xref: /openbmc/linux/arch/powerpc/mm/pgtable_32.c (revision 2cf1c348)
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 
36 static u8 early_fixmap_pagetable[FIXMAP_PTE_SIZE] __page_aligned_data;
37 
38 notrace 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 
51 static void __init *early_alloc_pgtable(unsigned long size)
52 {
53 	void *ptr = memblock_alloc(size, size);
54 
55 	if (!ptr)
56 		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
57 		      __func__, size, size);
58 
59 	return ptr;
60 }
61 
62 pte_t __init *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va)
63 {
64 	if (pmd_none(*pmdp)) {
65 		pte_t *ptep = early_alloc_pgtable(PTE_FRAG_SIZE);
66 
67 		pmd_populate_kernel(&init_mm, pmdp, ptep);
68 	}
69 	return pte_offset_kernel(pmdp, va);
70 }
71 
72 
73 int __ref map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot)
74 {
75 	pmd_t *pd;
76 	pte_t *pg;
77 	int err = -ENOMEM;
78 
79 	/* Use upper 10 bits of VA to index the first level map */
80 	pd = pmd_off_k(va);
81 	/* Use middle 10 bits of VA to index the second-level map */
82 	if (likely(slab_is_available()))
83 		pg = pte_alloc_kernel(pd, va);
84 	else
85 		pg = early_pte_alloc_kernel(pd, va);
86 	if (pg) {
87 		err = 0;
88 		/* The PTE should never be already set nor present in the
89 		 * hash table
90 		 */
91 		BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) && pgprot_val(prot));
92 		set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot));
93 	}
94 	smp_wmb();
95 	return err;
96 }
97 
98 /*
99  * Map in a chunk of physical memory starting at start.
100  */
101 static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
102 {
103 	unsigned long v, s;
104 	phys_addr_t p;
105 	bool ktext;
106 
107 	s = offset;
108 	v = PAGE_OFFSET + s;
109 	p = memstart_addr + s;
110 	for (; s < top; s += PAGE_SIZE) {
111 		ktext = core_kernel_text(v);
112 		map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL);
113 		v += PAGE_SIZE;
114 		p += PAGE_SIZE;
115 	}
116 }
117 
118 void __init mapin_ram(void)
119 {
120 	phys_addr_t base, end;
121 	u64 i;
122 
123 	for_each_mem_range(i, &base, &end) {
124 		phys_addr_t top = min(end, total_lowmem);
125 
126 		if (base >= top)
127 			continue;
128 		base = mmu_mapin_ram(base, top);
129 		__mapin_ram_chunk(base, top);
130 	}
131 }
132 
133 void mark_initmem_nx(void)
134 {
135 	unsigned long numpages = PFN_UP((unsigned long)_einittext) -
136 				 PFN_DOWN((unsigned long)_sinittext);
137 
138 	if (v_block_mapped((unsigned long)_sinittext))
139 		mmu_mark_initmem_nx();
140 	else
141 		set_memory_attr((unsigned long)_sinittext, numpages, PAGE_KERNEL);
142 }
143 
144 #ifdef CONFIG_STRICT_KERNEL_RWX
145 void mark_rodata_ro(void)
146 {
147 	unsigned long numpages;
148 
149 	if (v_block_mapped((unsigned long)_stext + 1)) {
150 		mmu_mark_rodata_ro();
151 		ptdump_check_wx();
152 		return;
153 	}
154 
155 	numpages = PFN_UP((unsigned long)_etext) -
156 		   PFN_DOWN((unsigned long)_stext);
157 
158 	set_memory_attr((unsigned long)_stext, numpages, PAGE_KERNEL_ROX);
159 	/*
160 	 * mark .rodata as read only. Use __init_begin rather than __end_rodata
161 	 * to cover NOTES and EXCEPTION_TABLE.
162 	 */
163 	numpages = PFN_UP((unsigned long)__init_begin) -
164 		   PFN_DOWN((unsigned long)__start_rodata);
165 
166 	set_memory_attr((unsigned long)__start_rodata, numpages, PAGE_KERNEL_RO);
167 
168 	// mark_initmem_nx() should have already run by now
169 	ptdump_check_wx();
170 }
171 #endif
172 
173 #if defined(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) && defined(CONFIG_DEBUG_PAGEALLOC)
174 void __kernel_map_pages(struct page *page, int numpages, int enable)
175 {
176 	unsigned long addr = (unsigned long)page_address(page);
177 
178 	if (PageHighMem(page))
179 		return;
180 
181 	if (enable)
182 		set_memory_attr(addr, numpages, PAGE_KERNEL);
183 	else
184 		set_memory_attr(addr, numpages, __pgprot(0));
185 }
186 #endif /* CONFIG_DEBUG_PAGEALLOC */
187