xref: /linux/arch/x86/mm/pgtable_32.c (revision 9f6d3c4b76314c40c866a935d78c80fd284768bd)
1 #include <linux/sched.h>
2 #include <linux/kernel.h>
3 #include <linux/errno.h>
4 #include <linux/mm.h>
5 #include <linux/nmi.h>
6 #include <linux/swap.h>
7 #include <linux/smp.h>
8 #include <linux/highmem.h>
9 #include <linux/pagemap.h>
10 #include <linux/spinlock.h>
11 #include <linux/module.h>
12 #include <linux/quicklist.h>
13 
14 #include <asm/system.h>
15 #include <asm/pgtable.h>
16 #include <asm/pgalloc.h>
17 #include <asm/fixmap.h>
18 #include <asm/e820.h>
19 #include <asm/tlb.h>
20 #include <asm/tlbflush.h>
21 #include <asm/io.h>
22 
23 unsigned int __VMALLOC_RESERVE = 128 << 20;
24 
25 /*
26  * Associate a virtual page frame with a given physical page frame
27  * and protection flags for that frame.
28  */
29 void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
30 {
31 	pgd_t *pgd;
32 	pud_t *pud;
33 	pmd_t *pmd;
34 	pte_t *pte;
35 
36 	pgd = swapper_pg_dir + pgd_index(vaddr);
37 	if (pgd_none(*pgd)) {
38 		BUG();
39 		return;
40 	}
41 	pud = pud_offset(pgd, vaddr);
42 	if (pud_none(*pud)) {
43 		BUG();
44 		return;
45 	}
46 	pmd = pmd_offset(pud, vaddr);
47 	if (pmd_none(*pmd)) {
48 		BUG();
49 		return;
50 	}
51 	pte = pte_offset_kernel(pmd, vaddr);
52 	if (pte_val(pteval))
53 		set_pte_at(&init_mm, vaddr, pte, pteval);
54 	else
55 		pte_clear(&init_mm, vaddr, pte);
56 
57 	/*
58 	 * It's enough to flush this one mapping.
59 	 * (PGE mappings get flushed as well)
60 	 */
61 	__flush_tlb_one(vaddr);
62 }
63 
64 /*
65  * Associate a large virtual page frame with a given physical page frame
66  * and protection flags for that frame. pfn is for the base of the page,
67  * vaddr is what the page gets mapped to - both must be properly aligned.
68  * The pmd must already be instantiated. Assumes PAE mode.
69  */
70 void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
71 {
72 	pgd_t *pgd;
73 	pud_t *pud;
74 	pmd_t *pmd;
75 
76 	if (vaddr & (PMD_SIZE-1)) {		/* vaddr is misaligned */
77 		printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
78 		return; /* BUG(); */
79 	}
80 	if (pfn & (PTRS_PER_PTE-1)) {		/* pfn is misaligned */
81 		printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
82 		return; /* BUG(); */
83 	}
84 	pgd = swapper_pg_dir + pgd_index(vaddr);
85 	if (pgd_none(*pgd)) {
86 		printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
87 		return; /* BUG(); */
88 	}
89 	pud = pud_offset(pgd, vaddr);
90 	pmd = pmd_offset(pud, vaddr);
91 	set_pmd(pmd, pfn_pmd(pfn, flags));
92 	/*
93 	 * It's enough to flush this one mapping.
94 	 * (PGE mappings get flushed as well)
95 	 */
96 	__flush_tlb_one(vaddr);
97 }
98 
99 unsigned long __FIXADDR_TOP = 0xfffff000;
100 EXPORT_SYMBOL(__FIXADDR_TOP);
101 
102 /*
103  * vmalloc=size forces the vmalloc area to be exactly 'size'
104  * bytes. This can be used to increase (or decrease) the
105  * vmalloc area - the default is 128m.
106  */
107 static int __init parse_vmalloc(char *arg)
108 {
109 	if (!arg)
110 		return -EINVAL;
111 
112 	/* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
113 	__VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
114 	return 0;
115 }
116 early_param("vmalloc", parse_vmalloc);
117 
118 /*
119  * reservetop=size reserves a hole at the top of the kernel address space which
120  * a hypervisor can load into later.  Needed for dynamically loaded hypervisors,
121  * so relocating the fixmap can be done before paging initialization.
122  */
123 static int __init parse_reservetop(char *arg)
124 {
125 	unsigned long address;
126 
127 	if (!arg)
128 		return -EINVAL;
129 
130 	address = memparse(arg, &arg);
131 	reserve_top_address(address);
132 	fixup_early_ioremap();
133 	return 0;
134 }
135 early_param("reservetop", parse_reservetop);
136