arch/powerpc/mm/init-common.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  PowerPC version
   4  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   5  *
   6  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
   7  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
   8  *    Copyright (C) 1996 Paul Mackerras
   9  *
  10  *  Derived from "arch/i386/mm/init.c"
  11  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  12  *
  13  *  Dave Engebretsen <engebret@us.ibm.com>
  14  *      Rework for PPC64 port.
  15  */
  16
  17 #undef DEBUG
  18
  19 #include <linux/string.h>
  20 #include <linux/pgtable.h>
  21 #include <asm/pgalloc.h>
  22 #include <asm/kup.h>
  23 #include <asm/smp.h>
  24
  25 phys_addr_t memstart_addr __ro_after_init = (phys_addr_t)~0ull;
  26 EXPORT_SYMBOL_GPL(memstart_addr);
  27 phys_addr_t kernstart_addr __ro_after_init;
  28 EXPORT_SYMBOL_GPL(kernstart_addr);
  29 unsigned long kernstart_virt_addr __ro_after_init = KERNELBASE;
  30 EXPORT_SYMBOL_GPL(kernstart_virt_addr);
  31
  32 bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP);
  33 bool disable_kuap = !IS_ENABLED(CONFIG_PPC_KUAP);
  34 #ifdef CONFIG_KFENCE
  35 bool __ro_after_init kfence_disabled;
  36 bool __ro_after_init kfence_early_init = !!CONFIG_KFENCE_SAMPLE_INTERVAL;
  37 #endif
  38
  39 static int __init parse_nosmep(char *p)
  40 {
  41         if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))
  42                 return 0;
  43
  44         disable_kuep = true;
  45         pr_warn("Disabling Kernel Userspace Execution Prevention\n");
  46         return 0;
  47 }
  48 early_param("nosmep", parse_nosmep);
  49
  50 static int __init parse_nosmap(char *p)
  51 {
  52         disable_kuap = true;
  53         pr_warn("Disabling Kernel Userspace Access Protection\n");
  54         return 0;
  55 }
  56 early_param("nosmap", parse_nosmap);
  57
  58 void __weak setup_kuep(bool disabled)
  59 {
  60         if (!IS_ENABLED(CONFIG_PPC_KUEP) || disabled)
  61                 return;
  62
  63         if (smp_processor_id() != boot_cpuid)
  64                 return;
  65
  66         pr_info("Activating Kernel Userspace Execution Prevention\n");
  67 }
  68
  69 void setup_kup(void)
  70 {
  71         setup_kuap(disable_kuap);
  72         setup_kuep(disable_kuep);
  73 }
  74
  75 #define CTOR(shift) static void ctor_##shift(void *addr) \
  76 {                                                       \
  77         memset(addr, 0, sizeof(pgd_t) << (shift));      \
  78 }
  79
  80 CTOR(0); CTOR(1); CTOR(2); CTOR(3); CTOR(4); CTOR(5); CTOR(6); CTOR(7);
  81 CTOR(8); CTOR(9); CTOR(10); CTOR(11); CTOR(12); CTOR(13); CTOR(14); CTOR(15);
  82
  83 static inline void (*ctor(int shift))(void *)
  84 {
  85         BUILD_BUG_ON(MAX_PGTABLE_INDEX_SIZE != 15);
  86
  87         switch (shift) {
  88         case 0: return ctor_0;
  89         case 1: return ctor_1;
  90         case 2: return ctor_2;
  91         case 3: return ctor_3;
  92         case 4: return ctor_4;
  93         case 5: return ctor_5;
  94         case 6: return ctor_6;
  95         case 7: return ctor_7;
  96         case 8: return ctor_8;
  97         case 9: return ctor_9;
  98         case 10: return ctor_10;
  99         case 11: return ctor_11;
 100         case 12: return ctor_12;
 101         case 13: return ctor_13;
 102         case 14: return ctor_14;
 103         case 15: return ctor_15;
 104         }
 105         return NULL;
 106 }
 107
 108 struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE + 1];
 109 EXPORT_SYMBOL_GPL(pgtable_cache);       /* used by kvm_hv module */
 110
 111 /*
 112  * Create a kmem_cache() for pagetables.  This is not used for PTE
 113  * pages - they're linked to struct page, come from the normal free
 114  * pages pool and have a different entry size (see real_pte_t) to
 115  * everything else.  Caches created by this function are used for all
 116  * the higher level pagetables, and for hugepage pagetables.
 117  */
 118 void pgtable_cache_add(unsigned int shift)
 119 {
 120         char *name;
 121         unsigned long table_size = sizeof(pgd_t) << shift;
 122         unsigned long align = table_size;
 123
 124         /* When batching pgtable pointers for RCU freeing, we store
 125          * the index size in the low bits.  Table alignment must be
 126          * big enough to fit it.
 127          */
 128         unsigned long minalign = MAX_PGTABLE_INDEX_SIZE + 1;
 129         struct kmem_cache *new = NULL;
 130
 131         /* It would be nice if this was a BUILD_BUG_ON(), but at the
 132          * moment, gcc doesn't seem to recognize is_power_of_2 as a
 133          * constant expression, so so much for that. */
 134         BUG_ON(!is_power_of_2(minalign));
 135         BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
 136
 137         if (PGT_CACHE(shift))
 138                 return; /* Already have a cache of this size */
 139
 140         align = max_t(unsigned long, align, minalign);
 141         name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
 142         if (name)
 143                 new = kmem_cache_create(name, table_size, align, 0, ctor(shift));
 144         if (!new)
 145                 panic("Could not allocate pgtable cache for order %d", shift);
 146
 147         kfree(name);
 148         pgtable_cache[shift] = new;
 149
 150         pr_debug("Allocated pgtable cache for order %d\n", shift);
 151 }
 152 EXPORT_SYMBOL_GPL(pgtable_cache_add);   /* used by kvm_hv module */
 153
 154 void pgtable_cache_init(void)
 155 {
 156         pgtable_cache_add(PGD_INDEX_SIZE);
 157
 158         if (PMD_CACHE_INDEX)
 159                 pgtable_cache_add(PMD_CACHE_INDEX);
 160         /*
 161          * In all current configs, when the PUD index exists it's the
 162          * same size as either the pgd or pmd index except with THP enabled
 163          * on book3s 64
 164          */
 165         if (PUD_CACHE_INDEX)
 166                 pgtable_cache_add(PUD_CACHE_INDEX);
 167 }