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/lmb.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
  22 /* This symbol is provided by the linker - let it fill in the paca
  23  * field correctly */
  24 extern unsigned long __toc_start;
  25
  26 #ifdef CONFIG_PPC_BOOK3S
  27
  28 /*
  29  * The structure which the hypervisor knows about - this structure
  30  * should not cross a page boundary.  The vpa_init/register_vpa call
  31  * is now known to fail if the lppaca structure crosses a page
  32  * boundary.  The lppaca is also used on legacy iSeries and POWER5
  33  * pSeries boxes.  The lppaca is 640 bytes long, and cannot readily
  34  * change since the hypervisor knows its layout, so a 1kB alignment
  35  * will suffice to ensure that it doesn't cross a page boundary.
  36  */
  37 struct lppaca lppaca[] = {
  38         [0 ... (NR_CPUS-1)] = {
  39                 .desc = 0xd397d781,     /* "LpPa" */
  40                 .size = sizeof(struct lppaca),
  41                 .dyn_proc_status = 2,
  42                 .decr_val = 0x00ff0000,
  43                 .fpregs_in_use = 1,
  44                 .end_of_quantum = 0xfffffffffffffffful,
  45                 .slb_count = 64,
  46                 .vmxregs_in_use = 0,
  47                 .page_ins = 0,
  48         },
  49 };
  50
  51 #endif /* CONFIG_PPC_BOOK3S */
  52
  53 #ifdef CONFIG_PPC_STD_MMU_64
  54
  55 /*
  56  * 3 persistent SLBs are registered here.  The buffer will be zero
  57  * initially, hence will all be invaild until we actually write them.
  58  */
  59 struct slb_shadow slb_shadow[] __cacheline_aligned = {
  60         [0 ... (NR_CPUS-1)] = {
  61                 .persistent = SLB_NUM_BOLTED,
  62                 .buffer_length = sizeof(struct slb_shadow),
  63         },
  64 };
  65
  66 #endif /* CONFIG_PPC_STD_MMU_64 */
  67
  68 /* The Paca is an array with one entry per processor.  Each contains an
  69  * lppaca, which contains the information shared between the
  70  * hypervisor and Linux.
  71  * On systems with hardware multi-threading, there are two threads
  72  * per processor.  The Paca array must contain an entry for each thread.
  73  * The VPD Areas will give a max logical processors = 2 * max physical
  74  * processors.  The processor VPD array needs one entry per physical
  75  * processor (not thread).
  76  */
  77 struct paca_struct *paca;
  78 EXPORT_SYMBOL(paca);
  79
  80 struct paca_struct boot_paca;
  81
  82 void __init initialise_paca(struct paca_struct *new_paca, int cpu)
  83 {
  84        /* The TOC register (GPR2) points 32kB into the TOC, so that 64kB
  85         * of the TOC can be addressed using a single machine instruction.
  86         */
  87         unsigned long kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL;
  88
  89 #ifdef CONFIG_PPC_BOOK3S
  90         new_paca->lppaca_ptr = &lppaca[cpu];
  91 #else
  92         new_paca->kernel_pgd = swapper_pg_dir;
  93 #endif
  94         new_paca->lock_token = 0x8000;
  95         new_paca->paca_index = cpu;
  96         new_paca->kernel_toc = kernel_toc;
  97         new_paca->kernelbase = (unsigned long) _stext;
  98         new_paca->kernel_msr = MSR_KERNEL;
  99         new_paca->hw_cpu_id = 0xffff;
 100         new_paca->__current = &init_task;
 101 #ifdef CONFIG_PPC_STD_MMU_64
 102         new_paca->slb_shadow_ptr = &slb_shadow[cpu];
 103 #endif /* CONFIG_PPC_STD_MMU_64 */
 104 }
 105
 106 static int __initdata paca_size;
 107
 108 void __init allocate_pacas(void)
 109 {
 110         int nr_cpus, cpu, limit;
 111
 112         /*
 113          * We can't take SLB misses on the paca, and we want to access them
 114          * in real mode, so allocate them within the RMA and also within
 115          * the first segment. On iSeries they must be within the area mapped
 116          * by the HV, which is HvPagesToMap * HVPAGESIZE bytes.
 117          */
 118         limit = min(0x10000000ULL, lmb.rmo_size);
 119         if (firmware_has_feature(FW_FEATURE_ISERIES))
 120                 limit = min(limit, HvPagesToMap * HVPAGESIZE);
 121
 122         nr_cpus = NR_CPUS;
 123         /* On iSeries we know we can never have more than 64 cpus */
 124         if (firmware_has_feature(FW_FEATURE_ISERIES))
 125                 nr_cpus = min(64, nr_cpus);
 126
 127         paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpus);
 128
 129         paca = __va(lmb_alloc_base(paca_size, PAGE_SIZE, limit));
 130         memset(paca, 0, paca_size);
 131
 132         printk(KERN_DEBUG "Allocated %u bytes for %d pacas at %p\n",
 133                 paca_size, nr_cpus, paca);
 134
 135         /* Can't use for_each_*_cpu, as they aren't functional yet */
 136         for (cpu = 0; cpu < nr_cpus; cpu++)
 137                 initialise_paca(&paca[cpu], cpu);
 138 }
 139
 140 void __init free_unused_pacas(void)
 141 {
 142         int new_size;
 143
 144         new_size = PAGE_ALIGN(sizeof(struct paca_struct) * num_possible_cpus());
 145
 146         if (new_size >= paca_size)
 147                 return;
 148
 149         lmb_free(__pa(paca) + new_size, paca_size - new_size);
 150
 151         printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
 152                 paca_size - new_size);
 153
 154         paca_size = new_size;
 155 }