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 = 0xd397d781,     /* "LpPa" */
  38                 .size = sizeof(struct lppaca),
  39                 .dyn_proc_status = 2,
  40                 .decr_val = 0x00ff0000,
  41                 .fpregs_in_use = 1,
  42                 .end_of_quantum = 0xfffffffffffffffful,
  43                 .slb_count = 64,
  44                 .vmxregs_in_use = 0,
  45                 .page_ins = 0,
  46         },
  47 };
  48
  49 static struct lppaca *extra_lppacas;
  50 static long __initdata lppaca_size;
  51
  52 static void allocate_lppacas(int nr_cpus, unsigned long limit)
  53 {
  54         if (nr_cpus <= NR_LPPACAS)
  55                 return;
  56
  57         lppaca_size = PAGE_ALIGN(sizeof(struct lppaca) *
  58                                  (nr_cpus - NR_LPPACAS));
  59         extra_lppacas = __va(memblock_alloc_base(lppaca_size,
  60                                                  PAGE_SIZE, limit));
  61 }
  62
  63 static struct lppaca *new_lppaca(int cpu)
  64 {
  65         struct lppaca *lp;
  66
  67         if (cpu < NR_LPPACAS)
  68                 return &lppaca[cpu];
  69
  70         lp = extra_lppacas + (cpu - NR_LPPACAS);
  71         *lp = lppaca[0];
  72
  73         return lp;
  74 }
  75
  76 static void free_lppacas(void)
  77 {
  78         long new_size = 0, nr;
  79
  80         if (!lppaca_size)
  81                 return;
  82         nr = num_possible_cpus() - NR_LPPACAS;
  83         if (nr > 0)
  84                 new_size = PAGE_ALIGN(nr * sizeof(struct lppaca));
  85         if (new_size >= lppaca_size)
  86                 return;
  87
  88         memblock_free(__pa(extra_lppacas) + new_size, lppaca_size - new_size);
  89         lppaca_size = new_size;
  90 }
  91
  92 #else
  93
  94 static inline void allocate_lppacas(int nr_cpus, unsigned long limit) { }
  95 static inline void free_lppacas(void) { }
  96
  97 #endif /* CONFIG_PPC_BOOK3S */
  98
  99 #ifdef CONFIG_PPC_STD_MMU_64
 100
 101 /*
 102  * 3 persistent SLBs are registered here.  The buffer will be zero
 103  * initially, hence will all be invaild until we actually write them.
 104  */
 105 struct slb_shadow slb_shadow[] __cacheline_aligned = {
 106         [0 ... (NR_CPUS-1)] = {
 107                 .persistent = SLB_NUM_BOLTED,
 108                 .buffer_length = sizeof(struct slb_shadow),
 109         },
 110 };
 111
 112 #endif /* CONFIG_PPC_STD_MMU_64 */
 113
 114 /* The Paca is an array with one entry per processor.  Each contains an
 115  * lppaca, which contains the information shared between the
 116  * hypervisor and Linux.
 117  * On systems with hardware multi-threading, there are two threads
 118  * per processor.  The Paca array must contain an entry for each thread.
 119  * The VPD Areas will give a max logical processors = 2 * max physical
 120  * processors.  The processor VPD array needs one entry per physical
 121  * processor (not thread).
 122  */
 123 struct paca_struct *paca;
 124 EXPORT_SYMBOL(paca);
 125
 126 struct paca_struct boot_paca;
 127
 128 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 129 {
 130        /* The TOC register (GPR2) points 32kB into the TOC, so that 64kB
 131         * of the TOC can be addressed using a single machine instruction.
 132         */
 133         unsigned long kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL;
 134
 135 #ifdef CONFIG_PPC_BOOK3S
 136         new_paca->lppaca_ptr = new_lppaca(cpu);
 137 #else
 138         new_paca->kernel_pgd = swapper_pg_dir;
 139 #endif
 140         new_paca->lock_token = 0x8000;
 141         new_paca->paca_index = cpu;
 142         new_paca->kernel_toc = kernel_toc;
 143         new_paca->kernelbase = (unsigned long) _stext;
 144         new_paca->kernel_msr = MSR_KERNEL;
 145         new_paca->hw_cpu_id = 0xffff;
 146         new_paca->kexec_state = KEXEC_STATE_NONE;
 147         new_paca->__current = &init_task;
 148 #ifdef CONFIG_PPC_STD_MMU_64
 149         new_paca->slb_shadow_ptr = &slb_shadow[cpu];
 150 #endif /* CONFIG_PPC_STD_MMU_64 */
 151 }
 152
 153 /* Put the paca pointer into r13 and SPRG_PACA */
 154 void setup_paca(struct paca_struct *new_paca)
 155 {
 156         /* Setup r13 */
 157         local_paca = new_paca;
 158
 159 #ifdef CONFIG_PPC_BOOK3E
 160         /* On Book3E, initialize the TLB miss exception frames */
 161         mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
 162 #else
 163         /* In HV mode, we setup both HPACA and PACA to avoid problems
 164          * if we do a GET_PACA() before the feature fixups have been
 165          * applied
 166          */
 167         if (cpu_has_feature(CPU_FTR_HVMODE))
 168                 mtspr(SPRN_SPRG_HPACA, local_paca);
 169 #endif
 170         mtspr(SPRN_SPRG_PACA, local_paca);
 171
 172 }
 173
 174 static int __initdata paca_size;
 175
 176 void __init allocate_pacas(void)
 177 {
 178         int cpu, limit;
 179
 180         /*
 181          * We can't take SLB misses on the paca, and we want to access them
 182          * in real mode, so allocate them within the RMA and also within
 183          * the first segment.
 184          */
 185         limit = min(0x10000000ULL, ppc64_rma_size);
 186
 187         paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 188
 189         paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
 190         memset(paca, 0, paca_size);
 191
 192         printk(KERN_DEBUG "Allocated %u bytes for %d pacas at %p\n",
 193                 paca_size, nr_cpu_ids, paca);
 194
 195         allocate_lppacas(nr_cpu_ids, limit);
 196
 197         /* Can't use for_each_*_cpu, as they aren't functional yet */
 198         for (cpu = 0; cpu < nr_cpu_ids; cpu++)
 199                 initialise_paca(&paca[cpu], cpu);
 200 }
 201
 202 void __init free_unused_pacas(void)
 203 {
 204         int new_size;
 205
 206         new_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 207
 208         if (new_size >= paca_size)
 209                 return;
 210
 211         memblock_free(__pa(paca) + new_size, paca_size - new_size);
 212
 213         printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
 214                 paca_size - new_size);
 215
 216         paca_size = new_size;
 217
 218         free_lppacas();
 219 }