xref: /openbmc/linux/arch/x86/mm/pgtable_32.c (revision 08157984)
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 
13 #include <asm/pgtable.h>
14 #include <asm/pgalloc.h>
15 #include <asm/fixmap.h>
16 #include <asm/e820.h>
17 #include <asm/tlb.h>
18 #include <asm/tlbflush.h>
19 #include <asm/io.h>
20 
21 unsigned int __VMALLOC_RESERVE = 128 << 20;
22 
23 /*
24  * Associate a virtual page frame with a given physical page frame
25  * and protection flags for that frame.
26  */
27 void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
28 {
29 	pgd_t *pgd;
30 	pud_t *pud;
31 	pmd_t *pmd;
32 	pte_t *pte;
33 
34 	pgd = swapper_pg_dir + pgd_index(vaddr);
35 	if (pgd_none(*pgd)) {
36 		BUG();
37 		return;
38 	}
39 	pud = pud_offset(pgd, vaddr);
40 	if (pud_none(*pud)) {
41 		BUG();
42 		return;
43 	}
44 	pmd = pmd_offset(pud, vaddr);
45 	if (pmd_none(*pmd)) {
46 		BUG();
47 		return;
48 	}
49 	pte = pte_offset_kernel(pmd, vaddr);
50 	if (pte_val(pteval))
51 		set_pte_at(&init_mm, vaddr, pte, pteval);
52 	else
53 		pte_clear(&init_mm, vaddr, pte);
54 
55 	/*
56 	 * It's enough to flush this one mapping.
57 	 * (PGE mappings get flushed as well)
58 	 */
59 	__flush_tlb_one(vaddr);
60 }
61 
62 /*
63  * Associate a large virtual page frame with a given physical page frame
64  * and protection flags for that frame. pfn is for the base of the page,
65  * vaddr is what the page gets mapped to - both must be properly aligned.
66  * The pmd must already be instantiated. Assumes PAE mode.
67  */
68 void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
69 {
70 	pgd_t *pgd;
71 	pud_t *pud;
72 	pmd_t *pmd;
73 
74 	if (vaddr & (PMD_SIZE-1)) {		/* vaddr is misaligned */
75 		printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
76 		return; /* BUG(); */
77 	}
78 	if (pfn & (PTRS_PER_PTE-1)) {		/* pfn is misaligned */
79 		printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
80 		return; /* BUG(); */
81 	}
82 	pgd = swapper_pg_dir + pgd_index(vaddr);
83 	if (pgd_none(*pgd)) {
84 		printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
85 		return; /* BUG(); */
86 	}
87 	pud = pud_offset(pgd, vaddr);
88 	pmd = pmd_offset(pud, vaddr);
89 	set_pmd(pmd, pfn_pmd(pfn, flags));
90 	/*
91 	 * It's enough to flush this one mapping.
92 	 * (PGE mappings get flushed as well)
93 	 */
94 	__flush_tlb_one(vaddr);
95 }
96 
97 unsigned long __FIXADDR_TOP = 0xfffff000;
98 EXPORT_SYMBOL(__FIXADDR_TOP);
99 
100 /*
101  * vmalloc=size forces the vmalloc area to be exactly 'size'
102  * bytes. This can be used to increase (or decrease) the
103  * vmalloc area - the default is 128m.
104  */
105 static int __init parse_vmalloc(char *arg)
106 {
107 	if (!arg)
108 		return -EINVAL;
109 
110 	/* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
111 	__VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
112 	return 0;
113 }
114 early_param("vmalloc", parse_vmalloc);
115 
116 /*
117  * reservetop=size reserves a hole at the top of the kernel address space which
118  * a hypervisor can load into later.  Needed for dynamically loaded hypervisors,
119  * so relocating the fixmap can be done before paging initialization.
120  */
121 static int __init parse_reservetop(char *arg)
122 {
123 	unsigned long address;
124 
125 	if (!arg)
126 		return -EINVAL;
127 
128 	address = memparse(arg, &arg);
129 	reserve_top_address(address);
130 	fixup_early_ioremap();
131 	return 0;
132 }
133 early_param("reservetop", parse_reservetop);
134