arch/powerpc/platforms/iseries/htab.c

   1 /*
   2  * iSeries hashtable management.
   3  *      Derived from pSeries_htab.c
   4  *
   5  * SMP scalability work:
   6  *    Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; either version
  11  * 2 of the License, or (at your option) any later version.
  12  */
  13 #include <asm/machdep.h>
  14 #include <asm/pgtable.h>
  15 #include <asm/mmu.h>
  16 #include <asm/mmu_context.h>
  17 #include <asm/abs_addr.h>
  18 #include <linux/spinlock.h>
  19
  20 #include "call_hpt.h"
  21
  22 static spinlock_t iSeries_hlocks[64] __cacheline_aligned_in_smp =
  23         { [0 ... 63] = SPIN_LOCK_UNLOCKED};
  24
  25 /*
  26  * Very primitive algorithm for picking up a lock
  27  */
  28 static inline void iSeries_hlock(unsigned long slot)
  29 {
  30         if (slot & 0x8)
  31                 slot = ~slot;
  32         spin_lock(&iSeries_hlocks[(slot >> 4) & 0x3f]);
  33 }
  34
  35 static inline void iSeries_hunlock(unsigned long slot)
  36 {
  37         if (slot & 0x8)
  38                 slot = ~slot;
  39         spin_unlock(&iSeries_hlocks[(slot >> 4) & 0x3f]);
  40 }
  41
  42 static long iSeries_hpte_insert(unsigned long hpte_group, unsigned long va,
  43                          unsigned long pa, unsigned long rflags,
  44                          unsigned long vflags, int psize, int ssize)
  45 {
  46         long slot;
  47         struct hash_pte lhpte;
  48         int secondary = 0;
  49
  50         BUG_ON(psize != MMU_PAGE_4K);
  51
  52         /*
  53          * The hypervisor tries both primary and secondary.
  54          * If we are being called to insert in the secondary,
  55          * it means we have already tried both primary and secondary,
  56          * so we return failure immediately.
  57          */
  58         if (vflags & HPTE_V_SECONDARY)
  59                 return -1;
  60
  61         iSeries_hlock(hpte_group);
  62
  63         slot = HvCallHpt_findValid(&lhpte, va >> HW_PAGE_SHIFT);
  64         if (unlikely(lhpte.v & HPTE_V_VALID)) {
  65                 if (vflags & HPTE_V_BOLTED) {
  66                         HvCallHpt_setSwBits(slot, 0x10, 0);
  67                         HvCallHpt_setPp(slot, PP_RWXX);
  68                         iSeries_hunlock(hpte_group);
  69                         if (slot < 0)
  70                                 return 0x8 | (slot & 7);
  71                         else
  72                                 return slot & 7;
  73                 }
  74                 BUG();
  75         }
  76
  77         if (slot == -1) { /* No available entry found in either group */
  78                 iSeries_hunlock(hpte_group);
  79                 return -1;
  80         }
  81
  82         if (slot < 0) {         /* MSB set means secondary group */
  83                 vflags |= HPTE_V_SECONDARY;
  84                 secondary = 1;
  85                 slot &= 0x7fffffffffffffff;
  86         }
  87
  88
  89         lhpte.v = hpte_encode_v(va, MMU_PAGE_4K, MMU_SEGSIZE_256M) |
  90                 vflags | HPTE_V_VALID;
  91         lhpte.r = hpte_encode_r(phys_to_abs(pa), MMU_PAGE_4K) | rflags;
  92
  93         /* Now fill in the actual HPTE */
  94         HvCallHpt_addValidate(slot, secondary, &lhpte);
  95
  96         iSeries_hunlock(hpte_group);
  97
  98         return (secondary << 3) | (slot & 7);
  99 }
 100
 101 static unsigned long iSeries_hpte_getword0(unsigned long slot)
 102 {
 103         struct hash_pte hpte;
 104
 105         HvCallHpt_get(&hpte, slot);
 106         return hpte.v;
 107 }
 108
 109 static long iSeries_hpte_remove(unsigned long hpte_group)
 110 {
 111         unsigned long slot_offset;
 112         int i;
 113         unsigned long hpte_v;
 114
 115         /* Pick a random slot to start at */
 116         slot_offset = mftb() & 0x7;
 117
 118         iSeries_hlock(hpte_group);
 119
 120         for (i = 0; i < HPTES_PER_GROUP; i++) {
 121                 hpte_v = iSeries_hpte_getword0(hpte_group + slot_offset);
 122
 123                 if (! (hpte_v & HPTE_V_BOLTED)) {
 124                         HvCallHpt_invalidateSetSwBitsGet(hpte_group +
 125                                                          slot_offset, 0, 0);
 126                         iSeries_hunlock(hpte_group);
 127                         return i;
 128                 }
 129
 130                 slot_offset++;
 131                 slot_offset &= 0x7;
 132         }
 133
 134         iSeries_hunlock(hpte_group);
 135
 136         return -1;
 137 }
 138
 139 /*
 140  * The HyperVisor expects the "flags" argument in this form:
 141  *      bits  0..59 : reserved
 142  *      bit      60 : N
 143  *      bits 61..63 : PP2,PP1,PP0
 144  */
 145 static long iSeries_hpte_updatepp(unsigned long slot, unsigned long newpp,
 146                         unsigned long va, int psize, int ssize, int local)
 147 {
 148         struct hash_pte hpte;
 149         unsigned long want_v;
 150
 151         iSeries_hlock(slot);
 152
 153         HvCallHpt_get(&hpte, slot);
 154         want_v = hpte_encode_v(va, MMU_PAGE_4K, MMU_SEGSIZE_256M);
 155
 156         if (HPTE_V_COMPARE(hpte.v, want_v) && (hpte.v & HPTE_V_VALID)) {
 157                 /*
 158                  * Hypervisor expects bits as NPPP, which is
 159                  * different from how they are mapped in our PP.
 160                  */
 161                 HvCallHpt_setPp(slot, (newpp & 0x3) | ((newpp & 0x4) << 1));
 162                 iSeries_hunlock(slot);
 163                 return 0;
 164         }
 165         iSeries_hunlock(slot);
 166
 167         return -1;
 168 }
 169
 170 /*
 171  * Functions used to find the PTE for a particular virtual address.
 172  * Only used during boot when bolting pages.
 173  *
 174  * Input : vpn      : virtual page number
 175  * Output: PTE index within the page table of the entry
 176  *         -1 on failure
 177  */
 178 static long iSeries_hpte_find(unsigned long vpn)
 179 {
 180         struct hash_pte hpte;
 181         long slot;
 182
 183         /*
 184          * The HvCallHpt_findValid interface is as follows:
 185          * 0xffffffffffffffff : No entry found.
 186          * 0x00000000xxxxxxxx : Entry found in primary group, slot x
 187          * 0x80000000xxxxxxxx : Entry found in secondary group, slot x
 188          */
 189         slot = HvCallHpt_findValid(&hpte, vpn);
 190         if (hpte.v & HPTE_V_VALID) {
 191                 if (slot < 0) {
 192                         slot &= 0x7fffffffffffffff;
 193                         slot = -slot;
 194                 }
 195         } else
 196                 slot = -1;
 197         return slot;
 198 }
 199
 200 /*
 201  * Update the page protection bits. Intended to be used to create
 202  * guard pages for kernel data structures on pages which are bolted
 203  * in the HPT. Assumes pages being operated on will not be stolen.
 204  * Does not work on large pages.
 205  *
 206  * No need to lock here because we should be the only user.
 207  */
 208 static void iSeries_hpte_updateboltedpp(unsigned long newpp, unsigned long ea,
 209                                         int psize, int ssize)
 210 {
 211         unsigned long vsid,va,vpn;
 212         long slot;
 213
 214         BUG_ON(psize != MMU_PAGE_4K);
 215
 216         vsid = get_kernel_vsid(ea, MMU_SEGSIZE_256M);
 217         va = (vsid << 28) | (ea & 0x0fffffff);
 218         vpn = va >> HW_PAGE_SHIFT;
 219         slot = iSeries_hpte_find(vpn);
 220         if (slot == -1)
 221                 panic("updateboltedpp: Could not find page to bolt\n");
 222         HvCallHpt_setPp(slot, newpp);
 223 }
 224
 225 static void iSeries_hpte_invalidate(unsigned long slot, unsigned long va,
 226                                     int psize, int ssize, int local)
 227 {
 228         unsigned long hpte_v;
 229         unsigned long avpn = va >> 23;
 230         unsigned long flags;
 231
 232         local_irq_save(flags);
 233
 234         iSeries_hlock(slot);
 235
 236         hpte_v = iSeries_hpte_getword0(slot);
 237
 238         if ((HPTE_V_AVPN_VAL(hpte_v) == avpn) && (hpte_v & HPTE_V_VALID))
 239                 HvCallHpt_invalidateSetSwBitsGet(slot, 0, 0);
 240
 241         iSeries_hunlock(slot);
 242
 243         local_irq_restore(flags);
 244 }
 245
 246 void __init hpte_init_iSeries(void)
 247 {
 248         ppc_md.hpte_invalidate  = iSeries_hpte_invalidate;
 249         ppc_md.hpte_updatepp    = iSeries_hpte_updatepp;
 250         ppc_md.hpte_updateboltedpp = iSeries_hpte_updateboltedpp;
 251         ppc_md.hpte_insert      = iSeries_hpte_insert;
 252         ppc_md.hpte_remove      = iSeries_hpte_remove;
 253 }