1// SPDX-License-Identifier: GPL-2.0
2#define BOOT_CTYPE_H
3#include "misc.h"
4#include "error.h"
5#include "../string.h"
6#include "efi.h"
7
8#include <linux/numa.h>
9
10/*
11 * Longest parameter of 'acpi=' is 'copy_dsdt', plus an extra '\0'
12 * for termination.
13 */
14#define MAX_ACPI_ARG_LENGTH 10
15
16/*
17 * Immovable memory regions representation. Max amount of memory regions is
18 * MAX_NUMNODES*2.
19 */
20struct mem_vector immovable_mem[MAX_NUMNODES*2];
21
22static acpi_physical_address
23__efi_get_rsdp_addr(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len)
24{
25#ifdef CONFIG_EFI
26 unsigned long rsdp_addr;
27 int ret;
28
29 /*
30 * Search EFI system tables for RSDP. Preferred is ACPI_20_TABLE_GUID to
31 * ACPI_TABLE_GUID because it has more features.
32 */
33 rsdp_addr = efi_find_vendor_table(bp: boot_params_ptr, cfg_tbl_pa, cfg_tbl_len,
34 ACPI_20_TABLE_GUID);
35 if (rsdp_addr)
36 return (acpi_physical_address)rsdp_addr;
37
38 /* No ACPI_20_TABLE_GUID found, fallback to ACPI_TABLE_GUID. */
39 rsdp_addr = efi_find_vendor_table(bp: boot_params_ptr, cfg_tbl_pa, cfg_tbl_len,
40 ACPI_TABLE_GUID);
41 if (rsdp_addr)
42 return (acpi_physical_address)rsdp_addr;
43
44 debug_putstr("Error getting RSDP address.\n");
45#endif
46 return 0;
47}
48
49static acpi_physical_address efi_get_rsdp_addr(void)
50{
51#ifdef CONFIG_EFI
52 unsigned long cfg_tbl_pa = 0;
53 unsigned int cfg_tbl_len;
54 unsigned long systab_pa;
55 unsigned int nr_tables;
56 enum efi_type et;
57 int ret;
58
59 et = efi_get_type(bp: boot_params_ptr);
60 if (et == EFI_TYPE_NONE)
61 return 0;
62
63 systab_pa = efi_get_system_table(bp: boot_params_ptr);
64 if (!systab_pa)
65 error(m: "EFI support advertised, but unable to locate system table.");
66
67 ret = efi_get_conf_table(bp: boot_params_ptr, cfg_tbl_pa: &cfg_tbl_pa, cfg_tbl_len: &cfg_tbl_len);
68 if (ret || !cfg_tbl_pa)
69 error(m: "EFI config table not found.");
70
71 return __efi_get_rsdp_addr(cfg_tbl_pa, cfg_tbl_len);
72#else
73 return 0;
74#endif
75}
76
77static u8 compute_checksum(u8 *buffer, u32 length)
78{
79 u8 *end = buffer + length;
80 u8 sum = 0;
81
82 while (buffer < end)
83 sum += *(buffer++);
84
85 return sum;
86}
87
88/* Search a block of memory for the RSDP signature. */
89static u8 *scan_mem_for_rsdp(u8 *start, u32 length)
90{
91 struct acpi_table_rsdp *rsdp;
92 u8 *address, *end;
93
94 end = start + length;
95
96 /* Search from given start address for the requested length */
97 for (address = start; address < end; address += ACPI_RSDP_SCAN_STEP) {
98 /*
99 * Both RSDP signature and checksum must be correct.
100 * Note: Sometimes there exists more than one RSDP in memory;
101 * the valid RSDP has a valid checksum, all others have an
102 * invalid checksum.
103 */
104 rsdp = (struct acpi_table_rsdp *)address;
105
106 /* BAD Signature */
107 if (!ACPI_VALIDATE_RSDP_SIG(rsdp->signature))
108 continue;
109
110 /* Check the standard checksum */
111 if (compute_checksum(buffer: (u8 *)rsdp, ACPI_RSDP_CHECKSUM_LENGTH))
112 continue;
113
114 /* Check extended checksum if table version >= 2 */
115 if ((rsdp->revision >= 2) &&
116 (compute_checksum(buffer: (u8 *)rsdp, ACPI_RSDP_XCHECKSUM_LENGTH)))
117 continue;
118
119 /* Signature and checksum valid, we have found a real RSDP */
120 return address;
121 }
122 return NULL;
123}
124
125/* Search RSDP address in EBDA. */
126static acpi_physical_address bios_get_rsdp_addr(void)
127{
128 unsigned long address;
129 u8 *rsdp;
130
131 /* Get the location of the Extended BIOS Data Area (EBDA) */
132 address = *(u16 *)ACPI_EBDA_PTR_LOCATION;
133 address <<= 4;
134
135 /*
136 * Search EBDA paragraphs (EBDA is required to be a minimum of
137 * 1K length)
138 */
139 if (address > 0x400) {
140 rsdp = scan_mem_for_rsdp(start: (u8 *)address, ACPI_EBDA_WINDOW_SIZE);
141 if (rsdp)
142 return (acpi_physical_address)(unsigned long)rsdp;
143 }
144
145 /* Search upper memory: 16-byte boundaries in E0000h-FFFFFh */
146 rsdp = scan_mem_for_rsdp(start: (u8 *) ACPI_HI_RSDP_WINDOW_BASE,
147 ACPI_HI_RSDP_WINDOW_SIZE);
148 if (rsdp)
149 return (acpi_physical_address)(unsigned long)rsdp;
150
151 return 0;
152}
153
154/* Return RSDP address on success, otherwise 0. */
155acpi_physical_address get_rsdp_addr(void)
156{
157 acpi_physical_address pa;
158
159 pa = boot_params_ptr->acpi_rsdp_addr;
160
161 if (!pa)
162 pa = efi_get_rsdp_addr();
163
164 if (!pa)
165 pa = bios_get_rsdp_addr();
166
167 return pa;
168}
169
170#if defined(CONFIG_RANDOMIZE_BASE) && defined(CONFIG_MEMORY_HOTREMOVE)
171/*
172 * Max length of 64-bit hex address string is 19, prefix "0x" + 16 hex
173 * digits, and '\0' for termination.
174 */
175#define MAX_ADDR_LEN 19
176
177static unsigned long get_cmdline_acpi_rsdp(void)
178{
179 unsigned long addr = 0;
180
181#ifdef CONFIG_KEXEC
182 char val[MAX_ADDR_LEN] = { };
183 int ret;
184
185 ret = cmdline_find_option(option: "acpi_rsdp", buffer: val, MAX_ADDR_LEN);
186 if (ret < 0)
187 return 0;
188
189 if (boot_kstrtoul(s: val, base: 16, res: &addr))
190 return 0;
191#endif
192 return addr;
193}
194
195/* Compute SRAT address from RSDP. */
196static unsigned long get_acpi_srat_table(void)
197{
198 unsigned long root_table, acpi_table;
199 struct acpi_table_header *header;
200 struct acpi_table_rsdp *rsdp;
201 u32 num_entries, size, len;
202 char arg[10];
203 u8 *entry;
204
205 /*
206 * Check whether we were given an RSDP on the command line. We don't
207 * stash this in boot params because the kernel itself may have
208 * different ideas about whether to trust a command-line parameter.
209 */
210 rsdp = (struct acpi_table_rsdp *)get_cmdline_acpi_rsdp();
211 if (!rsdp)
212 rsdp = (struct acpi_table_rsdp *)(long)
213 boot_params_ptr->acpi_rsdp_addr;
214
215 if (!rsdp)
216 return 0;
217
218 /* Get ACPI root table from RSDP.*/
219 if (!(cmdline_find_option(option: "acpi", buffer: arg, bufsize: sizeof(arg)) == 4 &&
220 !strncmp(cs: arg, ct: "rsdt", count: 4)) &&
221 rsdp->xsdt_physical_address &&
222 rsdp->revision > 1) {
223 root_table = rsdp->xsdt_physical_address;
224 size = ACPI_XSDT_ENTRY_SIZE;
225 } else {
226 root_table = rsdp->rsdt_physical_address;
227 size = ACPI_RSDT_ENTRY_SIZE;
228 }
229
230 if (!root_table)
231 return 0;
232
233 header = (struct acpi_table_header *)root_table;
234 len = header->length;
235 if (len < sizeof(struct acpi_table_header) + size)
236 return 0;
237
238 num_entries = (len - sizeof(struct acpi_table_header)) / size;
239 entry = (u8 *)(root_table + sizeof(struct acpi_table_header));
240
241 while (num_entries--) {
242 if (size == ACPI_RSDT_ENTRY_SIZE)
243 acpi_table = *(u32 *)entry;
244 else
245 acpi_table = *(u64 *)entry;
246
247 if (acpi_table) {
248 header = (struct acpi_table_header *)acpi_table;
249
250 if (ACPI_COMPARE_NAMESEG(header->signature, ACPI_SIG_SRAT))
251 return acpi_table;
252 }
253 entry += size;
254 }
255 return 0;
256}
257
258/**
259 * count_immovable_mem_regions - Parse SRAT and cache the immovable
260 * memory regions into the immovable_mem array.
261 *
262 * Return the number of immovable memory regions on success, 0 on failure:
263 *
264 * - Too many immovable memory regions
265 * - ACPI off or no SRAT found
266 * - No immovable memory region found.
267 */
268int count_immovable_mem_regions(void)
269{
270 unsigned long table_addr, table_end, table;
271 struct acpi_subtable_header *sub_table;
272 struct acpi_table_header *table_header;
273 char arg[MAX_ACPI_ARG_LENGTH];
274 int num = 0;
275
276 if (cmdline_find_option(option: "acpi", buffer: arg, bufsize: sizeof(arg)) == 3 &&
277 !strncmp(cs: arg, ct: "off", count: 3))
278 return 0;
279
280 table_addr = get_acpi_srat_table();
281 if (!table_addr)
282 return 0;
283
284 table_header = (struct acpi_table_header *)table_addr;
285 table_end = table_addr + table_header->length;
286 table = table_addr + sizeof(struct acpi_table_srat);
287
288 while (table + sizeof(struct acpi_subtable_header) < table_end) {
289
290 sub_table = (struct acpi_subtable_header *)table;
291 if (!sub_table->length) {
292 debug_putstr("Invalid zero length SRAT subtable.\n");
293 return 0;
294 }
295
296 if (sub_table->type == ACPI_SRAT_TYPE_MEMORY_AFFINITY) {
297 struct acpi_srat_mem_affinity *ma;
298
299 ma = (struct acpi_srat_mem_affinity *)sub_table;
300 if (!(ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE) && ma->length) {
301 immovable_mem[num].start = ma->base_address;
302 immovable_mem[num].size = ma->length;
303 num++;
304 }
305
306 if (num >= MAX_NUMNODES*2) {
307 debug_putstr("Too many immovable memory regions, aborting.\n");
308 return 0;
309 }
310 }
311 table += sub_table->length;
312 }
313 return num;
314}
315#endif /* CONFIG_RANDOMIZE_BASE && CONFIG_MEMORY_HOTREMOVE */
316

source code of linux/arch/x86/boot/compressed/acpi.c