xref: /linux/arch/powerpc/include/asm/book3s/64/mmu-hash.h (revision cc3ae7b0af27118994c1e491382b253be3b762bf)
1 #ifndef _ASM_POWERPC_BOOK3S_64_MMU_HASH_H_
2 #define _ASM_POWERPC_BOOK3S_64_MMU_HASH_H_
3 /*
4  * PowerPC64 memory management structures
5  *
6  * Dave Engebretsen & Mike Corrigan <{engebret|mikejc}@us.ibm.com>
7  *   PPC64 rework.
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License
11  * as published by the Free Software Foundation; either version
12  * 2 of the License, or (at your option) any later version.
13  */
14 
15 #include <asm/asm-compat.h>
16 #include <asm/page.h>
17 #include <asm/bug.h>
18 
19 /*
20  * This is necessary to get the definition of PGTABLE_RANGE which we
21  * need for various slices related matters. Note that this isn't the
22  * complete pgtable.h but only a portion of it.
23  */
24 #include <asm/book3s/64/pgtable.h>
25 #include <asm/bug.h>
26 #include <asm/processor.h>
27 
28 /*
29  * SLB
30  */
31 
32 #define SLB_NUM_BOLTED		3
33 #define SLB_CACHE_ENTRIES	8
34 #define SLB_MIN_SIZE		32
35 
36 /* Bits in the SLB ESID word */
37 #define SLB_ESID_V		ASM_CONST(0x0000000008000000) /* valid */
38 
39 /* Bits in the SLB VSID word */
40 #define SLB_VSID_SHIFT		12
41 #define SLB_VSID_SHIFT_1T	24
42 #define SLB_VSID_SSIZE_SHIFT	62
43 #define SLB_VSID_B		ASM_CONST(0xc000000000000000)
44 #define SLB_VSID_B_256M		ASM_CONST(0x0000000000000000)
45 #define SLB_VSID_B_1T		ASM_CONST(0x4000000000000000)
46 #define SLB_VSID_KS		ASM_CONST(0x0000000000000800)
47 #define SLB_VSID_KP		ASM_CONST(0x0000000000000400)
48 #define SLB_VSID_N		ASM_CONST(0x0000000000000200) /* no-execute */
49 #define SLB_VSID_L		ASM_CONST(0x0000000000000100)
50 #define SLB_VSID_C		ASM_CONST(0x0000000000000080) /* class */
51 #define SLB_VSID_LP		ASM_CONST(0x0000000000000030)
52 #define SLB_VSID_LP_00		ASM_CONST(0x0000000000000000)
53 #define SLB_VSID_LP_01		ASM_CONST(0x0000000000000010)
54 #define SLB_VSID_LP_10		ASM_CONST(0x0000000000000020)
55 #define SLB_VSID_LP_11		ASM_CONST(0x0000000000000030)
56 #define SLB_VSID_LLP		(SLB_VSID_L|SLB_VSID_LP)
57 
58 #define SLB_VSID_KERNEL		(SLB_VSID_KP)
59 #define SLB_VSID_USER		(SLB_VSID_KP|SLB_VSID_KS|SLB_VSID_C)
60 
61 #define SLBIE_C			(0x08000000)
62 #define SLBIE_SSIZE_SHIFT	25
63 
64 /*
65  * Hash table
66  */
67 
68 #define HPTES_PER_GROUP 8
69 
70 #define HPTE_V_SSIZE_SHIFT	62
71 #define HPTE_V_AVPN_SHIFT	7
72 #define HPTE_V_AVPN		ASM_CONST(0x3fffffffffffff80)
73 #define HPTE_V_AVPN_VAL(x)	(((x) & HPTE_V_AVPN) >> HPTE_V_AVPN_SHIFT)
74 #define HPTE_V_COMPARE(x,y)	(!(((x) ^ (y)) & 0xffffffffffffff80UL))
75 #define HPTE_V_BOLTED		ASM_CONST(0x0000000000000010)
76 #define HPTE_V_LOCK		ASM_CONST(0x0000000000000008)
77 #define HPTE_V_LARGE		ASM_CONST(0x0000000000000004)
78 #define HPTE_V_SECONDARY	ASM_CONST(0x0000000000000002)
79 #define HPTE_V_VALID		ASM_CONST(0x0000000000000001)
80 
81 /*
82  * ISA 3.0 have a different HPTE format.
83  */
84 #define HPTE_R_3_0_SSIZE_SHIFT	58
85 #define HPTE_R_PP0		ASM_CONST(0x8000000000000000)
86 #define HPTE_R_TS		ASM_CONST(0x4000000000000000)
87 #define HPTE_R_KEY_HI		ASM_CONST(0x3000000000000000)
88 #define HPTE_R_RPN_SHIFT	12
89 #define HPTE_R_RPN		ASM_CONST(0x0ffffffffffff000)
90 #define HPTE_R_PP		ASM_CONST(0x0000000000000003)
91 #define HPTE_R_PPP		ASM_CONST(0x8000000000000003)
92 #define HPTE_R_N		ASM_CONST(0x0000000000000004)
93 #define HPTE_R_G		ASM_CONST(0x0000000000000008)
94 #define HPTE_R_M		ASM_CONST(0x0000000000000010)
95 #define HPTE_R_I		ASM_CONST(0x0000000000000020)
96 #define HPTE_R_W		ASM_CONST(0x0000000000000040)
97 #define HPTE_R_WIMG		ASM_CONST(0x0000000000000078)
98 #define HPTE_R_C		ASM_CONST(0x0000000000000080)
99 #define HPTE_R_R		ASM_CONST(0x0000000000000100)
100 #define HPTE_R_KEY_LO		ASM_CONST(0x0000000000000e00)
101 
102 #define HPTE_V_1TB_SEG		ASM_CONST(0x4000000000000000)
103 #define HPTE_V_VRMA_MASK	ASM_CONST(0x4001ffffff000000)
104 
105 /* Values for PP (assumes Ks=0, Kp=1) */
106 #define PP_RWXX	0	/* Supervisor read/write, User none */
107 #define PP_RWRX 1	/* Supervisor read/write, User read */
108 #define PP_RWRW 2	/* Supervisor read/write, User read/write */
109 #define PP_RXRX 3	/* Supervisor read,       User read */
110 #define PP_RXXX	(HPTE_R_PP0 | 2)	/* Supervisor read, user none */
111 
112 /* Fields for tlbiel instruction in architecture 2.06 */
113 #define TLBIEL_INVAL_SEL_MASK	0xc00	/* invalidation selector */
114 #define  TLBIEL_INVAL_PAGE	0x000	/* invalidate a single page */
115 #define  TLBIEL_INVAL_SET_LPID	0x800	/* invalidate a set for current LPID */
116 #define  TLBIEL_INVAL_SET	0xc00	/* invalidate a set for all LPIDs */
117 #define TLBIEL_INVAL_SET_MASK	0xfff000	/* set number to inval. */
118 #define TLBIEL_INVAL_SET_SHIFT	12
119 
120 #define POWER7_TLB_SETS		128	/* # sets in POWER7 TLB */
121 #define POWER8_TLB_SETS		512	/* # sets in POWER8 TLB */
122 #define POWER9_TLB_SETS_HASH	256	/* # sets in POWER9 TLB Hash mode */
123 #define POWER9_TLB_SETS_RADIX	128	/* # sets in POWER9 TLB Radix mode */
124 
125 #ifndef __ASSEMBLY__
126 
127 struct hash_pte {
128 	__be64 v;
129 	__be64 r;
130 };
131 
132 extern struct hash_pte *htab_address;
133 extern unsigned long htab_size_bytes;
134 extern unsigned long htab_hash_mask;
135 
136 
137 static inline int shift_to_mmu_psize(unsigned int shift)
138 {
139 	int psize;
140 
141 	for (psize = 0; psize < MMU_PAGE_COUNT; ++psize)
142 		if (mmu_psize_defs[psize].shift == shift)
143 			return psize;
144 	return -1;
145 }
146 
147 static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
148 {
149 	if (mmu_psize_defs[mmu_psize].shift)
150 		return mmu_psize_defs[mmu_psize].shift;
151 	BUG();
152 }
153 
154 #endif /* __ASSEMBLY__ */
155 
156 /*
157  * Segment sizes.
158  * These are the values used by hardware in the B field of
159  * SLB entries and the first dword of MMU hashtable entries.
160  * The B field is 2 bits; the values 2 and 3 are unused and reserved.
161  */
162 #define MMU_SEGSIZE_256M	0
163 #define MMU_SEGSIZE_1T		1
164 
165 /*
166  * encode page number shift.
167  * in order to fit the 78 bit va in a 64 bit variable we shift the va by
168  * 12 bits. This enable us to address upto 76 bit va.
169  * For hpt hash from a va we can ignore the page size bits of va and for
170  * hpte encoding we ignore up to 23 bits of va. So ignoring lower 12 bits ensure
171  * we work in all cases including 4k page size.
172  */
173 #define VPN_SHIFT	12
174 
175 /*
176  * HPTE Large Page (LP) details
177  */
178 #define LP_SHIFT	12
179 #define LP_BITS		8
180 #define LP_MASK(i)	((0xFF >> (i)) << LP_SHIFT)
181 
182 #ifndef __ASSEMBLY__
183 
184 static inline int slb_vsid_shift(int ssize)
185 {
186 	if (ssize == MMU_SEGSIZE_256M)
187 		return SLB_VSID_SHIFT;
188 	return SLB_VSID_SHIFT_1T;
189 }
190 
191 static inline int segment_shift(int ssize)
192 {
193 	if (ssize == MMU_SEGSIZE_256M)
194 		return SID_SHIFT;
195 	return SID_SHIFT_1T;
196 }
197 
198 /*
199  * The current system page and segment sizes
200  */
201 extern int mmu_kernel_ssize;
202 extern int mmu_highuser_ssize;
203 extern u16 mmu_slb_size;
204 extern unsigned long tce_alloc_start, tce_alloc_end;
205 
206 /*
207  * If the processor supports 64k normal pages but not 64k cache
208  * inhibited pages, we have to be prepared to switch processes
209  * to use 4k pages when they create cache-inhibited mappings.
210  * If this is the case, mmu_ci_restrictions will be set to 1.
211  */
212 extern int mmu_ci_restrictions;
213 
214 /*
215  * This computes the AVPN and B fields of the first dword of a HPTE,
216  * for use when we want to match an existing PTE.  The bottom 7 bits
217  * of the returned value are zero.
218  */
219 static inline unsigned long hpte_encode_avpn(unsigned long vpn, int psize,
220 					     int ssize)
221 {
222 	unsigned long v;
223 	/*
224 	 * The AVA field omits the low-order 23 bits of the 78 bits VA.
225 	 * These bits are not needed in the PTE, because the
226 	 * low-order b of these bits are part of the byte offset
227 	 * into the virtual page and, if b < 23, the high-order
228 	 * 23-b of these bits are always used in selecting the
229 	 * PTEGs to be searched
230 	 */
231 	v = (vpn >> (23 - VPN_SHIFT)) & ~(mmu_psize_defs[psize].avpnm);
232 	v <<= HPTE_V_AVPN_SHIFT;
233 	if (!cpu_has_feature(CPU_FTR_ARCH_300))
234 		v |= ((unsigned long) ssize) << HPTE_V_SSIZE_SHIFT;
235 	return v;
236 }
237 
238 /*
239  * This function sets the AVPN and L fields of the HPTE  appropriately
240  * using the base page size and actual page size.
241  */
242 static inline unsigned long hpte_encode_v(unsigned long vpn, int base_psize,
243 					  int actual_psize, int ssize)
244 {
245 	unsigned long v;
246 	v = hpte_encode_avpn(vpn, base_psize, ssize);
247 	if (actual_psize != MMU_PAGE_4K)
248 		v |= HPTE_V_LARGE;
249 	return v;
250 }
251 
252 /*
253  * This function sets the ARPN, and LP fields of the HPTE appropriately
254  * for the page size. We assume the pa is already "clean" that is properly
255  * aligned for the requested page size
256  */
257 static inline unsigned long hpte_encode_r(unsigned long pa, int base_psize,
258 					  int actual_psize, int ssize)
259 {
260 
261 	if (cpu_has_feature(CPU_FTR_ARCH_300))
262 		pa |= ((unsigned long) ssize) << HPTE_R_3_0_SSIZE_SHIFT;
263 
264 	/* A 4K page needs no special encoding */
265 	if (actual_psize == MMU_PAGE_4K)
266 		return pa & HPTE_R_RPN;
267 	else {
268 		unsigned int penc = mmu_psize_defs[base_psize].penc[actual_psize];
269 		unsigned int shift = mmu_psize_defs[actual_psize].shift;
270 		return (pa & ~((1ul << shift) - 1)) | (penc << LP_SHIFT);
271 	}
272 }
273 
274 /*
275  * Build a VPN_SHIFT bit shifted va given VSID, EA and segment size.
276  */
277 static inline unsigned long hpt_vpn(unsigned long ea,
278 				    unsigned long vsid, int ssize)
279 {
280 	unsigned long mask;
281 	int s_shift = segment_shift(ssize);
282 
283 	mask = (1ul << (s_shift - VPN_SHIFT)) - 1;
284 	return (vsid << (s_shift - VPN_SHIFT)) | ((ea >> VPN_SHIFT) & mask);
285 }
286 
287 /*
288  * This hashes a virtual address
289  */
290 static inline unsigned long hpt_hash(unsigned long vpn,
291 				     unsigned int shift, int ssize)
292 {
293 	int mask;
294 	unsigned long hash, vsid;
295 
296 	/* VPN_SHIFT can be atmost 12 */
297 	if (ssize == MMU_SEGSIZE_256M) {
298 		mask = (1ul << (SID_SHIFT - VPN_SHIFT)) - 1;
299 		hash = (vpn >> (SID_SHIFT - VPN_SHIFT)) ^
300 			((vpn & mask) >> (shift - VPN_SHIFT));
301 	} else {
302 		mask = (1ul << (SID_SHIFT_1T - VPN_SHIFT)) - 1;
303 		vsid = vpn >> (SID_SHIFT_1T - VPN_SHIFT);
304 		hash = vsid ^ (vsid << 25) ^
305 			((vpn & mask) >> (shift - VPN_SHIFT)) ;
306 	}
307 	return hash & 0x7fffffffffUL;
308 }
309 
310 #define HPTE_LOCAL_UPDATE	0x1
311 #define HPTE_NOHPTE_UPDATE	0x2
312 
313 extern int __hash_page_4K(unsigned long ea, unsigned long access,
314 			  unsigned long vsid, pte_t *ptep, unsigned long trap,
315 			  unsigned long flags, int ssize, int subpage_prot);
316 extern int __hash_page_64K(unsigned long ea, unsigned long access,
317 			   unsigned long vsid, pte_t *ptep, unsigned long trap,
318 			   unsigned long flags, int ssize);
319 struct mm_struct;
320 unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap);
321 extern int hash_page_mm(struct mm_struct *mm, unsigned long ea,
322 			unsigned long access, unsigned long trap,
323 			unsigned long flags);
324 extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap,
325 		     unsigned long dsisr);
326 int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
327 		     pte_t *ptep, unsigned long trap, unsigned long flags,
328 		     int ssize, unsigned int shift, unsigned int mmu_psize);
329 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
330 extern int __hash_page_thp(unsigned long ea, unsigned long access,
331 			   unsigned long vsid, pmd_t *pmdp, unsigned long trap,
332 			   unsigned long flags, int ssize, unsigned int psize);
333 #else
334 static inline int __hash_page_thp(unsigned long ea, unsigned long access,
335 				  unsigned long vsid, pmd_t *pmdp,
336 				  unsigned long trap, unsigned long flags,
337 				  int ssize, unsigned int psize)
338 {
339 	BUG();
340 	return -1;
341 }
342 #endif
343 extern void hash_failure_debug(unsigned long ea, unsigned long access,
344 			       unsigned long vsid, unsigned long trap,
345 			       int ssize, int psize, int lpsize,
346 			       unsigned long pte);
347 extern int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
348 			     unsigned long pstart, unsigned long prot,
349 			     int psize, int ssize);
350 int htab_remove_mapping(unsigned long vstart, unsigned long vend,
351 			int psize, int ssize);
352 extern void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages);
353 extern void demote_segment_4k(struct mm_struct *mm, unsigned long addr);
354 
355 extern void hpte_init_native(void);
356 extern void hpte_init_lpar(void);
357 extern void hpte_init_beat(void);
358 extern void hpte_init_beat_v3(void);
359 
360 extern void slb_initialize(void);
361 extern void slb_flush_and_rebolt(void);
362 
363 extern void slb_vmalloc_update(void);
364 extern void slb_set_size(u16 size);
365 #endif /* __ASSEMBLY__ */
366 
367 /*
368  * VSID allocation (256MB segment)
369  *
370  * We first generate a 37-bit "proto-VSID". Proto-VSIDs are generated
371  * from mmu context id and effective segment id of the address.
372  *
373  * For user processes max context id is limited to ((1ul << 19) - 5)
374  * for kernel space, we use the top 4 context ids to map address as below
375  * NOTE: each context only support 64TB now.
376  * 0x7fffc -  [ 0xc000000000000000 - 0xc0003fffffffffff ]
377  * 0x7fffd -  [ 0xd000000000000000 - 0xd0003fffffffffff ]
378  * 0x7fffe -  [ 0xe000000000000000 - 0xe0003fffffffffff ]
379  * 0x7ffff -  [ 0xf000000000000000 - 0xf0003fffffffffff ]
380  *
381  * The proto-VSIDs are then scrambled into real VSIDs with the
382  * multiplicative hash:
383  *
384  *	VSID = (proto-VSID * VSID_MULTIPLIER) % VSID_MODULUS
385  *
386  * VSID_MULTIPLIER is prime, so in particular it is
387  * co-prime to VSID_MODULUS, making this a 1:1 scrambling function.
388  * Because the modulus is 2^n-1 we can compute it efficiently without
389  * a divide or extra multiply (see below). The scramble function gives
390  * robust scattering in the hash table (at least based on some initial
391  * results).
392  *
393  * We also consider VSID 0 special. We use VSID 0 for slb entries mapping
394  * bad address. This enables us to consolidate bad address handling in
395  * hash_page.
396  *
397  * We also need to avoid the last segment of the last context, because that
398  * would give a protovsid of 0x1fffffffff. That will result in a VSID 0
399  * because of the modulo operation in vsid scramble. But the vmemmap
400  * (which is what uses region 0xf) will never be close to 64TB in size
401  * (it's 56 bytes per page of system memory).
402  */
403 
404 #define CONTEXT_BITS		19
405 #define ESID_BITS		18
406 #define ESID_BITS_1T		6
407 
408 /*
409  * 256MB segment
410  * The proto-VSID space has 2^(CONTEX_BITS + ESID_BITS) - 1 segments
411  * available for user + kernel mapping. The top 4 contexts are used for
412  * kernel mapping. Each segment contains 2^28 bytes. Each
413  * context maps 2^46 bytes (64TB) so we can support 2^19-1 contexts
414  * (19 == 37 + 28 - 46).
415  */
416 #define MAX_USER_CONTEXT	((ASM_CONST(1) << CONTEXT_BITS) - 5)
417 
418 /*
419  * This should be computed such that protovosid * vsid_mulitplier
420  * doesn't overflow 64 bits. It should also be co-prime to vsid_modulus
421  */
422 #define VSID_MULTIPLIER_256M	ASM_CONST(12538073)	/* 24-bit prime */
423 #define VSID_BITS_256M		(CONTEXT_BITS + ESID_BITS)
424 #define VSID_MODULUS_256M	((1UL<<VSID_BITS_256M)-1)
425 
426 #define VSID_MULTIPLIER_1T	ASM_CONST(12538073)	/* 24-bit prime */
427 #define VSID_BITS_1T		(CONTEXT_BITS + ESID_BITS_1T)
428 #define VSID_MODULUS_1T		((1UL<<VSID_BITS_1T)-1)
429 
430 
431 #define USER_VSID_RANGE	(1UL << (ESID_BITS + SID_SHIFT))
432 
433 /*
434  * This macro generates asm code to compute the VSID scramble
435  * function.  Used in slb_allocate() and do_stab_bolted.  The function
436  * computed is: (protovsid*VSID_MULTIPLIER) % VSID_MODULUS
437  *
438  *	rt = register continaing the proto-VSID and into which the
439  *		VSID will be stored
440  *	rx = scratch register (clobbered)
441  *
442  * 	- rt and rx must be different registers
443  * 	- The answer will end up in the low VSID_BITS bits of rt.  The higher
444  * 	  bits may contain other garbage, so you may need to mask the
445  * 	  result.
446  */
447 #define ASM_VSID_SCRAMBLE(rt, rx, size)					\
448 	lis	rx,VSID_MULTIPLIER_##size@h;				\
449 	ori	rx,rx,VSID_MULTIPLIER_##size@l;				\
450 	mulld	rt,rt,rx;		/* rt = rt * MULTIPLIER */	\
451 									\
452 	srdi	rx,rt,VSID_BITS_##size;					\
453 	clrldi	rt,rt,(64-VSID_BITS_##size);				\
454 	add	rt,rt,rx;		/* add high and low bits */	\
455 	/* NOTE: explanation based on VSID_BITS_##size = 36		\
456 	 * Now, r3 == VSID (mod 2^36-1), and lies between 0 and		\
457 	 * 2^36-1+2^28-1.  That in particular means that if r3 >=	\
458 	 * 2^36-1, then r3+1 has the 2^36 bit set.  So, if r3+1 has	\
459 	 * the bit clear, r3 already has the answer we want, if it	\
460 	 * doesn't, the answer is the low 36 bits of r3+1.  So in all	\
461 	 * cases the answer is the low 36 bits of (r3 + ((r3+1) >> 36))*/\
462 	addi	rx,rt,1;						\
463 	srdi	rx,rx,VSID_BITS_##size;	/* extract 2^VSID_BITS bit */	\
464 	add	rt,rt,rx
465 
466 /* 4 bits per slice and we have one slice per 1TB */
467 #define SLICE_ARRAY_SIZE  (H_PGTABLE_RANGE >> 41)
468 
469 #ifndef __ASSEMBLY__
470 
471 #ifdef CONFIG_PPC_SUBPAGE_PROT
472 /*
473  * For the sub-page protection option, we extend the PGD with one of
474  * these.  Basically we have a 3-level tree, with the top level being
475  * the protptrs array.  To optimize speed and memory consumption when
476  * only addresses < 4GB are being protected, pointers to the first
477  * four pages of sub-page protection words are stored in the low_prot
478  * array.
479  * Each page of sub-page protection words protects 1GB (4 bytes
480  * protects 64k).  For the 3-level tree, each page of pointers then
481  * protects 8TB.
482  */
483 struct subpage_prot_table {
484 	unsigned long maxaddr;	/* only addresses < this are protected */
485 	unsigned int **protptrs[(TASK_SIZE_USER64 >> 43)];
486 	unsigned int *low_prot[4];
487 };
488 
489 #define SBP_L1_BITS		(PAGE_SHIFT - 2)
490 #define SBP_L2_BITS		(PAGE_SHIFT - 3)
491 #define SBP_L1_COUNT		(1 << SBP_L1_BITS)
492 #define SBP_L2_COUNT		(1 << SBP_L2_BITS)
493 #define SBP_L2_SHIFT		(PAGE_SHIFT + SBP_L1_BITS)
494 #define SBP_L3_SHIFT		(SBP_L2_SHIFT + SBP_L2_BITS)
495 
496 extern void subpage_prot_free(struct mm_struct *mm);
497 extern void subpage_prot_init_new_context(struct mm_struct *mm);
498 #else
499 static inline void subpage_prot_free(struct mm_struct *mm) {}
500 static inline void subpage_prot_init_new_context(struct mm_struct *mm) { }
501 #endif /* CONFIG_PPC_SUBPAGE_PROT */
502 
503 #if 0
504 /*
505  * The code below is equivalent to this function for arguments
506  * < 2^VSID_BITS, which is all this should ever be called
507  * with.  However gcc is not clever enough to compute the
508  * modulus (2^n-1) without a second multiply.
509  */
510 #define vsid_scramble(protovsid, size) \
511 	((((protovsid) * VSID_MULTIPLIER_##size) % VSID_MODULUS_##size))
512 
513 #else /* 1 */
514 #define vsid_scramble(protovsid, size) \
515 	({								 \
516 		unsigned long x;					 \
517 		x = (protovsid) * VSID_MULTIPLIER_##size;		 \
518 		x = (x >> VSID_BITS_##size) + (x & VSID_MODULUS_##size); \
519 		(x + ((x+1) >> VSID_BITS_##size)) & VSID_MODULUS_##size; \
520 	})
521 #endif /* 1 */
522 
523 /* Returns the segment size indicator for a user address */
524 static inline int user_segment_size(unsigned long addr)
525 {
526 	/* Use 1T segments if possible for addresses >= 1T */
527 	if (addr >= (1UL << SID_SHIFT_1T))
528 		return mmu_highuser_ssize;
529 	return MMU_SEGSIZE_256M;
530 }
531 
532 static inline unsigned long get_vsid(unsigned long context, unsigned long ea,
533 				     int ssize)
534 {
535 	/*
536 	 * Bad address. We return VSID 0 for that
537 	 */
538 	if ((ea & ~REGION_MASK) >= H_PGTABLE_RANGE)
539 		return 0;
540 
541 	if (ssize == MMU_SEGSIZE_256M)
542 		return vsid_scramble((context << ESID_BITS)
543 				     | (ea >> SID_SHIFT), 256M);
544 	return vsid_scramble((context << ESID_BITS_1T)
545 			     | (ea >> SID_SHIFT_1T), 1T);
546 }
547 
548 /*
549  * This is only valid for addresses >= PAGE_OFFSET
550  *
551  * For kernel space, we use the top 4 context ids to map address as below
552  * 0x7fffc -  [ 0xc000000000000000 - 0xc0003fffffffffff ]
553  * 0x7fffd -  [ 0xd000000000000000 - 0xd0003fffffffffff ]
554  * 0x7fffe -  [ 0xe000000000000000 - 0xe0003fffffffffff ]
555  * 0x7ffff -  [ 0xf000000000000000 - 0xf0003fffffffffff ]
556  */
557 static inline unsigned long get_kernel_vsid(unsigned long ea, int ssize)
558 {
559 	unsigned long context;
560 
561 	/*
562 	 * kernel take the top 4 context from the available range
563 	 */
564 	context = (MAX_USER_CONTEXT) + ((ea >> 60) - 0xc) + 1;
565 	return get_vsid(context, ea, ssize);
566 }
567 
568 unsigned htab_shift_for_mem_size(unsigned long mem_size);
569 
570 #endif /* __ASSEMBLY__ */
571 
572 #endif /* _ASM_POWERPC_BOOK3S_64_MMU_HASH_H_ */
573