pgtable_32.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * This file contains the routines setting up the linux page tables.
  4 *  -- paulus
  5 *
  6 *  Derived from arch/ppc/mm/init.c:
  7 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  8 *
  9 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
 10 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 11 *    Copyright (C) 1996 Paul Mackerras
 12 *
 13 *  Derived from "arch/i386/mm/init.c"
 14 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 15 */
 16
 17#include <linux/kernel.h>
 18#include <linux/module.h>
 19#include <linux/types.h>
 20#include <linux/mm.h>
 21#include <linux/vmalloc.h>
 22#include <linux/init.h>
 23#include <linux/highmem.h>
 24#include <linux/memblock.h>
 25#include <linux/slab.h>
 26#include <linux/set_memory.h>
 27
 28#include <asm/pgalloc.h>
 29#include <asm/fixmap.h>
 30#include <asm/setup.h>
 31#include <asm/sections.h>
 32#include <asm/early_ioremap.h>
 33
 34#include <mm/mmu_decl.h>
 35
 36static u8 early_fixmap_pagetable[FIXMAP_PTE_SIZE] __page_aligned_data;
 37
 38notrace void __init early_ioremap_init(void)
 39{
 40	unsigned long addr = ALIGN_DOWN(FIXADDR_START, PGDIR_SIZE);
 41	pte_t *ptep = (pte_t *)early_fixmap_pagetable;
 42	pmd_t *pmdp = pmd_off_k(addr);
 43
 44	for (; (s32)(FIXADDR_TOP - addr) > 0;
 45	     addr += PGDIR_SIZE, ptep += PTRS_PER_PTE, pmdp++)
 46		pmd_populate_kernel(&init_mm, pmdp, ptep);
 47
 48	early_ioremap_setup();
 49}
 50
 51void __init *early_alloc_pgtable(unsigned long size)
 52{
 53	return memblock_alloc_or_panic(size, size);
 54
 55}
 56
 57pte_t __init *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va)
 58{
 59	if (pmd_none(*pmdp)) {
 60		pte_t *ptep = early_alloc_pgtable(PTE_FRAG_SIZE);
 61
 62		pmd_populate_kernel(&init_mm, pmdp, ptep);
 63	}
 64	return pte_offset_kernel(pmdp, va);
 65}
 66
 67
 68int __ref map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot)
 69{
 70	pmd_t *pd;
 71	pte_t *pg;
 72	int err = -ENOMEM;
 73
 74	/* Use upper 10 bits of VA to index the first level map */
 75	pd = pmd_off_k(va);
 76	/* Use middle 10 bits of VA to index the second-level map */
 77	if (likely(slab_is_available()))
 78		pg = pte_alloc_kernel(pd, va);
 79	else
 80		pg = early_pte_alloc_kernel(pd, va);
 81	if (pg) {
 82		err = 0;
 83		/* The PTE should never be already set nor present in the
 84		 * hash table
 85		 */
 86		BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) && pgprot_val(prot));
 87		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot));
 88	}
 89	smp_wmb();
 90	return err;
 91}
 92
 93/*
 94 * Map in a chunk of physical memory starting at start.
 95 */
 96static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
 97{
 98	unsigned long v, s;
 99	phys_addr_t p;
100	bool ktext;
101
102	s = offset;
103	v = PAGE_OFFSET + s;
104	p = memstart_addr + s;
105	for (; s < top; s += PAGE_SIZE) {
106		ktext = core_kernel_text(v);
107		map_kernel_page(v, p, ktext ? PAGE_KERNEL_X : PAGE_KERNEL);
108		v += PAGE_SIZE;
109		p += PAGE_SIZE;
110	}
111}
112
113void __init mapin_ram(void)
114{
115	phys_addr_t base, end;
116	u64 i;
117
118	for_each_mem_range(i, &base, &end) {
119		phys_addr_t top = min(end, total_lowmem);
120
121		if (base >= top)
122			continue;
123		base = mmu_mapin_ram(base, top);
124		__mapin_ram_chunk(base, top);
125	}
126}
127
128static int __mark_initmem_nx(void)
129{
130	unsigned long numpages = PFN_UP((unsigned long)_einittext) -
131				 PFN_DOWN((unsigned long)_sinittext);
132	int err;
133
134	err = mmu_mark_initmem_nx();
135
136	if (!v_block_mapped((unsigned long)_sinittext)) {
137		err = set_memory_nx((unsigned long)_sinittext, numpages);
138		if (err)
139			return err;
140		err = set_memory_rw((unsigned long)_sinittext, numpages);
141	}
142	return err;
143}
144
145void mark_initmem_nx(void)
146{
147	int err = __mark_initmem_nx();
148
149	if (err)
150		panic("%s() failed, err = %d\n", __func__, err);
151}
152
153#ifdef CONFIG_STRICT_KERNEL_RWX
154static int __mark_rodata_ro(void)
155{
156	unsigned long numpages;
157
158	if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX) && mmu_has_feature(MMU_FTR_HPTE_TABLE))
159		pr_warn("This platform has HASH MMU, STRICT_MODULE_RWX won't work\n");
160
161	if (v_block_mapped((unsigned long)_stext + 1))
162		return mmu_mark_rodata_ro();
163
164	/*
165	 * mark text and rodata as read only. __end_rodata is set by
166	 * powerpc's linker script and includes tables and data
167	 * requiring relocation which are not put in RO_DATA.
168	 */
169	numpages = PFN_UP((unsigned long)__end_rodata) -
170		   PFN_DOWN((unsigned long)_stext);
171
172	return set_memory_ro((unsigned long)_stext, numpages);
173}
174
175void mark_rodata_ro(void)
176{
177	int err = __mark_rodata_ro();
178
179	if (err)
180		panic("%s() failed, err = %d\n", __func__, err);
181}
182#endif