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
21unsigned 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 */
27void 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
68unsigned long __FIXADDR_TOP = 0xfffff000;
69EXPORT_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 */
76static 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}
85early_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 */
92static 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}
104early_param("reservetop", parse_reservetop);
105