arch/ppc64/mm/slb.c

   1 /*
   2  * PowerPC64 SLB support.
   3  *
   4  * Copyright (C) 2004 David Gibson <dwg@au.ibm.com>, IBM
   5  * Based on earlier code writteh by:
   6  * Dave Engebretsen and Mike Corrigan {engebret|mikejc}@us.ibm.com
   7  *    Copyright (c) 2001 Dave Engebretsen
   8  * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
   9  *
  10  *
  11  *      This program is free software; you can redistribute it and/or
  12  *      modify it under the terms of the GNU General Public License
  13  *      as published by the Free Software Foundation; either version
  14  *      2 of the License, or (at your option) any later version.
  15  */
  16
  17 #include <linux/config.h>
  18 #include <asm/pgtable.h>
  19 #include <asm/mmu.h>
  20 #include <asm/mmu_context.h>
  21 #include <asm/paca.h>
  22 #include <asm/cputable.h>
  23
  24 extern void slb_allocate(unsigned long ea);
  25
  26 static inline unsigned long mk_esid_data(unsigned long ea, unsigned long slot)
  27 {
  28         return (ea & ESID_MASK) | SLB_ESID_V | slot;
  29 }
  30
  31 static inline unsigned long mk_vsid_data(unsigned long ea, unsigned long flags)
  32 {
  33         return (get_kernel_vsid(ea) << SLB_VSID_SHIFT) | flags;
  34 }
  35
  36 static inline void create_slbe(unsigned long ea, unsigned long flags,
  37                                unsigned long entry)
  38 {
  39         asm volatile("slbmte  %0,%1" :
  40                      : "r" (mk_vsid_data(ea, flags)),
  41                        "r" (mk_esid_data(ea, entry))
  42                      : "memory" );
  43 }
  44
  45 static void slb_flush_and_rebolt(void)
  46 {
  47         /* If you change this make sure you change SLB_NUM_BOLTED
  48          * appropriately too. */
  49         unsigned long ksp_flags = SLB_VSID_KERNEL;
  50         unsigned long ksp_esid_data;
  51
  52         WARN_ON(!irqs_disabled());
  53
  54         if (cpu_has_feature(CPU_FTR_16M_PAGE))
  55                 ksp_flags |= SLB_VSID_L;
  56
  57         ksp_esid_data = mk_esid_data(get_paca()->kstack, 2);
  58         if ((ksp_esid_data & ESID_MASK) == KERNELBASE)
  59                 ksp_esid_data &= ~SLB_ESID_V;
  60
  61         /* We need to do this all in asm, so we're sure we don't touch
  62          * the stack between the slbia and rebolting it. */
  63         asm volatile("isync\n"
  64                      "slbia\n"
  65                      /* Slot 1 - first VMALLOC segment */
  66                      "slbmte    %0,%1\n"
  67                      /* Slot 2 - kernel stack */
  68                      "slbmte    %2,%3\n"
  69                      "isync"
  70                      :: "r"(mk_vsid_data(VMALLOCBASE, SLB_VSID_KERNEL)),
  71                         "r"(mk_esid_data(VMALLOCBASE, 1)),
  72                         "r"(mk_vsid_data(ksp_esid_data, ksp_flags)),
  73                         "r"(ksp_esid_data)
  74                      : "memory");
  75 }
  76
  77 /* Flush all user entries from the segment table of the current processor. */
  78 void switch_slb(struct task_struct *tsk, struct mm_struct *mm)
  79 {
  80         unsigned long offset = get_paca()->slb_cache_ptr;
  81         unsigned long esid_data = 0;
  82         unsigned long pc = KSTK_EIP(tsk);
  83         unsigned long stack = KSTK_ESP(tsk);
  84         unsigned long unmapped_base;
  85
  86         if (offset <= SLB_CACHE_ENTRIES) {
  87                 int i;
  88                 asm volatile("isync" : : : "memory");
  89                 for (i = 0; i < offset; i++) {
  90                         esid_data = (unsigned long)get_paca()->slb_cache[i]
  91                                 << SID_SHIFT;
  92                         asm volatile("slbie %0" : : "r" (esid_data));
  93                 }
  94                 asm volatile("isync" : : : "memory");
  95         } else {
  96                 slb_flush_and_rebolt();
  97         }
  98
  99         /* Workaround POWER5 < DD2.1 issue */
 100         if (offset == 1 || offset > SLB_CACHE_ENTRIES)
 101                 asm volatile("slbie %0" : : "r" (esid_data));
 102
 103         get_paca()->slb_cache_ptr = 0;
 104         get_paca()->context = mm->context;
 105
 106         /*
 107          * preload some userspace segments into the SLB.
 108          */
 109         if (test_tsk_thread_flag(tsk, TIF_32BIT))
 110                 unmapped_base = TASK_UNMAPPED_BASE_USER32;
 111         else
 112                 unmapped_base = TASK_UNMAPPED_BASE_USER64;
 113
 114         if (pc >= KERNELBASE)
 115                 return;
 116         slb_allocate(pc);
 117
 118         if (GET_ESID(pc) == GET_ESID(stack))
 119                 return;
 120
 121         if (stack >= KERNELBASE)
 122                 return;
 123         slb_allocate(stack);
 124
 125         if ((GET_ESID(pc) == GET_ESID(unmapped_base))
 126             || (GET_ESID(stack) == GET_ESID(unmapped_base)))
 127                 return;
 128
 129         if (unmapped_base >= KERNELBASE)
 130                 return;
 131         slb_allocate(unmapped_base);
 132 }
 133
 134 void slb_initialize(void)
 135 {
 136         /* On iSeries the bolted entries have already been set up by
 137          * the hypervisor from the lparMap data in head.S */
 138 #ifndef CONFIG_PPC_ISERIES
 139         unsigned long flags = SLB_VSID_KERNEL;
 140
 141         /* Invalidate the entire SLB (even slot 0) & all the ERATS */
 142         if (cpu_has_feature(CPU_FTR_16M_PAGE))
 143                 flags |= SLB_VSID_L;
 144
 145         asm volatile("isync":::"memory");
 146         asm volatile("slbmte  %0,%0"::"r" (0) : "memory");
 147         asm volatile("isync; slbia; isync":::"memory");
 148         create_slbe(KERNELBASE, flags, 0);
 149         create_slbe(VMALLOCBASE, SLB_VSID_KERNEL, 1);
 150         /* We don't bolt the stack for the time being - we're in boot,
 151          * so the stack is in the bolted segment.  By the time it goes
 152          * elsewhere, we'll call _switch() which will bolt in the new
 153          * one. */
 154         asm volatile("isync":::"memory");
 155 #endif
 156
 157         get_paca()->stab_rr = SLB_NUM_BOLTED;
 158 }