include/asm-ppc64/mmu.h

   1 /*
   2  * PowerPC memory management structures
   3  *
   4  * Dave Engebretsen & Mike Corrigan <{engebret|mikejc}@us.ibm.com>
   5  *   PPC64 rework.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the License, or (at your option) any later version.
  11  */
  12
  13 #ifndef _PPC64_MMU_H_
  14 #define _PPC64_MMU_H_
  15
  16 #include <linux/config.h>
  17 #include <asm/ppc_asm.h> /* for ASM_CONST */
  18 #include <asm/page.h>
  19
  20 /*
  21  * Segment table
  22  */
  23
  24 #define STE_ESID_V      0x80
  25 #define STE_ESID_KS     0x20
  26 #define STE_ESID_KP     0x10
  27 #define STE_ESID_N      0x08
  28
  29 #define STE_VSID_SHIFT  12
  30
  31 /* Location of cpu0's segment table */
  32 #define STAB0_PAGE      0x6
  33 #define STAB0_PHYS_ADDR (STAB0_PAGE<<12)
  34
  35 #ifndef __ASSEMBLY__
  36 extern char initial_stab[];
  37 #endif /* ! __ASSEMBLY */
  38
  39 /*
  40  * SLB
  41  */
  42
  43 #define SLB_NUM_BOLTED          3
  44 #define SLB_CACHE_ENTRIES       8
  45
  46 /* Bits in the SLB ESID word */
  47 #define SLB_ESID_V              ASM_CONST(0x0000000008000000) /* valid */
  48
  49 /* Bits in the SLB VSID word */
  50 #define SLB_VSID_SHIFT          12
  51 #define SLB_VSID_B              ASM_CONST(0xc000000000000000)
  52 #define SLB_VSID_B_256M         ASM_CONST(0x0000000000000000)
  53 #define SLB_VSID_B_1T           ASM_CONST(0x4000000000000000)
  54 #define SLB_VSID_KS             ASM_CONST(0x0000000000000800)
  55 #define SLB_VSID_KP             ASM_CONST(0x0000000000000400)
  56 #define SLB_VSID_N              ASM_CONST(0x0000000000000200) /* no-execute */
  57 #define SLB_VSID_L              ASM_CONST(0x0000000000000100)
  58 #define SLB_VSID_C              ASM_CONST(0x0000000000000080) /* class */
  59 #define SLB_VSID_LP             ASM_CONST(0x0000000000000030)
  60 #define SLB_VSID_LP_00          ASM_CONST(0x0000000000000000)
  61 #define SLB_VSID_LP_01          ASM_CONST(0x0000000000000010)
  62 #define SLB_VSID_LP_10          ASM_CONST(0x0000000000000020)
  63 #define SLB_VSID_LP_11          ASM_CONST(0x0000000000000030)
  64 #define SLB_VSID_LLP            (SLB_VSID_L|SLB_VSID_LP)
  65
  66 #define SLB_VSID_KERNEL         (SLB_VSID_KP)
  67 #define SLB_VSID_USER           (SLB_VSID_KP|SLB_VSID_KS|SLB_VSID_C)
  68
  69 #define SLBIE_C                 (0x08000000)
  70
  71 /*
  72  * Hash table
  73  */
  74
  75 #define HPTES_PER_GROUP 8
  76
  77 #define HPTE_V_AVPN_SHIFT       7
  78 #define HPTE_V_AVPN             ASM_CONST(0xffffffffffffff80)
  79 #define HPTE_V_AVPN_VAL(x)      (((x) & HPTE_V_AVPN) >> HPTE_V_AVPN_SHIFT)
  80 #define HPTE_V_COMPARE(x,y)     (!(((x) ^ (y)) & HPTE_V_AVPN))
  81 #define HPTE_V_BOLTED           ASM_CONST(0x0000000000000010)
  82 #define HPTE_V_LOCK             ASM_CONST(0x0000000000000008)
  83 #define HPTE_V_LARGE            ASM_CONST(0x0000000000000004)
  84 #define HPTE_V_SECONDARY        ASM_CONST(0x0000000000000002)
  85 #define HPTE_V_VALID            ASM_CONST(0x0000000000000001)
  86
  87 #define HPTE_R_PP0              ASM_CONST(0x8000000000000000)
  88 #define HPTE_R_TS               ASM_CONST(0x4000000000000000)
  89 #define HPTE_R_RPN_SHIFT        12
  90 #define HPTE_R_RPN              ASM_CONST(0x3ffffffffffff000)
  91 #define HPTE_R_FLAGS            ASM_CONST(0x00000000000003ff)
  92 #define HPTE_R_PP               ASM_CONST(0x0000000000000003)
  93 #define HPTE_R_N                ASM_CONST(0x0000000000000004)
  94
  95 /* Values for PP (assumes Ks=0, Kp=1) */
  96 /* pp0 will always be 0 for linux     */
  97 #define PP_RWXX 0       /* Supervisor read/write, User none */
  98 #define PP_RWRX 1       /* Supervisor read/write, User read */
  99 #define PP_RWRW 2       /* Supervisor read/write, User read/write */
 100 #define PP_RXRX 3       /* Supervisor read,       User read */
 101
 102 #ifndef __ASSEMBLY__
 103
 104 typedef struct {
 105         unsigned long v;
 106         unsigned long r;
 107 } hpte_t;
 108
 109 extern hpte_t *htab_address;
 110 extern unsigned long htab_hash_mask;
 111
 112 /*
 113  * Page size definition
 114  *
 115  *    shift : is the "PAGE_SHIFT" value for that page size
 116  *    sllp  : is a bit mask with the value of SLB L || LP to be or'ed
 117  *            directly to a slbmte "vsid" value
 118  *    penc  : is the HPTE encoding mask for the "LP" field:
 119  *
 120  */
 121 struct mmu_psize_def
 122 {
 123         unsigned int    shift;  /* number of bits */
 124         unsigned int    penc;   /* HPTE encoding */
 125         unsigned int    tlbiel; /* tlbiel supported for that page size */
 126         unsigned long   avpnm;  /* bits to mask out in AVPN in the HPTE */
 127         unsigned long   sllp;   /* SLB L||LP (exact mask to use in slbmte) */
 128 };
 129
 130 #endif /* __ASSEMBLY__ */
 131
 132 /*
 133  * The kernel use the constants below to index in the page sizes array.
 134  * The use of fixed constants for this purpose is better for performances
 135  * of the low level hash refill handlers.
 136  *
 137  * A non supported page size has a "shift" field set to 0
 138  *
 139  * Any new page size being implemented can get a new entry in here. Whether
 140  * the kernel will use it or not is a different matter though. The actual page
 141  * size used by hugetlbfs is not defined here and may be made variable
 142  */
 143
 144 #define MMU_PAGE_4K             0       /* 4K */
 145 #define MMU_PAGE_64K            1       /* 64K */
 146 #define MMU_PAGE_64K_AP         2       /* 64K Admixed (in a 4K segment) */
 147 #define MMU_PAGE_1M             3       /* 1M */
 148 #define MMU_PAGE_16M            4       /* 16M */
 149 #define MMU_PAGE_16G            5       /* 16G */
 150 #define MMU_PAGE_COUNT          6
 151
 152 #ifndef __ASSEMBLY__
 153
 154 /*
 155  * The current system page sizes
 156  */
 157 extern struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT];
 158 extern int mmu_linear_psize;
 159 extern int mmu_virtual_psize;
 160
 161 #ifdef CONFIG_HUGETLB_PAGE
 162 /*
 163  * The page size index of the huge pages for use by hugetlbfs
 164  */
 165 extern int mmu_huge_psize;
 166
 167 #endif /* CONFIG_HUGETLB_PAGE */
 168
 169 /*
 170  * This function sets the AVPN and L fields of the HPTE  appropriately
 171  * for the page size
 172  */
 173 static inline unsigned long hpte_encode_v(unsigned long va, int psize)
 174 {
 175         unsigned long v =
 176         v = (va >> 23) & ~(mmu_psize_defs[psize].avpnm);
 177         v <<= HPTE_V_AVPN_SHIFT;
 178         if (psize != MMU_PAGE_4K)
 179                 v |= HPTE_V_LARGE;
 180         return v;
 181 }
 182
 183 /*
 184  * This function sets the ARPN, and LP fields of the HPTE appropriately
 185  * for the page size. We assume the pa is already "clean" that is properly
 186  * aligned for the requested page size
 187  */
 188 static inline unsigned long hpte_encode_r(unsigned long pa, int psize)
 189 {
 190         unsigned long r;
 191
 192         /* A 4K page needs no special encoding */
 193         if (psize == MMU_PAGE_4K)
 194                 return pa & HPTE_R_RPN;
 195         else {
 196                 unsigned int penc = mmu_psize_defs[psize].penc;
 197                 unsigned int shift = mmu_psize_defs[psize].shift;
 198                 return (pa & ~((1ul << shift) - 1)) | (penc << 12);
 199         }
 200         return r;
 201 }
 202
 203 /*
 204  * This hashes a virtual address for a 256Mb segment only for now
 205  */
 206
 207 static inline unsigned long hpt_hash(unsigned long va, unsigned int shift)
 208 {
 209         return ((va >> 28) & 0x7fffffffffUL) ^ ((va & 0x0fffffffUL) >> shift);
 210 }
 211
 212 extern int __hash_page_4K(unsigned long ea, unsigned long access,
 213                           unsigned long vsid, pte_t *ptep, unsigned long trap,
 214                           unsigned int local);
 215 extern int __hash_page_64K(unsigned long ea, unsigned long access,
 216                            unsigned long vsid, pte_t *ptep, unsigned long trap,
 217                            unsigned int local);
 218 struct mm_struct;
 219 extern int hash_huge_page(struct mm_struct *mm, unsigned long access,
 220                           unsigned long ea, unsigned long vsid, int local);
 221
 222 extern void htab_finish_init(void);
 223 extern int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
 224                              unsigned long pstart, unsigned long mode,
 225                              int psize);
 226
 227 extern void hpte_init_native(void);
 228 extern void hpte_init_lpar(void);
 229 extern void hpte_init_iSeries(void);
 230
 231 extern long pSeries_lpar_hpte_insert(unsigned long hpte_group,
 232                                      unsigned long va, unsigned long prpn,
 233                                      unsigned long rflags,
 234                                      unsigned long vflags, int psize);
 235
 236 extern long native_hpte_insert(unsigned long hpte_group,
 237                                unsigned long va, unsigned long prpn,
 238                                unsigned long rflags,
 239                                unsigned long vflags, int psize);
 240
 241 extern long iSeries_hpte_insert(unsigned long hpte_group,
 242                                 unsigned long va, unsigned long prpn,
 243                                 unsigned long rflags,
 244                                 unsigned long vflags, int psize);
 245
 246 extern void stabs_alloc(void);
 247 extern void slb_initialize(void);
 248
 249 #endif /* __ASSEMBLY__ */
 250
 251 /*
 252  * VSID allocation
 253  *
 254  * We first generate a 36-bit "proto-VSID".  For kernel addresses this
 255  * is equal to the ESID, for user addresses it is:
 256  *      (context << 15) | (esid & 0x7fff)
 257  *
 258  * The two forms are distinguishable because the top bit is 0 for user
 259  * addresses, whereas the top two bits are 1 for kernel addresses.
 260  * Proto-VSIDs with the top two bits equal to 0b10 are reserved for
 261  * now.
 262  *
 263  * The proto-VSIDs are then scrambled into real VSIDs with the
 264  * multiplicative hash:
 265  *
 266  *      VSID = (proto-VSID * VSID_MULTIPLIER) % VSID_MODULUS
 267  *      where   VSID_MULTIPLIER = 268435399 = 0xFFFFFC7
 268  *              VSID_MODULUS = 2^36-1 = 0xFFFFFFFFF
 269  *
 270  * This scramble is only well defined for proto-VSIDs below
 271  * 0xFFFFFFFFF, so both proto-VSID and actual VSID 0xFFFFFFFFF are
 272  * reserved.  VSID_MULTIPLIER is prime, so in particular it is
 273  * co-prime to VSID_MODULUS, making this a 1:1 scrambling function.
 274  * Because the modulus is 2^n-1 we can compute it efficiently without
 275  * a divide or extra multiply (see below).
 276  *
 277  * This scheme has several advantages over older methods:
 278  *
 279  *      - We have VSIDs allocated for every kernel address
 280  * (i.e. everything above 0xC000000000000000), except the very top
 281  * segment, which simplifies several things.
 282  *
 283  *      - We allow for 15 significant bits of ESID and 20 bits of
 284  * context for user addresses.  i.e. 8T (43 bits) of address space for
 285  * up to 1M contexts (although the page table structure and context
 286  * allocation will need changes to take advantage of this).
 287  *
 288  *      - The scramble function gives robust scattering in the hash
 289  * table (at least based on some initial results).  The previous
 290  * method was more susceptible to pathological cases giving excessive
 291  * hash collisions.
 292  */
 293 /*
 294  * WARNING - If you change these you must make sure the asm
 295  * implementations in slb_allocate (slb_low.S), do_stab_bolted
 296  * (head.S) and ASM_VSID_SCRAMBLE (below) are changed accordingly.
 297  *
 298  * You'll also need to change the precomputed VSID values in head.S
 299  * which are used by the iSeries firmware.
 300  */
 301
 302 #define VSID_MULTIPLIER ASM_CONST(200730139)    /* 28-bit prime */
 303 #define VSID_BITS       36
 304 #define VSID_MODULUS    ((1UL<<VSID_BITS)-1)
 305
 306 #define CONTEXT_BITS    19
 307 #define USER_ESID_BITS  16
 308
 309 #define USER_VSID_RANGE (1UL << (USER_ESID_BITS + SID_SHIFT))
 310
 311 /*
 312  * This macro generates asm code to compute the VSID scramble
 313  * function.  Used in slb_allocate() and do_stab_bolted.  The function
 314  * computed is: (protovsid*VSID_MULTIPLIER) % VSID_MODULUS
 315  *
 316  *      rt = register continaing the proto-VSID and into which the
 317  *              VSID will be stored
 318  *      rx = scratch register (clobbered)
 319  *
 320  *      - rt and rx must be different registers
 321  *      - The answer will end up in the low 36 bits of rt.  The higher
 322  *        bits may contain other garbage, so you may need to mask the
 323  *        result.
 324  */
 325 #define ASM_VSID_SCRAMBLE(rt, rx)       \
 326         lis     rx,VSID_MULTIPLIER@h;                                   \
 327         ori     rx,rx,VSID_MULTIPLIER@l;                                \
 328         mulld   rt,rt,rx;               /* rt = rt * MULTIPLIER */      \
 329                                                                         \
 330         srdi    rx,rt,VSID_BITS;                                        \
 331         clrldi  rt,rt,(64-VSID_BITS);                                   \
 332         add     rt,rt,rx;               /* add high and low bits */     \
 333         /* Now, r3 == VSID (mod 2^36-1), and lies between 0 and         \
 334          * 2^36-1+2^28-1.  That in particular means that if r3 >=       \
 335          * 2^36-1, then r3+1 has the 2^36 bit set.  So, if r3+1 has     \
 336          * the bit clear, r3 already has the answer we want, if it      \
 337          * doesn't, the answer is the low 36 bits of r3+1.  So in all   \
 338          * cases the answer is the low 36 bits of (r3 + ((r3+1) >> 36))*/\
 339         addi    rx,rt,1;                                                \
 340         srdi    rx,rx,VSID_BITS;        /* extract 2^36 bit */          \
 341         add     rt,rt,rx
 342
 343
 344 #ifndef __ASSEMBLY__
 345
 346 typedef unsigned long mm_context_id_t;
 347
 348 typedef struct {
 349         mm_context_id_t id;
 350 #ifdef CONFIG_HUGETLB_PAGE
 351         u16 low_htlb_areas, high_htlb_areas;
 352 #endif
 353 } mm_context_t;
 354
 355
 356 static inline unsigned long vsid_scramble(unsigned long protovsid)
 357 {
 358 #if 0
 359         /* The code below is equivalent to this function for arguments
 360          * < 2^VSID_BITS, which is all this should ever be called
 361          * with.  However gcc is not clever enough to compute the
 362          * modulus (2^n-1) without a second multiply. */
 363         return ((protovsid * VSID_MULTIPLIER) % VSID_MODULUS);
 364 #else /* 1 */
 365         unsigned long x;
 366
 367         x = protovsid * VSID_MULTIPLIER;
 368         x = (x >> VSID_BITS) + (x & VSID_MODULUS);
 369         return (x + ((x+1) >> VSID_BITS)) & VSID_MODULUS;
 370 #endif /* 1 */
 371 }
 372
 373 /* This is only valid for addresses >= KERNELBASE */
 374 static inline unsigned long get_kernel_vsid(unsigned long ea)
 375 {
 376         return vsid_scramble(ea >> SID_SHIFT);
 377 }
 378
 379 /* This is only valid for user addresses (which are below 2^41) */
 380 static inline unsigned long get_vsid(unsigned long context, unsigned long ea)
 381 {
 382         return vsid_scramble((context << USER_ESID_BITS)
 383                              | (ea >> SID_SHIFT));
 384 }
 385
 386 #define VSID_SCRAMBLE(pvsid)    (((pvsid) * VSID_MULTIPLIER) % VSID_MODULUS)
 387 #define KERNEL_VSID(ea)         VSID_SCRAMBLE(GET_ESID(ea))
 388
 389 #endif /* __ASSEMBLY */
 390
 391 #endif /* _PPC64_MMU_H_ */