1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * fake_mem.c
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (C) 2015 FUJITSU LIMITED
6*4882a593Smuzhiyun * Author: Taku Izumi <izumi.taku@jp.fujitsu.com>
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * This code introduces new boot option named "efi_fake_mem"
9*4882a593Smuzhiyun * By specifying this parameter, you can add arbitrary attribute to
10*4882a593Smuzhiyun * specific memory range by updating original (firmware provided) EFI
11*4882a593Smuzhiyun * memmap.
12*4882a593Smuzhiyun */
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun #include <linux/kernel.h>
15*4882a593Smuzhiyun #include <linux/efi.h>
16*4882a593Smuzhiyun #include <linux/init.h>
17*4882a593Smuzhiyun #include <linux/memblock.h>
18*4882a593Smuzhiyun #include <linux/types.h>
19*4882a593Smuzhiyun #include <linux/sort.h>
20*4882a593Smuzhiyun #include "fake_mem.h"
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun struct efi_mem_range efi_fake_mems[EFI_MAX_FAKEMEM];
23*4882a593Smuzhiyun int nr_fake_mem;
24*4882a593Smuzhiyun
cmp_fake_mem(const void * x1,const void * x2)25*4882a593Smuzhiyun static int __init cmp_fake_mem(const void *x1, const void *x2)
26*4882a593Smuzhiyun {
27*4882a593Smuzhiyun const struct efi_mem_range *m1 = x1;
28*4882a593Smuzhiyun const struct efi_mem_range *m2 = x2;
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun if (m1->range.start < m2->range.start)
31*4882a593Smuzhiyun return -1;
32*4882a593Smuzhiyun if (m1->range.start > m2->range.start)
33*4882a593Smuzhiyun return 1;
34*4882a593Smuzhiyun return 0;
35*4882a593Smuzhiyun }
36*4882a593Smuzhiyun
efi_fake_range(struct efi_mem_range * efi_range)37*4882a593Smuzhiyun static void __init efi_fake_range(struct efi_mem_range *efi_range)
38*4882a593Smuzhiyun {
39*4882a593Smuzhiyun struct efi_memory_map_data data = { 0 };
40*4882a593Smuzhiyun int new_nr_map = efi.memmap.nr_map;
41*4882a593Smuzhiyun efi_memory_desc_t *md;
42*4882a593Smuzhiyun void *new_memmap;
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun /* count up the number of EFI memory descriptor */
45*4882a593Smuzhiyun for_each_efi_memory_desc(md)
46*4882a593Smuzhiyun new_nr_map += efi_memmap_split_count(md, &efi_range->range);
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun /* allocate memory for new EFI memmap */
49*4882a593Smuzhiyun if (efi_memmap_alloc(new_nr_map, &data) != 0)
50*4882a593Smuzhiyun return;
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun /* create new EFI memmap */
53*4882a593Smuzhiyun new_memmap = early_memremap(data.phys_map, data.size);
54*4882a593Smuzhiyun if (!new_memmap) {
55*4882a593Smuzhiyun __efi_memmap_free(data.phys_map, data.size, data.flags);
56*4882a593Smuzhiyun return;
57*4882a593Smuzhiyun }
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun efi_memmap_insert(&efi.memmap, new_memmap, efi_range);
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun /* swap into new EFI memmap */
62*4882a593Smuzhiyun early_memunmap(new_memmap, data.size);
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun efi_memmap_install(&data);
65*4882a593Smuzhiyun }
66*4882a593Smuzhiyun
efi_fake_memmap(void)67*4882a593Smuzhiyun void __init efi_fake_memmap(void)
68*4882a593Smuzhiyun {
69*4882a593Smuzhiyun int i;
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem)
72*4882a593Smuzhiyun return;
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun for (i = 0; i < nr_fake_mem; i++)
75*4882a593Smuzhiyun efi_fake_range(&efi_fake_mems[i]);
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun /* print new EFI memmap */
78*4882a593Smuzhiyun efi_print_memmap();
79*4882a593Smuzhiyun }
80*4882a593Smuzhiyun
setup_fake_mem(char * p)81*4882a593Smuzhiyun static int __init setup_fake_mem(char *p)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun u64 start = 0, mem_size = 0, attribute = 0;
84*4882a593Smuzhiyun int i;
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun if (!p)
87*4882a593Smuzhiyun return -EINVAL;
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun while (*p != '\0') {
90*4882a593Smuzhiyun mem_size = memparse(p, &p);
91*4882a593Smuzhiyun if (*p == '@')
92*4882a593Smuzhiyun start = memparse(p+1, &p);
93*4882a593Smuzhiyun else
94*4882a593Smuzhiyun break;
95*4882a593Smuzhiyun
96*4882a593Smuzhiyun if (*p == ':')
97*4882a593Smuzhiyun attribute = simple_strtoull(p+1, &p, 0);
98*4882a593Smuzhiyun else
99*4882a593Smuzhiyun break;
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun if (nr_fake_mem >= EFI_MAX_FAKEMEM)
102*4882a593Smuzhiyun break;
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun efi_fake_mems[nr_fake_mem].range.start = start;
105*4882a593Smuzhiyun efi_fake_mems[nr_fake_mem].range.end = start + mem_size - 1;
106*4882a593Smuzhiyun efi_fake_mems[nr_fake_mem].attribute = attribute;
107*4882a593Smuzhiyun nr_fake_mem++;
108*4882a593Smuzhiyun
109*4882a593Smuzhiyun if (*p == ',')
110*4882a593Smuzhiyun p++;
111*4882a593Smuzhiyun }
112*4882a593Smuzhiyun
113*4882a593Smuzhiyun sort(efi_fake_mems, nr_fake_mem, sizeof(struct efi_mem_range),
114*4882a593Smuzhiyun cmp_fake_mem, NULL);
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun for (i = 0; i < nr_fake_mem; i++)
117*4882a593Smuzhiyun pr_info("efi_fake_mem: add attr=0x%016llx to [mem 0x%016llx-0x%016llx]",
118*4882a593Smuzhiyun efi_fake_mems[i].attribute, efi_fake_mems[i].range.start,
119*4882a593Smuzhiyun efi_fake_mems[i].range.end);
120*4882a593Smuzhiyun
121*4882a593Smuzhiyun return *p == '\0' ? 0 : -EINVAL;
122*4882a593Smuzhiyun }
123*4882a593Smuzhiyun
124*4882a593Smuzhiyun early_param("efi_fake_mem", setup_fake_mem);
125