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
 25phys_addr_t memstart_addr __ro_after_init = (phys_addr_t)~0ull;
 26EXPORT_SYMBOL_GPL(memstart_addr);
 27phys_addr_t kernstart_addr __ro_after_init;
 28EXPORT_SYMBOL_GPL(kernstart_addr);
 29unsigned long kernstart_virt_addr __ro_after_init = KERNELBASE;
 30EXPORT_SYMBOL_GPL(kernstart_virt_addr);
 31
 32bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP);
 33bool disable_kuap = !IS_ENABLED(CONFIG_PPC_KUAP);
 34
 35static int __init parse_nosmep(char *p)
 36{
 37	if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))
 38		return 0;
 39
 40	disable_kuep = true;
 41	pr_warn("Disabling Kernel Userspace Execution Prevention\n");
 42	return 0;
 43}
 44early_param("nosmep", parse_nosmep);
 45
 46static int __init parse_nosmap(char *p)
 47{
 48	disable_kuap = true;
 49	pr_warn("Disabling Kernel Userspace Access Protection\n");
 50	return 0;
 51}
 52early_param("nosmap", parse_nosmap);
 53
 54void __weak setup_kuep(bool disabled)
 55{
 56	if (!IS_ENABLED(CONFIG_PPC_KUEP) || disabled)
 57		return;
 58
 59	if (smp_processor_id() != boot_cpuid)
 60		return;
 61
 62	pr_info("Activating Kernel Userspace Execution Prevention\n");
 63}
 64
 65void setup_kup(void)
 66{
 67	setup_kuap(disable_kuap);
 68	setup_kuep(disable_kuep);
 69}
 70
 71#define CTOR(shift) static void ctor_##shift(void *addr) \
 72{							\
 73	memset(addr, 0, sizeof(void *) << (shift));	\
 74}
 75
 76CTOR(0); CTOR(1); CTOR(2); CTOR(3); CTOR(4); CTOR(5); CTOR(6); CTOR(7);
 77CTOR(8); CTOR(9); CTOR(10); CTOR(11); CTOR(12); CTOR(13); CTOR(14); CTOR(15);
 78
 79static inline void (*ctor(int shift))(void *)
 80{
 81	BUILD_BUG_ON(MAX_PGTABLE_INDEX_SIZE != 15);
 82
 83	switch (shift) {
 84	case 0: return ctor_0;
 85	case 1: return ctor_1;
 86	case 2: return ctor_2;
 87	case 3: return ctor_3;
 88	case 4: return ctor_4;
 89	case 5: return ctor_5;
 90	case 6: return ctor_6;
 91	case 7: return ctor_7;
 92	case 8: return ctor_8;
 93	case 9: return ctor_9;
 94	case 10: return ctor_10;
 95	case 11: return ctor_11;
 96	case 12: return ctor_12;
 97	case 13: return ctor_13;
 98	case 14: return ctor_14;
 99	case 15: return ctor_15;
100	}
101	return NULL;
102}
103
104struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE + 1];
105EXPORT_SYMBOL_GPL(pgtable_cache);	/* used by kvm_hv module */
106
107/*
108 * Create a kmem_cache() for pagetables.  This is not used for PTE
109 * pages - they're linked to struct page, come from the normal free
110 * pages pool and have a different entry size (see real_pte_t) to
111 * everything else.  Caches created by this function are used for all
112 * the higher level pagetables, and for hugepage pagetables.
113 */
114void pgtable_cache_add(unsigned int shift)
115{
116	char *name;
117	unsigned long table_size = sizeof(void *) << shift;
118	unsigned long align = table_size;
119
120	/* When batching pgtable pointers for RCU freeing, we store
121	 * the index size in the low bits.  Table alignment must be
122	 * big enough to fit it.
123	 *
124	 * Likewise, hugeapge pagetable pointers contain a (different)
125	 * shift value in the low bits.  All tables must be aligned so
126	 * as to leave enough 0 bits in the address to contain it. */
127	unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
128				     HUGEPD_SHIFT_MASK + 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}
152EXPORT_SYMBOL_GPL(pgtable_cache_add);	/* used by kvm_hv module */
153
154void 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}