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/firmware.h>
  15 #include <asm/lppaca.h>
  16 #include <asm/paca.h>
  17 #include <asm/sections.h>
  18 #include <asm/pgtable.h>
  19 #include <asm/iseries/lpar_map.h>
  20 #include <asm/iseries/hv_types.h>
  21 #include <asm/kexec.h>
  22
  23 /* This symbol is provided by the linker - let it fill in the paca
  24  * field correctly */
  25 extern unsigned long __toc_start;
  26
  27 #ifdef CONFIG_PPC_BOOK3S
  28
  29 /*
  30  * The structure which the hypervisor knows about - this structure
  31  * should not cross a page boundary.  The vpa_init/register_vpa call
  32  * is now known to fail if the lppaca structure crosses a page
  33  * boundary.  The lppaca is also used on legacy iSeries and POWER5
  34  * pSeries boxes.  The lppaca is 640 bytes long, and cannot readily
  35  * change since the hypervisor knows its layout, so a 1kB alignment
  36  * will suffice to ensure that it doesn't cross a page boundary.
  37  */
  38 struct lppaca lppaca[] = {
  39         [0 ... (NR_LPPACAS-1)] = {
  40                 .desc = 0xd397d781,     /* "LpPa" */
  41                 .size = sizeof(struct lppaca),
  42                 .dyn_proc_status = 2,
  43                 .decr_val = 0x00ff0000,
  44                 .fpregs_in_use = 1,
  45                 .end_of_quantum = 0xfffffffffffffffful,
  46                 .slb_count = 64,
  47                 .vmxregs_in_use = 0,
  48                 .page_ins = 0,
  49         },
  50 };
  51
  52 static struct lppaca *extra_lppacas;
  53 static long __initdata lppaca_size;
  54
  55 static void allocate_lppacas(int nr_cpus, unsigned long limit)
  56 {
  57         if (nr_cpus <= NR_LPPACAS)
  58                 return;
  59
  60         lppaca_size = PAGE_ALIGN(sizeof(struct lppaca) *
  61                                  (nr_cpus - NR_LPPACAS));
  62         extra_lppacas = __va(memblock_alloc_base(lppaca_size,
  63                                                  PAGE_SIZE, limit));
  64 }
  65
  66 static struct lppaca *new_lppaca(int cpu)
  67 {
  68         struct lppaca *lp;
  69
  70         if (cpu < NR_LPPACAS)
  71                 return &lppaca[cpu];
  72
  73         lp = extra_lppacas + (cpu - NR_LPPACAS);
  74         *lp = lppaca[0];
  75
  76         return lp;
  77 }
  78
  79 static void free_lppacas(void)
  80 {
  81         long new_size = 0, nr;
  82
  83         if (!lppaca_size)
  84                 return;
  85         nr = num_possible_cpus() - NR_LPPACAS;
  86         if (nr > 0)
  87                 new_size = PAGE_ALIGN(nr * sizeof(struct lppaca));
  88         if (new_size >= lppaca_size)
  89                 return;
  90
  91         memblock_free(__pa(extra_lppacas) + new_size, lppaca_size - new_size);
  92         lppaca_size = new_size;
  93 }
  94
  95 #else
  96
  97 static inline void allocate_lppacas(int nr_cpus, unsigned long limit) { }
  98 static inline void free_lppacas(void) { }
  99
 100 #endif /* CONFIG_PPC_BOOK3S */
 101
 102 #ifdef CONFIG_PPC_STD_MMU_64
 103
 104 /*
 105  * 3 persistent SLBs are registered here.  The buffer will be zero
 106  * initially, hence will all be invaild until we actually write them.
 107  */
 108 struct slb_shadow slb_shadow[] __cacheline_aligned = {
 109         [0 ... (NR_CPUS-1)] = {
 110                 .persistent = SLB_NUM_BOLTED,
 111                 .buffer_length = sizeof(struct slb_shadow),
 112         },
 113 };
 114
 115 #endif /* CONFIG_PPC_STD_MMU_64 */
 116
 117 /* The Paca is an array with one entry per processor.  Each contains an
 118  * lppaca, which contains the information shared between the
 119  * hypervisor and Linux.
 120  * On systems with hardware multi-threading, there are two threads
 121  * per processor.  The Paca array must contain an entry for each thread.
 122  * The VPD Areas will give a max logical processors = 2 * max physical
 123  * processors.  The processor VPD array needs one entry per physical
 124  * processor (not thread).
 125  */
 126 struct paca_struct *paca;
 127 EXPORT_SYMBOL(paca);
 128
 129 struct paca_struct boot_paca;
 130
 131 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 132 {
 133        /* The TOC register (GPR2) points 32kB into the TOC, so that 64kB
 134         * of the TOC can be addressed using a single machine instruction.
 135         */
 136         unsigned long kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL;
 137
 138 #ifdef CONFIG_PPC_BOOK3S
 139         new_paca->lppaca_ptr = new_lppaca(cpu);
 140 #else
 141         new_paca->kernel_pgd = swapper_pg_dir;
 142 #endif
 143         new_paca->lock_token = 0x8000;
 144         new_paca->paca_index = cpu;
 145         new_paca->kernel_toc = kernel_toc;
 146         new_paca->kernelbase = (unsigned long) _stext;
 147         new_paca->kernel_msr = MSR_KERNEL;
 148         new_paca->hw_cpu_id = 0xffff;
 149         new_paca->kexec_state = KEXEC_STATE_NONE;
 150         new_paca->__current = &init_task;
 151 #ifdef CONFIG_PPC_STD_MMU_64
 152         new_paca->slb_shadow_ptr = &slb_shadow[cpu];
 153 #endif /* CONFIG_PPC_STD_MMU_64 */
 154 }
 155
 156 /* Put the paca pointer into r13 and SPRG_PACA */
 157 void setup_paca(struct paca_struct *new_paca)
 158 {
 159         /* Setup r13 */
 160         local_paca = new_paca;
 161
 162 #ifdef CONFIG_PPC_BOOK3E
 163         /* On Book3E, initialize the TLB miss exception frames */
 164         mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
 165 #else
 166         /* In HV mode, we setup both HPACA and PACA to avoid problems
 167          * if we do a GET_PACA() before the feature fixups have been
 168          * applied
 169          */
 170         if (cpu_has_feature(CPU_FTR_HVMODE))
 171                 mtspr(SPRN_SPRG_HPACA, local_paca);
 172 #endif
 173         mtspr(SPRN_SPRG_PACA, local_paca);
 174
 175 }
 176
 177 static int __initdata paca_size;
 178
 179 void __init allocate_pacas(void)
 180 {
 181         int cpu, limit;
 182
 183         /*
 184          * We can't take SLB misses on the paca, and we want to access them
 185          * in real mode, so allocate them within the RMA and also within
 186          * the first segment. On iSeries they must be within the area mapped
 187          * by the HV, which is HvPagesToMap * HVPAGESIZE bytes.
 188          */
 189         limit = min(0x10000000ULL, ppc64_rma_size);
 190         if (firmware_has_feature(FW_FEATURE_ISERIES))
 191                 limit = min(limit, HvPagesToMap * HVPAGESIZE);
 192
 193         paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 194
 195         paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
 196         memset(paca, 0, paca_size);
 197
 198         printk(KERN_DEBUG "Allocated %u bytes for %d pacas at %p\n",
 199                 paca_size, nr_cpu_ids, paca);
 200
 201         allocate_lppacas(nr_cpu_ids, limit);
 202
 203         /* Can't use for_each_*_cpu, as they aren't functional yet */
 204         for (cpu = 0; cpu < nr_cpu_ids; cpu++)
 205                 initialise_paca(&paca[cpu], cpu);
 206 }
 207
 208 void __init free_unused_pacas(void)
 209 {
 210         int new_size;
 211
 212         new_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
 213
 214         if (new_size >= paca_size)
 215                 return;
 216
 217         memblock_free(__pa(paca) + new_size, paca_size - new_size);
 218
 219         printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
 220                 paca_size - new_size);
 221
 222         paca_size = new_size;
 223
 224         free_lppacas();
 225 }