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/threads.h>
  11 #include <linux/module.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  * We only have to have statically allocated lppaca structs on
  31  * legacy iSeries, which supports at most 64 cpus.
  32  */
  33 #ifdef CONFIG_PPC_ISERIES
  34 #if NR_CPUS < 64
  35 #define NR_LPPACAS      NR_CPUS
  36 #else
  37 #define NR_LPPACAS      64
  38 #endif
  39 #else /* not iSeries */
  40 #define NR_LPPACAS      1
  41 #endif
  42
  43 /*
  44  * The structure which the hypervisor knows about - this structure
  45  * should not cross a page boundary.  The vpa_init/register_vpa call
  46  * is now known to fail if the lppaca structure crosses a page
  47  * boundary.  The lppaca is also used on legacy iSeries and POWER5
  48  * pSeries boxes.  The lppaca is 640 bytes long, and cannot readily
  49  * change since the hypervisor knows its layout, so a 1kB alignment
  50  * will suffice to ensure that it doesn't cross a page boundary.
  51  */
  52 struct lppaca lppaca[] = {
  53         [0 ... (NR_LPPACAS-1)] = {
  54                 .desc = 0xd397d781,     /* "LpPa" */
  55                 .size = sizeof(struct lppaca),
  56                 .dyn_proc_status = 2,
  57                 .decr_val = 0x00ff0000,
  58                 .fpregs_in_use = 1,
  59                 .end_of_quantum = 0xfffffffffffffffful,
  60                 .slb_count = 64,
  61                 .vmxregs_in_use = 0,
  62                 .page_ins = 0,
  63         },
  64 };
  65
  66 static struct lppaca *extra_lppacas;
  67 static long __initdata lppaca_size;
  68
  69 static void allocate_lppacas(int nr_cpus, unsigned long limit)
  70 {
  71         if (nr_cpus <= NR_LPPACAS)
  72                 return;
  73
  74         lppaca_size = PAGE_ALIGN(sizeof(struct lppaca) *
  75                                  (nr_cpus - NR_LPPACAS));
  76         extra_lppacas = __va(memblock_alloc_base(lppaca_size,
  77                                                  PAGE_SIZE, limit));
  78 }
  79
  80 static struct lppaca *new_lppaca(int cpu)
  81 {
  82         struct lppaca *lp;
  83
  84         if (cpu < NR_LPPACAS)
  85                 return &lppaca[cpu];
  86
  87         lp = extra_lppacas + (cpu - NR_LPPACAS);
  88         *lp = lppaca[0];
  89
  90         return lp;
  91 }
  92
  93 static void free_lppacas(void)
  94 {
  95         long new_size = 0, nr;
  96
  97         if (!lppaca_size)
  98                 return;
  99         nr = num_possible_cpus() - NR_LPPACAS;
 100         if (nr > 0)
 101                 new_size = PAGE_ALIGN(nr * sizeof(struct lppaca));
 102         if (new_size >= lppaca_size)
 103                 return;
 104
 105         memblock_free(__pa(extra_lppacas) + new_size, lppaca_size - new_size);
 106         lppaca_size = new_size;
 107 }
 108
 109 #else
 110
 111 static inline void allocate_lppacas(int nr_cpus, unsigned long limit) { }
 112 static inline void free_lppacas(void) { }
 113
 114 #endif /* CONFIG_PPC_BOOK3S */
 115
 116 #ifdef CONFIG_PPC_STD_MMU_64
 117
 118 /*
 119  * 3 persistent SLBs are registered here.  The buffer will be zero
 120  * initially, hence will all be invaild until we actually write them.
 121  */
 122 struct slb_shadow slb_shadow[] __cacheline_aligned = {
 123         [0 ... (NR_CPUS-1)] = {
 124                 .persistent = SLB_NUM_BOLTED,
 125                 .buffer_length = sizeof(struct slb_shadow),
 126         },
 127 };
 128
 129 #endif /* CONFIG_PPC_STD_MMU_64 */
 130
 131 /* The Paca is an array with one entry per processor.  Each contains an
 132  * lppaca, which contains the information shared between the
 133  * hypervisor and Linux.
 134  * On systems with hardware multi-threading, there are two threads
 135  * per processor.  The Paca array must contain an entry for each thread.
 136  * The VPD Areas will give a max logical processors = 2 * max physical
 137  * processors.  The processor VPD array needs one entry per physical
 138  * processor (not thread).
 139  */
 140 struct paca_struct *paca;
 141 EXPORT_SYMBOL(paca);
 142
 143 struct paca_struct boot_paca;
 144
 145 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 146 {
 147        /* The TOC register (GPR2) points 32kB into the TOC, so that 64kB
 148         * of the TOC can be addressed using a single machine instruction.
 149         */
 150         unsigned long kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL;
 151
 152 #ifdef CONFIG_PPC_BOOK3S
 153         new_paca->lppaca_ptr = new_lppaca(cpu);
 154 #else
 155         new_paca->kernel_pgd = swapper_pg_dir;
 156 #endif
 157         new_paca->lock_token = 0x8000;
 158         new_paca->paca_index = cpu;
 159         new_paca->kernel_toc = kernel_toc;
 160         new_paca->kernelbase = (unsigned long) _stext;
 161         new_paca->kernel_msr = MSR_KERNEL;
 162         new_paca->hw_cpu_id = 0xffff;
 163         new_paca->kexec_state = KEXEC_STATE_NONE;
 164         new_paca->__current = &init_task;
 165 #ifdef CONFIG_PPC_STD_MMU_64
 166         new_paca->slb_shadow_ptr = &slb_shadow[cpu];
 167 #endif /* CONFIG_PPC_STD_MMU_64 */
 168 }
 169
 170 /* Put the paca pointer into r13 and SPRG_PACA */
 171 void setup_paca(struct paca_struct *new_paca)
 172 {
 173         local_paca = new_paca;
 174         mtspr(SPRN_SPRG_PACA, local_paca);
 175 #ifdef CONFIG_PPC_BOOK3E
 176         mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
 177 #endif
 178 }
 179
 180 static int __initdata paca_size;
 181
 182 void __init allocate_pacas(void)
 183 {
 184         int nr_cpus, cpu, limit;
 185
 186         /*
 187          * We can't take SLB misses on the paca, and we want to access them
 188          * in real mode, so allocate them within the RMA and also within
 189          * the first segment. On iSeries they must be within the area mapped
 190          * by the HV, which is HvPagesToMap * HVPAGESIZE bytes.
 191          */
 192         limit = min(0x10000000ULL, ppc64_rma_size);
 193         if (firmware_has_feature(FW_FEATURE_ISERIES))
 194                 limit = min(limit, HvPagesToMap * HVPAGESIZE);
 195
 196         nr_cpus = NR_CPUS;
 197         /* On iSeries we know we can never have more than 64 cpus */
 198         if (firmware_has_feature(FW_FEATURE_ISERIES))
 199                 nr_cpus = min(64, nr_cpus);
 200
 201         paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpus);
 202
 203         paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
 204         memset(paca, 0, paca_size);
 205
 206         printk(KERN_DEBUG "Allocated %u bytes for %d pacas at %p\n",
 207                 paca_size, nr_cpus, paca);
 208
 209         allocate_lppacas(nr_cpus, limit);
 210
 211         /* Can't use for_each_*_cpu, as they aren't functional yet */
 212         for (cpu = 0; cpu < nr_cpus; cpu++)
 213                 initialise_paca(&paca[cpu], cpu);
 214 }
 215
 216 void __init free_unused_pacas(void)
 217 {
 218         int new_size;
 219
 220         new_size = PAGE_ALIGN(sizeof(struct paca_struct) * num_possible_cpus());
 221
 222         if (new_size >= paca_size)
 223                 return;
 224
 225         memblock_free(__pa(paca) + new_size, paca_size - new_size);
 226
 227         printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
 228                 paca_size - new_size);
 229
 230         paca_size = new_size;
 231
 232         free_lppacas();
 233 }