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 /* This symbol is provided by the linker - let it fill in the paca
  21  * field correctly */
  22 extern unsigned long __toc_start;
  23
  24 #ifdef CONFIG_PPC_BOOK3S
  25
  26 /*
  27  * The structure which the hypervisor knows about - this structure
  28  * should not cross a page boundary.  The vpa_init/register_vpa call
  29  * is now known to fail if the lppaca structure crosses a page
  30  * boundary.  The lppaca is also used on POWER5 pSeries boxes.
  31  * The lppaca is 640 bytes long, and cannot readily
  32  * change since the hypervisor knows its layout, so a 1kB alignment
  33  * will suffice to ensure that it doesn't cross a page boundary.
  34  */
  35 struct lppaca lppaca[] = {
  36         [0 ... (NR_LPPACAS-1)] = {
  37                 .desc = cpu_to_be32(0xd397d781),        /* "LpPa" */
  38                 .size = cpu_to_be16(sizeof(struct lppaca)),
  39                 .fpregs_in_use = 1,
  40                 .slb_count = cpu_to_be16(64),
  41                 .vmxregs_in_use = 0,
  42                 .page_ins = 0,
  43         },
  44 };
  45
  46 static struct lppaca *extra_lppacas;
  47 static long __initdata lppaca_size;
  48
  49 static void allocate_lppacas(int nr_cpus, unsigned long limit)
  50 {
  51         if (nr_cpus <= NR_LPPACAS)
  52                 return;
  53
  54         lppaca_size = PAGE_ALIGN(sizeof(struct lppaca) *
  55                                  (nr_cpus - NR_LPPACAS));
  56         extra_lppacas = __va(memblock_alloc_base(lppaca_size,
  57                                                  PAGE_SIZE, limit));
  58 }
  59
  60 static struct lppaca *new_lppaca(int cpu)
  61 {
  62         struct lppaca *lp;
  63
  64         if (cpu < NR_LPPACAS)
  65                 return &lppaca[cpu];
  66
  67         lp = extra_lppacas + (cpu - NR_LPPACAS);
  68         *lp = lppaca[0];
  69
  70         return lp;
  71 }
  72
  73 static void free_lppacas(void)
  74 {
  75         long new_size = 0, nr;
  76
  77         if (!lppaca_size)
  78                 return;
  79         nr = num_possible_cpus() - NR_LPPACAS;
  80         if (nr > 0)
  81                 new_size = PAGE_ALIGN(nr * sizeof(struct lppaca));
  82         if (new_size >= lppaca_size)
  83                 return;
  84
  85         memblock_free(__pa(extra_lppacas) + new_size, lppaca_size - new_size);
  86         lppaca_size = new_size;
  87 }
  88
  89 #else
  90
  91 static inline void allocate_lppacas(int nr_cpus, unsigned long limit) { }
  92 static inline void free_lppacas(void) { }
  93
  94 #endif /* CONFIG_PPC_BOOK3S */
  95
  96 #ifdef CONFIG_PPC_STD_MMU_64
  97
  98 /*
  99  * 3 persistent SLBs are registered here.  The buffer will be zero
 100  * initially, hence will all be invaild until we actually write them.
 101  */
 102 struct slb_shadow slb_shadow[] __cacheline_aligned = {
 103         [0 ... (NR_CPUS-1)] = {
 104                 .persistent = cpu_to_be32(SLB_NUM_BOLTED),
 105                 .buffer_length = cpu_to_be32(sizeof(struct slb_shadow)),
 106         },
 107 };
 108
 109 #endif /* CONFIG_PPC_STD_MMU_64 */
 110
 111 /* The Paca is an array with one entry per processor.  Each contains an
 112  * lppaca, which contains the information shared between the
 113  * hypervisor and Linux.
 114  * On systems with hardware multi-threading, there are two threads
 115  * per processor.  The Paca array must contain an entry for each thread.
 116  * The VPD Areas will give a max logical processors = 2 * max physical
 117  * processors.  The processor VPD array needs one entry per physical
 118  * processor (not thread).
 119  */
 120 struct paca_struct *paca;
 121 EXPORT_SYMBOL(paca);
 122
 123 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 124 {
 125        /* The TOC register (GPR2) points 32kB into the TOC, so that 64kB
 126         * of the TOC can be addressed using a single machine instruction.
 127         */
 128         unsigned long kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL;
 129
 130 #ifdef CONFIG_PPC_BOOK3S
 131         new_paca->lppaca_ptr = new_lppaca(cpu);
 132 #else
 133         new_paca->kernel_pgd = swapper_pg_dir;
 134 #endif
 135         new_paca->lock_token = 0x8000;
 136         new_paca->paca_index = cpu;
 137         new_paca->kernel_toc = kernel_toc;
 138         new_paca->kernelbase = (unsigned long) _stext;
 139         new_paca->kernel_msr = MSR_KERNEL;
 140         new_paca->hw_cpu_id = 0xffff;
 141         new_paca->kexec_state = KEXEC_STATE_NONE;
 142         new_paca->__current = &init_task;
 143         new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
 144 #ifdef CONFIG_PPC_STD_MMU_64
 145         new_paca->slb_shadow_ptr = &slb_shadow[cpu];
 146 #endif /* CONFIG_PPC_STD_MMU_64 */
 147 }
 148
 149 /* Put the paca pointer into r13 and SPRG_PACA */
 150 void setup_paca(struct paca_struct *new_paca)
 151 {
 152         /* Setup r13 */
 153         local_paca = new_paca;
 154
 155 #ifdef CONFIG_PPC_BOOK3E
 156         /* On Book3E, initialize the TLB miss exception frames */
 157         mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
 158 #else
 159         /* In HV mode, we setup both HPACA and PACA to avoid problems
 160          * if we do a GET_PACA() before the feature fixups have been
 161          * applied
 162          */
 163         if (cpu_has_feature(CPU_FTR_HVMODE))
 164                 mtspr(SPRN_SPRG_HPACA, local_paca);
 165 #endif
 166         mtspr(SPRN_SPRG_PACA, local_paca);
 167
 168 }
 169
 170 static int __initdata paca_size;
 171
 172 void __init allocate_pacas(void)
 173 {
 174         int cpu, limit;
 175
 176         /*
 177          * We can't take SLB misses on the paca, and we want to access them
 178          * in real mode, so allocate them within the RMA and also within
 179          * the first segment.
 180          */
 181         limit = min(0x10000000ULL, ppc64_rma_size);
 182
 183         paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 184
 185         paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
 186         memset(paca, 0, paca_size);
 187
 188         printk(KERN_DEBUG "Allocated %u bytes for %d pacas at %p\n",
 189                 paca_size, nr_cpu_ids, paca);
 190
 191         allocate_lppacas(nr_cpu_ids, limit);
 192
 193         /* Can't use for_each_*_cpu, as they aren't functional yet */
 194         for (cpu = 0; cpu < nr_cpu_ids; cpu++)
 195                 initialise_paca(&paca[cpu], cpu);
 196 }
 197
 198 void __init free_unused_pacas(void)
 199 {
 200         int new_size;
 201
 202         new_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 203
 204         if (new_size >= paca_size)
 205                 return;
 206
 207         memblock_free(__pa(paca) + new_size, paca_size - new_size);
 208
 209         printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
 210                 paca_size - new_size);
 211
 212         paca_size = new_size;
 213
 214         free_lppacas();
 215 }