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 #include <linux/sched/task.h>
  14
  15 #include <asm/lppaca.h>
  16 #include <asm/paca.h>
  17 #include <asm/sections.h>
  18 #include <asm/pgtable.h>
  19 #include <asm/kexec.h>
  20
  21 #include "setup.h"
  22
  23 #ifdef CONFIG_PPC_PSERIES
  24
  25 /*
  26  * The structure which the hypervisor knows about - this structure
  27  * should not cross a page boundary.  The vpa_init/register_vpa call
  28  * is now known to fail if the lppaca structure crosses a page
  29  * boundary.  The lppaca is also used on POWER5 pSeries boxes.
  30  * The lppaca is 640 bytes long, and cannot readily
  31  * change since the hypervisor knows its layout, so a 1kB alignment
  32  * will suffice to ensure that it doesn't cross a page boundary.
  33  */
  34 struct lppaca lppaca[] = {
  35         [0 ... (NR_LPPACAS-1)] = {
  36                 .desc = cpu_to_be32(0xd397d781),        /* "LpPa" */
  37                 .size = cpu_to_be16(sizeof(struct lppaca)),
  38                 .fpregs_in_use = 1,
  39                 .slb_count = cpu_to_be16(64),
  40                 .vmxregs_in_use = 0,
  41                 .page_ins = 0,
  42         },
  43 };
  44
  45 static struct lppaca *extra_lppacas;
  46 static long __initdata lppaca_size;
  47
  48 static void __init allocate_lppacas(int nr_cpus, unsigned long limit)
  49 {
  50         if (early_cpu_has_feature(CPU_FTR_HVMODE))
  51                 return;
  52
  53         if (nr_cpus <= NR_LPPACAS)
  54                 return;
  55
  56         lppaca_size = PAGE_ALIGN(sizeof(struct lppaca) *
  57                                  (nr_cpus - NR_LPPACAS));
  58         extra_lppacas = __va(memblock_alloc_base(lppaca_size,
  59                                                  PAGE_SIZE, limit));
  60 }
  61
  62 static struct lppaca * __init new_lppaca(int cpu)
  63 {
  64         struct lppaca *lp;
  65
  66         if (early_cpu_has_feature(CPU_FTR_HVMODE))
  67                 return NULL;
  68
  69         if (cpu < NR_LPPACAS)
  70                 return &lppaca[cpu];
  71
  72         lp = extra_lppacas + (cpu - NR_LPPACAS);
  73         *lp = lppaca[0];
  74
  75         return lp;
  76 }
  77
  78 static void __init free_lppacas(void)
  79 {
  80         long new_size = 0, nr;
  81
  82         if (early_cpu_has_feature(CPU_FTR_HVMODE))
  83                 return;
  84
  85         if (!lppaca_size)
  86                 return;
  87         nr = num_possible_cpus() - NR_LPPACAS;
  88         if (nr > 0)
  89                 new_size = PAGE_ALIGN(nr * sizeof(struct lppaca));
  90         if (new_size >= lppaca_size)
  91                 return;
  92
  93         memblock_free(__pa(extra_lppacas) + new_size, lppaca_size - new_size);
  94         lppaca_size = new_size;
  95 }
  96
  97 #else
  98
  99 static inline void allocate_lppacas(int nr_cpus, unsigned long limit) { }
 100 static inline void free_lppacas(void) { }
 101
 102 #endif /* CONFIG_PPC_BOOK3S */
 103
 104 #ifdef CONFIG_PPC_BOOK3S_64
 105
 106 /*
 107  * 3 persistent SLBs are registered here.  The buffer will be zero
 108  * initially, hence will all be invaild until we actually write them.
 109  *
 110  * If you make the number of persistent SLB entries dynamic, please also
 111  * update PR KVM to flush and restore them accordingly.
 112  */
 113 static struct slb_shadow * __initdata slb_shadow;
 114
 115 static void __init allocate_slb_shadows(int nr_cpus, int limit)
 116 {
 117         int size = PAGE_ALIGN(sizeof(struct slb_shadow) * nr_cpus);
 118
 119         if (early_radix_enabled())
 120                 return;
 121
 122         slb_shadow = __va(memblock_alloc_base(size, PAGE_SIZE, limit));
 123         memset(slb_shadow, 0, size);
 124 }
 125
 126 static struct slb_shadow * __init init_slb_shadow(int cpu)
 127 {
 128         struct slb_shadow *s;
 129
 130         if (early_radix_enabled())
 131                 return NULL;
 132
 133         s = &slb_shadow[cpu];
 134
 135         /*
 136          * When we come through here to initialise boot_paca, the slb_shadow
 137          * buffers are not allocated yet. That's OK, we'll get one later in
 138          * boot, but make sure we don't corrupt memory at 0.
 139          */
 140         if (!slb_shadow)
 141                 return NULL;
 142
 143         s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
 144         s->buffer_length = cpu_to_be32(sizeof(*s));
 145
 146         return s;
 147 }
 148
 149 #else /* !CONFIG_PPC_BOOK3S_64 */
 150
 151 static void __init allocate_slb_shadows(int nr_cpus, int limit) { }
 152
 153 #endif /* CONFIG_PPC_BOOK3S_64 */
 154
 155 /* The Paca is an array with one entry per processor.  Each contains an
 156  * lppaca, which contains the information shared between the
 157  * hypervisor and Linux.
 158  * On systems with hardware multi-threading, there are two threads
 159  * per processor.  The Paca array must contain an entry for each thread.
 160  * The VPD Areas will give a max logical processors = 2 * max physical
 161  * processors.  The processor VPD array needs one entry per physical
 162  * processor (not thread).
 163  */
 164 struct paca_struct **paca_ptrs __read_mostly;
 165 EXPORT_SYMBOL(paca_ptrs);
 166
 167 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 168 {
 169 #ifdef CONFIG_PPC_PSERIES
 170         new_paca->lppaca_ptr = new_lppaca(cpu);
 171 #endif
 172 #ifdef CONFIG_PPC_BOOK3E
 173         new_paca->kernel_pgd = swapper_pg_dir;
 174 #endif
 175         new_paca->lock_token = 0x8000;
 176         new_paca->paca_index = cpu;
 177         new_paca->kernel_toc = kernel_toc_addr();
 178         new_paca->kernelbase = (unsigned long) _stext;
 179         /* Only set MSR:IR/DR when MMU is initialized */
 180         new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
 181         new_paca->hw_cpu_id = 0xffff;
 182         new_paca->kexec_state = KEXEC_STATE_NONE;
 183         new_paca->__current = &init_task;
 184         new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
 185 #ifdef CONFIG_PPC_BOOK3S_64
 186         new_paca->slb_shadow_ptr = init_slb_shadow(cpu);
 187 #endif
 188
 189 #ifdef CONFIG_PPC_BOOK3E
 190         /* For now -- if we have threads this will be adjusted later */
 191         new_paca->tcd_ptr = &new_paca->tcd;
 192 #endif
 193 }
 194
 195 /* Put the paca pointer into r13 and SPRG_PACA */
 196 void setup_paca(struct paca_struct *new_paca)
 197 {
 198         /* Setup r13 */
 199         local_paca = new_paca;
 200
 201 #ifdef CONFIG_PPC_BOOK3E
 202         /* On Book3E, initialize the TLB miss exception frames */
 203         mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
 204 #else
 205         /* In HV mode, we setup both HPACA and PACA to avoid problems
 206          * if we do a GET_PACA() before the feature fixups have been
 207          * applied
 208          */
 209         if (early_cpu_has_feature(CPU_FTR_HVMODE))
 210                 mtspr(SPRN_SPRG_HPACA, local_paca);
 211 #endif
 212         mtspr(SPRN_SPRG_PACA, local_paca);
 213
 214 }
 215
 216 static int __initdata paca_nr_cpu_ids;
 217 static int __initdata paca_ptrs_size;
 218
 219 void __init allocate_pacas(void)
 220 {
 221         u64 limit;
 222         unsigned long size = 0;
 223         int cpu;
 224
 225 #ifdef CONFIG_PPC_BOOK3S_64
 226         /*
 227          * We access pacas in real mode, and cannot take SLB faults
 228          * on them when in virtual mode, so allocate them accordingly.
 229          */
 230         limit = min(ppc64_bolted_size(), ppc64_rma_size);
 231 #else
 232         limit = ppc64_rma_size;
 233 #endif
 234
 235         paca_nr_cpu_ids = nr_cpu_ids;
 236
 237         paca_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
 238         paca_ptrs = __va(memblock_alloc_base(paca_ptrs_size, 0, limit));
 239         memset(paca_ptrs, 0, paca_ptrs_size);
 240
 241         size += paca_ptrs_size;
 242
 243         for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
 244                 unsigned long pa;
 245
 246                 pa = memblock_alloc_base(sizeof(struct paca_struct),
 247                                                 L1_CACHE_BYTES, limit);
 248                 paca_ptrs[cpu] = __va(pa);
 249                 memset(paca_ptrs[cpu], 0, sizeof(struct paca_struct));
 250
 251                 size += sizeof(struct paca_struct);
 252         }
 253
 254         printk(KERN_DEBUG "Allocated %lu bytes for %u pacas\n",
 255                         size, nr_cpu_ids);
 256
 257         allocate_lppacas(nr_cpu_ids, limit);
 258
 259         allocate_slb_shadows(nr_cpu_ids, limit);
 260
 261         /* Can't use for_each_*_cpu, as they aren't functional yet */
 262         for (cpu = 0; cpu < nr_cpu_ids; cpu++)
 263                 initialise_paca(paca_ptrs[cpu], cpu);
 264 }
 265
 266 void __init free_unused_pacas(void)
 267 {
 268         unsigned long size = 0;
 269         int new_ptrs_size;
 270         int cpu;
 271
 272         for (cpu = 0; cpu < paca_nr_cpu_ids; cpu++) {
 273                 if (!cpu_possible(cpu)) {
 274                         unsigned long pa = __pa(paca_ptrs[cpu]);
 275                         memblock_free(pa, sizeof(struct paca_struct));
 276                         paca_ptrs[cpu] = NULL;
 277                         size += sizeof(struct paca_struct);
 278                 }
 279         }
 280
 281         new_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
 282         if (new_ptrs_size < paca_ptrs_size) {
 283                 memblock_free(__pa(paca_ptrs) + new_ptrs_size,
 284                                         paca_ptrs_size - new_ptrs_size);
 285                 size += paca_ptrs_size - new_ptrs_size;
 286         }
 287
 288         if (size)
 289                 printk(KERN_DEBUG "Freed %lu bytes for unused pacas\n", size);
 290
 291         free_lppacas();
 292
 293         paca_nr_cpu_ids = nr_cpu_ids;
 294         paca_ptrs_size = new_ptrs_size;
 295 }
 296
 297 void copy_mm_to_paca(struct mm_struct *mm)
 298 {
 299 #ifdef CONFIG_PPC_BOOK3S
 300         mm_context_t *context = &mm->context;
 301
 302         get_paca()->mm_ctx_id = context->id;
 303 #ifdef CONFIG_PPC_MM_SLICES
 304         VM_BUG_ON(!mm->context.slb_addr_limit);
 305         get_paca()->mm_ctx_slb_addr_limit = mm->context.slb_addr_limit;
 306         get_paca()->mm_ctx_low_slices_psize = context->low_slices_psize;
 307         memcpy(&get_paca()->mm_ctx_high_slices_psize,
 308                &context->high_slices_psize, TASK_SLICE_ARRAY_SZ(mm));
 309 #else /* CONFIG_PPC_MM_SLICES */
 310         get_paca()->mm_ctx_user_psize = context->user_psize;
 311         get_paca()->mm_ctx_sllp = context->sllp;
 312 #endif
 313 #else /* !CONFIG_PPC_BOOK3S */
 314         return;
 315 #endif
 316 }