xref: /openbmc/linux/arch/x86/mm/pgtable_32.c (revision 293d5b43)
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 
12 #include <asm/pgtable.h>
13 #include <asm/pgalloc.h>
14 #include <asm/fixmap.h>
15 #include <asm/e820.h>
16 #include <asm/tlb.h>
17 #include <asm/tlbflush.h>
18 #include <asm/io.h>
19 
20 unsigned int __VMALLOC_RESERVE = 128 << 20;
21 
22 /*
23  * Associate a virtual page frame with a given physical page frame
24  * and protection flags for that frame.
25  */
26 void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
27 {
28 	pgd_t *pgd;
29 	pud_t *pud;
30 	pmd_t *pmd;
31 	pte_t *pte;
32 
33 	pgd = swapper_pg_dir + pgd_index(vaddr);
34 	if (pgd_none(*pgd)) {
35 		BUG();
36 		return;
37 	}
38 	pud = pud_offset(pgd, vaddr);
39 	if (pud_none(*pud)) {
40 		BUG();
41 		return;
42 	}
43 	pmd = pmd_offset(pud, vaddr);
44 	if (pmd_none(*pmd)) {
45 		BUG();
46 		return;
47 	}
48 	pte = pte_offset_kernel(pmd, vaddr);
49 	if (!pte_none(pteval))
50 		set_pte_at(&init_mm, vaddr, pte, pteval);
51 	else
52 		pte_clear(&init_mm, vaddr, pte);
53 
54 	/*
55 	 * It's enough to flush this one mapping.
56 	 * (PGE mappings get flushed as well)
57 	 */
58 	__flush_tlb_one(vaddr);
59 }
60 
61 unsigned long __FIXADDR_TOP = 0xfffff000;
62 EXPORT_SYMBOL(__FIXADDR_TOP);
63 
64 /*
65  * vmalloc=size forces the vmalloc area to be exactly 'size'
66  * bytes. This can be used to increase (or decrease) the
67  * vmalloc area - the default is 128m.
68  */
69 static int __init parse_vmalloc(char *arg)
70 {
71 	if (!arg)
72 		return -EINVAL;
73 
74 	/* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
75 	__VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
76 	return 0;
77 }
78 early_param("vmalloc", parse_vmalloc);
79 
80 /*
81  * reservetop=size reserves a hole at the top of the kernel address space which
82  * a hypervisor can load into later.  Needed for dynamically loaded hypervisors,
83  * so relocating the fixmap can be done before paging initialization.
84  */
85 static int __init parse_reservetop(char *arg)
86 {
87 	unsigned long address;
88 
89 	if (!arg)
90 		return -EINVAL;
91 
92 	address = memparse(arg, &arg);
93 	reserve_top_address(address);
94 	early_ioremap_init();
95 	return 0;
96 }
97 early_param("reservetop", parse_reservetop);
98