arch/powerpc/kernel/paca.c

   1 /*
   2  * c 2001 PPC 64 Team, IBM Corp
   3  *
   4  *      This program is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU General Public License
   6  *      as published by the Free Software Foundation; either version
   7  *      2 of the License, or (at your option) any later version.
   8  */
   9
  10 #include <linux/smp.h>
  11 #include <linux/export.h>
  12 #include <linux/memblock.h>
  13
  14 #include <asm/lppaca.h>
  15 #include <asm/paca.h>
  16 #include <asm/sections.h>
  17 #include <asm/pgtable.h>
  18 #include <asm/kexec.h>
  19
  20 #ifdef CONFIG_PPC_BOOK3S
  21
  22 /*
  23  * The structure which the hypervisor knows about - this structure
  24  * should not cross a page boundary.  The vpa_init/register_vpa call
  25  * is now known to fail if the lppaca structure crosses a page
  26  * boundary.  The lppaca is also used on POWER5 pSeries boxes.
  27  * The lppaca is 640 bytes long, and cannot readily
  28  * change since the hypervisor knows its layout, so a 1kB alignment
  29  * will suffice to ensure that it doesn't cross a page boundary.
  30  */
  31 struct lppaca lppaca[] = {
  32         [0 ... (NR_LPPACAS-1)] = {
  33                 .desc = cpu_to_be32(0xd397d781),        /* "LpPa" */
  34                 .size = cpu_to_be16(sizeof(struct lppaca)),
  35                 .fpregs_in_use = 1,
  36                 .slb_count = cpu_to_be16(64),
  37                 .vmxregs_in_use = 0,
  38                 .page_ins = 0,
  39         },
  40 };
  41
  42 static struct lppaca *extra_lppacas;
  43 static long __initdata lppaca_size;
  44
  45 static void __init allocate_lppacas(int nr_cpus, unsigned long limit)
  46 {
  47         if (nr_cpus <= NR_LPPACAS)
  48                 return;
  49
  50         lppaca_size = PAGE_ALIGN(sizeof(struct lppaca) *
  51                                  (nr_cpus - NR_LPPACAS));
  52         extra_lppacas = __va(memblock_alloc_base(lppaca_size,
  53                                                  PAGE_SIZE, limit));
  54 }
  55
  56 static struct lppaca * __init new_lppaca(int cpu)
  57 {
  58         struct lppaca *lp;
  59
  60         if (cpu < NR_LPPACAS)
  61                 return &lppaca[cpu];
  62
  63         lp = extra_lppacas + (cpu - NR_LPPACAS);
  64         *lp = lppaca[0];
  65
  66         return lp;
  67 }
  68
  69 static void __init free_lppacas(void)
  70 {
  71         long new_size = 0, nr;
  72
  73         if (!lppaca_size)
  74                 return;
  75         nr = num_possible_cpus() - NR_LPPACAS;
  76         if (nr > 0)
  77                 new_size = PAGE_ALIGN(nr * sizeof(struct lppaca));
  78         if (new_size >= lppaca_size)
  79                 return;
  80
  81         memblock_free(__pa(extra_lppacas) + new_size, lppaca_size - new_size);
  82         lppaca_size = new_size;
  83 }
  84
  85 #else
  86
  87 static inline void allocate_lppacas(int nr_cpus, unsigned long limit) { }
  88 static inline void free_lppacas(void) { }
  89
  90 #endif /* CONFIG_PPC_BOOK3S */
  91
  92 #ifdef CONFIG_PPC_STD_MMU_64
  93
  94 /*
  95  * 3 persistent SLBs are registered here.  The buffer will be zero
  96  * initially, hence will all be invaild until we actually write them.
  97  *
  98  * If you make the number of persistent SLB entries dynamic, please also
  99  * update PR KVM to flush and restore them accordingly.
 100  */
 101 static struct slb_shadow *slb_shadow;
 102
 103 static void __init allocate_slb_shadows(int nr_cpus, int limit)
 104 {
 105         int size = PAGE_ALIGN(sizeof(struct slb_shadow) * nr_cpus);
 106         slb_shadow = __va(memblock_alloc_base(size, PAGE_SIZE, limit));
 107         memset(slb_shadow, 0, size);
 108 }
 109
 110 static struct slb_shadow * __init init_slb_shadow(int cpu)
 111 {
 112         struct slb_shadow *s = &slb_shadow[cpu];
 113
 114         /*
 115          * When we come through here to initialise boot_paca, the slb_shadow
 116          * buffers are not allocated yet. That's OK, we'll get one later in
 117          * boot, but make sure we don't corrupt memory at 0.
 118          */
 119         if (!slb_shadow)
 120                 return NULL;
 121
 122         s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
 123         s->buffer_length = cpu_to_be32(sizeof(*s));
 124
 125         return s;
 126 }
 127
 128 #else /* CONFIG_PPC_STD_MMU_64 */
 129
 130 static void __init allocate_slb_shadows(int nr_cpus, int limit) { }
 131
 132 #endif /* CONFIG_PPC_STD_MMU_64 */
 133
 134 /* The Paca is an array with one entry per processor.  Each contains an
 135  * lppaca, which contains the information shared between the
 136  * hypervisor and Linux.
 137  * On systems with hardware multi-threading, there are two threads
 138  * per processor.  The Paca array must contain an entry for each thread.
 139  * The VPD Areas will give a max logical processors = 2 * max physical
 140  * processors.  The processor VPD array needs one entry per physical
 141  * processor (not thread).
 142  */
 143 struct paca_struct *paca;
 144 EXPORT_SYMBOL(paca);
 145
 146 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 147 {
 148 #ifdef CONFIG_PPC_BOOK3S
 149         new_paca->lppaca_ptr = new_lppaca(cpu);
 150 #else
 151         new_paca->kernel_pgd = swapper_pg_dir;
 152 #endif
 153         new_paca->lock_token = 0x8000;
 154         new_paca->paca_index = cpu;
 155         new_paca->kernel_toc = kernel_toc_addr();
 156         new_paca->kernelbase = (unsigned long) _stext;
 157         /* Only set MSR:IR/DR when MMU is initialized */
 158         new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
 159         new_paca->hw_cpu_id = 0xffff;
 160         new_paca->kexec_state = KEXEC_STATE_NONE;
 161         new_paca->__current = &init_task;
 162         new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
 163 #ifdef CONFIG_PPC_STD_MMU_64
 164         new_paca->slb_shadow_ptr = init_slb_shadow(cpu);
 165 #endif /* CONFIG_PPC_STD_MMU_64 */
 166
 167 #ifdef CONFIG_PPC_BOOK3E
 168         /* For now -- if we have threads this will be adjusted later */
 169         new_paca->tcd_ptr = &new_paca->tcd;
 170 #endif
 171 }
 172
 173 /* Put the paca pointer into r13 and SPRG_PACA */
 174 void setup_paca(struct paca_struct *new_paca)
 175 {
 176         /* Setup r13 */
 177         local_paca = new_paca;
 178
 179 #ifdef CONFIG_PPC_BOOK3E
 180         /* On Book3E, initialize the TLB miss exception frames */
 181         mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
 182 #else
 183         /* In HV mode, we setup both HPACA and PACA to avoid problems
 184          * if we do a GET_PACA() before the feature fixups have been
 185          * applied
 186          */
 187         if (cpu_has_feature(CPU_FTR_HVMODE))
 188                 mtspr(SPRN_SPRG_HPACA, local_paca);
 189 #endif
 190         mtspr(SPRN_SPRG_PACA, local_paca);
 191
 192 }
 193
 194 static int __initdata paca_size;
 195
 196 void __init allocate_pacas(void)
 197 {
 198         u64 limit;
 199         int cpu;
 200
 201         limit = ppc64_rma_size;
 202
 203 #ifdef CONFIG_PPC_BOOK3S_64
 204         /*
 205          * We can't take SLB misses on the paca, and we want to access them
 206          * in real mode, so allocate them within the RMA and also within
 207          * the first segment.
 208          */
 209         limit = min(0x10000000ULL, limit);
 210 #endif
 211
 212         paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 213
 214         paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
 215         memset(paca, 0, paca_size);
 216
 217         printk(KERN_DEBUG "Allocated %u bytes for %d pacas at %p\n",
 218                 paca_size, nr_cpu_ids, paca);
 219
 220         allocate_lppacas(nr_cpu_ids, limit);
 221
 222         allocate_slb_shadows(nr_cpu_ids, limit);
 223
 224         /* Can't use for_each_*_cpu, as they aren't functional yet */
 225         for (cpu = 0; cpu < nr_cpu_ids; cpu++)
 226                 initialise_paca(&paca[cpu], cpu);
 227 }
 228
 229 void __init free_unused_pacas(void)
 230 {
 231         int new_size;
 232
 233         new_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 234
 235         if (new_size >= paca_size)
 236                 return;
 237
 238         memblock_free(__pa(paca) + new_size, paca_size - new_size);
 239
 240         printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
 241                 paca_size - new_size);
 242
 243         paca_size = new_size;
 244
 245         free_lppacas();
 246 }