LXR linux/arch/sparc/include/asm/tsb.h

   1#ifndef _SPARC64_TSB_H
   2#define _SPARC64_TSB_H
   3
   4/* The sparc64 TSB is similar to the powerpc hashtables.  It's a
   5 * power-of-2 sized table of TAG/PTE pairs.  The cpu precomputes
   6 * pointers into this table for 8K and 64K page sizes, and also a
   7 * comparison TAG based upon the virtual address and context which
   8 * faults.
   9 *
  10 * TLB miss trap handler software does the actual lookup via something
  11 * of the form:
  12 *
  13 *      ldxa            [%g0] ASI_{D,I}MMU_TSB_8KB_PTR, %g1
  14 *      ldxa            [%g0] ASI_{D,I}MMU, %g6
  15 *      sllx            %g6, 22, %g6
  16 *      srlx            %g6, 22, %g6
  17 *      ldda            [%g1] ASI_NUCLEUS_QUAD_LDD, %g4
  18 *      cmp             %g4, %g6
  19 *      bne,pn  %xcc, tsb_miss_{d,i}tlb
  20 *       mov            FAULT_CODE_{D,I}TLB, %g3
  21 *      stxa            %g5, [%g0] ASI_{D,I}TLB_DATA_IN
  22 *      retry
  23 *
  24 *
  25 * Each 16-byte slot of the TSB is the 8-byte tag and then the 8-byte
  26 * PTE.  The TAG is of the same layout as the TLB TAG TARGET mmu
  27 * register which is:
  28 *
  29 * -------------------------------------------------
  30 * |  -  |  CONTEXT |  -  |    VADDR bits 63:22    |
  31 * -------------------------------------------------
  32 *  63 61 60      48 47 42 41                     0
  33 *
  34 * But actually, since we use per-mm TSB's, we zero out the CONTEXT
  35 * field.
  36 *
  37 * Like the powerpc hashtables we need to use locking in order to
  38 * synchronize while we update the entries.  PTE updates need locking
  39 * as well.
  40 *
  41 * We need to carefully choose a lock bits for the TSB entry.  We
  42 * choose to use bit 47 in the tag.  Also, since we never map anything
  43 * at page zero in context zero, we use zero as an invalid tag entry.
  44 * When the lock bit is set, this forces a tag comparison failure.
  45 */
  46
  47#define TSB_TAG_LOCK_BIT        47
  48#define TSB_TAG_LOCK_HIGH       (1 << (TSB_TAG_LOCK_BIT - 32))
  49
  50#define TSB_TAG_INVALID_BIT     46
  51#define TSB_TAG_INVALID_HIGH    (1 << (TSB_TAG_INVALID_BIT - 32))
  52
  53/* Some cpus support physical address quad loads.  We want to use
  54 * those if possible so we don't need to hard-lock the TSB mapping
  55 * into the TLB.  We encode some instruction patching in order to
  56 * support this.
  57 *
  58 * The kernel TSB is locked into the TLB by virtue of being in the
  59 * kernel image, so we don't play these games for swapper_tsb access.
  60 */
  61#ifndef __ASSEMBLY__
  62struct tsb_ldquad_phys_patch_entry {
  63        unsigned int    addr;
  64        unsigned int    sun4u_insn;
  65        unsigned int    sun4v_insn;
  66};
  67extern struct tsb_ldquad_phys_patch_entry __tsb_ldquad_phys_patch,
  68        __tsb_ldquad_phys_patch_end;
  69
  70struct tsb_phys_patch_entry {
  71        unsigned int    addr;
  72        unsigned int    insn;
  73};
  74extern struct tsb_phys_patch_entry __tsb_phys_patch, __tsb_phys_patch_end;
  75#endif
  76#define TSB_LOAD_QUAD(TSB, REG) \
  77661:    ldda            [TSB] ASI_NUCLEUS_QUAD_LDD, REG; \
  78        .section        .tsb_ldquad_phys_patch, "ax"; \
  79        .word           661b; \
  80        ldda            [TSB] ASI_QUAD_LDD_PHYS, REG; \
  81        ldda            [TSB] ASI_QUAD_LDD_PHYS_4V, REG; \
  82        .previous
  83
  84#define TSB_LOAD_TAG_HIGH(TSB, REG) \
  85661:    lduwa           [TSB] ASI_N, REG; \
  86        .section        .tsb_phys_patch, "ax"; \
  87        .word           661b; \
  88        lduwa           [TSB] ASI_PHYS_USE_EC, REG; \
  89        .previous
  90
  91#define TSB_LOAD_TAG(TSB, REG) \
  92661:    ldxa            [TSB] ASI_N, REG; \
  93        .section        .tsb_phys_patch, "ax"; \
  94        .word           661b; \
  95        ldxa            [TSB] ASI_PHYS_USE_EC, REG; \
  96        .previous
  97
  98#define TSB_CAS_TAG_HIGH(TSB, REG1, REG2) \
  99661:    casa            [TSB] ASI_N, REG1, REG2; \
 100        .section        .tsb_phys_patch, "ax"; \
 101        .word           661b; \
 102        casa            [TSB] ASI_PHYS_USE_EC, REG1, REG2; \
 103        .previous
 104
 105#define TSB_CAS_TAG(TSB, REG1, REG2) \
 106661:    casxa           [TSB] ASI_N, REG1, REG2; \
 107        .section        .tsb_phys_patch, "ax"; \
 108        .word           661b; \
 109        casxa           [TSB] ASI_PHYS_USE_EC, REG1, REG2; \
 110        .previous
 111
 112#define TSB_STORE(ADDR, VAL) \
 113661:    stxa            VAL, [ADDR] ASI_N; \
 114        .section        .tsb_phys_patch, "ax"; \
 115        .word           661b; \
 116        stxa            VAL, [ADDR] ASI_PHYS_USE_EC; \
 117        .previous
 118
 119#define TSB_LOCK_TAG(TSB, REG1, REG2)   \
 12099:     TSB_LOAD_TAG_HIGH(TSB, REG1);   \
 121        sethi   %hi(TSB_TAG_LOCK_HIGH), REG2;\
 122        andcc   REG1, REG2, %g0;        \
 123        bne,pn  %icc, 99b;              \
 124         nop;                           \
 125        TSB_CAS_TAG_HIGH(TSB, REG1, REG2);      \
 126        cmp     REG1, REG2;             \
 127        bne,pn  %icc, 99b;              \
 128         nop;                           \
 129
 130#define TSB_WRITE(TSB, TTE, TAG) \
 131        add     TSB, 0x8, TSB;   \
 132        TSB_STORE(TSB, TTE);     \
 133        sub     TSB, 0x8, TSB;   \
 134        TSB_STORE(TSB, TAG);
 135
 136        /* Do a kernel page table walk.  Leaves physical PTE pointer in
 137         * REG1.  Jumps to FAIL_LABEL on early page table walk termination.
 138         * VADDR will not be clobbered, but REG2 will.
 139         */
 140#define KERN_PGTABLE_WALK(VADDR, REG1, REG2, FAIL_LABEL)        \
 141        sethi           %hi(swapper_pg_dir), REG1; \
 142        or              REG1, %lo(swapper_pg_dir), REG1; \
 143        sllx            VADDR, 64 - (PGDIR_SHIFT + PGDIR_BITS), REG2; \
 144        srlx            REG2, 64 - PAGE_SHIFT, REG2; \
 145        andn            REG2, 0x7, REG2; \
 146        ldx             [REG1 + REG2], REG1; \
 147        brz,pn          REG1, FAIL_LABEL; \
 148         sllx           VADDR, 64 - (PMD_SHIFT + PMD_BITS), REG2; \
 149        srlx            REG2, 64 - PAGE_SHIFT, REG2; \
 150        andn            REG2, 0x7, REG2; \
 151        ldxa            [REG1 + REG2] ASI_PHYS_USE_EC, REG1; \
 152        brz,pn          REG1, FAIL_LABEL; \
 153         sllx           VADDR, 64 - PMD_SHIFT, REG2; \
 154        srlx            REG2, 64 - PAGE_SHIFT, REG2; \
 155        andn            REG2, 0x7, REG2; \
 156        add             REG1, REG2, REG1;
 157
 158        /* PMD has been loaded into REG1, interpret the value, seeing
 159         * if it is a HUGE PMD or a normal one.  If it is not valid
 160         * then jump to FAIL_LABEL.  If it is a HUGE PMD, and it
 161         * translates to a valid PTE, branch to PTE_LABEL.
 162         *
 163         * We have to propagate the 4MB bit of the virtual address
 164         * because we are fabricating 8MB pages using 4MB hw pages.
 165         */
 166#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 167#define USER_PGTABLE_CHECK_PMD_HUGE(VADDR, REG1, REG2, FAIL_LABEL, PTE_LABEL) \
 168        brz,pn          REG1, FAIL_LABEL;               \
 169         sethi          %uhi(_PAGE_PMD_HUGE), REG2;     \
 170        sllx            REG2, 32, REG2;                 \
 171        andcc           REG1, REG2, %g0;                \
 172        be,pt           %xcc, 700f;                     \
 173         sethi          %hi(4 * 1024 * 1024), REG2;     \
 174        brgez,pn        REG1, FAIL_LABEL;               \
 175         andn           REG1, REG2, REG1;               \
 176        and             VADDR, REG2, REG2;              \
 177        brlz,pt         REG1, PTE_LABEL;                \
 178         or             REG1, REG2, REG1;               \
 179700:
 180#else
 181#define USER_PGTABLE_CHECK_PMD_HUGE(VADDR, REG1, REG2, FAIL_LABEL, PTE_LABEL) \
 182        brz,pn          REG1, FAIL_LABEL; \
 183         nop;
 184#endif
 185
 186        /* Do a user page table walk in MMU globals.  Leaves final,
 187         * valid, PTE value in REG1.  Jumps to FAIL_LABEL on early
 188         * page table walk termination or if the PTE is not valid.
 189         *
 190         * Physical base of page tables is in PHYS_PGD which will not
 191         * be modified.
 192         *
 193         * VADDR will not be clobbered, but REG1 and REG2 will.
 194         */
 195#define USER_PGTABLE_WALK_TL1(VADDR, PHYS_PGD, REG1, REG2, FAIL_LABEL)  \
 196        sllx            VADDR, 64 - (PGDIR_SHIFT + PGDIR_BITS), REG2; \
 197        srlx            REG2, 64 - PAGE_SHIFT, REG2; \
 198        andn            REG2, 0x7, REG2; \
 199        ldxa            [PHYS_PGD + REG2] ASI_PHYS_USE_EC, REG1; \
 200        brz,pn          REG1, FAIL_LABEL; \
 201         sllx           VADDR, 64 - (PMD_SHIFT + PMD_BITS), REG2; \
 202        srlx            REG2, 64 - PAGE_SHIFT, REG2; \
 203        andn            REG2, 0x7, REG2; \
 204        ldxa            [REG1 + REG2] ASI_PHYS_USE_EC, REG1; \
 205        USER_PGTABLE_CHECK_PMD_HUGE(VADDR, REG1, REG2, FAIL_LABEL, 800f) \
 206        sllx            VADDR, 64 - PMD_SHIFT, REG2; \
 207        srlx            REG2, 64 - PAGE_SHIFT, REG2; \
 208        andn            REG2, 0x7, REG2; \
 209        add             REG1, REG2, REG1; \
 210        ldxa            [REG1] ASI_PHYS_USE_EC, REG1; \
 211        brgez,pn        REG1, FAIL_LABEL; \
 212         nop; \
 213800:
 214
 215/* Lookup a OBP mapping on VADDR in the prom_trans[] table at TL>0.
 216 * If no entry is found, FAIL_LABEL will be branched to.  On success
 217 * the resulting PTE value will be left in REG1.  VADDR is preserved
 218 * by this routine.
 219 */
 220#define OBP_TRANS_LOOKUP(VADDR, REG1, REG2, REG3, FAIL_LABEL) \
 221        sethi           %hi(prom_trans), REG1; \
 222        or              REG1, %lo(prom_trans), REG1; \
 22397:     ldx             [REG1 + 0x00], REG2; \
 224        brz,pn          REG2, FAIL_LABEL; \
 225         nop; \
 226        ldx             [REG1 + 0x08], REG3; \
 227        add             REG2, REG3, REG3; \
 228        cmp             REG2, VADDR; \
 229        bgu,pt          %xcc, 98f; \
 230         cmp            VADDR, REG3; \
 231        bgeu,pt         %xcc, 98f; \
 232         ldx            [REG1 + 0x10], REG3; \
 233        sub             VADDR, REG2, REG2; \
 234        ba,pt           %xcc, 99f; \
 235         add            REG3, REG2, REG1; \
 23698:     ba,pt           %xcc, 97b; \
 237         add            REG1, (3 * 8), REG1; \
 23899:
 239
 240        /* We use a 32K TSB for the whole kernel, this allows to
 241         * handle about 16MB of modules and vmalloc mappings without
 242         * incurring many hash conflicts.
 243         */
 244#define KERNEL_TSB_SIZE_BYTES   (32 * 1024)
 245#define KERNEL_TSB_NENTRIES     \
 246        (KERNEL_TSB_SIZE_BYTES / 16)
 247#define KERNEL_TSB4M_NENTRIES   4096
 248
 249#define KTSB_PHYS_SHIFT         15
 250
 251        /* Do a kernel TSB lookup at tl>0 on VADDR+TAG, branch to OK_LABEL
 252         * on TSB hit.  REG1, REG2, REG3, and REG4 are used as temporaries
 253         * and the found TTE will be left in REG1.  REG3 and REG4 must
 254         * be an even/odd pair of registers.
 255         *
 256         * VADDR and TAG will be preserved and not clobbered by this macro.
 257         */
 258#define KERN_TSB_LOOKUP_TL1(VADDR, TAG, REG1, REG2, REG3, REG4, OK_LABEL) \
 259661:    sethi           %hi(swapper_tsb), REG1;                 \
 260        or              REG1, %lo(swapper_tsb), REG1; \
 261        .section        .swapper_tsb_phys_patch, "ax"; \
 262        .word           661b; \
 263        .previous; \
 264661:    nop; \
 265        .section        .tsb_ldquad_phys_patch, "ax"; \
 266        .word           661b; \
 267        sllx            REG1, KTSB_PHYS_SHIFT, REG1; \
 268        sllx            REG1, KTSB_PHYS_SHIFT, REG1; \
 269        .previous; \
 270        srlx            VADDR, PAGE_SHIFT, REG2; \
 271        and             REG2, (KERNEL_TSB_NENTRIES - 1), REG2; \
 272        sllx            REG2, 4, REG2; \
 273        add             REG1, REG2, REG2; \
 274        TSB_LOAD_QUAD(REG2, REG3); \
 275        cmp             REG3, TAG; \
 276        be,a,pt         %xcc, OK_LABEL; \
 277         mov            REG4, REG1;
 278
 279#ifndef CONFIG_DEBUG_PAGEALLOC
 280        /* This version uses a trick, the TAG is already (VADDR >> 22) so
 281         * we can make use of that for the index computation.
 282         */
 283#define KERN_TSB4M_LOOKUP_TL1(TAG, REG1, REG2, REG3, REG4, OK_LABEL) \
 284661:    sethi           %hi(swapper_4m_tsb), REG1;           \
 285        or              REG1, %lo(swapper_4m_tsb), REG1; \
 286        .section        .swapper_4m_tsb_phys_patch, "ax"; \
 287        .word           661b; \
 288        .previous; \
 289661:    nop; \
 290        .section        .tsb_ldquad_phys_patch, "ax"; \
 291        .word           661b; \
 292        sllx            REG1, KTSB_PHYS_SHIFT, REG1; \
 293        sllx            REG1, KTSB_PHYS_SHIFT, REG1; \
 294        .previous; \
 295        and             TAG, (KERNEL_TSB4M_NENTRIES - 1), REG2; \
 296        sllx            REG2, 4, REG2; \
 297        add             REG1, REG2, REG2; \
 298        TSB_LOAD_QUAD(REG2, REG3); \
 299        cmp             REG3, TAG; \
 300        be,a,pt         %xcc, OK_LABEL; \
 301         mov            REG4, REG1;
 302#endif
 303
 304#endif /* !(_SPARC64_TSB_H) */
 305