linux/arch/powerpc/platforms/iseries/htab.c
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   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
  22static spinlock_t iSeries_hlocks[64] __cacheline_aligned_in_smp;
  23
  24/*
  25 * Very primitive algorithm for picking up a lock
  26 */
  27static 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
  34static 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
  41static 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
 100static 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
 108static 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 */
 144static 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 */
 177static 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 */
 207static 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
 224static 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
 245void __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}
 258