70 #define PAGE_COPY_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
71 #define PAGE_READONLY	__pgprot(_PAGE_BASE | _PAGE_USER)
72 #define PAGE_READONLY_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
73 
74 /* Permission masks used for kernel mappings */
75 #define PAGE_KERNEL	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RW)
76 #define PAGE_KERNEL_NC	__pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | _PAGE_NO_CACHE)
77 #define PAGE_KERNEL_NCG	__pgprot(_PAGE_BASE_NC | _PAGE_KERNEL_RW | \
78 				 _PAGE_NO_CACHE | _PAGE_GUARDED)
79 #define PAGE_KERNEL_X	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RWX)
80 #define PAGE_KERNEL_RO	__pgprot(_PAGE_BASE | _PAGE_KERNEL_RO)
81 #define PAGE_KERNEL_ROX	__pgprot(_PAGE_BASE | _PAGE_KERNEL_ROX)
82 
83 /*
84  * Protection used for kernel text. We want the debuggers to be able to
85  * set breakpoints anywhere, so don't write protect the kernel text
86  * on platforms where such control is possible.
87  */
88 #if defined(CONFIG_KGDB) || defined(CONFIG_XMON) || defined(CONFIG_BDI_SWITCH) ||\
89 	defined(CONFIG_KPROBES) || defined(CONFIG_DYNAMIC_FTRACE)
90 #define PAGE_KERNEL_TEXT	PAGE_KERNEL_X
91 #else
92 #define PAGE_KERNEL_TEXT	PAGE_KERNEL_ROX
93 #endif
94 
95 /* Make modules code happy. We don't set RO yet */
96 #define PAGE_KERNEL_EXEC	PAGE_KERNEL_X
97 
98 /* Advertise special mapping type for AGP */
99 #define PAGE_AGP		(PAGE_KERNEL_NC)
100 #define HAVE_PAGE_AGP
101 
102 #define PTE_INDEX_SIZE	PTE_SHIFT
103 #define PMD_INDEX_SIZE	0
104 #define PUD_INDEX_SIZE	0
105 #define PGD_INDEX_SIZE	(32 - PGDIR_SHIFT)
106 
107 #define PMD_CACHE_INDEX	PMD_INDEX_SIZE
108 #define PUD_CACHE_INDEX	PUD_INDEX_SIZE
109 
110 #ifndef __ASSEMBLY__
111 #define PTE_TABLE_SIZE	(sizeof(pte_t) << PTE_INDEX_SIZE)
112 #define PMD_TABLE_SIZE	0
113 #define PUD_TABLE_SIZE	0
114 #define PGD_TABLE_SIZE	(sizeof(pgd_t) << PGD_INDEX_SIZE)
115 #endif	/* __ASSEMBLY__ */
116 
117 #define PTRS_PER_PTE	(1 << PTE_INDEX_SIZE)
118 #define PTRS_PER_PGD	(1 << PGD_INDEX_SIZE)
119 
120 /*
121  * The normal case is that PTEs are 32-bits and we have a 1-page
122  * 1024-entry pgdir pointing to 1-page 1024-entry PTE pages.  -- paulus
123  *
124  * For any >32-bit physical address platform, we can use the following
125  * two level page table layout where the pgdir is 8KB and the MS 13 bits
126  * are an index to the second level table.  The combined pgdir/pmd first
127  * level has 2048 entries and the second level has 512 64-bit PTE entries.
128  * -Matt
129  */
130 /* PGDIR_SHIFT determines what a top-level page table entry can map */
131 #define PGDIR_SHIFT	(PAGE_SHIFT + PTE_INDEX_SIZE)
132 #define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
133 #define PGDIR_MASK	(~(PGDIR_SIZE-1))
134 
135 #define USER_PTRS_PER_PGD	(TASK_SIZE / PGDIR_SIZE)
136 
137 #ifndef __ASSEMBLY__
138 
139 int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
140 
141 #endif /* !__ASSEMBLY__ */
142 
143 /*
144  * This is the bottom of the PKMAP area with HIGHMEM or an arbitrary
145  * value (for now) on others, from where we can start layout kernel
146  * virtual space that goes below PKMAP and FIXMAP
147  */
148 #include <asm/fixmap.h>
149 
150 /*
151  * ioremap_bot starts at that address. Early ioremaps move down from there,
152  * until mem_init() at which point this becomes the top of the vmalloc
153  * and ioremap space
154  */
155 #ifdef CONFIG_HIGHMEM
156 #define IOREMAP_TOP	PKMAP_BASE
157 #else
158 #define IOREMAP_TOP	FIXADDR_START
159 #endif
160 
161 /* PPC32 shares vmalloc area with ioremap */
162 #define IOREMAP_START	VMALLOC_START
163 #define IOREMAP_END	VMALLOC_END
164 
165 /*
166  * Just any arbitrary offset to the start of the vmalloc VM area: the
167  * current 16MB value just means that there will be a 64MB "hole" after the
168  * physical memory until the kernel virtual memory starts.  That means that
169  * any out-of-bounds memory accesses will hopefully be caught.
170  * The vmalloc() routines leaves a hole of 4kB between each vmalloced
171  * area for the same reason. ;)
172  *
173  * We no longer map larger than phys RAM with the BATs so we don't have
174  * to worry about the VMALLOC_OFFSET causing problems.  We do have to worry
175  * about clashes between our early calls to ioremap() that start growing down
176  * from ioremap_base being run into the VM area allocations (growing upwards
177  * from VMALLOC_START).  For this reason we have ioremap_bot to check when
178  * we actually run into our mappings setup in the early boot with the VM
179  * system.  This really does become a problem for machines with good amounts
180  * of RAM.  -- Cort
181  */
182 #define VMALLOC_OFFSET (0x1000000) /* 16M */
183 
184 /*
185  * With CONFIG_STRICT_KERNEL_RWX, kernel segments are set NX. But when modules
186  * are used, NX cannot be set on VMALLOC space. So vmalloc VM space and linear
187  * memory shall not share segments.
188  */
189 #if defined(CONFIG_STRICT_KERNEL_RWX) && defined(CONFIG_MODULES)
190 #define VMALLOC_START ((_ALIGN((long)high_memory, 256L << 20) + VMALLOC_OFFSET) & \
191 		       ~(VMALLOC_OFFSET - 1))
192 #else
193 #define VMALLOC_START ((((long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
194 #endif
195 
196 #ifdef CONFIG_KASAN_VMALLOC
197 #define VMALLOC_END	_ALIGN_DOWN(ioremap_bot, PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
198 #else
199 #define VMALLOC_END	ioremap_bot
200 #endif
201 
202 #ifndef __ASSEMBLY__
203 #include <linux/sched.h>
204 #include <linux/threads.h>
205 
206 /* Bits to mask out from a PGD to get to the PUD page */
207 #define PGD_MASKED_BITS		0
208 
209 #define pte_ERROR(e) \
210 	pr_err("%s:%d: bad pte %llx.\n", __FILE__, __LINE__, \
211 		(unsigned long long)pte_val(e))
212 #define pgd_ERROR(e) \
213 	pr_err("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
214 /*
215  * Bits in a linux-style PTE.  These match the bits in the
216  * (hardware-defined) PowerPC PTE as closely as possible.
217  */
218 
219 #define pte_clear(mm, addr, ptep) \
220 	do { pte_update(ptep, ~_PAGE_HASHPTE, 0); } while (0)
221 
222 #define pmd_none(pmd)		(!pmd_val(pmd))
223 #define	pmd_bad(pmd)		(pmd_val(pmd) & _PMD_BAD)
224 #define	pmd_present(pmd)	(pmd_val(pmd) & _PMD_PRESENT_MASK)
225 static inline void pmd_clear(pmd_t *pmdp)
226 {
227 	*pmdp = __pmd(0);
228 }
229 
230 
231 /*
232  * When flushing the tlb entry for a page, we also need to flush the hash
233  * table entry.  flush_hash_pages is assembler (for speed) in hashtable.S.
234  */
235 extern int flush_hash_pages(unsigned context, unsigned long va,
236 			    unsigned long pmdval, int count);
237 
238 /* Add an HPTE to the hash table */
239 extern void add_hash_page(unsigned context, unsigned long va,
240 			  unsigned long pmdval);
241 
242 /* Flush an entry from the TLB/hash table */
243 extern void flush_hash_entry(struct mm_struct *mm, pte_t *ptep,
244 			     unsigned long address);
245 
246 /*
247  * PTE updates. This function is called whenever an existing
248  * valid PTE is updated. This does -not- include set_pte_at()
249  * which nowadays only sets a new PTE.
250  *
251  * Depending on the type of MMU, we may need to use atomic updates
252  * and the PTE may be either 32 or 64 bit wide. In the later case,
253  * when using atomic updates, only the low part of the PTE is
254  * accessed atomically.
255  *
256  * In addition, on 44x, we also maintain a global flag indicating
257  * that an executable user mapping was modified, which is needed
258  * to properly flush the virtually tagged instruction cache of
259  * those implementations.
260  */
261 #ifndef CONFIG_PTE_64BIT
262 static inline unsigned long pte_update(pte_t *p,
263 				       unsigned long clr,
264 				       unsigned long set)
265 {
266 	unsigned long old, tmp;
267 
268 	__asm__ __volatile__("\
269 1:	lwarx	%0,0,%3\n\
270 	andc	%1,%0,%4\n\
271 	or	%1,%1,%5\n"
272 "	stwcx.	%1,0,%3\n\
273 	bne-	1b"
274 	: "=&r" (old), "=&r" (tmp), "=m" (*p)
275 	: "r" (p), "r" (clr), "r" (set), "m" (*p)
276 	: "cc" );
277 
278 	return old;
279 }
280 #else /* CONFIG_PTE_64BIT */
281 static inline unsigned long long pte_update(pte_t *p,
282 					    unsigned long clr,
283 					    unsigned long set)
284 {
285 	unsigned long long old;
286 	unsigned long tmp;
287 
288 	__asm__ __volatile__("\
289 1:	lwarx	%L0,0,%4\n\
290 	lwzx	%0,0,%3\n\
291 	andc	%1,%L0,%5\n\
292 	or	%1,%1,%6\n"
293 "	stwcx.	%1,0,%4\n\
294 	bne-	1b"
295 	: "=&r" (old), "=&r" (tmp), "=m" (*p)
296 	: "r" (p), "r" ((unsigned long)(p) + 4), "r" (clr), "r" (set), "m" (*p)
297 	: "cc" );
298 
299 	return old;
300 }
301 #endif /* CONFIG_PTE_64BIT */
302 
303 /*
304  * 2.6 calls this without flushing the TLB entry; this is wrong
305  * for our hash-based implementation, we fix that up here.
306  */
307 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
308 static inline int __ptep_test_and_clear_young(unsigned int context, unsigned long addr, pte_t *ptep)
309 {
310 	unsigned long old;
311 	old = pte_update(ptep, _PAGE_ACCESSED, 0);
312 	if (old & _PAGE_HASHPTE) {
313 		unsigned long ptephys = __pa(ptep) & PAGE_MASK;
314 		flush_hash_pages(context, addr, ptephys, 1);
315 	}
316 	return (old & _PAGE_ACCESSED) != 0;
317 }
318 #define ptep_test_and_clear_young(__vma, __addr, __ptep) \
319 	__ptep_test_and_clear_young((__vma)->vm_mm->context.id, __addr, __ptep)
320 
321 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
322 static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
323 				       pte_t *ptep)
324 {
325 	return __pte(pte_update(ptep, ~_PAGE_HASHPTE, 0));
326 }
327 
328 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
329 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
330 				      pte_t *ptep)
331 {
332 	pte_update(ptep, _PAGE_RW, 0);
333 }
334 
335 static inline void __ptep_set_access_flags(struct vm_area_struct *vma,
336 					   pte_t *ptep, pte_t entry,
337 					   unsigned long address,
338 					   int psize)
339 {
340 	unsigned long set = pte_val(entry) &
341 		(_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW | _PAGE_EXEC);
342 
343 	pte_update(ptep, 0, set);
344 
345 	flush_tlb_page(vma, address);
346 }
347 
348 #define __HAVE_ARCH_PTE_SAME
349 #define pte_same(A,B)	(((pte_val(A) ^ pte_val(B)) & ~_PAGE_HASHPTE) == 0)
350 
351 #define pmd_page_vaddr(pmd)	\
352 	((unsigned long)__va(pmd_val(pmd) & ~(PTE_TABLE_SIZE - 1)))
353 #define pmd_page(pmd)		\
354 	pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT)
355 
356 /* to find an entry in a kernel page-table-directory */
357 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
358 
359 /* to find an entry in a page-table-directory */
360 #define pgd_index(address)	 ((address) >> PGDIR_SHIFT)
361 #define pgd_offset(mm, address)	 ((mm)->pgd + pgd_index(address))
362 
363 /* Find an entry in the third-level page table.. */
364 #define pte_index(address)		\
365 	(((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
366 #define pte_offset_kernel(dir, addr)	\
367 	((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(addr))
368 #define pte_offset_map(dir, addr)	pte_offset_kernel((dir), (addr))
369 static inline void pte_unmap(pte_t *pte) { }
370 
371 /*
372  * Encode and decode a swap entry.
373  * Note that the bits we use in a PTE for representing a swap entry
374  * must not include the _PAGE_PRESENT bit or the _PAGE_HASHPTE bit (if used).
375  *   -- paulus
376  */
377 #define __swp_type(entry)		((entry).val & 0x1f)
378 #define __swp_offset(entry)		((entry).val >> 5)
379 #define __swp_entry(type, offset)	((swp_entry_t) { (type) | ((offset) << 5) })
380 #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) >> 3 })
381 #define __swp_entry_to_pte(x)		((pte_t) { (x).val << 3 })
382 
383 /* Generic accessors to PTE bits */
384 static inline int pte_write(pte_t pte)		{ return !!(pte_val(pte) & _PAGE_RW);}
385 static inline int pte_read(pte_t pte)		{ return 1; }
386 static inline int pte_dirty(pte_t pte)		{ return !!(pte_val(pte) & _PAGE_DIRTY); }
387 static inline int pte_young(pte_t pte)		{ return !!(pte_val(pte) & _PAGE_ACCESSED); }
388 static inline int pte_special(pte_t pte)	{ return !!(pte_val(pte) & _PAGE_SPECIAL); }
389 static inline int pte_none(pte_t pte)		{ return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }
390 static inline bool pte_exec(pte_t pte)		{ return pte_val(pte) & _PAGE_EXEC; }
391 
392 static inline int pte_present(pte_t pte)
393 {
394 	return pte_val(pte) & _PAGE_PRESENT;
395 }
396 
397 static inline bool pte_hw_valid(pte_t pte)
398 {
399 	return pte_val(pte) & _PAGE_PRESENT;
400 }
401 
402 static inline bool pte_hashpte(pte_t pte)
403 {
404 	return !!(pte_val(pte) & _PAGE_HASHPTE);
405 }
406 
407 static inline bool pte_ci(pte_t pte)
408 {
409 	return !!(pte_val(pte) & _PAGE_NO_CACHE);
410 }
411 
412 /*
413  * We only find page table entry in the last level
414  * Hence no need for other accessors
415  */
416 #define pte_access_permitted pte_access_permitted
417 static inline bool pte_access_permitted(pte_t pte, bool write)
418 {
419 	/*
420 	 * A read-only access is controlled by _PAGE_USER bit.
421 	 * We have _PAGE_READ set for WRITE and EXECUTE
422 	 */
423 	if (!pte_present(pte) || !pte_user(pte) || !pte_read(pte))
424 		return false;
425 
426 	if (write && !pte_write(pte))
427 		return false;
428 
429 	return true;
430 }
431 
432 /* Conversion functions: convert a page and protection to a page entry,
433  * and a page entry and page directory to the page they refer to.
434  *
435  * Even if PTEs can be unsigned long long, a PFN is always an unsigned
436  * long for now.
437  */
438 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
439 {
440 	return __pte(((pte_basic_t)(pfn) << PTE_RPN_SHIFT) |
441 		     pgprot_val(pgprot));
442 }
443 
444 static inline unsigned long pte_pfn(pte_t pte)
445 {
446 	return pte_val(pte) >> PTE_RPN_SHIFT;
447 }
448 
449 /* Generic modifiers for PTE bits */
450 static inline pte_t pte_wrprotect(pte_t pte)
451 {
452 	return __pte(pte_val(pte) & ~_PAGE_RW);
453 }
454 
455 static inline pte_t pte_exprotect(pte_t pte)
456 {
457 	return __pte(pte_val(pte) & ~_PAGE_EXEC);
458 }
459 
460 static inline pte_t pte_mkclean(pte_t pte)
461 {
462 	return __pte(pte_val(pte) & ~_PAGE_DIRTY);
463 }
464 
465 static inline pte_t pte_mkold(pte_t pte)
466 {
467 	return __pte(pte_val(pte) & ~_PAGE_ACCESSED);
468 }
469 
470 static inline pte_t pte_mkexec(pte_t pte)
471 {
472 	return __pte(pte_val(pte) | _PAGE_EXEC);
473 }
474 
475 static inline pte_t pte_mkpte(pte_t pte)
476 {
477 	return pte;
478 }
479 
480 static inline pte_t pte_mkwrite(pte_t pte)
481 {
482 	return __pte(pte_val(pte) | _PAGE_RW);
483 }
484 
485 static inline pte_t pte_mkdirty(pte_t pte)
486 {
487 	return __pte(pte_val(pte) | _PAGE_DIRTY);
488 }
489 
490 static inline pte_t pte_mkyoung(pte_t pte)
491 {
492 	return __pte(pte_val(pte) | _PAGE_ACCESSED);
493 }
494 
495 static inline pte_t pte_mkspecial(pte_t pte)
496 {
497 	return __pte(pte_val(pte) | _PAGE_SPECIAL);
498 }
499 
500 static inline pte_t pte_mkhuge(pte_t pte)
501 {
502 	return pte;
503 }
504 
505 static inline pte_t pte_mkprivileged(pte_t pte)
506 {
507 	return __pte(pte_val(pte) & ~_PAGE_USER);
508 }
509 
510 static inline pte_t pte_mkuser(pte_t pte)
511 {
512 	return __pte(pte_val(pte) | _PAGE_USER);
513 }
514 
515 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
516 {
517 	return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
518 }
519 
520 
521 
522 /* This low level function performs the actual PTE insertion
523  * Setting the PTE depends on the MMU type and other factors. It's
524  * an horrible mess that I'm not going to try to clean up now but
525  * I'm keeping it in one place rather than spread around
526  */
527 static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
528 				pte_t *ptep, pte_t pte, int percpu)
529 {
530 #if defined(CONFIG_SMP) && !defined(CONFIG_PTE_64BIT)
531 	/* First case is 32-bit Hash MMU in SMP mode with 32-bit PTEs. We use the
532 	 * helper pte_update() which does an atomic update. We need to do that
533 	 * because a concurrent invalidation can clear _PAGE_HASHPTE. If it's a
534 	 * per-CPU PTE such as a kmap_atomic, we do a simple update preserving
535 	 * the hash bits instead (ie, same as the non-SMP case)
536 	 */
537 	if (percpu)
538 		*ptep = __pte((pte_val(*ptep) & _PAGE_HASHPTE)
539 			      | (pte_val(pte) & ~_PAGE_HASHPTE));
540 	else
541 		pte_update(ptep, ~_PAGE_HASHPTE, pte_val(pte));
542 
543 #elif defined(CONFIG_PTE_64BIT)
544 	/* Second case is 32-bit with 64-bit PTE.  In this case, we
545 	 * can just store as long as we do the two halves in the right order
546 	 * with a barrier in between. This is possible because we take care,
547 	 * in the hash code, to pre-invalidate if the PTE was already hashed,
548 	 * which synchronizes us with any concurrent invalidation.
549 	 * In the percpu case, we also fallback to the simple update preserving
550 	 * the hash bits
551 	 */
552 	if (percpu) {
553 		*ptep = __pte((pte_val(*ptep) & _PAGE_HASHPTE)
554 			      | (pte_val(pte) & ~_PAGE_HASHPTE));
555 		return;
556 	}
557 	if (pte_val(*ptep) & _PAGE_HASHPTE)
558 		flush_hash_entry(mm, ptep, addr);
559 	__asm__ __volatile__("\
560 		stw%U0%X0 %2,%0\n\
561 		eieio\n\
562 		stw%U0%X0 %L2,%1"
563 	: "=m" (*ptep), "=m" (*((unsigned char *)ptep+4))
564 	: "r" (pte) : "memory");
565 
566 #else
567 	/* Third case is 32-bit hash table in UP mode, we need to preserve
568 	 * the _PAGE_HASHPTE bit since we may not have invalidated the previous
569 	 * translation in the hash yet (done in a subsequent flush_tlb_xxx())
570 	 * and see we need to keep track that this PTE needs invalidating
571 	 */
572 	*ptep = __pte((pte_val(*ptep) & _PAGE_HASHPTE)
573 		      | (pte_val(pte) & ~_PAGE_HASHPTE));
574 #endif
575 }
576 
577 /*
578  * Macro to mark a page protection value as "uncacheable".
579  */
580 
581 #define _PAGE_CACHE_CTL	(_PAGE_COHERENT | _PAGE_GUARDED | _PAGE_NO_CACHE | \
582 			 _PAGE_WRITETHRU)
583 
584 #define pgprot_noncached pgprot_noncached
585 static inline pgprot_t pgprot_noncached(pgprot_t prot)
586 {
587 	return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
588 			_PAGE_NO_CACHE | _PAGE_GUARDED);
589 }
590 
591 #define pgprot_noncached_wc pgprot_noncached_wc
592 static inline pgprot_t pgprot_noncached_wc(pgprot_t prot)
593 {
594 	return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
595 			_PAGE_NO_CACHE);
596 }
597 
598 #define pgprot_cached pgprot_cached
599 static inline pgprot_t pgprot_cached(pgprot_t prot)
600 {
601 	return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
602 			_PAGE_COHERENT);
603 }
604 
605 #define pgprot_cached_wthru pgprot_cached_wthru
606 static inline pgprot_t pgprot_cached_wthru(pgprot_t prot)
607 {
608 	return __pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) |
609 			_PAGE_COHERENT | _PAGE_WRITETHRU);
610 }
611 
612 #define pgprot_cached_noncoherent pgprot_cached_noncoherent
613 static inline pgprot_t pgprot_cached_noncoherent(pgprot_t prot)
614 {
615 	return __pgprot(pgprot_val(prot) & ~_PAGE_CACHE_CTL);
616 }
617 
618 #define pgprot_writecombine pgprot_writecombine
619 static inline pgprot_t pgprot_writecombine(pgprot_t prot)
620 {
621 	return pgprot_noncached_wc(prot);
622 }
623 
624 #endif /* !__ASSEMBLY__ */
625 
626 #endif /*  _ASM_POWERPC_BOOK3S_32_PGTABLE_H */
627