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 #ifdef CONFIG_PPC_BOOK3S
  22
  23 /*
  24  * The structure which the hypervisor knows about - this structure
  25  * should not cross a page boundary.  The vpa_init/register_vpa call
  26  * is now known to fail if the lppaca structure crosses a page
  27  * boundary.  The lppaca is also used on POWER5 pSeries boxes.
  28  * The lppaca is 640 bytes long, and cannot readily
  29  * change since the hypervisor knows its layout, so a 1kB alignment
  30  * will suffice to ensure that it doesn't cross a page boundary.
  31  */
  32 struct lppaca lppaca[] = {
  33         [0 ... (NR_LPPACAS-1)] = {
  34                 .desc = cpu_to_be32(0xd397d781),        /* "LpPa" */
  35                 .size = cpu_to_be16(sizeof(struct lppaca)),
  36                 .fpregs_in_use = 1,
  37                 .slb_count = cpu_to_be16(64),
  38                 .vmxregs_in_use = 0,
  39                 .page_ins = 0,
  40         },
  41 };
  42
  43 static struct lppaca *extra_lppacas;
  44 static long __initdata lppaca_size;
  45
  46 static void __init allocate_lppacas(int nr_cpus, unsigned long limit)
  47 {
  48         if (nr_cpus <= NR_LPPACAS)
  49                 return;
  50
  51         lppaca_size = PAGE_ALIGN(sizeof(struct lppaca) *
  52                                  (nr_cpus - NR_LPPACAS));
  53         extra_lppacas = __va(memblock_alloc_base(lppaca_size,
  54                                                  PAGE_SIZE, limit));
  55 }
  56
  57 static struct lppaca * __init new_lppaca(int cpu)
  58 {
  59         struct lppaca *lp;
  60
  61         if (cpu < NR_LPPACAS)
  62                 return &lppaca[cpu];
  63
  64         lp = extra_lppacas + (cpu - NR_LPPACAS);
  65         *lp = lppaca[0];
  66
  67         return lp;
  68 }
  69
  70 static void __init free_lppacas(void)
  71 {
  72         long new_size = 0, nr;
  73
  74         if (!lppaca_size)
  75                 return;
  76         nr = num_possible_cpus() - NR_LPPACAS;
  77         if (nr > 0)
  78                 new_size = PAGE_ALIGN(nr * sizeof(struct lppaca));
  79         if (new_size >= lppaca_size)
  80                 return;
  81
  82         memblock_free(__pa(extra_lppacas) + new_size, lppaca_size - new_size);
  83         lppaca_size = new_size;
  84 }
  85
  86 #else
  87
  88 static inline void allocate_lppacas(int nr_cpus, unsigned long limit) { }
  89 static inline void free_lppacas(void) { }
  90
  91 #endif /* CONFIG_PPC_BOOK3S */
  92
  93 #ifdef CONFIG_PPC_STD_MMU_64
  94
  95 /*
  96  * 3 persistent SLBs are registered here.  The buffer will be zero
  97  * initially, hence will all be invaild until we actually write them.
  98  *
  99  * If you make the number of persistent SLB entries dynamic, please also
 100  * update PR KVM to flush and restore them accordingly.
 101  */
 102 static struct slb_shadow *slb_shadow;
 103
 104 static void __init allocate_slb_shadows(int nr_cpus, int limit)
 105 {
 106         int size = PAGE_ALIGN(sizeof(struct slb_shadow) * nr_cpus);
 107         slb_shadow = __va(memblock_alloc_base(size, PAGE_SIZE, limit));
 108         memset(slb_shadow, 0, size);
 109 }
 110
 111 static struct slb_shadow * __init init_slb_shadow(int cpu)
 112 {
 113         struct slb_shadow *s = &slb_shadow[cpu];
 114
 115         /*
 116          * When we come through here to initialise boot_paca, the slb_shadow
 117          * buffers are not allocated yet. That's OK, we'll get one later in
 118          * boot, but make sure we don't corrupt memory at 0.
 119          */
 120         if (!slb_shadow)
 121                 return NULL;
 122
 123         s->persistent = cpu_to_be32(SLB_NUM_BOLTED);
 124         s->buffer_length = cpu_to_be32(sizeof(*s));
 125
 126         return s;
 127 }
 128
 129 #else /* CONFIG_PPC_STD_MMU_64 */
 130
 131 static void __init allocate_slb_shadows(int nr_cpus, int limit) { }
 132
 133 #endif /* CONFIG_PPC_STD_MMU_64 */
 134
 135 /* The Paca is an array with one entry per processor.  Each contains an
 136  * lppaca, which contains the information shared between the
 137  * hypervisor and Linux.
 138  * On systems with hardware multi-threading, there are two threads
 139  * per processor.  The Paca array must contain an entry for each thread.
 140  * The VPD Areas will give a max logical processors = 2 * max physical
 141  * processors.  The processor VPD array needs one entry per physical
 142  * processor (not thread).
 143  */
 144 struct paca_struct *paca;
 145 EXPORT_SYMBOL(paca);
 146
 147 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 148 {
 149 #ifdef CONFIG_PPC_BOOK3S
 150         new_paca->lppaca_ptr = new_lppaca(cpu);
 151 #else
 152         new_paca->kernel_pgd = swapper_pg_dir;
 153 #endif
 154         new_paca->lock_token = 0x8000;
 155         new_paca->paca_index = cpu;
 156         new_paca->kernel_toc = kernel_toc_addr();
 157         new_paca->kernelbase = (unsigned long) _stext;
 158         /* Only set MSR:IR/DR when MMU is initialized */
 159         new_paca->kernel_msr = MSR_KERNEL & ~(MSR_IR | MSR_DR);
 160         new_paca->hw_cpu_id = 0xffff;
 161         new_paca->kexec_state = KEXEC_STATE_NONE;
 162         new_paca->__current = &init_task;
 163         new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
 164 #ifdef CONFIG_PPC_STD_MMU_64
 165         new_paca->slb_shadow_ptr = init_slb_shadow(cpu);
 166 #endif /* CONFIG_PPC_STD_MMU_64 */
 167
 168 #ifdef CONFIG_PPC_BOOK3E
 169         /* For now -- if we have threads this will be adjusted later */
 170         new_paca->tcd_ptr = &new_paca->tcd;
 171 #endif
 172 }
 173
 174 /* Put the paca pointer into r13 and SPRG_PACA */
 175 void setup_paca(struct paca_struct *new_paca)
 176 {
 177         /* Setup r13 */
 178         local_paca = new_paca;
 179
 180 #ifdef CONFIG_PPC_BOOK3E
 181         /* On Book3E, initialize the TLB miss exception frames */
 182         mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
 183 #else
 184         /* In HV mode, we setup both HPACA and PACA to avoid problems
 185          * if we do a GET_PACA() before the feature fixups have been
 186          * applied
 187          */
 188         if (early_cpu_has_feature(CPU_FTR_HVMODE))
 189                 mtspr(SPRN_SPRG_HPACA, local_paca);
 190 #endif
 191         mtspr(SPRN_SPRG_PACA, local_paca);
 192
 193 }
 194
 195 static int __initdata paca_size;
 196
 197 void __init allocate_pacas(void)
 198 {
 199         u64 limit;
 200         int cpu;
 201
 202         limit = ppc64_rma_size;
 203
 204 #ifdef CONFIG_PPC_BOOK3S_64
 205         /*
 206          * We can't take SLB misses on the paca, and we want to access them
 207          * in real mode, so allocate them within the RMA and also within
 208          * the first segment.
 209          */
 210         limit = min(0x10000000ULL, limit);
 211 #endif
 212
 213         paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 214
 215         paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
 216         memset(paca, 0, paca_size);
 217
 218         printk(KERN_DEBUG "Allocated %u bytes for %d pacas at %p\n",
 219                 paca_size, nr_cpu_ids, paca);
 220
 221         allocate_lppacas(nr_cpu_ids, limit);
 222
 223         allocate_slb_shadows(nr_cpu_ids, limit);
 224
 225         /* Can't use for_each_*_cpu, as they aren't functional yet */
 226         for (cpu = 0; cpu < nr_cpu_ids; cpu++)
 227                 initialise_paca(&paca[cpu], cpu);
 228 }
 229
 230 void __init free_unused_pacas(void)
 231 {
 232         int new_size;
 233
 234         new_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 235
 236         if (new_size >= paca_size)
 237                 return;
 238
 239         memblock_free(__pa(paca) + new_size, paca_size - new_size);
 240
 241         printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
 242                 paca_size - new_size);
 243
 244         paca_size = new_size;
 245
 246         free_lppacas();
 247 }
 248
 249 void copy_mm_to_paca(struct mm_struct *mm)
 250 {
 251 #ifdef CONFIG_PPC_BOOK3S
 252         mm_context_t *context = &mm->context;
 253
 254         get_paca()->mm_ctx_id = context->id;
 255 #ifdef CONFIG_PPC_MM_SLICES
 256         VM_BUG_ON(!mm->context.addr_limit);
 257         get_paca()->addr_limit = mm->context.addr_limit;
 258         get_paca()->mm_ctx_low_slices_psize = context->low_slices_psize;
 259         memcpy(&get_paca()->mm_ctx_high_slices_psize,
 260                &context->high_slices_psize, TASK_SLICE_ARRAY_SZ(mm));
 261 #else /* CONFIG_PPC_MM_SLICES */
 262         get_paca()->mm_ctx_user_psize = context->user_psize;
 263         get_paca()->mm_ctx_sllp = context->sllp;
 264 #endif
 265 #else /* CONFIG_PPC_BOOK3S */
 266         return;
 267 #endif
 268 }