xref: /openbmc/linux/arch/x86/mm/pgtable_32.c (revision df2634f43f5106947f3735a0b61a6527a4b278cd)
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/system.h>
14 #include <asm/pgtable.h>
15 #include <asm/pgalloc.h>
16 #include <asm/fixmap.h>
17 #include <asm/e820.h>
18 #include <asm/tlb.h>
19 #include <asm/tlbflush.h>
20 #include <asm/io.h>
21 
22 unsigned int __VMALLOC_RESERVE = 128 << 20;
23 
24 /*
25  * Associate a virtual page frame with a given physical page frame
26  * and protection flags for that frame.
27  */
28 void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
29 {
30 	pgd_t *pgd;
31 	pud_t *pud;
32 	pmd_t *pmd;
33 	pte_t *pte;
34 
35 	pgd = swapper_pg_dir + pgd_index(vaddr);
36 	if (pgd_none(*pgd)) {
37 		BUG();
38 		return;
39 	}
40 	pud = pud_offset(pgd, vaddr);
41 	if (pud_none(*pud)) {
42 		BUG();
43 		return;
44 	}
45 	pmd = pmd_offset(pud, vaddr);
46 	if (pmd_none(*pmd)) {
47 		BUG();
48 		return;
49 	}
50 	pte = pte_offset_kernel(pmd, vaddr);
51 	if (pte_val(pteval))
52 		set_pte_at(&init_mm, vaddr, pte, pteval);
53 	else
54 		pte_clear(&init_mm, vaddr, pte);
55 
56 	/*
57 	 * It's enough to flush this one mapping.
58 	 * (PGE mappings get flushed as well)
59 	 */
60 	__flush_tlb_one(vaddr);
61 }
62 
63 /*
64  * Associate a large virtual page frame with a given physical page frame
65  * and protection flags for that frame. pfn is for the base of the page,
66  * vaddr is what the page gets mapped to - both must be properly aligned.
67  * The pmd must already be instantiated. Assumes PAE mode.
68  */
69 void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
70 {
71 	pgd_t *pgd;
72 	pud_t *pud;
73 	pmd_t *pmd;
74 
75 	if (vaddr & (PMD_SIZE-1)) {		/* vaddr is misaligned */
76 		printk(KERN_WARNING "set_pmd_pfn: vaddr misaligned\n");
77 		return; /* BUG(); */
78 	}
79 	if (pfn & (PTRS_PER_PTE-1)) {		/* pfn is misaligned */
80 		printk(KERN_WARNING "set_pmd_pfn: pfn misaligned\n");
81 		return; /* BUG(); */
82 	}
83 	pgd = swapper_pg_dir + pgd_index(vaddr);
84 	if (pgd_none(*pgd)) {
85 		printk(KERN_WARNING "set_pmd_pfn: pgd_none\n");
86 		return; /* BUG(); */
87 	}
88 	pud = pud_offset(pgd, vaddr);
89 	pmd = pmd_offset(pud, vaddr);
90 	set_pmd(pmd, pfn_pmd(pfn, flags));
91 	/*
92 	 * It's enough to flush this one mapping.
93 	 * (PGE mappings get flushed as well)
94 	 */
95 	__flush_tlb_one(vaddr);
96 }
97 
98 unsigned long __FIXADDR_TOP = 0xfffff000;
99 EXPORT_SYMBOL(__FIXADDR_TOP);
100 
101 /*
102  * vmalloc=size forces the vmalloc area to be exactly 'size'
103  * bytes. This can be used to increase (or decrease) the
104  * vmalloc area - the default is 128m.
105  */
106 static int __init parse_vmalloc(char *arg)
107 {
108 	if (!arg)
109 		return -EINVAL;
110 
111 	/* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
112 	__VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
113 	return 0;
114 }
115 early_param("vmalloc", parse_vmalloc);
116 
117 /*
118  * reservetop=size reserves a hole at the top of the kernel address space which
119  * a hypervisor can load into later.  Needed for dynamically loaded hypervisors,
120  * so relocating the fixmap can be done before paging initialization.
121  */
122 static int __init parse_reservetop(char *arg)
123 {
124 	unsigned long address;
125 
126 	if (!arg)
127 		return -EINVAL;
128 
129 	address = memparse(arg, &arg);
130 	reserve_top_address(address);
131 	fixup_early_ioremap();
132 	return 0;
133 }
134 early_param("reservetop", parse_reservetop);
135