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_BOOK3S
  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 (nr_cpus <= NR_LPPACAS)
  51                 return;
  52
  53         lppaca_size = PAGE_ALIGN(sizeof(struct lppaca) *
  54                                  (nr_cpus - NR_LPPACAS));
  55         extra_lppacas = __va(memblock_alloc_base(lppaca_size,
  56                                                  PAGE_SIZE, limit));
  57 }
  58
  59 static struct lppaca * __init new_lppaca(int cpu)
  60 {
  61         struct lppaca *lp;
  62
  63         if (cpu < NR_LPPACAS)
  64                 return &lppaca[cpu];
  65
  66         lp = extra_lppacas + (cpu - NR_LPPACAS);
  67         *lp = lppaca[0];
  68
  69         return lp;
  70 }
  71
  72 static void __init free_lppacas(void)
  73 {
  74         long new_size = 0, nr;
  75
  76         if (!lppaca_size)
  77                 return;
  78         nr = num_possible_cpus() - NR_LPPACAS;
  79         if (nr > 0)
  80                 new_size = PAGE_ALIGN(nr * sizeof(struct lppaca));
  81         if (new_size >= lppaca_size)
  82                 return;
  83
  84         memblock_free(__pa(extra_lppacas) + new_size, lppaca_size - new_size);
  85         lppaca_size = new_size;
  86 }
  87
  88 #else
  89
  90 static inline void allocate_lppacas(int nr_cpus, unsigned long limit) { }
  91 static inline void free_lppacas(void) { }
  92
  93 #endif /* CONFIG_PPC_BOOK3S */
  94
  95 #ifdef CONFIG_PPC_BOOK3S_64
  96
  97 /*
  98  * 3 persistent SLBs are registered here.  The buffer will be zero
  99  * initially, hence will all be invaild until we actually write them.
 100  *
 101  * If you make the number of persistent SLB entries dynamic, please also
 102  * update PR KVM to flush and restore them accordingly.
 103  */
 104 static struct slb_shadow * __initdata slb_shadow;
 105
 106 static void __init allocate_slb_shadows(int nr_cpus, int limit)
 107 {
 108         int size = PAGE_ALIGN(sizeof(struct slb_shadow) * nr_cpus);
 109
 110         if (early_radix_enabled())
 111                 return;
 112
 113         slb_shadow = __va(memblock_alloc_base(size, PAGE_SIZE, limit));
 114         memset(slb_shadow, 0, size);
 115 }
 116
 117 static struct slb_shadow * __init init_slb_shadow(int cpu)
 118 {
 119         struct slb_shadow *s;
 120
 121         if (early_radix_enabled())
 122                 return NULL;
 123
 124         s = &slb_shadow[cpu];
 125
 126         /*
 127          * When we come through here to initialise boot_paca, the slb_shadow
 128          * buffers are not allocated yet. That's OK, we'll get one later in
 129          * boot, but make sure we don't corrupt memory at 0.
 130          */
 131         if (!slb_shadow)
 132                 return NULL;
 133
 134         s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
 135         s->buffer_length = cpu_to_be32(sizeof(*s));
 136
 137         return s;
 138 }
 139
 140 #else /* !CONFIG_PPC_BOOK3S_64 */
 141
 142 static void __init allocate_slb_shadows(int nr_cpus, int limit) { }
 143
 144 #endif /* CONFIG_PPC_BOOK3S_64 */
 145
 146 /* The Paca is an array with one entry per processor.  Each contains an
 147  * lppaca, which contains the information shared between the
 148  * hypervisor and Linux.
 149  * On systems with hardware multi-threading, there are two threads
 150  * per processor.  The Paca array must contain an entry for each thread.
 151  * The VPD Areas will give a max logical processors = 2 * max physical
 152  * processors.  The processor VPD array needs one entry per physical
 153  * processor (not thread).
 154  */
 155 struct paca_struct *paca;
 156 EXPORT_SYMBOL(paca);
 157
 158 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 159 {
 160 #ifdef CONFIG_PPC_BOOK3S
 161         new_paca->lppaca_ptr = new_lppaca(cpu);
 162 #else
 163         new_paca->kernel_pgd = swapper_pg_dir;
 164 #endif
 165         new_paca->lock_token = 0x8000;
 166         new_paca->paca_index = cpu;
 167         new_paca->kernel_toc = kernel_toc_addr();
 168         new_paca->kernelbase = (unsigned long) _stext;
 169         /* Only set MSR:IR/DR when MMU is initialized */
 170         new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
 171         new_paca->hw_cpu_id = 0xffff;
 172         new_paca->kexec_state = KEXEC_STATE_NONE;
 173         new_paca->__current = &init_task;
 174         new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
 175 #ifdef CONFIG_PPC_BOOK3S_64
 176         new_paca->slb_shadow_ptr = init_slb_shadow(cpu);
 177 #endif
 178
 179 #ifdef CONFIG_PPC_BOOK3E
 180         /* For now -- if we have threads this will be adjusted later */
 181         new_paca->tcd_ptr = &new_paca->tcd;
 182 #endif
 183 }
 184
 185 /* Put the paca pointer into r13 and SPRG_PACA */
 186 void setup_paca(struct paca_struct *new_paca)
 187 {
 188         /* Setup r13 */
 189         local_paca = new_paca;
 190
 191 #ifdef CONFIG_PPC_BOOK3E
 192         /* On Book3E, initialize the TLB miss exception frames */
 193         mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
 194 #else
 195         /* In HV mode, we setup both HPACA and PACA to avoid problems
 196          * if we do a GET_PACA() before the feature fixups have been
 197          * applied
 198          */
 199         if (early_cpu_has_feature(CPU_FTR_HVMODE))
 200                 mtspr(SPRN_SPRG_HPACA, local_paca);
 201 #endif
 202         mtspr(SPRN_SPRG_PACA, local_paca);
 203
 204 }
 205
 206 static int __initdata paca_size;
 207
 208 void __init allocate_pacas(void)
 209 {
 210         u64 limit;
 211         int cpu;
 212
 213 #ifdef CONFIG_PPC_BOOK3S_64
 214         /*
 215          * We access pacas in real mode, and cannot take SLB faults
 216          * on them when in virtual mode, so allocate them accordingly.
 217          */
 218         limit = min(ppc64_bolted_size(), ppc64_rma_size);
 219 #else
 220         limit = ppc64_rma_size;
 221 #endif
 222
 223         paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 224
 225         paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
 226         memset(paca, 0, paca_size);
 227
 228         printk(KERN_DEBUG "Allocated %u bytes for %u pacas at %p\n",
 229                 paca_size, nr_cpu_ids, paca);
 230
 231         allocate_lppacas(nr_cpu_ids, limit);
 232
 233         allocate_slb_shadows(nr_cpu_ids, limit);
 234
 235         /* Can't use for_each_*_cpu, as they aren't functional yet */
 236         for (cpu = 0; cpu < nr_cpu_ids; cpu++)
 237                 initialise_paca(&paca[cpu], cpu);
 238 }
 239
 240 void __init free_unused_pacas(void)
 241 {
 242         int new_size;
 243
 244         new_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 245
 246         if (new_size >= paca_size)
 247                 return;
 248
 249         memblock_free(__pa(paca) + new_size, paca_size - new_size);
 250
 251         printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
 252                 paca_size - new_size);
 253
 254         paca_size = new_size;
 255
 256         free_lppacas();
 257 }
 258
 259 void copy_mm_to_paca(struct mm_struct *mm)
 260 {
 261 #ifdef CONFIG_PPC_BOOK3S
 262         mm_context_t *context = &mm->context;
 263
 264         get_paca()->mm_ctx_id = context->id;
 265 #ifdef CONFIG_PPC_MM_SLICES
 266         VM_BUG_ON(!mm->context.slb_addr_limit);
 267         get_paca()->mm_ctx_slb_addr_limit = mm->context.slb_addr_limit;
 268         get_paca()->mm_ctx_low_slices_psize = context->low_slices_psize;
 269         memcpy(&get_paca()->mm_ctx_high_slices_psize,
 270                &context->high_slices_psize, TASK_SLICE_ARRAY_SZ(mm));
 271 #else /* CONFIG_PPC_MM_SLICES */
 272         get_paca()->mm_ctx_user_psize = context->user_psize;
 273         get_paca()->mm_ctx_sllp = context->sllp;
 274 #endif
 275 #else /* !CONFIG_PPC_BOOK3S */
 276         return;
 277 #endif
 278 }