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/pgtable.h>
15 #include <asm/pgalloc.h>
16 #include <asm/fixmap.h>
17 #include <asm/e820/api.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 */
set_pte_vaddr(unsigned long vaddr,pte_t pteval)28 void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
29 {
30 pgd_t *pgd;
31 p4d_t *p4d;
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 p4d = p4d_offset(pgd, vaddr);
42 if (p4d_none(*p4d)) {
43 BUG();
44 return;
45 }
46 pud = pud_offset(p4d, vaddr);
47 if (pud_none(*pud)) {
48 BUG();
49 return;
50 }
51 pmd = pmd_offset(pud, vaddr);
52 if (pmd_none(*pmd)) {
53 BUG();
54 return;
55 }
56 pte = pte_offset_kernel(pmd, vaddr);
57 if (!pte_none(pteval))
58 set_pte_at(&init_mm, vaddr, pte, pteval);
59 else
60 pte_clear(&init_mm, vaddr, pte);
61
62 /*
63 * It's enough to flush this one mapping.
64 * (PGE mappings get flushed as well)
65 */
66 __flush_tlb_one_kernel(vaddr);
67 }
68
69 unsigned long __FIXADDR_TOP = 0xfffff000;
70 EXPORT_SYMBOL(__FIXADDR_TOP);
71
72 /*
73 * vmalloc=size forces the vmalloc area to be exactly 'size'
74 * bytes. This can be used to increase (or decrease) the
75 * vmalloc area - the default is 128m.
76 */
parse_vmalloc(char * arg)77 static int __init parse_vmalloc(char *arg)
78 {
79 if (!arg)
80 return -EINVAL;
81
82 /* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
83 __VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
84 return 0;
85 }
86 early_param("vmalloc", parse_vmalloc);
87
88 /*
89 * reservetop=size reserves a hole at the top of the kernel address space which
90 * a hypervisor can load into later. Needed for dynamically loaded hypervisors,
91 * so relocating the fixmap can be done before paging initialization.
92 */
parse_reservetop(char * arg)93 static int __init parse_reservetop(char *arg)
94 {
95 unsigned long address;
96
97 if (!arg)
98 return -EINVAL;
99
100 address = memparse(arg, &arg);
101 reserve_top_address(address);
102 early_ioremap_init();
103 return 0;
104 }
105 early_param("reservetop", parse_reservetop);
106
