1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/sched.h>
3 #include <linux/kernel.h>
4 #include <linux/errno.h>
5 #include <linux/mm.h>
6 #include <linux/nmi.h>
7 #include <linux/swap.h>
8 #include <linux/smp.h>
9 #include <linux/highmem.h>
10 #include <linux/pagemap.h>
11 #include <linux/spinlock.h>
12
13 #include <asm/cpu_entry_area.h>
14 #include <asm/fixmap.h>
15 #include <asm/e820/api.h>
16 #include <asm/tlb.h>
17 #include <asm/tlbflush.h>
18 #include <asm/io.h>
19 #include <linux/vmalloc.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 p4d_t *p4d;
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 p4d = p4d_offset(pgd, vaddr);
41 if (p4d_none(*p4d)) {
42 BUG();
43 return;
44 }
45 pud = pud_offset(p4d, vaddr);
46 if (pud_none(*pud)) {
47 BUG();
48 return;
49 }
50 pmd = pmd_offset(pud, vaddr);
51 if (pmd_none(*pmd)) {
52 BUG();
53 return;
54 }
55 pte = pte_offset_kernel(pmd, vaddr);
56 if (!pte_none(pteval))
57 set_pte_at(&init_mm, vaddr, pte, pteval);
58 else
59 pte_clear(&init_mm, vaddr, pte);
60
61 /*
62 * It's enough to flush this one mapping.
63 * (PGE mappings get flushed as well)
64 */
65 flush_tlb_one_kernel(vaddr);
66 }
67
68 unsigned long __FIXADDR_TOP = 0xfffff000;
69 EXPORT_SYMBOL(__FIXADDR_TOP);
70
71 /*
72 * vmalloc=size forces the vmalloc area to be exactly 'size'
73 * bytes. This can be used to increase (or decrease) the
74 * vmalloc area - the default is 128m.
75 */
76 static int __init parse_vmalloc(char *arg)
77 {
78 if (!arg)
79 return -EINVAL;
80
81 /* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
82 __VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
83 return 0;
84 }
85 early_param("vmalloc", parse_vmalloc);
86
87 /*
88 * reservetop=size reserves a hole at the top of the kernel address space which
89 * a hypervisor can load into later. Needed for dynamically loaded hypervisors,
90 * so relocating the fixmap can be done before paging initialization.
91 */
92 static int __init parse_reservetop(char *arg)
93 {
94 unsigned long address;
95
96 if (!arg)
97 return -EINVAL;
98
99 address = memparse(arg, &arg);
100 reserve_top_address(address);
101 early_ioremap_init();
102 return 0;
103 }
104 early_param("reservetop", parse_reservetop);
105
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