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
  24 /*
  25  * Very primitive algorithm for picking up a lock
  26  */
  27 static inline void iSeries_hlock(unsigned long slot)
  28 {
  29         if (slot & 0x8)
  30                 slot = ~slot;
  31         spin_lock(&iSeries_hlocks[(slot >> 4) & 0x3f]);
  32 }
  33
  34 static inline void iSeries_hunlock(unsigned long slot)
  35 {
  36         if (slot & 0x8)
  37                 slot = ~slot;
  38         spin_unlock(&iSeries_hlocks[(slot >> 4) & 0x3f]);
  39 }
  40
  41 static long iSeries_hpte_insert(unsigned long hpte_group, unsigned long va,
  42                          unsigned long pa, unsigned long rflags,
  43                          unsigned long vflags, int psize, int ssize)
  44 {
  45         long slot;
  46         struct hash_pte lhpte;
  47         int secondary = 0;
  48
  49         BUG_ON(psize != MMU_PAGE_4K);
  50
  51         /*
  52          * The hypervisor tries both primary and secondary.
  53          * If we are being called to insert in the secondary,
  54          * it means we have already tried both primary and secondary,
  55          * so we return failure immediately.
  56          */
  57         if (vflags & HPTE_V_SECONDARY)
  58                 return -1;
  59
  60         iSeries_hlock(hpte_group);
  61
  62         slot = HvCallHpt_findValid(&lhpte, va >> HW_PAGE_SHIFT);
  63         if (unlikely(lhpte.v & HPTE_V_VALID)) {
  64                 if (vflags & HPTE_V_BOLTED) {
  65                         HvCallHpt_setSwBits(slot, 0x10, 0);
  66                         HvCallHpt_setPp(slot, PP_RWXX);
  67                         iSeries_hunlock(hpte_group);
  68                         if (slot < 0)
  69                                 return 0x8 | (slot & 7);
  70                         else
  71                                 return slot & 7;
  72                 }
  73                 BUG();
  74         }
  75
  76         if (slot == -1) { /* No available entry found in either group */
  77                 iSeries_hunlock(hpte_group);
  78                 return -1;
  79         }
  80
  81         if (slot < 0) {         /* MSB set means secondary group */
  82                 vflags |= HPTE_V_SECONDARY;
  83                 secondary = 1;
  84                 slot &= 0x7fffffffffffffff;
  85         }
  86
  87
  88         lhpte.v = hpte_encode_v(va, MMU_PAGE_4K, MMU_SEGSIZE_256M) |
  89                 vflags | HPTE_V_VALID;
  90         lhpte.r = hpte_encode_r(phys_to_abs(pa), MMU_PAGE_4K) | rflags;
  91
  92         /* Now fill in the actual HPTE */
  93         HvCallHpt_addValidate(slot, secondary, &lhpte);
  94
  95         iSeries_hunlock(hpte_group);
  96
  97         return (secondary << 3) | (slot & 7);
  98 }
  99
 100 static unsigned long iSeries_hpte_getword0(unsigned long slot)
 101 {
 102         struct hash_pte hpte;
 103
 104         HvCallHpt_get(&hpte, slot);
 105         return hpte.v;
 106 }
 107
 108 static long iSeries_hpte_remove(unsigned long hpte_group)
 109 {
 110         unsigned long slot_offset;
 111         int i;
 112         unsigned long hpte_v;
 113
 114         /* Pick a random slot to start at */
 115         slot_offset = mftb() & 0x7;
 116
 117         iSeries_hlock(hpte_group);
 118
 119         for (i = 0; i < HPTES_PER_GROUP; i++) {
 120                 hpte_v = iSeries_hpte_getword0(hpte_group + slot_offset);
 121
 122                 if (! (hpte_v & HPTE_V_BOLTED)) {
 123                         HvCallHpt_invalidateSetSwBitsGet(hpte_group +
 124                                                          slot_offset, 0, 0);
 125                         iSeries_hunlock(hpte_group);
 126                         return i;
 127                 }
 128
 129                 slot_offset++;
 130                 slot_offset &= 0x7;
 131         }
 132
 133         iSeries_hunlock(hpte_group);
 134
 135         return -1;
 136 }
 137
 138 /*
 139  * The HyperVisor expects the "flags" argument in this form:
 140  *      bits  0..59 : reserved
 141  *      bit      60 : N
 142  *      bits 61..63 : PP2,PP1,PP0
 143  */
 144 static long iSeries_hpte_updatepp(unsigned long slot, unsigned long newpp,
 145                         unsigned long va, int psize, int ssize, int local)
 146 {
 147         struct hash_pte hpte;
 148         unsigned long want_v;
 149
 150         iSeries_hlock(slot);
 151
 152         HvCallHpt_get(&hpte, slot);
 153         want_v = hpte_encode_v(va, MMU_PAGE_4K, MMU_SEGSIZE_256M);
 154
 155         if (HPTE_V_COMPARE(hpte.v, want_v) && (hpte.v & HPTE_V_VALID)) {
 156                 /*
 157                  * Hypervisor expects bits as NPPP, which is
 158                  * different from how they are mapped in our PP.
 159                  */
 160                 HvCallHpt_setPp(slot, (newpp & 0x3) | ((newpp & 0x4) << 1));
 161                 iSeries_hunlock(slot);
 162                 return 0;
 163         }
 164         iSeries_hunlock(slot);
 165
 166         return -1;
 167 }
 168
 169 /*
 170  * Functions used to find the PTE for a particular virtual address.
 171  * Only used during boot when bolting pages.
 172  *
 173  * Input : vpn      : virtual page number
 174  * Output: PTE index within the page table of the entry
 175  *         -1 on failure
 176  */
 177 static long iSeries_hpte_find(unsigned long vpn)
 178 {
 179         struct hash_pte hpte;
 180         long slot;
 181
 182         /*
 183          * The HvCallHpt_findValid interface is as follows:
 184          * 0xffffffffffffffff : No entry found.
 185          * 0x00000000xxxxxxxx : Entry found in primary group, slot x
 186          * 0x80000000xxxxxxxx : Entry found in secondary group, slot x
 187          */
 188         slot = HvCallHpt_findValid(&hpte, vpn);
 189         if (hpte.v & HPTE_V_VALID) {
 190                 if (slot < 0) {
 191                         slot &= 0x7fffffffffffffff;
 192                         slot = -slot;
 193                 }
 194         } else
 195                 slot = -1;
 196         return slot;
 197 }
 198
 199 /*
 200  * Update the page protection bits. Intended to be used to create
 201  * guard pages for kernel data structures on pages which are bolted
 202  * in the HPT. Assumes pages being operated on will not be stolen.
 203  * Does not work on large pages.
 204  *
 205  * No need to lock here because we should be the only user.
 206  */
 207 static void iSeries_hpte_updateboltedpp(unsigned long newpp, unsigned long ea,
 208                                         int psize, int ssize)
 209 {
 210         unsigned long vsid,va,vpn;
 211         long slot;
 212
 213         BUG_ON(psize != MMU_PAGE_4K);
 214
 215         vsid = get_kernel_vsid(ea, MMU_SEGSIZE_256M);
 216         va = (vsid << 28) | (ea & 0x0fffffff);
 217         vpn = va >> HW_PAGE_SHIFT;
 218         slot = iSeries_hpte_find(vpn);
 219         if (slot == -1)
 220                 panic("updateboltedpp: Could not find page to bolt\n");
 221         HvCallHpt_setPp(slot, newpp);
 222 }
 223
 224 static void iSeries_hpte_invalidate(unsigned long slot, unsigned long va,
 225                                     int psize, int ssize, int local)
 226 {
 227         unsigned long hpte_v;
 228         unsigned long avpn = va >> 23;
 229         unsigned long flags;
 230
 231         local_irq_save(flags);
 232
 233         iSeries_hlock(slot);
 234
 235         hpte_v = iSeries_hpte_getword0(slot);
 236
 237         if ((HPTE_V_AVPN_VAL(hpte_v) == avpn) && (hpte_v & HPTE_V_VALID))
 238                 HvCallHpt_invalidateSetSwBitsGet(slot, 0, 0);
 239
 240         iSeries_hunlock(slot);
 241
 242         local_irq_restore(flags);
 243 }
 244
 245 void __init hpte_init_iSeries(void)
 246 {
 247         int i;
 248
 249         for (i = 0; i < ARRAY_SIZE(iSeries_hlocks); i++)
 250                 spin_lock_init(&iSeries_hlocks[i]);
 251
 252         ppc_md.hpte_invalidate  = iSeries_hpte_invalidate;
 253         ppc_md.hpte_updatepp    = iSeries_hpte_updatepp;
 254         ppc_md.hpte_updateboltedpp = iSeries_hpte_updateboltedpp;
 255         ppc_md.hpte_insert      = iSeries_hpte_insert;
 256         ppc_md.hpte_remove      = iSeries_hpte_remove;
 257 }