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  * 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_CPUS-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 #endif /* CONFIG_PPC_BOOK3S */
  53
  54 #ifdef CONFIG_PPC_STD_MMU_64
  55
  56 /*
  57  * 3 persistent SLBs are registered here.  The buffer will be zero
  58  * initially, hence will all be invaild until we actually write them.
  59  */
  60 struct slb_shadow slb_shadow[] __cacheline_aligned = {
  61         [0 ... (NR_CPUS-1)] = {
  62                 .persistent = SLB_NUM_BOLTED,
  63                 .buffer_length = sizeof(struct slb_shadow),
  64         },
  65 };
  66
  67 #endif /* CONFIG_PPC_STD_MMU_64 */
  68
  69 /* The Paca is an array with one entry per processor.  Each contains an
  70  * lppaca, which contains the information shared between the
  71  * hypervisor and Linux.
  72  * On systems with hardware multi-threading, there are two threads
  73  * per processor.  The Paca array must contain an entry for each thread.
  74  * The VPD Areas will give a max logical processors = 2 * max physical
  75  * processors.  The processor VPD array needs one entry per physical
  76  * processor (not thread).
  77  */
  78 struct paca_struct *paca;
  79 EXPORT_SYMBOL(paca);
  80
  81 struct paca_struct boot_paca;
  82
  83 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
  84 {
  85        /* The TOC register (GPR2) points 32kB into the TOC, so that 64kB
  86         * of the TOC can be addressed using a single machine instruction.
  87         */
  88         unsigned long kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL;
  89
  90 #ifdef CONFIG_PPC_BOOK3S
  91         new_paca->lppaca_ptr = &lppaca[cpu];
  92 #else
  93         new_paca->kernel_pgd = swapper_pg_dir;
  94 #endif
  95         new_paca->lock_token = 0x8000;
  96         new_paca->paca_index = cpu;
  97         new_paca->kernel_toc = kernel_toc;
  98         new_paca->kernelbase = (unsigned long) _stext;
  99         new_paca->kernel_msr = MSR_KERNEL;
 100         new_paca->hw_cpu_id = 0xffff;
 101         new_paca->kexec_state = KEXEC_STATE_NONE;
 102         new_paca->__current = &init_task;
 103 #ifdef CONFIG_PPC_STD_MMU_64
 104         new_paca->slb_shadow_ptr = &slb_shadow[cpu];
 105 #endif /* CONFIG_PPC_STD_MMU_64 */
 106 }
 107
 108 /* Put the paca pointer into r13 and SPRG_PACA */
 109 void setup_paca(struct paca_struct *new_paca)
 110 {
 111         local_paca = new_paca;
 112         mtspr(SPRN_SPRG_PACA, local_paca);
 113 #ifdef CONFIG_PPC_BOOK3E
 114         mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb);
 115 #endif
 116 }
 117
 118 static int __initdata paca_size;
 119
 120 void __init allocate_pacas(void)
 121 {
 122         int nr_cpus, cpu, limit;
 123
 124         /*
 125          * We can't take SLB misses on the paca, and we want to access them
 126          * in real mode, so allocate them within the RMA and also within
 127          * the first segment. On iSeries they must be within the area mapped
 128          * by the HV, which is HvPagesToMap * HVPAGESIZE bytes.
 129          */
 130         limit = min(0x10000000ULL, memblock.rmo_size);
 131         if (firmware_has_feature(FW_FEATURE_ISERIES))
 132                 limit = min(limit, HvPagesToMap * HVPAGESIZE);
 133
 134         nr_cpus = NR_CPUS;
 135         /* On iSeries we know we can never have more than 64 cpus */
 136         if (firmware_has_feature(FW_FEATURE_ISERIES))
 137                 nr_cpus = min(64, nr_cpus);
 138
 139         paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpus);
 140
 141         paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
 142         memset(paca, 0, paca_size);
 143
 144         printk(KERN_DEBUG "Allocated %u bytes for %d pacas at %p\n",
 145                 paca_size, nr_cpus, paca);
 146
 147         /* Can't use for_each_*_cpu, as they aren't functional yet */
 148         for (cpu = 0; cpu < nr_cpus; cpu++)
 149                 initialise_paca(&paca[cpu], cpu);
 150 }
 151
 152 void __init free_unused_pacas(void)
 153 {
 154         int new_size;
 155
 156         new_size = PAGE_ALIGN(sizeof(struct paca_struct) * num_possible_cpus());
 157
 158         if (new_size >= paca_size)
 159                 return;
 160
 161         memblock_free(__pa(paca) + new_size, paca_size - new_size);
 162
 163         printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
 164                 paca_size - new_size);
 165
 166         paca_size = new_size;
 167 }